Piezotronic effect tuned AlGaN/GaN high electron mobility transistor

Science.gov (United States)

Jiang, Chunyan; Liu, Ting; Du, Chunhua; Huang, Xin; Liu, Mengmeng; Zhao, Zhenfu; Li, Linxuan; Pu, Xiong; Zhai, Junyi; Hu, Weiguo; Wang, Zhong Lin

2017-11-01

The piezotronic effect utilizes strain-induced piezoelectric polarization charges to tune the carrier transportation across the interface/junction. We fabricated a high-performance AlGaN/GaN high electron mobility transistor (HEMT), and the transport property was proven to be enhanced by applying an external stress for the first time. The enhanced source-drain current was also observed at any gate voltage and the maximum enhancement of the saturation current was up to 21% with 15 N applied stress (0.18 GPa at center) at -1 V gate voltage. The physical mechanism of HEMT with/without external compressive stress conditions was carefully illustrated and further confirmed by a self-consistent solution of the Schrödinger-Poisson equations. This study proves the cause-and-effect relationship between the piezoelectric polarization effect and 2D electron gas formation, which provides a tunable solution to enhance the device performance. The strain tuned HEMT has potential applications in human-machine interface and the security control of the power system.

Electron Raman scattering in a double quantum well tuned by an external nonresonant intense laser field

Science.gov (United States)

Tiutiunnyk, A.; Mora-Ramos, M. E.; Morales, A. L.; Duque, C. M.; Restrepo, R. L.; Ungan, F.; Martínez-Orozco, J. C.; Kasapoglu, E.; Duque, C. A.

2017-02-01

In this work we shall present a study of inelastic light scattering involving inter-subband electron transitions in coupled GaAs-(Ga,Al)As quantum wells. Calculations include the electron related Raman differential cross section and Raman gain. The effects of an external nonresonant intense laser field are used in order to tune these output properties. The confined electron states will be described by means of a diagonalization procedure within the effective mass and parabolic band approximations. It is shown that the application of the intense laser field can produce values of the intersubband electron Raman gain above 400 cm-1. The system proposed here is an alternative choice for the development of AlxGa1-xAs semiconductor laser diodes that can be tuned via an external nonresonant intense laser field.

Tuning electronic properties of graphene nanoflake polyaromatic hydrocarbon through molecular charge-transfer interactions

Science.gov (United States)

Sharma, Vaishali; Dabhi, Shweta D.; Shinde, Satyam; Jha, Prafulla K.

2018-05-01

By means of first principles calculation we have tuned the electronic properties of graphene nanoflake polyaromatic hydrocarbon via molecular charge transfer. Acceptor/donor Tetracyanoquinodimethane (TCNQ) and Tetrathiafulvalene (TTF) organic molecules are adsorbed on polyaromatic hydrocarbons (PAH) in order to introduce the charge transfer. The substrate's n- or p- type nature depends on the accepting/donating behavior of dopant molecules. Two different classes of PAH (extended form of triangulene) namely Bow-tie graphene nanoflake (BTGNF) and triangular zigzag graphene nanoflake (TZGNF). It is revealed that all the TCNQ and TTF modified graphene nanoflakes exhibit significant changes in HOMO-LUMO gap in range from 0.58 eV to 0.64 eV and 0.01 eV to 0.05 eV respectively. The adsorption energies are in the range of -0.05 kcal/mol to -2.6 kcal/mol. The change in work function is also calculated and discussed, the maximum charge transfer is for TCNQ adsorbed BTGNF. These alluring findings in the tuning of electronic properties will be advantageous for promoting graphene nanoflake polyaromatic hydrocarbon for their applications in electronic devices.

Tuning Electronic Structures of BN and C Double-Wall Hetero-Nanotubes

Directory of Open Access Journals (Sweden)

Xueran Liu

2015-01-01

Full Text Available First principle calculations based on density functional theory with the generalized gradient approximation were carried out to investigate the energetic and electronic properties of carbon and boron nitride double-wall hetero-nanotubes (C/BN-DWHNTs with different chirality and size, including an armchair (n, n carbon nanotube (CNT enclosed in (m, m boron nitride nanotube (BNNT and a zigzag (n, 0 CNT enclosed in (m, 0 BNNT. The electronic structure of these DWHNTs under a transverse electric field was also investigated. The ability to tune the band gap with changing the intertube distance (di and imposing an external electric field (F of zigzag DWHNTs provides the possibility for future electronic and electrooptic nanodevice applications.

Tuning of Schottky barrier height of Al/n-Si by electron beam irradiation

Energy Technology Data Exchange (ETDEWEB)

Vali, Indudhar Panduranga [Manipal Institute of Technology, Manipal University, Manipal 576104 (India); Shetty, Pramoda Kumara, E-mail: pramod.shetty@manipal.edu [Manipal Institute of Technology, Manipal University, Manipal 576104 (India); Mahesha, M.G. [Manipal Institute of Technology, Manipal University, Manipal 576104 (India); Petwal, V.C.; Dwivedi, Jishnu [Raja Ramanna Centre for Advanced Technology, Department of Atomic Energy, Government of India, Indore 452012 (India); Choudhary, R.J. [UGC-DAE Consortium for Scientific Research, University Campus, Khandwa Road, Indore 452017 (India)

2017-06-15

Highlights: • Tuning of Schottky barrier height has been achieved by electron beam irradiation at different doses on n-Si wafer prior to the fabrication of Schottky contact. • The XPS analyses have shown irradiation induced defects and the formation of several localized chemical states in Si/SiOx interface that influences the Schottky barrier height. • High ideality factor indicates metal-insulator-semiconductor configuration of the Schottky diode and the inhomogeneous nature of the Schottky barrier height. • The modifications in I–V characteristics have been observed as a function of electron dose. This is caused due to changes in the Schottky diode parameters and different transport mechanisms. - Abstract: The effect of electron beam irradiation (EBI) on Al/n-Si Schottky diode has been studied by I–V characterization at room temperature. The behavior of the metal-semiconductor (MS) interface is analyzed by means of variations in the MS contact parameters such as, Schottky barrier height (Φ{sub B}), ideality factor (n) and series resistance (R{sub s}). These parameters were found to depend on the EBI dose having a fixed incident beam of energy 7.5 MeV. At different doses (500, 1000, 1500 kGy) of EBI, the Schottky contacts were prepared and extracted their contact parameters by applying thermionic emission and Cheung models. Remarkably, the tuning of Φ{sub B} was observed as a function of EBI dose. The improved n with increased Φ{sub B} is seen for all the EBI doses. As a consequence of which the thermionic emission is more favored. However, the competing transport mechanisms such as space charge limited emission, tunneling and tunneling through the trap states were ascribed due to n > 1. The analysis of XPS spectra have shown the presence of native oxide and increased radiation induced defect states. The thickness variation in the MS interface contributing to Schottky contact behavior is discussed. This study explains a new technique to tune

An analytic model for the electrostatic contribution of the electron cloud to the vertical tune-shift

International Nuclear Information System (INIS)

Schaechter, Levi

2008-01-01

An analytic quasi-static model is developed for the analysis of the tune-shift associated with the presence of an electron cloud in a damping ring. The essential assumption is that in its direction of motion, a bunch experiences a uniform cloud density but the latter varies from one bunch to another. A second important component of the model is the life-time since it controls the build-up, the equilibrium as well as the decay of the cloud. It is demonstrated analytically that in case of a train of positron bunches, electrons may be trapped in the vertical direction for the entire train duration. Assuming that the ring is dominated by vertical magnetic fields due to either bends or wigglers, we found excellent agreement between the theoretical predictions and the experimental results reported at Cornell Electron/Positron Storage Ring. The ratio between the vertical and horizontal tune-shifts is shown to be indicative of the distribution of the cloud in the beam-chamber

Electronic Resource Management Systems

Directory of Open Access Journals (Sweden)

Mark Ellingsen

2004-10-01

Full Text Available Computer applications which deal with electronic resource management (ERM are quite a recent development. They have grown out of the need to manage the burgeoning number of electronic resources particularly electronic journals. Typically, in the early years of e-journal acquisition, library staff provided an easy means of accessing these journals by providing an alphabetical list on a web page. Some went as far as categorising the e-journals by subject and then grouping the journals either on a single web page or by using multiple pages. It didn't take long before it was recognised that it would be more efficient to dynamically generate the pages from a database rather than to continually edit the pages manually. Of course, once the descriptive metadata for an electronic journal was held within a database the next logical step was to provide administrative forms whereby that metadata could be manipulated. This in turn led to demands for incorporating more information and more functionality into the developing application.

Enhancing the Electronic Conductivity of Vanadium-tellurite Glasses by Tuning the Redox State

DEFF Research Database (Denmark)

Kjeldsen, Jonas; Yue, Yuanzheng

Transition metal oxides are used in a variety of electronic purposes, e.g., vanadium tellurite as cathode material in high-power demanding batteries. By tuning the redox state of vanadium, it is possible to achieve a lower internal resistance within the entire battery unit, thus a higher capacity....... In this work we vary the redox state of a given vanadium tellurite system by performing post heat-treatment in controlled atmosphere. This process is in theory not limited only to varying electronic conductivity, but also varying the glass structure, and hence, changing properties of the glasses, e.g, thermal...... and mechanical properties. Finally we give insight into the relation between the redox state and electronic conductivity....

Electronic Resources Management Project Presentation 2012

KAUST Repository

Ramli, Rindra M.

2012-11-05

This presentation describes the electronic resources management project undertaken by the KAUST library. The objectives of this project is to migrate information from MS Sharepoint to Millennium ERM module. One of the advantages of this migration is to consolidate all electronic resources into a single and centralized location. This would allow for better information sharing among library staff.

Tuning the electronic properties of gated multilayer phosphorene: A self-consistent tight-binding study

Science.gov (United States)

Li, L. L.; Partoens, B.; Peeters, F. M.

2018-04-01

By taking account of the electric-field-induced charge screening, a self-consistent calculation within the framework of the tight-binding approach is employed to obtain the electronic band structure of gated multilayer phosphorene and the charge densities on the different phosphorene layers. We find charge density and screening anomalies in single-gated multilayer phosphorene and electron-hole bilayers in dual-gated multilayer phosphorene. Due to the unique puckered lattice structure, both intralayer and interlayer charge screenings are important in gated multilayer phosphorene. We find that the electric-field tuning of the band structure of multilayer phosphorene is distinctively different in the presence and absence of charge screening. For instance, it is shown that the unscreened band gap of multilayer phosphorene decreases dramatically with increasing electric-field strength. However, in the presence of charge screening, the magnitude of this band-gap decrease is significantly reduced and the reduction depends strongly on the number of phosphorene layers. Our theoretical results of the band-gap tuning are compared with recent experiments and good agreement is found.

PRINCIPLES OF CONTENT FORMATION EDUCATIONAL ELECTRONIC RESOURCE

Directory of Open Access Journals (Sweden)

О Ю Заславская

2017-12-01

Full Text Available The article considers modern possibilities of information and communication technologies for the design of electronic educational resources. The conceptual basis of the open educational multimedia system is based on the modular architecture of the electronic educational resource. The content of the electronic training module can be implemented in several versions of the modules: obtaining information, practical exercises, control. The regularities in the teaching process in modern pedagogical theory are considered: general and specific, and the principles for the formation of the content of instruction at different levels are defined, based on the formulated regularities. On the basis of the analysis, the principles of the formation of the electronic educational resource are determined, taking into account the general and didactic patterns of teaching.As principles of the formation of educational material for obtaining information for the electronic educational resource, the article considers: the principle of methodological orientation, the principle of general scientific orientation, the principle of systemic nature, the principle of fundamentalization, the principle of accounting intersubject communications, the principle of minimization. The principles of the formation of the electronic training module of practical studies in the article include: the principle of systematic and dose based consistency, the principle of rational use of study time, the principle of accessibility. The principles of the formation of the module for monitoring the electronic educational resource can be: the principle of the operationalization of goals, the principle of unified identification diagnosis.

Tuning of few-electron states and optical absorption anisotropy in GaAs quantum rings.

Science.gov (United States)

Wu, Zhenhua; Li, Jian; Li, Jun; Yin, Huaxiang; Liu, Yu

2017-11-15

The electronic and optical properties of a GaAs quantum ring (QR) with few electrons in the presence of the Rashba spin-orbit interaction (RSOI) and the Dresselhaus spin-orbit interaction (DSOI) have been investigated theoretically. The configuration interaction (CI) method is employed to calculate the eigenvalues and eigenstates of the multiple-electron QR accurately. Our numerical results demonstrate that the symmetry breaking induced by the RSOI and DSOI leads to an anisotropic distribution of multi-electron states. The Coulomb interaction offers additional modulation of the electron distribution and thus the optical absorption indices in the quantum rings. By tuning the magnetic/electric fields and/or electron numbers in a quantum ring, one can change its optical properties significantly. Our theory provides a new way to control the multi-electron states and optical properties of a QR by hybrid modulations or by electrical means only.

Implementing CORAL: An Electronic Resource Management System

Science.gov (United States)

Whitfield, Sharon

2011-01-01

A 2010 electronic resource management survey conducted by Maria Collins of North Carolina State University and Jill E. Grogg of University of Alabama Libraries found that the top six electronic resources management priorities included workflow management, communications management, license management, statistics management, administrative…

Tuning the Electronic Structure of Titanium Oxide Support to Enhance the Electrochemical Activity of Platinum Nanoparticles

KAUST Repository

Shi, Feifei; Baker, L. Robert; Hervier, Antoine; Somorjai, Gabor A.; Komvopoulos, Kyriakos

2013-01-01

on pristine TiO2 support were achieved by tuning the electronic structure of the titanium oxide support of Pt nanoparticle catalysts. This was accomplished by adding oxygen vacancies or doping with fluorine. Experimental trends are interpreted in the context

Towards double-functionalized small diamondoids: selective electronic band-gap tuning

International Nuclear Information System (INIS)

Adhikari, Bibek; Fyta, Maria

2015-01-01

Diamondoids are nanoscale diamond-like cage structures with hydrogen terminations, which can occur in various sizes and with a diverse type of modifications. In this work, we focus on the structural alterations and the effect of doping and functionalization on the electronic properties of diamondoids, from the smallest adamantane to heptamantane. The results are based on quantum mechanical calculations. We perform a self-consistent study, starting with doping the smallest diamondoid, adamantane. Boron, nitrogen, silicon, oxygen, and phosphorus are chosen as dopants at sites which have been previously optimized and are also consistent with the literature. At a next step, an amine- and a thiol- group are separately used to functionalize the adamantane molecule. We mainly focus on a double functionalization of diamondoids up to heptamantane using both these atomic groups. The effect of isomeration in the case of tetramantane is also studied. We discuss the higher efficiency of a double-functionalization compared to doping or a single-functionalization of diamondoids in tuning the electronic properties, such as the electronic band-gap, of modified small diamondoids in view of their novel nanotechnological applications. (paper)

Managing electronic resources a LITA guide

CERN Document Server

Weir, Ryan O

2012-01-01

Informative, useful, current, Managing Electronic Resources: A LITA Guide shows how to successfully manage time, resources, and relationships with vendors and staff to ensure personal, professional, and institutional success.

Tuning and Quantifying Steric and Electronic Effects of N-Heterocyclic Carbenes

KAUST Repository

Falivene, Laura

2014-07-12

This chapter states that the main handles for tuning steric and electronic effects are the substituents on N atoms, the nature of the C4-C5 bridge (either saturated or unsaturated), and the substituents on the C4 and C5 atoms. The initial intuition that steric properties of N-heterocyclic carbenes (NHCs) could be modulated and could impact catalytic behavior stimulated the development of steric descriptors to quantify the steric requirement of different NHCs and, possibly, to compare them with tertiary phosphines. NHCs can be classified as typically strong σ-basic/π-acid ligands, although they have been also shown to exhibit reasonable π-basic properties. This electronic modularity allows NHC ligands to adapt flexibly to different chemical environments represented by a transition metal and the other ligands. © 2014 Wiley-VCH Verlag GmbH & Co. KGaA. All rights reserved.

Fine-tuning of electronic properties in donor-acceptor conjugated polymers based on oligothiophenes

Science.gov (United States)

Imae, Ichiro; Sagawa, Hitoshi; Harima, Yutaka

2018-03-01

A novel series of donor-acceptor conjugated polymers having oligothiophenes with well-defined structures were synthesized and their optical, electrochemical, and photovoltaic properties were investigated. It was found that the absorption bands of polymers were red-shifted with increasing number of ethylenedioxy groups added to each oligothiophene unit and that their band edges reached over 1000 nm. The systematical fine-tuning of the electronic properties was achieved using the chemical structures of oligothiophene units. Photovoltaic cells based on polymer/(6,6)-phenyl C61 butyric acid methyl ester (PC61BM) exhibited power conversion efficiencies in the range from 0.004 to 1.10%, reflecting the electronic properties of the polymers.

Oracle SQL tuning with Oracle SQLTXPLAIN

CERN Document Server

Charalambides, Stelios

2013-01-01

Oracle SQL Tuning with SQLTXPLAIN is a practical guide to SQL tuning the way Oracle's own experts do it, using a freely downloadable tool called SQLTXPLAIN. Using this simple tool you'll learn how to tune even the most complex SQL, and you'll learn to do it quickly, without the huge learning curve usually associated with tuning as a whole.  Firmly based in real world problems, this book helps you reclaim system resources and avoid the most common bottleneck in overall performance, badly tuned SQL.  You'll learn how the optimizer works, how to take advantage of its latest features, and when it'

Tuning the Electron Gas at an Oxide Heterointerface via Free Surface Charges

Energy Technology Data Exchange (ETDEWEB)

Bell, Christopher

2011-08-11

Oxide heterointerfaces are emerging as one of the most exciting materials systems in condensed matter science. One remarkable example is the LaAlO{sub 3}/SrTiO{sub 3} (LAO/STO) interface, a model system in which a highly mobile electron gas forms between two band insulators, exhibiting two dimensional superconductivity and unusual magnetotransport properties. An ideal tool to tune such an electron gas is the electrostatic field effect. In principle, the electrostatic field can be generated by bound charges due to polarization (as in the normal and ferroelectric field effects) or by adding excess free charge. In previous studies, a large modulation of the carrier density and mobility of the LAO/STO interface has been achieved using the normal field effect. However, little attention has been paid to the field effect generated by free charges. This issue is scarcely addressed, even in conventional semiconductor devices, since the free charges are typically not stable. Here, we demonstrate an unambiguous tuning of the LAO/STO interface conductivity via free surface charges written using conducting atomic force microscopy (AFM). The modulation of the carrier density was found to be reversible, nonvolatile and surprisingly large, {approx}3 x 10{sup 13} cm{sup -2}, comparable to the maximum modulation by the normal field effect. Our finding reveal the efficiency of free charges in controlling the conductivity of this oxide interface, and suggest that this technique may be extended more generally to other oxide systems.

Gender Analysis Of Electronic Information Resource Use: The Case ...

African Journals Online (AJOL)

Based on the findings the study concluded that access and use of electronic information resources creates a “social digital divide” along gender lines. The study ... Finally, the library needs to change its marketing strategies on the availability of electronic information resources to increase awareness of these resources.

Users satisfaction with electronic information resources and services ...

African Journals Online (AJOL)

This study investigated users satisfaction on the use of electronic information resources and services in MTN Net libraries in ABU & UNIBEN. Two objectives and one null hypotheses were formulated and tested with respect to the users' satisfaction on electronic information resources and services in MTN Net libraries in ...

Organizational matters of competition in electronic educational resources

Directory of Open Access Journals (Sweden)

Ирина Карловна Войтович

2015-12-01

Full Text Available The article examines the experience of the Udmurt State University in conducting competitions of educational publications and electronic resources. The purpose of such competitions is to provide methodological support to educational process. The main focus is on competition of electronic educational resources. The technology of such contests is discussed through detailed analysis of the main stages of the contest. It is noted that the main task of the preparatory stage of the competition is related to the development of regulations on competition and the definition of criteria for selection of the submitted works. The paper also proposes a system of evaluation criteria of electronic educational resources developed by members of the contest organizing committee and jury members. The article emphasizes the importance of not only the preparatory stages of the competition, but also measures for its completion, aimed at training teachers create quality e-learning resources.

CHALLENGES OF ELECTRONIC INFORMATION RESOURCES IN ...

African Journals Online (AJOL)

This paper discusses the role of policy for proper and efficient library services in the electronic era. It points out some of the possible dangers of embarking in electronic resources without a proper focus at hand. Thus, it calls for today's librarians and policy makers to brainstorm and come up with working policies suitable to ...

Tuning of electronic properties and dynamical stability of graphene oxide with different functional groups

Science.gov (United States)

Dabhi, Shweta D.; Jha, Prafulla K.

2017-09-01

The structural, electronic and vibrational properties of graphene oxide (GO) with varying proportion of epoxy and hydroxyl functional groups have been studied using density functional theory. The functional groups and oxygen density have an obvious influence on the electronic and vibrational properties. The dependence of band gap on associated functional groups and oxygen density shows a possibility of tuning the band gap of graphene by varying the functional groups as well as oxidation level. The absorption of high oxygen content in graphene leads to the gap opening and resulting in a transition from semimetal to semiconductor. Phonon dispersion curves show no imaginary frequency or no softening of any phonon mode throughout the Brillouin zone which confirms the dynamical stability of all considered GO models. Different groups and different oxygen density result into the varying characteristics of phonon modes. The computed results show good agreement with the experimental observations. Our results present interesting possibilities for engineering the electronic properties of graphene and GO and impact the fabrication of new electronics.

Use of Electronic Resources in a Private University in Nigeria ...

African Journals Online (AJOL)

The study examined awareness and constraints in the use of electronic resources by lecturers and students of Ajayi Crowther University, Oyo, Nigeria. It aimed at justifying the resources expended in the provision of electronic resources in terms of awareness, patronage and factors that may be affecting awareness and use ...

Electronic Resources Management System: Recommendation Report 2017

KAUST Repository

Ramli, Rindra M.

2017-05-01

This recommendation report provides an overview of the selection process for the new Electronic Resources Management System. The library has decided to move away from Innovative Interfaces Millennium ERM module. The library reviewed 3 system as potential replacements namely: Proquest 360 Resource Manager, Ex Libris Alma and Open Source CORAL ERMS. After comparing and trialling the systems, it was decided to go for Proquest 360 Resource Manager.

use of electronic resources by graduate students of the department

African Journals Online (AJOL)

respondent's access electronic resources from the internet via Cybercafé .There is a high ... KEY WORDS: Use, Electronic Resources, Graduate Students, Cybercafé. INTRODUCTION ... Faculty of Education, University of Uyo, Uyo. Olu Olat ...

Electronically Tuned Local Oscillators for the NOEMA Interferometer

Science.gov (United States)

Mattiocco, Francois; Garnier, Olivier; Maier, Doris; Navarrini, Alessandro; Serres, Patrice

2016-03-01

We present an overview of the electronically tuned local oscillator (LO) system developed at the Institut de RadioAstronomie millimetrique (IRAM) for the superconductor-insulator-superconductor (SIS) receivers of the NOrthern Extended Millimeter Array interferometer (NOEMA). We modified the frequency bands and extended the bandwidths of the LO designs developed by the National Radio Astronomy Observatory (NRAO) for the Atacama Large Millimeter Array (ALMA) project to cover the four NOEMA LO frequency ranges 82-108.3 GHz (Band 1), 138.6-171.3 GHz (Band 2), 207.7-264.4 GHz (Band 3), and 283-365 GHz (Band 4). The NOEMA LO system employs commercially available MMICs and GaAs millimeter MMICs from NRAO which are micro-assembled into active multiplied chain (AMC) and power amplifier (PA) modules. We discuss the problem of the LO spurious harmonics and of the LO signal directly multiplied by the SIS mixers that add extra noise and lead to detections of unwanted spectral lines from higher order sidebands. A waveguide filter in the LO path is used to reduce the higher order harmonics level of the LO at the output of the final frequency multiplier, thus mitigating the undesired effects and improving the system noise temperature.

Electronic resource management practical perspectives in a new technical services model

CERN Document Server

Elguindi, Anne

2012-01-01

A significant shift is taking place in libraries, with the purchase of e-resources accounting for the bulk of materials spending. Electronic Resource Management makes the case that technical services workflows need to make a corresponding shift toward e-centric models and highlights the increasing variety of e-formats that are forcing new developments in the field.Six chapters cover key topics, including: technical services models, both past and emerging; staffing and workflow in electronic resource management; implementation and transformation of electronic resource management systems; the ro

Utilization of electronic information resources by academic staff at ...

African Journals Online (AJOL)

The study investigated the utilization of Electronic Information resources by the academic staff of Makerere University in Uganda. It examined the academic staff awareness of the resources available, the types of resources provided by the Makerere University Library, the factors affecting resource utilization. The study was ...

Electronic Resources Management Project Presentation 2012

KAUST Repository

Ramli, Rindra M.

2012-01-01

This presentation describes the electronic resources management project undertaken by the KAUST library. The objectives of this project is to migrate information from MS Sharepoint to Millennium ERM module. One of the advantages of this migration

Practical guide to electronic resources in the humanities

CERN Document Server

Dubnjakovic, Ana

2010-01-01

From full-text article databases to digitized collections of primary source materials, newly emerging electronic resources have radically impacted how research in the humanities is conducted and discovered. This book, covering high-quality, up-to-date electronic resources for the humanities, is an easy-to-use annotated guide for the librarian, student, and scholar alike. It covers online databases, indexes, archives, and many other critical tools in key humanities disciplines including philosophy, religion, languages and literature, and performing and visual arts. Succinct overviews of key eme

Tuning the electronic properties at the surface of BaBiO{sub 3} thin films

Energy Technology Data Exchange (ETDEWEB)

Ferreyra, C. [GIyA y INN, CNEA, Av.Gral Paz 1499, (1650), San Martín, Buenos Aires (Argentina); Departamento de Física, Facultad Ciencias Exactas y Naturales, Universidad de Buenos Aires (Argentina); Guller, F.; Llois, A. M.; Vildosola, V. [GIyA y INN, CNEA, Av.Gral Paz 1499, (1650), San Martín, Buenos Aires (Argentina); Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) (Argentina); Marchini, F.; Williams, F. J. [Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) (Argentina); Departamento de Química Inorgánica, Analítica y Química-Física, INQUIMAE-CONICET, Facultad Ciencias Exactas y Naturales, Universidad de Buenos Aires, Pabellón 2, Ciudad Universitaria, Buenos Aires (Argentina); Lüders, U. [CRISMAT, CNRS UMR 6508, ENSICAEN, 6 Boulevard Maréchal Juin, 14050 Caen Cedex 4 (France); Albornoz, C. [GIyA y INN, CNEA, Av.Gral Paz 1499, (1650), San Martín, Buenos Aires (Argentina); Leyva, A. G. [GIyA y INN, CNEA, Av.Gral Paz 1499, (1650), San Martín, Buenos Aires (Argentina); Escuela de Ciencia y Tecnología, UNSAM, Campus Miguelete, (1650), San Martín, Buenos Aires (Argentina); and others

2016-06-15

The presence of 2D electron gases at surfaces or interfaces in oxide thin films remains a hot topic in condensed matter physics. In particular, BaBiO{sub 3} appears as a very interesting system as it was theoretically proposed that its (001) surface should become metallic if a Bi-termination is achieved (Vildosola et al., PRL 110, 206805 (2013)). Here we report on the preparation by pulsed laser deposition and characterization of BaBiO{sub 3} thin films on silicon. We show that the texture of the films can be tuned by controlling the growth conditions, being possible to stabilize strongly (100)-textured films. We find significant differences on the spectroscopic and transport properties between (100)-textured and non-textured films. We rationalize these experimental results by performing first principles calculations, which indicate the existence of electron doping at the (100) surface. This stabilizes Bi ions in a 3+ state, shortens Bi-O bonds and reduces the electronic band gap, increasing the surface conductivity. Our results emphasize the importance of surface effects on the electronic properties of perovskites, and provide strategies to design novel oxide heterostructures with potential interface-related 2D electron gases.

Utilisation of Electronic Information Resources By Lecturers in ...

African Journals Online (AJOL)

This study assesses the use of information resources, specifically, electronic databases by lecturers/teachers in Universities and Colleges of Education in South Western Nigeria. Information resources are central to teachers' education. It provides lecturers/teachers access to information that enhances research and ...

Discipline, availability of electronic resources and the use of Finnish National Electronic Library - FinELib

Directory of Open Access Journals (Sweden)

Sanna Torma

2004-01-01

Full Text Available This study elaborated relations between digital library use by university faculty, users' discipline and the availability of key resources in the Finnish National Electronic Library (FinELib, Finnish national digital library, by using nationwide representative survey data. The results show that the perceived availability of key electronic resources by researchers in FinELib was a stronger predictor of the frequency and purpose of use of its services than users' discipline. Regardless of discipline a good perceived provision of central resources led to a more frequent use of FinELib. The satisfaction with the services did not vary with the discipline, but with the perceived availability of resources.

The Role of the Acquisitions Librarian in Electronic Resources Management

Science.gov (United States)

Pomerantz, Sarah B.

2010-01-01

With the ongoing shift to electronic formats for library resources, acquisitions librarians, like the rest of the profession, must adapt to the rapidly changing landscape of electronic resources by keeping up with trends and mastering new skills related to digital publishing, technology, and licensing. The author sought to know what roles…

Analysis of Pedagogic Potential of Electronic Educational Resources with Elements of Autodidactics

Directory of Open Access Journals (Sweden)

Igor A.

2018-03-01

Full Text Available Introduction: in recent years didactic properties of electronic educational resources undergo considerable changes, nevertheless, the question of studying of such complete phenomenon as “an electronic educational resource with autodidactics elements” remains open, despite sufficient scientific base of researches of the terms making this concept. Article purpose – determination of essence of electronic educational resources with autodidactics elements. Materials and Methods: the main method of research was the theoretical analysis of the pedagogical and psychological literature on the problem under study. We used the theoretical (analysis, synthesis, comparison and generalization methods, the method of interpretation, pedagogical modeling, and empirical methods (observation, testing, conversation, interview, analysis of students’ performance, pedagogical experiment, peer review. Results: we detected the advantages of electronic educational resources in comparison with traditional ones. The concept of autodidactics as applied to the subject of research is considered. Properties of electronic educational resources with a linear and nonlinear principle of construction are studied.The influence of the principle of construction on the development of the learners’ qualities is shown. We formulated an integral definition of electronic educational resources with elements of autodidactics, namely, the variability, adaptivity and cyclicity of training. A model of the teaching-learning process with electronic educational resources is developed. Discussion and Conclusions: further development of a problem will allow to define whether electronic educational resources with autodidactics elements pedagogical potential for realization of educational and self-educational activity of teachers have, to modify technological procedures taking into account age features of students, their specialties and features of the organization of process of training of

Preservation and conservation of electronic information resources of ...

African Journals Online (AJOL)

The major holdings of the broadcast libraries of the Nigerian Television Authority (NTA) are electronic information resources; therefore, providing safe places for general management of these resources have aroused interest in the industry in Nigeria for sometimes. The need to study the preservation and conservation of ...

Building an electronic resource collection a practical guide

CERN Document Server

Lee, Stuart D

2004-01-01

This practical book guides information professionals step-by-step through building and managing an electronic resource collection. It outlines the range of electronic products currently available in abstracting and indexing, bibliographic, and other services and then describes how to effectively select, evaluate and purchase them.

Analysis of Human Resources Management Strategy in China Electronic Commerce Enterprises

Science.gov (United States)

Shao, Fang

The paper discussed electronic-commerce's influence on enterprise human resources management, proposed and proved the human resources management strategy which electronic commerce enterprise should adopt from recruitment strategy to training strategy, keeping talent strategy and other ways.

Using XML Technologies to Organize Electronic Reference Resources

OpenAIRE

Huser, Vojtech; Del Fiol, Guilherme; Rocha, Roberto A.

2005-01-01

Provision of access to reference electronic resources to clinicians is becoming increasingly important. We have created a framework for librarians to manage access to these resources at an enterprise level, rather than at the individual hospital libraries. We describe initial project requirements, implementation details, and some preliminary results.

Electronic Resources and Mission Creep: Reorganizing the Library for the Twenty-First Century

Science.gov (United States)

Stachokas, George

2009-01-01

The position of electronic resources librarian was created to serve as a specialist in the negotiation of license agreements for electronic resources, but mission creep has added more functions to the routine work of electronic resources such as cataloging, gathering information for collection development, and technical support. As electronic…

Electronic Resources Management System: Recommendation Report 2017

KAUST Repository

Ramli, Rindra M.

2017-01-01

This recommendation report provides an overview of the selection process for the new Electronic Resources Management System. The library has decided to move away from Innovative Interfaces Millennium ERM module. The library reviewed 3 system

Vibration Suppression of Electronic Box by a Dual Function Piezoelectric Energy Harvester-Tuned Vibration Absorber

Directory of Open Access Journals (Sweden)

Sajid Rafique

2014-04-01

Full Text Available Over the past few years, remarkable developments in piezoelectric materials have motivated many researchers to work in the field of vibration energy harvesting by using piezoelectric beam like smart structures. This paper aimed to present the most recent application of a dual function piezoelectric device which can suppress vibration and harvest vibration energy simultaneously and a brief illustration of conventional mechanical and electrical TVAs (Tuned Vibration Absorber. It is shown that the proposed dual function device combines the benefits of conventional mechanical and electrical TVAs and reduces their relative disadvantages. Conversion of mechanical energy into electrical energy introduces damping and, hence, the optimal damping required by this TVA is generated by the energy harvesting effects. This paper presents the methodology of implementing the theory of 'electromechanical' TVAs to suppress the response of any real world structure. The work also illustrates the prospect of extensive applications of such novel "electromechanical" TVAs in defence and industry. The results show that the optimum degree of vibration suppression of an electronic box is achieved by this dual function TVA through suitable tuning of the attached electrical circuitry

Vibration suppression of electronic box by a dual function piezoelectric energy harvester-tuned vibration absorber

International Nuclear Information System (INIS)

Rafique, S.; Shah, S.

2014-01-01

Over the past few years, remarkable developments in piezoelectric materials have motivated many researchers to work in the field of vibration energy harvesting by using piezoelectric beam like smart structures. This paper aimed to present the most recent application of a dual function piezoelectric device which can suppress vibration and harvest vibration energy simultaneously and a brief illustration of conventional mechanical and electrical TVAs (Tuned Vibration Absorber). It is shown that the proposed dual function device combines the benefits of conventional mechanical and electrical TVAs and reduces their relative disadvantages. Conversion of mechanical energy into electrical energy introduces damping and, hence, the optimal damping required by this TVA is generated by the energy harvesting effects. This paper presents the methodology of implementing the theory of electromechanical TVAs to suppress the response of any real world structure. The work also illustrates the prospect of extensive applications of such novel electromechanical TVAs in defence and industry. The results show that the optimum degree of vibration suppression of an electronic box is achieved by this dual function TVA through suitable tuning of the attached electrical circuitry. (author)

The Internet School of Medicine: use of electronic resources by medical trainees and the reliability of those resources.

Science.gov (United States)

Egle, Jonathan P; Smeenge, David M; Kassem, Kamal M; Mittal, Vijay K

2015-01-01

Electronic sources of medical information are plentiful, and numerous studies have demonstrated the use of the Internet by patients and the variable reliability of these sources. Studies have investigated neither the use of web-based resources by residents, nor the reliability of the information available on these websites. A web-based survey was distributed to surgical residents in Michigan and third- and fourth-year medical students at an American allopathic and osteopathic medical school and a Caribbean allopathic school regarding their preferred sources of medical information in various situations. A set of 254 queries simulating those faced by medical trainees on rounds, on a written examination, or during patient care was developed. The top 5 electronic resources cited by the trainees were evaluated for their ability to answer these questions accurately, using standard textbooks as the point of reference. The respondents reported a wide variety of overall preferred resources. Most of the 73 responding medical trainees favored textbooks or board review books for prolonged studying, but electronic resources are frequently used for quick studying, clinical decision-making questions, and medication queries. The most commonly used electronic resources were UpToDate, Google, Medscape, Wikipedia, and Epocrates. UpToDate and Epocrates had the highest percentage of correct answers (47%) and Wikipedia had the lowest (26%). Epocrates also had the highest percentage of wrong answers (30%), whereas Google had the lowest percentage (18%). All resources had a significant number of questions that they were unable to answer. Though hardcopy books have not been completely replaced by electronic resources, more than half of medical students and nearly half of residents prefer web-based sources of information. For quick questions and studying, both groups prefer Internet sources. However, the most commonly used electronic resources fail to answer clinical queries more than half

Making oxidation potentials predictable: Coordination of additives applied to the electronic fine tuning of an iron(II) complex

KAUST Repository

Haslinger, Stefan

2014-11-03

This work examines the impact of axially coordinating additives on the electronic structure of a bioinspired octahedral low-spin iron(II) N-heterocyclic carbene (Fe-NHC) complex. Bearing two labile trans-acetonitrile ligands, the Fe-NHC complex, which is also an excellent oxidation catalyst, is prone to axial ligand exchange. Phosphine- and pyridine-based additives are used for substitution of the acetonitrile ligands. On the basis of the resulting defined complexes, predictability of the oxidation potentials is demonstrated, based on a correlation between cyclic voltammetry experiments and density functional theory calculated molecular orbital energies. Fundamental insights into changes of the electronic properties upon axial ligand exchange and the impact on related attributes will finally lead to target-oriented manipulation of the electronic properties and consequently to the effective tuning of the reactivity of bioinspired systems.

Making oxidation potentials predictable: Coordination of additives applied to the electronic fine tuning of an iron(II) complex

KAUST Repository

Haslinger, Stefan; Kü ck, Jens W.; Hahn, Eva M.; Cokoja, Mirza; Pö thig, Alexander; Basset, Jean-Marie; Kü hn, Fritz

2014-01-01

This work examines the impact of axially coordinating additives on the electronic structure of a bioinspired octahedral low-spin iron(II) N-heterocyclic carbene (Fe-NHC) complex. Bearing two labile trans-acetonitrile ligands, the Fe-NHC complex, which is also an excellent oxidation catalyst, is prone to axial ligand exchange. Phosphine- and pyridine-based additives are used for substitution of the acetonitrile ligands. On the basis of the resulting defined complexes, predictability of the oxidation potentials is demonstrated, based on a correlation between cyclic voltammetry experiments and density functional theory calculated molecular orbital energies. Fundamental insights into changes of the electronic properties upon axial ligand exchange and the impact on related attributes will finally lead to target-oriented manipulation of the electronic properties and consequently to the effective tuning of the reactivity of bioinspired systems.

Tuning of active vibration controllers for ACTEX by genetic algorithm

Science.gov (United States)

Kwak, Moon K.; Denoyer, Keith K.

1999-06-01

This paper is concerned with the optimal tuning of digitally programmable analog controllers on the ACTEX-1 smart structures flight experiment. The programmable controllers for each channel include a third order Strain Rate Feedback (SRF) controller, a fifth order SRF controller, a second order Positive Position Feedback (PPF) controller, and a fourth order PPF controller. Optimal manual tuning of several control parameters can be a difficult task even though the closed-loop control characteristics of each controller are well known. Hence, the automatic tuning of individual control parameters using Genetic Algorithms is proposed in this paper. The optimal control parameters of each control law are obtained by imposing a constraint on the closed-loop frequency response functions using the ACTEX mathematical model. The tuned control parameters are then uploaded to the ACTEX electronic control electronics and experiments on the active vibration control are carried out in space. The experimental results on ACTEX will be presented.

ANALYTICAL REVIEW OF ELECTRONIC RESOURCES FOR THE STUDY OF LATIN

Directory of Open Access Journals (Sweden)

Olena Yu. Balalaieva

2014-04-01

Full Text Available The article investigates the current state of development of e-learning content in the Latin language. It is noted that the introduction of ICT in the educational space has expanded the possibility of studying Latin, opened access to digital libraries resources, made it possible to use scientific and educational potential and teaching Latin best practices of world's leading universities. A review of foreign and Ukrainian information resources and electronic editions for the study of Latin is given. Much attention was paid to the didactic potential of local and online multimedia courses of Latin, electronic textbooks, workbooks of interactive tests and exercises, various dictionaries and software translators, databases and digital libraries. Based on analysis of the world market of educational services and products the main trends in the development of information resources and electronic books are examined. It was found that multimedia courses with interactive exercises or workbooks with interactive tests, online dictionaries and translators are the most widely represented and demanded. The noticeable lagging of Ukrainian education and computer linguistics in quantitative and qualitative measures in this industry is established. The obvious drawback of existing Ukrainian resources and electronic editions for the study of Latin is their noninteractive nature. The prospects of e-learning content in Latin in Ukraine are outlined.

Elektronik Bilgi Kaynaklarının Seçimi / Selection of Electronic Information Resources

Directory of Open Access Journals (Sweden)

Pınar Al

2003-04-01

Full Text Available For many years, library users have used only from the printed media in order to get the information that they have needed. Today with the widespread use of the Web and the addition of electronic information resources to library collections, the use of information in the electronic environment as well as in printed media is started to be used. In time, such types of information resources as, electronic journals, electronic books, electronic encyclopedias, electronic dictionaries and electronic theses have been added to library collections. In this study, selection criteria that can be used for electronic information resources are discussed and suggestions are provided for libraries that try to select electronic information resources for their collections.

Access to electronic resources by visually impaired people

Directory of Open Access Journals (Sweden)

Jenny Craven

2003-01-01

Full Text Available Research into access to electronic resources by visually impaired people undertaken by the Centre for Research in Library and Information Management has not only explored the accessibility of websites and levels of awareness in providing websites that adhere to design for all principles, but has sought to enhance understanding of information seeking behaviour of blind and visually impaired people when using digital resources.

Operational Experiences Tuning the ATF2 Final Focus Optics Towards Obtaining a 37nm Electron Beam IP Spot Size

CERN Document Server

White, Glen; Woodley, Mark; Bai, Sha; Bambade, Philip; Renier, Yves; Bolzon, Benoit; Kamiya, Yoshio; Komamiya, Sachio; Oroku, Masahiro; Yamaguchi, Yohei; Yamanaka, Takashi; Kubo, Kiyoshi; Kuroda, Shigeru; Okugi, Toshiyuki; Tauchi, Toshiaki; Marin, Eduardo

2010-01-01

The primary aim of the ATF2 research accelerator is to test a scaled version of the final focus optics planned for use in next-generation linear lepton colliders. ATF2 consists of a 1.3 GeV linac, damping ring providing lowemittance electron beams (<12pm in the vertical plane), extraction line and final focus optics. The design details of the final focus optics and implementation at ATF2 are presented elsewhere. The ATF2 accelerator is currently being commissioned, with a staged approach to achieving the design IP spot size. It is expected that as we implement more demanding optics and reduce the vertical beta function at the IP, the tuning becomes more difficult and takes longer. We present here a description of the implementation of the tuning procedures and describe operational experiences and performances

Library training to promote electronic resource usage

DEFF Research Database (Denmark)

Frandsen, Tove Faber; Tibyampansha, Dativa; Ibrahim, Glory

2017-01-01

Purpose: Increasing the usage of electronic resources is an issue of concern for many libraries all over the world. Several studies stress the importance of information literacy and instruction in order to increase the usage. Design/methodology/approach: The present article presents the results...

Why and How to Measure the Use of Electronic Resources

Directory of Open Access Journals (Sweden)

Jean Bernon

2008-11-01

Full Text Available A complete overview of library activity implies a complete and reliable measurement of the use of both electronic resources and printed materials. This measurement is based on three sets of definitions: document types, use types and user types. There is a common model of definitions for printed materials, but a lot of questions and technical issues remain for electronic resources. In 2006 a French national working group studied these questions. It relied on the COUNTER standard, but found it insufficient and pointed out the need for local tools such as web markers and deep analysis of proxy logs. Within the French national consortium COUPERIN, a new working group is testing ERMS, SUSHI standards, Shibboleth authentication, along with COUNTER standards, to improve the counting of the electronic resources use. At this stage this counting is insufficient and its improvement will be a European challenge for the future.

Organic electronic materials: Recent advances in the dft description of the ground and excited states using tuned range-separated hybrid functionals

KAUST Repository

Körzdörfer, Thomas

2014-11-18

Density functional theory (DFT) and its time-dependent extension (TD-DFT) are powerful tools enabling the theoretical prediction of the ground- and excited-state properties of organic electronic materials with reasonable accuracy at affordable computational costs. Due to their excellent accuracy-to-numerical-costs ratio, semilocal and global hybrid functionals such as B3LYP have become the workhorse for geometry optimizations and the prediction of vibrational spectra in modern theoretical organic chemistry. Despite the overwhelming success of these out-of-the-box functionals for such applications, the computational treatment of electronic and structural properties that are of particular interest in organic electronic materials sometimes reveals severe and qualitative failures of such functionals. Important examples include the overestimation of conjugation, torsional barriers, and electronic coupling as well as the underestimation of bond-length alternations or excited-state energies in low-band-gap polymers.In this Account, we highlight how these failures can be traced back to the delocalization error inherent to semilocal and global hybrid functionals, which leads to the spurious delocalization of electron densities and an overestimation of conjugation. The delocalization error for systems and functionals of interest can be quantified by allowing for fractional occupation of the highest occupied molecular orbital. It can be minimized by using long-range corrected hybrid functionals and a nonempirical tuning procedure for the range-separation parameter.We then review the benefits and drawbacks of using tuned long-range corrected hybrid functionals for the description of the ground and excited states of π-conjugated systems. In particular, we show that this approach provides for robust and efficient means of characterizing the electronic couplings in organic mixed-valence systems, for the calculation of accurate torsional barriers at the polymer limit, and for the

Tuning the electronic properties of armchair carbon nanoribbons by a selective boron doping

International Nuclear Information System (INIS)

Navarro-Santos, P; Ricardo-Chavez, J L; Lopez-Sandoval, R; Reyes-Reyes, M; Rivera, J L

2010-01-01

Armchair carbon nanoribbons (ACNRs) substitutionally doped with boron atoms are investigated in the framework of first-principles density functional theory. Different boron-boron arrangements and concentrations are considered in order to simulate possible aggregation patterns, their structural stability and electronic behavior are determined as a function of ribbon size. In agreement with previous studies, our results show that the dopant atoms have in general a preference for edge sites, but specific effects appear as a function of concentration that importantly modify the properties of the ribbons compared to the pristine case. Interesting tendencies are discovered as a function of dopant concentration that significantly affect the electronic properties of the ribbons. We have found that BC 3 island formation and edge doping are the most important factors for the structural stabilization of the ribbons with high boron concentration (>7%) whereas for the cases of low boron concentrations ( 3 island patterns give rise to highly localized B states on top of the Fermi level, resulting in semiconducting behavior. On the other hand, when the average distance between the B atoms increases beyond island stoichiometry, the localization of their states is reduced and the ribbons may become metallic due to a band crossing caused by the lowering of the Fermi level resulting from the positive charge doping. Thus, tuning the dopant interaction would be an appropriate way to tailor the electronic properties of the ribbons in a convenient manner in view of potential technological applications.

Tuned sources of submillimetre radiation

International Nuclear Information System (INIS)

Berezhnyj, V.L.

1981-01-01

The main present directions of development of sources of frequency coherent tuned radiation of electromagnetic waves in the submillimeter range: nonlinear mixing of different frequencies; semiconductor lasers; molecular lasers with optical pumping; relativistic electron beams in a magnetic field as submillimeter radiation sources; submillimeter radiation sources on the basis of SHF classical electrovacuum devices - are considered. The designs of generator systems and their specifications are presented. The main parameters of electromagnetic radiation of different sources, such as: power, stability, frequency, tuning range - are presented. The methods of improving sources and electromagnetic radiation parameters are proposed. The examples of possible applications of submillimeter radiation in different spheres of science and technology are given [ru

Computer-automated tuning of semiconductor double quantum dots into the single-electron regime

NARCIS (Netherlands)

Baart, T.A.; Eendebak, P.T.; Reichl, C.; Wegscheider, W.; Vandersypen, L.M.K.

2016-01-01

We report the computer-automated tuning of gate-defined semiconductor double quantum dots in GaAs heterostructures. We benchmark the algorithm by creating three double quantum dots inside a linear array of four quantum dots. The algorithm sets the correct gate voltages for all the gates to tune the

Understanding and tuning the quantum-confinement effect and edge magnetism in zigzag graphene nanoribbon.

Science.gov (United States)

Huang, Liang Feng; Zhang, Guo Ren; Zheng, Xiao Hong; Gong, Peng Lai; Cao, Teng Fei; Zeng, Zhi

2013-02-06

The electronic structure of zigzag graphene nanoribbon (ZGNR) is studied using density functional theory. The mechanisms underlying the quantum-confinement effect and edge magnetism in ZGNR are systematically investigated by combining the simulated results and some useful analytic models. The quantum-confinement effect and the inter-edge superexchange interaction can be tuned by varying the ribbon width, and the spin polarization and direct exchange splitting of the edge states can be tuned by varying their electronic occupations. The two edges of ZGNR can be equally or unequally tuned by charge doping or Li adsorption, respectively. The Li adatom has a site-selective adsorption on ZGNR, and it is a nondestructive and memorable approach to effectively modify the edge states in ZGNR. These systematic understanding and effective tuning of ZGNR electronics presented in this work are helpful for further investigation and application of ZGNR and other magnetic graphene systems.

Tuning of Hemes b Equilibrium Redox Potential Is Not Required for Cross-Membrane Electron Transfer.

Science.gov (United States)

Pintscher, Sebastian; Kuleta, Patryk; Cieluch, Ewelina; Borek, Arkadiusz; Sarewicz, Marcin; Osyczka, Artur

2016-03-25

In biological energy conversion, cross-membrane electron transfer often involves an assembly of two hemesb The hemes display a large difference in redox midpoint potentials (ΔEm_b), which in several proteins is assumed to facilitate cross-membrane electron transfer and overcome a barrier of membrane potential. Here we challenge this assumption reporting on hemebligand mutants of cytochromebc1in which, for the first time in transmembrane cytochrome, one natural histidine has been replaced by lysine without loss of the native low spin type of heme iron. With these mutants we show that ΔEm_b can be markedly increased, and the redox potential of one of the hemes can stay above the level of quinone pool, or ΔEm_b can be markedly decreased to the point that two hemes are almost isopotential, yet the enzyme retains catalytically competent electron transfer between quinone binding sites and remains functionalin vivo This reveals that cytochromebc1can accommodate large changes in ΔEm_b without hampering catalysis, as long as these changes do not impose overly endergonic steps on downhill electron transfer from substrate to product. We propose that hemesbin this cytochrome and in other membranous cytochromesbact as electronic connectors for the catalytic sites with no fine tuning in ΔEm_b required for efficient cross-membrane electron transfer. We link this concept with a natural flexibility in occurrence of several thermodynamic configurations of the direction of electron flow and the direction of the gradient of potential in relation to the vector of the electric membrane potential. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

Importance of beam-beam tune spread to collective beam-beam instability in hadron colliders

International Nuclear Information System (INIS)

Jin Lihui; Shi Jicong

2004-01-01

In hadron colliders, electron-beam compensation of beam-beam tune spread has been explored for a reduction of beam-beam effects. In this paper, effects of the tune-spread compensation on beam-beam instabilities were studied with a self-consistent beam-beam simulation in model lattices of Tevatron and Large Hodron Collider. It was found that the reduction of the tune spread with the electron-beam compensation could induce a coherent beam-beam instability. The merit of the compensation with different degrees of tune-spread reduction was evaluated based on beam-size growth. When two beams have a same betatron tune, the compensation could do more harm than good to the beams when only beam-beam effects are considered. If a tune split between two beams is large enough, the compensation with a small reduction of the tune spread could benefit beams as Landau damping suppresses the coherent beam-beam instability. The result indicates that nonlinear (nonintegrable) beam-beam effects could dominate beam dynamics and a reduction of beam-beam tune spread by introducing additional beam-beam interactions and reducing Landau damping may not improve the stability of beams

Euler European Libraries and Electronic Resources in Mathematical Sciences

CERN Document Server

The Euler Project. Karlsruhe

The European Libraries and Electronic Resources (EULER) Project in Mathematical Sciences provides the EulerService site for searching out "mathematical resources such as books, pre-prints, web-pages, abstracts, proceedings, serials, technical reports preprints) and NetLab (for Internet resources), this outstanding engine is capable of simple, full, and refined searches. It also offers a browse option, which responds to entries in the author, keyword, and title fields. Further information about the Project is provided at the EULER homepage.

Effects of Electronic Information Resources Skills Training for Lecturers on Pedagogical Practices and Research Productivity

Science.gov (United States)

Bhukuvhani, Crispen; Chiparausha, Blessing; Zuvalinyenga, Dorcas

2012-01-01

Lecturers use various electronic resources at different frequencies. The university library's information literacy skills workshops and seminars are the main sources of knowledge of accessing electronic resources. The use of electronic resources can be said to have positively affected lecturers' pedagogical practices and their work in general. The…

Electronic tuning of the transport properties of off-stoichiometric PbxSn1−xTe thermoelectric alloys by Bi2Te3 doping

International Nuclear Information System (INIS)

Guttmann, Gilad M.; Dadon, David; Gelbstein, Yaniv

2015-01-01

The recent energy demands affected by the dilution of conventional energy resources and the growing awareness of environmental considerations had motivated many researchers to seek for novel renewable energy conversion methods. Thermoelectric direct conversion of thermal into electrical energies is such a method, in which common compositions include IV-VI semiconducting compounds (e.g., PbTe and SnTe) and their alloys. For approaching practical thermoelectric devices, the current research is focused on electronic optimization of off-stoichiometric p-type Pb x Sn 1−x Te alloys by tuning of Bi 2 Te 3 doping and/or SnTe alloying levels, while avoiding the less mechanically favorable Na dopant. It was shown that upon such doping/alloying, higher ZTs, compared to those of previously reported undoped Pb 0.5 Sn 0.5 Te alloy, were obtained at temperatures lower than 210–340 °C, depending of the exact doping/alloying level. It was demonstrated that upon optimal grading of the carrier concentration, a maximal thermoelectric efficiency enhancement of ∼38%, compared to that of an undoped material, is expected

Tuning the Electronic Structure of Titanium Oxide Support to Enhance the Electrochemical Activity of Platinum Nanoparticles

KAUST Repository

Shi, Feifei

2013-09-11

Two times higher activity and three times higher stability in methanol oxidation reaction, a 0.12 V negative shift of the CO oxidation peak potential, and a 0.07 V positive shift of the oxygen reaction potential compared to Pt nanoparticles on pristine TiO2 support were achieved by tuning the electronic structure of the titanium oxide support of Pt nanoparticle catalysts. This was accomplished by adding oxygen vacancies or doping with fluorine. Experimental trends are interpreted in the context of an electronic structure model, showing an improvement in electrochemical activity when the Fermi level of the support material in Pt/TiOx systems is close to the Pt Fermi level and the redox potential of the reaction. The present approach provides guidance for the selection of the support material of Pt/TiOx systems and may be applied to other metal-oxide support materials, thus having direct implications in the design and optimization of fuel cell catalyst supports. © 2013 American Chemical Society.

Tuning the electronic properties of armchair carbon nanoribbons by a selective boron doping

Energy Technology Data Exchange (ETDEWEB)

Navarro-Santos, P; Ricardo-Chavez, J L; Lopez-Sandoval, R [Instituto Potosino de Investigacion Cientifica y Tecnologica, Camino a la presa San Jose 2055, San Luis Potosi 78216 (Mexico); Reyes-Reyes, M [Instituto de Investigacion en Comunicacion Optica, Universidad Autonoma de San Luis Potosi, Alvaro Obregon 64, San Luis Potosi 78000 (Mexico); Rivera, J L, E-mail: sandov@ipicyt.edu.m [Facultad de Ingenieria Quimica, Universidad Michoacana de San Nicolas de Hidalgo, Santiago Tapia 403, Morelia, Michoacan, 58000 (Mexico)

2010-12-22

Armchair carbon nanoribbons (ACNRs) substitutionally doped with boron atoms are investigated in the framework of first-principles density functional theory. Different boron-boron arrangements and concentrations are considered in order to simulate possible aggregation patterns, their structural stability and electronic behavior are determined as a function of ribbon size. In agreement with previous studies, our results show that the dopant atoms have in general a preference for edge sites, but specific effects appear as a function of concentration that importantly modify the properties of the ribbons compared to the pristine case. Interesting tendencies are discovered as a function of dopant concentration that significantly affect the electronic properties of the ribbons. We have found that BC{sub 3} island formation and edge doping are the most important factors for the structural stabilization of the ribbons with high boron concentration (>7%) whereas for the cases of low boron concentrations (<5%) the structural stabilities are similar. For all the doped cases, we have found that the BC{sub 3} island patterns give rise to highly localized B states on top of the Fermi level, resulting in semiconducting behavior. On the other hand, when the average distance between the B atoms increases beyond island stoichiometry, the localization of their states is reduced and the ribbons may become metallic due to a band crossing caused by the lowering of the Fermi level resulting from the positive charge doping. Thus, tuning the dopant interaction would be an appropriate way to tailor the electronic properties of the ribbons in a convenient manner in view of potential technological applications.

Electronic Commerce Resource Centers. An Industry--University Partnership.

Science.gov (United States)

Gulledge, Thomas R.; Sommer, Rainer; Tarimcilar, M. Murat

1999-01-01

Electronic Commerce Resource Centers focus on transferring emerging technologies to small businesses through university/industry partnerships. Successful implementation hinges on a strategic operating plan, creation of measurable value for customers, investment in customer-targeted training, and measurement of performance outputs. (SK)

Spin-polarized semiconductors: tuning the electronic structure of graphene by introducing a regular pattern of sp3 carbons on the graphene plane.

Science.gov (United States)

Jing, Long; Huang, Ping; Zhu, Huarui; Gao, Xueyun

2013-01-28

First-principles calculations (generalized gradient approximation, density functional therory (DFT) with dispersion corrections, and DFT plus local atomic potential) are carried out on the stability and electronic structures of superlattice configurations of nitrophenyl diazonium functionalized graphene with different coverage. In the calculations, the stabilities of these structures are strengthened significantly since van der Waals interactions between nitrophenyl groups are taken into account. Furthermore, spin-polarized and wider-bandgap electronic structures are obtained when the nitrophenyl groups break the sublattice symmetry of the graphene. The unpaired quasi-localized p electrons are responsible for this itinerant magnetism. The results provide a novel approach to tune graphene's electronic structures as well as to form ferromagnetic semiconductive graphene. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Achromatic and isochronous electron beam transport for tunable free electron lasers

International Nuclear Information System (INIS)

Bengtsson, J.; Kim, K.J.

1991-09-01

We have continued the study of a suitable electron beam transport line, which is both isochronous and achromatic, for the free electron laser being designed at Lawrence Berkeley Laboratory. A refined version of the beam transport optics is discussed that accommodates two different modes of FEL wavelength tuning. For the fine tuning involving a small change of the electron beam energy, sextupoles are added to cancel the leading nonlinear dispersion. For the main tuning involving the change of the undulator gap, a practical solution of maintaining the beam matching condition is presented. Calculation of the higher order aberrations is facilitated by a newly developed code. 11 refs., 4 figs., 3 tabs

Tune measurement in the NSLS booster synchrotron

International Nuclear Information System (INIS)

Blum, E.B.; Nawrocky, R.

1993-01-01

The NSLS booster synchrotron can accelerate an electron beam from approximately 80 to 750 MeV in 0.7 sec. The betatron tunes can change during acceleration by as much as 0.1 units, causing beam loss as they cross resonance lines. Precise measurements with a conventional swept spectrum analyzer have always been difficult because of the rapid variation of tune as the magnets are ramped. We are now using a system based on a Tektronix 3052 digital spectrum analyzer that can obtain a complete frequency spectrum over a 10 MHz bandwidth in 200 μsec. Betatron oscillations are stimulated for the measurements by applying white noise to the beam through stripline electrodes. We will describe the instrumentation, our measurements of tune as a function time during the acceleration cycle, and the resulting improvements to the booster operation

Ionization Energies, Electron Affinities, and Polarization Energies of Organic Molecular Crystals: Quantitative Estimations from a Polarizable Continuum Model (PCM)–Tuned Range-Separated Density Functional Approach

KAUST Repository

Sun, Haitao; Ryno, Sean; Zhong, Cheng; Ravva, Mahesh Kumar; Sun, Zhenrong; Kö rzdö rfer, Thomas; Bredas, Jean-Luc

2016-01-01

We propose a new methodology for the first-principles description of the electronic properties relevant for charge transport in organic molecular crystals. This methodology, which is based on the combination of a non-empirical, optimally tuned range

Hydrogen production by Tuning the Photonic Band Gap with the Electronic Band Gap of TiO2

KAUST Repository

Waterhouse, G. I. N.; Wahab, A. K.; Al-Oufi, M.; Jovic, V.; Anjum, Dalaver H.; Sun-Waterhouse, D.; Llorca, J.; Idriss, H.

2013-01-01

Tuning the photonic band gap (PBG) to the electronic band gap (EBG) of Au/TiO2 catalysts resulted in considerable enhancement of the photocatalytic water splitting to hydrogen under direct sunlight. Au/TiO2 (PBG-357 nm) photocatalyst exhibited superior photocatalytic performance under both UV and sunlight compared to the Au/TiO2 (PBG-585 nm) photocatalyst and both are higher than Au/TiO2 without the 3 dimensionally ordered macro-porous structure materials. The very high photocatalytic activity is attributed to suppression of a fraction of electron-hole recombination route due to the co-incidence of the PBG with the EBG of TiO2 These materials that maintain their activity with very small amount of sacrificial agents (down to 0.5 vol.% of ethanol) are poised to find direct applications because of their high activity, low cost of the process, simplicity and stability.

Hydrogen production by Tuning the Photonic Band Gap with the Electronic Band Gap of TiO2

KAUST Repository

Waterhouse, G. I. N.

2013-10-10

Tuning the photonic band gap (PBG) to the electronic band gap (EBG) of Au/TiO2 catalysts resulted in considerable enhancement of the photocatalytic water splitting to hydrogen under direct sunlight. Au/TiO2 (PBG-357 nm) photocatalyst exhibited superior photocatalytic performance under both UV and sunlight compared to the Au/TiO2 (PBG-585 nm) photocatalyst and both are higher than Au/TiO2 without the 3 dimensionally ordered macro-porous structure materials. The very high photocatalytic activity is attributed to suppression of a fraction of electron-hole recombination route due to the co-incidence of the PBG with the EBG of TiO2 These materials that maintain their activity with very small amount of sacrificial agents (down to 0.5 vol.% of ethanol) are poised to find direct applications because of their high activity, low cost of the process, simplicity and stability.

Tuning of light-graphene interactions

DEFF Research Database (Denmark)

Xiao, Sanshui

— Graphene opens up for novel optoelectronic applications thanks to its high carrier mobility, ultra-large absorption bandwidth, and extremely fast material response. In particular, the opportunity to control optoelectronic properties through Fermi-level tuning enables electrooptical modulation......, optical-optical switching, and other optoelectronics applications. Except for the statistic gating and chemical doping, the Fermi level of graphene can also be optically tuned. With the aid of external optical pumping, electrons can be excited in the substrate, then move to the graphene layer, leading...... to the electrical doping in graphene. In this talk, I will firstly discuss how the graphene property changes when applying the optical pumping with different incident power. Then I will discuss graphene-silicon microring devices with having a high modulation depth and with a relatively low bias voltage. Finally, I...

Performance Tuning of Fock Matrix and Two-Electron Integral Calculations for NWChem on Leading HPC Platforms

Energy Technology Data Exchange (ETDEWEB)

Shan, Hongzhan; Austin, Brian M.; De Jong, Wibe A.; Oliker, Leonid; Wright, Nicholas J.; Apra, Edoardo

2014-10-01

Attaining performance in the evaluation of two-electron repulsion integrals and constructing the Fock matrix is of considerable importance to the computational chemistry community. Due to its numerical complexity improving the performance behavior across a variety of leading supercomputing platforms is an increasing challenge due to the significant diversity in high-performance computing architectures. In this paper, we present our successful tuning methodology for these important numerical methods on the Cray XE6, the Cray XC30, the IBM BG/Q, as well as the Intel Xeon Phi. Our optimization schemes leverage key architectural features including vectorization and simultaneous multithreading, and results in speedups of up to 2.5x compared with the original implementation.

Alternate Tunings for the Linac Coherent Light Source Photoinjector

CERN Document Server

Limborg-Deprey, Cecile

2005-01-01

The Linac Coherent Light Source (LCLS) is an x-ray free-electron laser (FEL) project based on the SLAC linac. The LCLS Photoinjector beamline has been designed to deliver 10 ps long electron bunches of 1nC with a normalized transverse emittance of less than 1 mm.mrad for 80% of the slices constituting the core of the bunch at 135 MeV. Tolerances and regulation requirements are tight for this tuning. The main contribution to emittance is the "cathode emittance which counts for 0.72 mm.mrad for the nominal tuning. As the "cathode emittance" scales linearly with laser spot radius, the emittance will be dramatically reduced for smaller radius, but this is only possible at lower charge. In particular, for a 0.2nC, we believe we can achieve an emittance closer to 0.4 mm.mrad. This working point will be easier to tune and the beam quality should be much easier to maintain than for the nominal one. In this paper, we also discuss how emittance could be further reduced by using the appropriate laser pulse shaping.

A microcontroller based tuning mechanism for the magnetron

International Nuclear Information System (INIS)

Khan, A.M.; Mahfooz, M.; Hanumaiah, B.; Ganesh; Siddappa, K.

2006-01-01

In this paper we report on a control system developed to tune the magnetron frequency to get the maximum beam pulse in the microtron (electron accelerator facility at Mangalore University). The control system so designed consists of a microcontroller, a phase locked loop (PLL) and a digital to analog converter (DAC) to control the magnetron frequency. The voltage value given by the microcontroller through the DAC decides the reference frequency. The PLL gives the error voltage whenever there is difference between the reference and the magnetron frequencies. The microcontroller unit tracks the error voltage and tunes the magnetron with the help of a tuner mechanism connected through a stepper motor. The microcontroller also monitors the beam current level and accordingly adjusts the reference frequency to successfully tune the magnetron. (author)

Tune measurements with high intensity ion beams at GSI SIS-18

Energy Technology Data Exchange (ETDEWEB)

Singh, Rahul [GSI, Darmstadt (Germany); TEMF, TU Darmstadt (Germany); Forck, Peter; Kowina, Piotr; Kaufmann, Wolfgang [GSI, Darmstadt (Germany); Weiland, Thomas [TEMF, TU Darmstadt (Germany)

2012-07-01

A precise tune measurement during a full accelerating cycle is required to achieve stable high current operation. A new system has been commissioned at GSI for position, orbit and tune measurements. It consists of three distinct parts; an exciter which provides power to excite coherent betatron oscillations in the bunched beam; Fast ADCs to digitize the BPM signals at 125 MSa/s; the post processing electronics uses digitized BPM signals to acquire one position value per bunch. Subsequently the baseband tune is determined by Fourier transformation of the position data. Experiments were conducted to understand the effects of high beam intensity on tune at injection plateau (11.4 MeV/u) and during acceleration ramp (11.4-600 MeV/u). These experiments were performed with U{sup 73+} and Ar{sup 18+} ion beam at highest achievable intensities of 2.10{sup 9} and 2.5.10{sup 10} respectively. Tune shift with increased intensity was observed. The working principle of the tune measurement system and observed high intensity effects on tune will be reported in this contribution.

Tuning the conductivity threshold and carrier density of two-dimensional electron gas at oxide interfaces through interface engineering

Directory of Open Access Journals (Sweden)

H. J. Harsan Ma

2015-08-01

Full Text Available The two-dimensional electron gas (2DEG formed at the perovskite oxides heterostructures is of great interest because of its potential applications in oxides electronics and nanoscale multifunctional devices. A canonical example is the 2DEG at the interface between a polar oxide LaAlO3 (LAO and non-polar SrTiO3 (STO. Here, the LAO polar oxide can be regarded as the modulating or doping layer and is expected to define the electronic properties of 2DEG at the LAO/STO interface. However, to practically implement the 2DEG in electronics and device design, desired properties such as tunable 2D carrier density are necessary. Here, we report the tuning of conductivity threshold, carrier density and electronic properties of 2DEG in LAO/STO heterostructures by insertion of a La0.5Sr0.5TiO3 (LSTO layer of varying thicknesses, and thus modulating the amount of polarization of the oxide over layers. Our experimental result shows an enhancement of carrier density up to a value of about five times higher than that observed at the LAO/STO interface. A complete thickness dependent metal-insulator phase diagram is obtained by varying the thickness of LAO and LSTO providing an estimate for the critical thickness needed for the metallic phase. The observations are discussed in terms of electronic reconstruction induced by polar oxides.

Chemical surface tuning electrocatalysis of redox-active nanoparticles

DEFF Research Database (Denmark)

Zhu, Nan; Ulstrup, Jens; Chi, Qijin

This work focuses on electron transfer (ET) and electrocatalysis of inorganic hybrid Prussian blue nanoparticles (PBNPs, 6 nm) immobilized on different chemical surfaces. Through surface self-assembly chemistry, we have enabled to tune chemical properties of the electrode surface. Stable immobili...

Resource-Efficient, Hierarchical Auto-Tuning of a Hybrid Lattice Boltzmann Computation on the Cray XT4

International Nuclear Information System (INIS)

Williams, Samuel; Carter, Jonathan; Oliker, Leonid; Shalf, John; Yelick, Katherine

2009-01-01

We apply auto-tuning to a hybrid MPI-pthreads lattice Boltzmann computation running on the Cray XT4 at National Energy Research Scientific Computing Center (NERSC). Previous work showed that multicore-specific auto-tuning can improve the performance of lattice Boltzmann magnetohydrodynamics (LBMHD) by a factor of 4x when running on dual- and quad-core Opteron dual-socket SMPs. We extend these studies to the distributed memory arena via a hybrid MPI/pthreads implementation. In addition to conventional auto-tuning at the local SMP node, we tune at the message-passing level to determine the optimal aspect ratio as well as the correct balance between MPI tasks and threads per MPI task. Our study presents a detailed performance analysis when moving along an isocurve of constant hardware usage: fixed total memory, total cores, and total nodes. Overall, our work points to approaches for improving intra- and inter-node efficiency on large-scale multicore systems for demanding scientific applications

USE OF ELECTRONIC EDUCATIONAL RESOURCES WHEN TRAINING IN WORK WITH SPREADSHEETS

Directory of Open Access Journals (Sweden)

Х А Гербеков

2017-12-01

Full Text Available Today the tools for maintaining training courses based on opportunities of information and communication technologies are developed. Practically in all directions of preparation and on all subject matters electronic textbook and self-instruction manuals are created. Nevertheless the industry of computer educational and methodical materials actively develops and gets more and more areas of development and introduction. In this regard more and more urgent is a problem of development of the electronic educational resources adequate to modern educational requirements. Creation and the organization of training courses with use of electronic educational resources in particular on the basis of Internet technologies remains a difficult methodical task.In article the questions connected with development of electronic educational resources for use when studying the substantial line “Information technologies” of a school course of informatics in particular for studying of spreadsheets are considered. Also the analysis of maintenance of a school course and the unified state examination from the point of view of representation of task in him corresponding to the substantial line of studying “Information technologies” on mastering technology of information processing in spreadsheets and the methods of visualization given by means of charts and schedules is carried out.

Electronically tuned sulfonamide-based probes with ultra-sensitivity for Ga"3"+ or Al"3"+ detection in aqueous solution

International Nuclear Information System (INIS)

Kumar, Ashwani; Chae, Pil Seok

2017-01-01

Three electronically tuned fluorescent probes (1–3) were synthesized by conjugating a fluorescent unit to N,N-bis-(hydroxyethyl)ethylenediamine. Probe 1 bearing an electron-deficient naphthalenedimide unit did not give a fluorescence response to the presence of various metal ions including monovalent metal ions (Na"+, K"+, and Ag"+), divalent metal ions (Ca"2"+, Cd"2"+, Co"2"+, Ni"2"+, Cu"2"+, Hg"2"+, Pb"2"+, and Zn"2"+) and trivalent metal ions (Al"3"+, Ga"3"+, Fe"3"+, and Cr"3"+) in an aqueous solution. By contrast, probes 2 and 3 possessing 1,8-naphthalimide and pyrene fluorophores, respectively, exhibited selective fluorescent “OFF-ON” behaviors as a result of Ga"3"+/Al"3"+ binding among the diverse metal ions, suggesting the importance of fluorophore electronic character with regard to metal ion sensing. The ethylenediamine analog of probe 3, corresponding to probe 4, was unable to yield a significant change in fluorescence intensity in the presence of any metal ions tested here, revealing the essential role of two hydroxyl groups for metal ion binding. A high association constant of K_a = 2.99 × 10"5 M"−"1 was obtained for probe 3 with Ga"3"+, with a limit of detection (LOD) of 10 nM. This LOD is the lowest value known for Ga"3"+ detection using chemical sensors. Along with an increase in aggregate sizes, PET suppression of probes upon metal ion binding was the primary contributor to the enhancement in fluorescence emission necessary for the sensitive detection of the target ions. The probe-metal ion complexes were fully characterized via TEM, FE-SEM, "1H NMR, fluorescence spectroscopy techniques and DFT calculations. - Highlights: • Three electronically tuned sulfonamide-based probes (probes 1, 2, and 3) were developed for metal ion-sensing. • Probes 2 and 3 exhibited AIE behavior with increasing water-content. • Probes 2 and 3 displayed a selective fluorescence “OFF-ON“ behavior for Ga"3"+ detection with the LOD of 10 nM. • PET

ZIF-8 gate tuning via terminal group modification: a computational study

KAUST Repository

Zheng, Bin

2016-06-24

Tuning the pore structure of zeolitic imidazolate frameworks (ZIFs) enables unique control of their material properties. In this work, we used computational methods to examine the gate structure of ZIF-8 tuned by substitution terminal groups. The substitution position and electron affinity of the added groups were shown to be key factors in gate size. Electrostatic interactions are responsible for the variation in gate opening. These results suggest that the post-modification of terminal group in ZIFs can be used to finely tune the pore gate, opening up new strategies in the design of ZIFs with desired properties.

Re-tuning tuned mass dampers using ambient vibration measurements

International Nuclear Information System (INIS)

Hazra, B; Sadhu, A; Narasimhan, S; Lourenco, R

2010-01-01

Deterioration, accidental changes in the operating conditions, or incorrect estimates of the structure modal properties lead to de-tuning in tuned mass dampers (TMDs). To restore optimal performance, it is necessary to estimate the modal properties of the system, and re-tune the TMD to its optimal state. The presence of closely spaced modes and a relatively large amount of damping in the dominant modes renders the process of identification difficult. Furthermore, the process of estimating the modal properties of the bare structure using ambient vibration measurements of the structure with the TMD is challenging. In order to overcome these challenges, a novel identification and re-tuning algorithm is proposed. The process of identification consists of empirical mode decomposition to separate the closely spaced modes, followed by the blind identification of the remaining modes. Algorithms for estimating the fundamental frequency and the mode shape of the primary structure necessary for re-tuning the TMD are proposed. Experimental results from the application of the proposed algorithms to identify and re-tune a laboratory structure TMD system are presented

Analytical Study of Usage of Electronic Information Resources at Pharmacopoeial Libraries in India

Directory of Open Access Journals (Sweden)

Sunil Tyagi

2014-02-01

Full Text Available The objective of this study is to know the rate and purpose of the use of e-resource by the scientists at pharmacopoeial libraries in India. Among other things, this study examined the preferences of the scientists toward printed books and journals, electronic information resources, and pattern of using e-resources. Non-probability sampling specially accidental and purposive technique was applied in the collection of primary data through administration of user questionnaire. The sample respondents chosen for the study consists of principle scientific officer, senior scientific officer, scientific officer, and scientific assistant of different division of the laboratories, namely, research and development, pharmaceutical chemistry, pharmacovigilance, pharmacology, pharmacogonosy, and microbiology. The findings of the study reveal the personal experiences and perceptions they have had on practice and research activity using e-resource. The major findings indicate that of the total anticipated participants, 78% indicated that they perceived the ability to use computer for electronic information resources. The data analysis shows that all the scientists belonging to the pharmacopoeial libraries used electronic information resources to address issues relating to drug indexes and compendia, monographs, drugs obtained through online databases, e-journals, and the Internet sources—especially polices by regulatory agencies, contacts, drug promotional literature, and standards.

Application of mid-infrared free-electron laser tuned to amide bands for dissociation of aggregate structure of protein.

Science.gov (United States)

Kawasaki, Takayasu; Yaji, Toyonari; Ohta, Toshiaki; Tsukiyama, Koichi

2016-01-01

A mid-infrared free-electron laser (FEL) is a linearly polarized, high-peak powered pulse laser with tunable wavelength within the mid-infrared absorption region. It was recently found that pathogenic amyloid fibrils could be partially dissociated to the monomer form by the irradiation of the FEL targeting the amide I band (C=O stretching vibration), amide II band (N-H bending vibration) and amide III band (C-N stretching vibration). In this study, the irradiation effect of the FEL on keratin aggregate was tested as another model to demonstrate an applicability of the FEL for dissociation of protein aggregates. Synchrotron radiation infrared microscopy analysis showed that the α-helix content in the aggregate structure decreased to almost the same level as that in the monomer state after FEL irradiation tuned to 6.06 µm (amide I band). Both irradiations at 6.51 µm (amide II band) and 8.06 µm (amide III band) also decreased the content of the aggregate but to a lesser extent than for the irradiation at the amide I band. On the contrary, the irradiation tuned to 5.6 µm (non-absorbance region) changed little the secondary structure of the aggregate. Scanning-electron microscopy observation at the submicrometer order showed that the angular solid of the aggregate was converted to non-ordered fragments by the irradiation at each amide band, while the aggregate was hardly deformed by the irradiation at 5.6 µm. These results demonstrate that the amide-specific irradiation by the FEL was effective for dissociation of the protein aggregate to the monomer form.

Measurement and stabilization of the longitudinal and transversal tune on the fast energy ramp at ELSA

Energy Technology Data Exchange (ETDEWEB)

Eberhardt, Maren [Electron Stretcher Accelerator ELSA, Physikalisches Institut, Universitaet Bonn (Germany)

2008-07-01

At the electron stretcher accelerator ELSA, an external beam of unpolarized or polarized electrons is supplied to experimental set-ups. In order to correct for dynamic effects caused by eddy currents induced on the fast energy ramp, the accelerator tunes have to measured in situ with high precision. The measurements of betatron tunes during the fast energy ramp are based on the excitation of coherent betatron oscillations generated by a pulsed kicker magnet. The betatron frequency is determined by a Fourier analysis of the measured oscillations of the beam position. This technique was successfully applied to measure the horizontal tune on the fast energy ramp. During the fast energy ramp shifts of the betatron tune caused by eddy currents are induced. These tune shifts are measured and corrected when operating the accelerator with polarized beam. Measurements of coherent synchrotron oscillations will also be presented. These are excited by a phase modulation of the acceleration voltage using an electrical phase shifter in the reference RF signal path.

Page 170 Use of Electronic Resources by Undergraduates in Two ...

African Journals Online (AJOL)

undergraduate students use electronic resources such as NUC virtual library, HINARI, ... web pages articles from magazines, encyclopedias, pamphlets and other .... of Nigerian university libraries have Internet connectivity, some of the system.

Electron-mediated relaxation following ultrafast pumping of strongly correlated materials: model evidence of a correlation-tuned crossover between thermal and nonthermal states.

Science.gov (United States)

Moritz, B; Kemper, A F; Sentef, M; Devereaux, T P; Freericks, J K

2013-08-16

We examine electron-electron mediated relaxation following ultrafast electric field pump excitation of the fermionic degrees of freedom in the Falicov-Kimball model for correlated electrons. The results reveal a dichotomy in the temporal evolution of the system as one tunes through the Mott metal-to-insulator transition: in the metallic regime relaxation can be characterized by evolution toward a steady state well described by Fermi-Dirac statistics with an increased effective temperature; however, in the insulating regime this quasithermal paradigm breaks down with relaxation toward a nonthermal state with a complicated electronic distribution as a function of momentum. We characterize the behavior by studying changes in the energy, photoemission response, and electronic distribution as functions of time. This relaxation may be observable qualitatively on short enough time scales that the electrons behave like an isolated system not in contact with additional degrees of freedom which would act as a thermal bath, especially when using strong driving fields and studying materials whose physics may manifest the effects of correlations.

Model of e-learning with electronic educational resources of new generation

Directory of Open Access Journals (Sweden)

A. V. Loban

2017-01-01

Full Text Available Purpose of the article: improving of scientific and methodical base of the theory of the е-learning of variability. Methods used: conceptual and logical modeling of the е-learning of variability process with electronic educational resource of new generation and system analysis of the interconnection of the studied subject area, methods, didactics approaches and information and communication technologies means. Results: the formalization complex model of the е-learning of variability with electronic educational resource of new generation is developed, conditionally decomposed into three basic components: the formalization model of the course in the form of the thesaurusclassifier (“Author of e-resource”, the model of learning as management (“Coordination. Consultation. Control”, the learning model with the thesaurus-classifier (“Student”. Model “Author of e-resource” allows the student to achieve completeness, high degree of didactic elaboration and structuring of the studied material in triples of variants: modules of education information, practical task and control tasks; the result of the student’s (author’s of e-resource activity is the thesaurus-classifier. Model of learning as management is based on the principle of personal orientation of learning in computer environment and determines the logic of interaction between the lecturer and the student when determining the triple of variants individually for each student; organization of a dialogue between the lecturer and the student for consulting purposes; personal control of the student’s success (report generation and iterative search for the concept of the class assignment in the thesaurus-classifier before acquiring the required level of training. Model “Student” makes it possible to concretize the learning tasks in relation to the personality of the student and to the training level achieved; the assumption of the lecturer about the level of training of a

A survey of the use of electronic scientific information resources among medical and dental students

Directory of Open Access Journals (Sweden)

Aarnio Matti

2006-05-01

Full Text Available Abstract Background To evaluate medical and dental students' utilization of electronic information resources. Methods A web survey sent to 837 students (49.9% responded. Results Twenty-four per cent of medical students and ninteen per cent of dental students searched MEDLINE 2+ times/month for study purposes, and thiry-two per cent and twenty-four per cent respectively for research. Full-text articles were used 2+ times/month by thirty-three per cent of medical and ten per cent of dental students. Twelve per cent of respondents never utilized either MEDLINE or full-text articles. In multivariate models, the information-searching skills among students were significantly associated with use of MEDLINE and full-text articles. Conclusion Use of electronic resources differs among students. Forty percent were non-users of full-text articles. Information-searching skills are correlated with the use of electronic resources, but the level of basic PC skills plays not a major role in using these resources. The student data shows that adequate training in information-searching skills will increase the use of electronic information resources.

Enhancement of heterogeneous electron transfer dynamics tuning single-walled carbon nanotube forest height and density

International Nuclear Information System (INIS)

Lamberti, Francesco; Ferraro, Davide; Giomo, Monica; Elvassore, Nicola

2013-01-01

Electrochemical sensors are growing in number and importance. Surface modifications could enhance charge transfer properties occurring at the interfaces and carbon nanoassemblies is one of the most used strategy to improve sensitivity to measurements. However, well defined protocols of surface modification are needed in order to fabricate electrochemically effective nanostructured sensors. Therefore, we aim at investigating the electrochemical properties of single-walled carbon nanotube (SWCNT) forests as a function of height and nanotube surface density. Height of the forests is accurately controlled tuning the oxidation temperatures in the range of 293–313 K of SWCNTs. The surface density of carbon nanotubes was adjusted developing cysteamine/2-mercaptoethanol (CYS/ME) self-assembled monolayers (SAMs) on gold surfaces at different ratios (1:0, 1:3, 1:10, 1:100, 0:1). Apparent electron transfer rate was analyzed with electrochemical impedance spectroscopy (EIS) and experimental data show that transfer rate constant, k app , increases from 1 × 10 −4 cm/s to 6 × 10 −4 cm/s rising oxidation temperatures (i.e. lowering forest height); therefore forests with reduced height show higher electron transfer rate without significant difference in electrodic reversibility. On the other hand, tuning SWCNT surface density, forests obtained with no ME show optimal Δ peak value of 0.087 ± 0.015 V and highest k app value of 9.15 × 10 −3 cm/s. Surprisingly, electrochemical surface area analysis shows that samples with lower amount of cysteamine have an active surface area three times bigger than samples with 1:3 CYS/ME ratio. Low electrochemical efficiency associated with high active surface may be related to unwanted SWCNT bundles adsorbed on the surface for 1:10 and 1:100 CYS/ME ratio samples as confirmed by AFM morphological characterization. Further investigation shows that a transition from a semi-infinite planar diffusion mechanism to a radial diffusion one takes

Tuning the electrical and optical anisotropy of a monolayer black phosphorus magnetic superlattice

Science.gov (United States)

Li, X. J.; Yu, J. H.; Luo, K.; Wu, Z. H.; Yang, W.

2018-04-01

We investigate theoretically the effects of modulated periodic perpendicular magnetic fields on the electronic states and optical absorption spectrum in monolayer black phosphorus (phosphorene). We demonstrate that different phosphorene magnetic superlattice (PMS) orientations can give rise to distinct energy spectra, i.e. tuning the intrinsic electronic anisotropy. Rashba spin-orbit coupling (RSOC) develops a spin-splitting energy dispersion in this phosphorene magnetic superlattice. Anisotropic momentum-dependent carrier distributions along/perpendicular to the magnetic strips are demonstrated. The manipulations of these exotic electronic properties by tuning superlattice geometry, magnetic field and the RSOC term are addressed systematically. Accordingly, we find bright-to-dark transitions in the ground-state electron-hole pair transition rate spectrum and the PMS orientation-dependent anisotropic optical absorption spectrum. This feature offers us a practical way of modulating the electronic anisotropy in phosphorene by magnetic superlattice configurations and detecting this modulation capability by using an optical technique.

Access to electronic information resources by students of federal ...

African Journals Online (AJOL)

The paper discusses access to electronic information resources by students of Federal Colleges of Education in Eha-Amufu and Umunze. Descriptive survey design was used to investigate sample of 526 students. Sampling technique used was a Multi sampling technique. Data for the study were generated using ...

Adoption and use of electronic information resources by medical ...

African Journals Online (AJOL)

This study investigated the adoption and use of electronic information resources by medical science students of the University of Benin. The descriptive survey research design was adopted for the study and 390 students provided the data. Data collected were analysed with descriptive Statistics(Simple percentage and ...

Where Do Electronic Books Fit in the College Research Arsenal of Resources?

Science.gov (United States)

Barbier, Patricia

2007-01-01

Student use of electronic books has become an accepted supplement to traditional resources. Student use and satisfaction was monitored through an online course discussion board. Increased use of electronic books indicate this service is an accepted supplement to the print book collection.

Tune-Based Halo Diagnostics

International Nuclear Information System (INIS)

Cameron, Peter

2003-01-01

Tune-based halo diagnostics can be divided into two categories -- diagnostics for halo prevention, and diagnostics for halo measurement. Diagnostics for halo prevention are standard fare in accumulators, synchrotrons, and storage rings, and again can be divided into two categories -- diagnostics to measure the tune distribution (primarily to avoid resonances), and diagnostics to identify instabilities (which will not be discussed here). These diagnostic systems include kicked (coherent) tune measurement, phase-locked loop (PLL) tune measurement, Schottky tune measurement, beam transfer function (BTF) measurements, and measurement of transverse quadrupole mode envelope oscillations. We refer briefly to tune diagnostics used at RHIC and intended for the SNS, and then present experimental results. Tune-based diagnostics for halo measurement (as opposed to prevention) are considerably more difficult. We present one brief example of tune-based halo measurement

Tuning the effects of Landau level mixing on anisotropic transport in quantum Hall systems

International Nuclear Information System (INIS)

Smith, Peter M; Kennett, Malcolm P

2012-01-01

Electron-electron interactions in half-filled high Landau levels in two-dimensional electron gases in a strong perpendicular magnetic field can lead to states with anisotropic longitudinal resistance. This longitudinal resistance is generally believed to arise from broken rotational invariance, which is indicated by charge density wave order in Hartree-Fock calculations. We use the Hartree-Fock approximation to study the influence of externally tuned Landau level mixing on the formation of interaction-induced states that break rotational invariance in two-dimensional electron and hole systems. We focus on the situation when there are two non-interacting states in the vicinity of the Fermi level and construct a Landau theory to study coupled charge density wave order that can occur as interactions are tuned and the filling or mixing are varied. We consider numerically a specific example where mixing is tuned externally through Rashba spin-orbit coupling. We calculate the phase diagram and find the possibility of ordering involving coupled striped or triangular charge density waves in the two levels. Our results may be relevant to recent transport experiments on quantum Hall nematics in which Landau level mixing plays an important role. (paper)

Tuning the electronic structure of bulk FeSe with chemical pressure using quantum oscillations and angle resolved photoemission spectroscopy (ARPES)

Science.gov (United States)

Coldea, Amalia

FeSe is a unique and intriguing superconductor which can be tuned into a high temperature superconducting state using applied pressure, chemical intercalation and surface doping. In the absence of magnetism, the structural transition in FeSe is believed to be electronically driven, with the orbital degrees of freedom playing an important part. This scenario supports the stabilization of a nematic state in FeSe, which manifests as a Fermi surface deformation in the presence of strong interactions, as detected by ARPES. Another manifestation of the nematicity is the enhanced nematic susceptibility determined from elastoresistance measurements under applied strain. Isovalent Sulphur substitution onto the Selenium site constitutes a chemical pressure, which subtly modifies the electronic structure of FeSe, suppressing the structural transition without inducing high temperature superconductivity. I will present the evolution of the electronic structure with chemical pressure in FeSe, as determined from quantum oscillations and ARPES studies and I will discuss the suppression of the nematic electronic state and the role of electronic correlations. Experiments were performed at high magnetic field facilities in Tallahassee, Nijmegen and Toulouse and Diamond Light Source, UK. This work is mainly supported by EPSRC, UK (EP/I004475/1, EP/I017836/1) and I acknowledge my collaborators from Refs. .

Stark shift and g-factor tuning in nanowires with Rashba effect

International Nuclear Information System (INIS)

Alhaddad, Iman; Habanjar, Khulud; Sakr, M.R.

2015-01-01

We report on the Stark shift of the energy subbands and the possibility of tuning the g-factor of electrons in nanowires subjected to external magnetic field. The electric field is applied along the direction of quantum confinement. Our analysis is based on numerical and perturbation calculations in the weak Rashba regime. For in-plane magnetic fields, the Stark shift is rigid and depends on the square of the electric field. Such rigid shift results in a field independent g-factor. Perpendicular magnetic fields induce a similar Stark shift accompanied by a lateral displacement of the energy spectra that is linear in the electric field. In this case, the g-factor shows square dependence on weak electric fields that varies with the subband index. However, in strong electric fields, the g-factor becomes subband independent and varies linearly with the field. - Highlights: • Energy spectra of electrons in nanowires are calculated in the weak Rashba regime. • For in-plane magnetic field, the Stark shift is rigid and the g-factor cannot be tuned. • Perpendicular magnetic fields add lateral displacement to the Stark shift. • The g-factor can be tuned by external electric field in this case. • The tuning of the g-factor is linear and unique for all subbands at high fields

Stark shift and g-factor tuning in nanowires with Rashba effect

Energy Technology Data Exchange (ETDEWEB)

Alhaddad, Iman; Habanjar, Khulud [Department of Physics, Faculty of Science, Beirut Arab University, P.O. Box 11, 5020 Riad El Solh, 11072809 - Beirut (Lebanon); Sakr, M.R., E-mail: msakr@alexu.edu.eg [Department of Physics, Faculty of Science, Beirut Arab University, P.O. Box 11, 5020 Riad El Solh, 11072809 - Beirut (Lebanon); Department of Physics, Faculty of Science, Alexandria University, Moharram Bek, Alexandria 21511 (Egypt)

2015-10-15

We report on the Stark shift of the energy subbands and the possibility of tuning the g-factor of electrons in nanowires subjected to external magnetic field. The electric field is applied along the direction of quantum confinement. Our analysis is based on numerical and perturbation calculations in the weak Rashba regime. For in-plane magnetic fields, the Stark shift is rigid and depends on the square of the electric field. Such rigid shift results in a field independent g-factor. Perpendicular magnetic fields induce a similar Stark shift accompanied by a lateral displacement of the energy spectra that is linear in the electric field. In this case, the g-factor shows square dependence on weak electric fields that varies with the subband index. However, in strong electric fields, the g-factor becomes subband independent and varies linearly with the field. - Highlights: • Energy spectra of electrons in nanowires are calculated in the weak Rashba regime. • For in-plane magnetic field, the Stark shift is rigid and the g-factor cannot be tuned. • Perpendicular magnetic fields add lateral displacement to the Stark shift. • The g-factor can be tuned by external electric field in this case. • The tuning of the g-factor is linear and unique for all subbands at high fields.

Strategic Planning for Electronic Resources Management: A Case Study at Gustavus Adolphus College

Science.gov (United States)

Hulseberg, Anna; Monson, Sarah

2009-01-01

Electronic resources, the tools we use to manage them, and the needs and expectations of our users are constantly evolving; at the same time, the roles, responsibilities, and workflow of the library staff who manage e-resources are also in flux. Recognizing a need to be more intentional and proactive about how we manage e-resources, the…

REVIEW OF MOODLE PLUGINS FOR DESIGNING MULTIMEDIA ELECTRONIC EDUCATIONAL RESOURCES FROM LANGUAGE DISCIPLINES

Directory of Open Access Journals (Sweden)

Anton M. Avramchuk

2015-09-01

Full Text Available Today the problem of designing multimedia electronic educational resources from language disciplines in Moodle is very important. This system has a lot of different, powerful resources, plugins to facilitate the learning of students with language disciplines. This article presents an overview and comparative analysis of the five Moodle plugins for designing multimedia electronic educational resources from language disciplines. There have been considered their key features and functionality in order to choose the best for studying language disciplines in the Moodle. Plugins are compared by a group of experts according to the criteria: efficiency, functionality and easy use. For a comparative analysis of the plugins it is used the analytic hierarchy process.

Effects of Stimulus Octave and Timbre on the Tuning Accuracy of Advanced College Instrumentalists

Science.gov (United States)

Byo, James L.; Schlegel, Amanda L.

2016-01-01

The purpose of this study was to test the effects of octave and timbre on advanced college musicians' (N = 63) ability to tune their instruments. We asked: "Are there differences in tuning accuracy due to octave (B-flat 2, B-flat 4) and stimulus timbre (oboe, clarinet, electronic tuner, tuba)?" and "To what extent do participants'…

Active tuning of surface phonon polariton resonances via carrier photoinjection

Science.gov (United States)

Dunkelberger, Adam D.; Ellis, Chase T.; Ratchford, Daniel C.; Giles, Alexander J.; Kim, Mijin; Kim, Chul Soo; Spann, Bryan T.; Vurgaftman, Igor; Tischler, Joseph G.; Long, James P.; Glembocki, Orest J.; Owrutsky, Jeffrey C.; Caldwell, Joshua D.

2018-01-01

Surface phonon polaritons (SPhPs) are attractive alternatives to infrared plasmonics for subdiffractional confinement of infrared light. Localized SPhP resonances in semiconductor nanoresonators are narrow, but that linewidth and the limited extent of the Reststrahlen band limit spectral coverage. To address this limitation, we report active tuning of SPhP resonances in InP and 4H-SiC by photoinjecting free carriers into nanoresonators, taking advantage of the coupling between the carrier plasma and optic phonons to blueshift SPhP resonances. We demonstrate state-of-the-art tuning figures of merit upon continuous-wave excitation (in InP) or pulsed excitation (in 4H-SiC). Lifetime effects cause the tuning to saturate in InP, and carrier redistribution leads to rapid (electronic and phononic excitations.

Modern ICT Tools: Online Electronic Resources Sharing Using Web ...

African Journals Online (AJOL)

Modern ICT Tools: Online Electronic Resources Sharing Using Web 2.0 and Its Implications For Library And Information Practice In Nigeria. ... The PDF file you selected should load here if your Web browser has a PDF reader plug-in installed (for example, a recent version of Adobe Acrobat Reader). If you would like more ...

Tuning the DARHT Axis-II linear induction accelerator focusing

Energy Technology Data Exchange (ETDEWEB)

Ekdahl, Carl A. [Los Alamos National Laboratory

2012-04-24

Flash radiography of large hydrodynamic experiments driven by high explosives is a well-known diagnostic technique in use at many laboratories, and the Dual-Axis Radiography for Hydrodynamic Testing (DARHT) facility at Los Alamos produces flash radiographs of large hydrodynamic experiments. Two linear induction accelerators (LIAs) make the bremsstrahlung radiographic source spots for orthogonal views of each test. The 2-kA, 20-MeV Axis-I LIA creates a single 60-ns radiography pulse. The 1.7-kA, 16.5-MeV Axis-II LIA creates up to four radiography pulses by kicking them out of a longer pulse that has a 1.6-{mu}s flattop. The Axis-II injector, LIA, kicker, and downstream transport (DST) to the bremsstrahlung converter are described. Adjusting the magnetic focusing and steering elements to optimize the electron-beam transport through an LIA is often called 'tuning.' As in all high-current LIAs, the focusing field is designed to be as close to that of the ideal continuous solenoid as physically possible. In ideal continuous solenoidal transport a smoothly varying beam size can easily be found for which radial forces balance, and the beam is said to be 'matched' to the focusing field. A 'mismatched' beam exhibits unwanted oscillations in size, which are a source of free energy that contributes to emittance growth. This is undesirable, because in the absence of beam-target effects, the radiographic spot size is proportional to the emittance. Tuning the Axis-II LIA is done in two steps. First, the solenoidal focusing elements are set to values designed to provide a matched beam with little or no envelope oscillations, and little or no beam-breakup (BBU) instability growth. Then, steering elements are adjusted to minimize the motion of the centroid of a well-centered beam at the LIA exit. This article only describes the design of the tune for the focusing solenoids. The DARHT Axis-II LIA was required to be re-tuned after installing an

Electronic in-plane symmetry breaking at field-tuned quantum criticality in CeRhIn5.

Science.gov (United States)

Ronning, F; Helm, T; Shirer, K R; Bachmann, M D; Balicas, L; Chan, M K; Ramshaw, B J; McDonald, R D; Balakirev, F F; Jaime, M; Bauer, E D; Moll, P J W

2017-08-17

Electronic nematic materials are characterized by a lowered symmetry of the electronic system compared to the underlying lattice, in analogy to the directional alignment without translational order in nematic liquid crystals. Such nematic phases appear in the copper- and iron-based high-temperature superconductors, and their role in establishing superconductivity remains an open question. Nematicity may take an active part, cooperating or competing with superconductivity, or may appear accidentally in such systems. Here we present experimental evidence for a phase of fluctuating nematic character in a heavy-fermion superconductor, CeRhIn 5 (ref. 5). We observe a magnetic-field-induced state in the vicinity of a field-tuned antiferromagnetic quantum critical point at H c  ≈ 50 tesla. This phase appears above an out-of-plane critical field H* ≈ 28 tesla and is characterized by a substantial in-plane resistivity anisotropy in the presence of a small in-plane field component. The in-plane symmetry breaking has little apparent connection to the underlying lattice, as evidenced by the small magnitude of the magnetostriction anomaly at H*. Furthermore, no anomalies appear in the magnetic torque, suggesting the absence of metamagnetism in this field range. The appearance of nematic behaviour in a prototypical heavy-fermion superconductor highlights the interrelation of nematicity and unconventional superconductivity, suggesting nematicity to be common among correlated materials.

Dielectric Screening Meets Optimally Tuned Density Functionals.

Science.gov (United States)

Kronik, Leeor; Kümmel, Stephan

2018-04-17

A short overview of recent attempts at merging two independently developed methods is presented. These are the optimal tuning of a range-separated hybrid (OT-RSH) functional, developed to provide an accurate first-principles description of the electronic structure and optical properties of gas-phase molecules, and the polarizable continuum model (PCM), developed to provide an approximate but computationally tractable description of a solvent in terms of an effective dielectric medium. After a brief overview of the OT-RSH approach, its combination with the PCM as a potentially accurate yet low-cost approach to the study of molecular assemblies and solids, particularly in the context of photocatalysis and photovoltaics, is discussed. First, solvated molecules are considered, with an emphasis on the challenge of balancing eigenvalue and total energy trends. Then, it is shown that the same merging of methods can also be used to study the electronic and optical properties of molecular solids, with a similar discussion of the pros and cons. Tuning of the effective scalar dielectric constant as one recent approach that mitigates some of the difficulties in merging the two approaches is considered. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Cyto-molecular Tuning of Quantum Dots

Science.gov (United States)

Lee, Bong; Suresh, Sindhuja; Ekpenyong, Andrew

Quantum dots (QDs) are semiconductor nanoparticles composed of groups II-VI or III-V elements, with physical dimensions smaller than the exciton Bohr radius, and between 1-10 nm. Their applications and promising myriad applications in photovoltaic cells, biomedical imaging, targeted drug delivery, quantum computing, etc, have led to much research on their interactions with other systems. For biological systems, research has focused on biocompatibility and cytotoxicity of QDs in the context of imaging/therapy. However, there is a paucity of work on how biological systems might be used to tune QDs. Here, we hypothesize that the photo-electronic properties of QDs can be tuned by biological macromolecules following controlled changes in cellular activities. Using CdSe/ZnS core-shell QDs, we perform spectroscopic analysis of optically excited colloidal QDs with and without promyelocytic HL60 cells. Preliminary results show shifts in the emission spectra of the colloidal dispersions with and without cells. We will present results for activated HL60-derived cells where specific macromolecules produced by these cells perturb the electric dipole moments of the excited QDs and the associated electric fields, in ways that constitute what we describe as cyto-molecular tuning. Startup funds from the College of Arts and Sciences, Creighton University (to AEE).

Tuning the Electronic, Optical, and Magnetic Properties of Monolayer GaSe with a Vertical Electric Field

Science.gov (United States)

Ke, Congming; Wu, Yaping; Guo, Guang-Yu; Lin, Wei; Wu, Zhiming; Zhou, Changjie; Kang, Junyong

2018-04-01

Inspired by two-dimensional material with their unique physical properties and innovative device applications, here we report a design framework on monolayer GaSe, an important member of the two-dimensional material family, in an effort to tune the electronic, optical, and magnetic properties through a vertical electric field. A transition from indirect to direct band gap in monolayer GaSe is found with an electric field of 0.09 V /Å . The giant Stark effect results in a reduction of the band gap with a Stark coefficient of 3.54 Å. Optical and dielectric properties of monolayer GaSe are dependent on the vertical electric field. A large regulation range for polarization E ∥c ^ is found for the static dielectric constant. The optical anisotropy with the dipole transition from E ∥c ^ to E ⊥c ^ is achieved. Induced by the spin-orbit coupling, spin-splitting energy at the valence band maximum increases linearly with the electric field. The effective mass of holes is highly susceptible to the vertical electric field. Switchable spin-polarization features in spin texture of monolayer GaSe are predicted. The tunable electronic, optical, and magnetic properties of monolayer GaSe hold great promise for applications in both the optoelectronic and spintronic devices.

THE MODEL OF LINGUISTIC TEACHERS’ COMPETENCY DEVELOPMENT ON DESIGNING MULTIMEDIA ELECTRONIC EDUCATIONAL RESOURCES IN THE MOODLE SYSTEM

Directory of Open Access Journals (Sweden)

Anton M. Avramchuk

2017-10-01

Full Text Available The article is devoted to the problem of developing the competency of teachers of language disciplines on designing multimedia electronic educational resources in the Moodle system. The concept of "the competence of teachers of language disciplines on designing multimedia electronic educational resources in the Moodle system" is justified and defined. Identified and characterized the components by which the levels of the competency development of teachers of language disciplines on designing multimedia electronic educational resources in the Moodle system should be assessed. Developed a model for the development of the competency of teachers of language disciplines on designing multimedia electronic educational resources in the Moodle system, which is based on the main scientific approaches, used in adult education, and consists of five blocks: target, informative, technological, diagnostic and effective.

Developing Humanities Collections in the Digital Age: Exploring Humanities Faculty Engagement with Electronic and Print Resources

Science.gov (United States)

Kachaluba, Sarah Buck; Brady, Jessica Evans; Critten, Jessica

2014-01-01

This article is based on quantitative and qualitative research examining humanities scholars' understandings of the advantages and disadvantages of print versus electronic information resources. It explores how humanities' faculty members at Florida State University (FSU) use print and electronic resources, as well as how they perceive these…

Atomic layer deposition in nanostructured photovoltaics: tuning optical, electronic and surface properties

Science.gov (United States)

Palmstrom, Axel F.; Santra, Pralay K.; Bent, Stacey F.

2015-07-01

Nanostructured materials offer key advantages for third-generation photovoltaics, such as the ability to achieve high optical absorption together with enhanced charge carrier collection using low cost components. However, the extensive interfacial areas in nanostructured photovoltaic devices can cause high recombination rates and a high density of surface electronic states. In this feature article, we provide a brief review of some nanostructured photovoltaic technologies including dye-sensitized, quantum dot sensitized and colloidal quantum dot solar cells. We then introduce the technique of atomic layer deposition (ALD), which is a vapor phase deposition method using a sequence of self-limiting surface reaction steps to grow thin, uniform and conformal films. We discuss how ALD has established itself as a promising tool for addressing different aspects of nanostructured photovoltaics. Examples include the use of ALD to synthesize absorber materials for both quantum dot and plasmonic solar cells, to grow barrier layers for dye and quantum dot sensitized solar cells, and to infiltrate coatings into colloidal quantum dot solar cell to improve charge carrier mobilities as well as stability. We also provide an example of monolayer surface modification in which adsorbed ligand molecules on quantum dots are used to tune the band structure of colloidal quantum dot solar cells for improved charge collection. Finally, we comment on the present challenges and future outlook of the use of ALD for nanostructured photovoltaics.

PERI auto-tuning

Energy Technology Data Exchange (ETDEWEB)

Bailey, D H; Williams, S [Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Chame, J; Chen, C; Hall, M [USC/ISI, Marina del Rey, CA 90292 (United States); Dongarra, J; Moore, S; Seymour, K; You, H [University of Tennessee, Knoxville, TN 37996 (United States); Hollingsworth, J K; Tiwari, A [University of Maryland, College Park, MD 20742 (United States); Hovland, P; Shin, J [Argonne National Laboratory, Argonne, IL 60439 (United States)], E-mail: mhall@isi.edu

2008-07-15

The enormous and growing complexity of today's high-end systems has increased the already significant challenges of obtaining high performance on equally complex scientific applications. Application scientists are faced with a daunting challenge in tuning their codes to exploit performance-enhancing architectural features. The Performance Engineering Research Institute (PERI) is working toward the goal of automating portions of the performance tuning process. This paper describes PERI's overall strategy for auto-tuning tools and recent progress in both building auto-tuning tools and demonstrating their success on kernels, some taken from large-scale applications.

First-principles study of bandgap tuning in Ge1-xPbxSe

Science.gov (United States)

Lohani, Himanshu

2018-03-01

Narrow bandgap and its tuning are important aspects of materials for their technological applications. In this context group IV-VI semiconductors are one of the interesting candidates. In this paper, we explore the possibility of bandgap tuning in one of the family member of this family GeSe by using isoelectronic Pb doping. Our study is first-principles based electronic structure calculations of Ge1-xPbxSe. This study reveals that the Ge-p and Se-p states are strongly hybridized in GeSe and shows a gap in the DOS at Ef in GeSe. This gap reduces systematically with simultaneous enhancement of the states in the near Ef region as a function of Pb doping. This leads tuning of the indirect bandgap in GeSe via Pb doping. The results of the indirect bandgap decrement are consistent with the experimental findings. We propose a mechanism where the electrostatic effect of dopant Pb cation could be responsible for these changes in the electronic structure of GeSe.

Practical tuning for Oracle

International Nuclear Information System (INIS)

Kwon, Sun Yong

2005-02-01

This book deals with tuning for oracle application, which consists of twenty two chapters. These are the contents of this book : what is tuning?, procedure of tuning, collection of performance data using stats pack, collection of performance data in real time, disk IO dispersion, architecture on Index, partition and IOT, optimization of cluster Factor, optimizer, analysis on plan of operation, selection of Index, tuning of Index, parallel processing architecture, DML, analytic function join method, join type, analysis of application, Lock architecture, SGA architecture and wait event and segment tuning.

Long-range electron transfer in porphyrin-containing [2]-rotaxanes: tuning the rate by metal cation coordination.

Science.gov (United States)

Andersson, Mikael; Linke, Myriam; Chambron, Jean-Claude; Davidsson, Jan; Heitz, Valérie; Hammarström, Leif; Sauvage, Jean-Pierre

2002-04-24

A series of [2]-rotaxanes has been synthesized in which two Zn(II)-porphyrins (ZnP) electron donors were attached as stoppers on the rod. A macrocycle attached to a Au(III)-porphyrin (AuP+) acceptor was threaded on the rod. By selective excitation of either porphyrin, we could induce an electron transfer from the ZnP to the AuP+ unit that generated the same ZnP*+-AuP* charge-transfer state irrespective of which porphyrin was excited. Although the reactants were linked only by mechanical or coordination bonds, electron-transfer rate constants up to 1.2x10(10) x s(-1) were obtained over a 15-17 A edge-to-edge distance between the porphyrins. The resulting charge-transfer state had a relatively long lifetime of 10-40 ns and was formed in high yield (>80%) in most cases. By a simple variation of the link between the reactants, viz. a coordination of the phenanthroline units on the rotaxane rod and ring by either Ag+ or Cu+, we could enhance the electron-transfer rate from the ZnP to the excited 3AuP+. We interpret our data in terms of an enhanced superexchange mechanism with Ag+ and a change to a stepwise hopping mechanism with Cu+, involving the oxidized Cu(phen)22+ unit as a real intermediate. When the ZnP unit was excited instead, electron transfer from the excited 1ZnP to AuP+ was not affected, or even slowed, by Ag+ or Cu+. We discuss this asymmetry in terms of the different orbitals involved in mediating the reaction in an electron- and a hole-transfer mechanism. Our results show the possibility to tune the rates of electron transfer between noncovalently linked reactants by a convenient modification of the link. The different effect of Ag+ and Cu+ on the rate with ZnP and AuP+ excitation shows an additional possibility to control the electron-transfer reactions by selective excitation. We also found that coordination of the Cu+ introduced an energy-transfer reaction from 1ZnP to Cu(phen)2+ (k = 5.1x10(9) x s(-1)) that proceeded in competition with electron

Pressure tuning of the optical properties of GaAs nanowires

NARCIS (Netherlands)

Zardo, I.; Yazji, S.; Marini, C.; Uccelli, E.; Morral, A.F.I.; Abstreiter, G.; Postorino, P.

2012-01-01

The tuning of the optical and electronic properties of semiconductor nanowires can be achieved by crystal phase engineering. Zinc-blende and diamond semiconductors exhibit pressure-induced structural transitions as well as a strong pressure dependence of the band gaps. When reduced to nanoscale

A Caveat Note on Tuning in the Development of Coupled Climate Models

Science.gov (United States)

Dommenget, Dietmar; Rezny, Michael

2018-01-01

State-of-the-art coupled general circulation models (CGCMs) have substantial errors in their simulations of climate. In particular, these errors can lead to large uncertainties in the simulated climate response (both globally and regionally) to a doubling of CO2. Currently, tuning of the parameterization schemes in CGCMs is a significant part of the developed. It is not clear whether such tuning actually improves models. The tuning process is (in general) neither documented, nor reproducible. Alternative methods such as flux correcting are not used nor is it clear if such methods would perform better. In this study, ensembles of perturbed physics experiments are performed with the Globally Resolved Energy Balance (GREB) model to test the impact of tuning. The work illustrates that tuning has, in average, limited skill given the complexity of the system, the limited computing resources, and the limited observations to optimize parameters. While tuning may improve model performance (such as reproducing observed past climate), it will not get closer to the "true" physics nor will it significantly improve future climate change projections. Tuning will introduce artificial compensating error interactions between submodels that will hamper further model development. In turn, flux corrections do perform well in most, but not all aspects. A main advantage of flux correction is that it is much cheaper, simpler, more transparent, and it does not introduce artificial error interactions between submodels. These GREB model experiments should be considered as a pilot study to motivate further CGCM studies that address the issues of model tuning.

Design and construction of cavity frequency measurement and tuning systems of traveling wave electron linear accelerator

Directory of Open Access Journals (Sweden)

S Ahmadiannamin

2017-08-01

Full Text Available The main purpose for designing and constructing electroradio frequency linear accelerators is to reach better beam quality with higher power and energy by lower RF power consumption. The main step for this purpose is doing research and development in the area of designing, constructing, measuring and tuning of accelerator RF cavities. Institute for Research in Fundamental Sciences (IPM linear accelerator projecta is the first Iranian project for construction of electrolinear accelerator. In this paper, a brief introduction to construction procedure has been given. Then, the measurement and tuning of a disk-loaded periodic structure before and after tuning was reported. In addition, the detailed design and measurement setup for electric field measurement by perturbation method was investigated  

Electronic resource management systems a workflow approach

CERN Document Server

Anderson, Elsa K

2014-01-01

To get to the bottom of a successful approach to Electronic Resource Management (ERM), Anderson interviewed staff at 11 institutions about their ERM implementations. Among her conclusions, presented in this issue of Library Technology Reports, is that grasping the intricacies of your workflow-analyzing each step to reveal the gaps and problems-at the beginning is crucial to selecting and implementing an ERM. Whether the system will be used to fill a gap, aggregate critical data, or replace a tedious manual process, the best solution for your library depends on factors such as your current soft

Electronic Resource Management System. Vernetzung von Lizenzinformationen

Directory of Open Access Journals (Sweden)

Michaela Selbach

2014-12-01

Full Text Available In den letzten zehn Jahren spielen elektronische Ressourcen im Bereich der Erwerbung eine zunehmend wichtige Rolle: Eindeutig lässt sich hier ein Wandel in den Bibliotheken (fort vom reinen Printbestand zu immer größeren E-Only-Beständen feststellen. Die stetig wachsende Menge an E-Ressourcen und deren Heterogenität stellt Bibliotheken vor die Herausforderung, die E-Ressourcen effizient zu verwalten. Nicht nur Bibliotheken, sondern auch verhandlungsführende Institutionen von Konsortial- und Allianzlizenzen benötigen ein geeignetes Instrument zur Verwaltung von Lizenzinformationen, welches den komplexen Anforderungen moderner E-Ressourcen gerecht wird. Die Deutsche Forschungsgemeinschaft (DFG unterstützt ein Projekt des Hochschulbibliothekszentrums des Landes Nordrhein-Westfalen (hbz, der Universitätsbibliothek Freiburg, der Verbundzentrale des Gemeinsamen Bibliotheksverbundes (GBV und der Universitätsbibliothek Frankfurt, in dem ein bundesweit verfügbares Electronic Ressource Managementsystem (ERMS aufgebaut werden soll. Ein solches ERMS soll auf Basis einer zentralen Knowledge Base eine einheitliche Nutzung von Daten zur Lizenzverwaltung elektronischer Ressourcen auf lokaler, regionaler und nationaler Ebene ermöglichen. Statistische Auswertungen, Rechteverwaltung für alle angeschlossenen Bibliotheken, kooperative Datenpflege sowie ein über standardisierte Schnittstellen geführter Datenaustausch stehen bei der Erarbeitung der Anforderungen ebenso im Fokus wie die Entwicklung eines Daten- und Funktionsmodells. In the last few years the importance of electronic resources in library acquisitions has increased significantly. There has been a shift from mere print holdings to both e- and print combinations and even e-only subscriptions. This shift poses a double challenge for libraries: On the one hand they have to provide their e-resource collections to library users in an appealing way, on the other hand they have to manage these

The Electron Microscopy Outreach Program: A Web-based resource for research and education.

Science.gov (United States)

Sosinsky, G E; Baker, T S; Hand, G; Ellisman, M H

1999-01-01

We have developed a centralized World Wide Web (WWW)-based environment that serves as a resource of software tools and expertise for biological electron microscopy. A major focus is molecular electron microscopy, but the site also includes information and links on structural biology at all levels of resolution. This site serves to help integrate or link structural biology techniques in accordance with user needs. The WWW site, called the Electron Microscopy (EM) Outreach Program (URL: http://emoutreach.sdsc.edu), provides scientists with computational and educational tools for their research and edification. In particular, we have set up a centralized resource containing course notes, references, and links to image analysis and three-dimensional reconstruction software for investigators wanting to learn about EM techniques either within or outside of their fields of expertise. Copyright 1999 Academic Press.

Technical Communicator: A New Model for the Electronic Resources Librarian?

Science.gov (United States)

Hulseberg, Anna

2016-01-01

This article explores whether technical communicator is a useful model for electronic resources (ER) librarians. The fields of ER librarianship and technical communication (TC) originated and continue to develop in relation to evolving technologies. A review of the literature reveals four common themes for ER librarianship and TC. While the…

Tuning the electronic properties by width and length modifications of narrow-diameter carbon nanotubes for nanomedicine

KAUST Repository

Poater, Albert; Saliner, Ana Gallegos; Cavallo, Luigi; Poch, Manel P.; Solà , Miquel; Worth, Andrew P.

2012-01-01

The distinctive characteristics of nanoparticles, resulting from properties that arise at the nano-scale, underlie their potential applications in the biomedical sector. However, the very same characteristics also result in widespread concerns about the potentially toxic effects of nanoparticles. Given the large number of nanoparticles that are being developed for possible biomedical use, there is a need to develop rapid screening methods based on in silico methods. This study illustrates the application of conceptual Density Functional Theory (DFT) to some carbon nanotubes (CNTs) optimized by means of static DFT calculations. The computational efforts are focused on the geometry of a family of packed narrow-diameter carbon nanotubes (CNTs) formed by units from four to twelve carbons evaluating the strength of the C-C bonds by means of Mayer Bond Orders (MBO). Thus, width and length are geometrical features that might be used to tune the electronic properties of the CNTs. At infinite length, partial semi-conductor characteristics are expected. © 2012 Bentham Science Publishers.

Tuning the electronic properties by width and length modifications of narrow-diameter carbon nanotubes for nanomedicine

KAUST Repository

Poater, Albert

2012-10-01

The distinctive characteristics of nanoparticles, resulting from properties that arise at the nano-scale, underlie their potential applications in the biomedical sector. However, the very same characteristics also result in widespread concerns about the potentially toxic effects of nanoparticles. Given the large number of nanoparticles that are being developed for possible biomedical use, there is a need to develop rapid screening methods based on in silico methods. This study illustrates the application of conceptual Density Functional Theory (DFT) to some carbon nanotubes (CNTs) optimized by means of static DFT calculations. The computational efforts are focused on the geometry of a family of packed narrow-diameter carbon nanotubes (CNTs) formed by units from four to twelve carbons evaluating the strength of the C-C bonds by means of Mayer Bond Orders (MBO). Thus, width and length are geometrical features that might be used to tune the electronic properties of the CNTs. At infinite length, partial semi-conductor characteristics are expected. © 2012 Bentham Science Publishers.

SQL Tuning

CERN Document Server

Tow, Dan

2003-01-01

A poorly performing database application not only costs users time, but also has an impact on other applications running on the same computer or the same network. SQL Tuning provides an essential next step for SQL developers and database administrators who want to extend their SQL tuning expertise and get the most from their database applications.There are two basic issues to focus on when tuning SQL: how to find and interpret the execution plan of an SQL statement and how to change SQL to get a specific alternate execution plan. SQL Tuning provides answers to these questions and addresses a third issue that's even more important: how to find the optimal execution plan for the query to use.Author Dan Tow outlines a timesaving method he's developed for finding the optimum execution plan--rapidly and systematically--regardless of the complexity of the SQL or the database platform being used. You'll learn how to understand and control SQL execution plans and how to diagram SQL queries to deduce the best executio...

Ionization Energies, Electron Affinities, and Polarization Energies of Organic Molecular Crystals: Quantitative Estimations from a Polarizable Continuum Model (PCM)–Tuned Range-Separated Density Functional Approach

KAUST Repository

Sun, Haitao

2016-05-16

We propose a new methodology for the first-principles description of the electronic properties relevant for charge transport in organic molecular crystals. This methodology, which is based on the combination of a non-empirical, optimally tuned range-separated hybrid functional with the polarizable continuum model, is applied to a series of eight representative molecular semiconductor crystals. We show that it provides ionization energies, electron affinities, and transport gaps in very good agreement with experimental values as well as with the results of many-body perturbation theory within the GW approximation at a fraction of the computational costs. Hence, this approach represents an easily applicable and computationally efficient tool to estimate the gas-to-crystal-phase shifts of the frontier-orbital quasiparticle energies in organic electronic materials.

Electronic energy transfer through non-adiabatic vibrational-electronic resonance. I. Theory for a dimer

Science.gov (United States)

Tiwari, Vivek; Peters, William K.; Jonas, David M.

2017-10-01

Non-adiabatic vibrational-electronic resonance in the excited electronic states of natural photosynthetic antennas drastically alters the adiabatic framework, in which electronic energy transfer has been conventionally studied, and suggests the possibility of exploiting non-adiabatic dynamics for directed energy transfer. Here, a generalized dimer model incorporates asymmetries between pigments, coupling to the environment, and the doubly excited state relevant for nonlinear spectroscopy. For this generalized dimer model, the vibrational tuning vector that drives energy transfer is derived and connected to decoherence between singly excited states. A correlation vector is connected to decoherence between the ground state and the doubly excited state. Optical decoherence between the ground and singly excited states involves linear combinations of the correlation and tuning vectors. Excitonic coupling modifies the tuning vector. The correlation and tuning vectors are not always orthogonal, and both can be asymmetric under pigment exchange, which affects energy transfer. For equal pigment vibrational frequencies, the nonadiabatic tuning vector becomes an anti-correlated delocalized linear combination of intramolecular vibrations of the two pigments, and the nonadiabatic energy transfer dynamics become separable. With exchange symmetry, the correlation and tuning vectors become delocalized intramolecular vibrations that are symmetric and antisymmetric under pigment exchange. Diabatic criteria for vibrational-excitonic resonance demonstrate that anti-correlated vibrations increase the range and speed of vibronically resonant energy transfer (the Golden Rule rate is a factor of 2 faster). A partial trace analysis shows that vibronic decoherence for a vibrational-excitonic resonance between two excitons is slower than their purely excitonic decoherence.

MODEL OF AN ELECTRONIC EDUCATIONAL RESOURCE OF NEW GENERATION

Directory of Open Access Journals (Sweden)

Anatoliy V. Loban

2016-01-01

Full Text Available The mathematical structure of the modular architecture of an electronic educational resource (EER of new generation, which allows to decompose the process of studying the subjects of the course at a hierarchically ordered set of data (knowledge and procedures for manipulating them, to determine the roles of participants of process of training of and technology the development and use of EOR in the study procrate.

Kaxiras’s Porphyrin: DFT Modeling of Redox-Tuned Optical and Electronic Properties in a Theoretically Designed Catechol-Based Bioinspired Platform

Directory of Open Access Journals (Sweden)

Orlando Crescenzi

2017-11-01

Full Text Available A detailed computational investigation of the 5,6-dihydroxyindole (DHI-based porphyrin-type tetramer first described by Kaxiras as a theoretical structural model for eumelanin biopolymers is reported herein, with a view to predicting the technological potential of this unique bioinspired tetracatechol system. All possible tautomers/conformers, as well as alternative protonation states, were explored for the species at various degrees of oxidation and all structures were geometry optimized at the density functional theory (DFT level. Comparison of energy levels for each oxidized species indicated a marked instability of most oxidation states except the six-electron level, and an unexpected resilience to disproportionation of the one-electron oxidation free radical species. Changes in the highest energy occupied molecular orbital (HOMO–lowest energy unoccupied molecular orbital (LUMO gaps with oxidation state and tautomerism were determined along with the main electronic transitions: more or less intense absorption in the visible region is predicted for most oxidized species. Data indicated that the peculiar symmetry of the oxygenation pattern pertaining to the four catechol/quinone/quinone methide moieties, in concert with the NH centers, fine-tunes the optical and electronic properties of the porphyrin system. For several oxidation levels, conjugated systems extending over two or more indole units play a major role in determining the preferred tautomeric state: thus, the highest stability of the six-electron oxidation state reflects porphyrin-type aromaticity. These results provide new clues for the design of innovative bioinspired optoelectronic materials.

Electronically tuned sulfonamide-based probes with ultra-sensitivity for Ga{sup 3+} or Al{sup 3+} detection in aqueous solution

Energy Technology Data Exchange (ETDEWEB)

Kumar, Ashwani, E-mail: ashwanirubal@gmail.com; Chae, Pil Seok, E-mail: pchae@hanyang.ac.kr

2017-03-15

Three electronically tuned fluorescent probes (1–3) were synthesized by conjugating a fluorescent unit to N,N-bis-(hydroxyethyl)ethylenediamine. Probe 1 bearing an electron-deficient naphthalenedimide unit did not give a fluorescence response to the presence of various metal ions including monovalent metal ions (Na{sup +}, K{sup +}, and Ag{sup +}), divalent metal ions (Ca{sup 2+}, Cd{sup 2+}, Co{sup 2+}, Ni{sup 2+}, Cu{sup 2+}, Hg{sup 2+}, Pb{sup 2+}, and Zn{sup 2+}) and trivalent metal ions (Al{sup 3+}, Ga{sup 3+}, Fe{sup 3+}, and Cr{sup 3+}) in an aqueous solution. By contrast, probes 2 and 3 possessing 1,8-naphthalimide and pyrene fluorophores, respectively, exhibited selective fluorescent “OFF-ON” behaviors as a result of Ga{sup 3+}/Al{sup 3+} binding among the diverse metal ions, suggesting the importance of fluorophore electronic character with regard to metal ion sensing. The ethylenediamine analog of probe 3, corresponding to probe 4, was unable to yield a significant change in fluorescence intensity in the presence of any metal ions tested here, revealing the essential role of two hydroxyl groups for metal ion binding. A high association constant of K{sub a} = 2.99 × 10{sup 5} M{sup −1} was obtained for probe 3 with Ga{sup 3+}, with a limit of detection (LOD) of 10 nM. This LOD is the lowest value known for Ga{sup 3+} detection using chemical sensors. Along with an increase in aggregate sizes, PET suppression of probes upon metal ion binding was the primary contributor to the enhancement in fluorescence emission necessary for the sensitive detection of the target ions. The probe-metal ion complexes were fully characterized via TEM, FE-SEM, {sup 1}H NMR, fluorescence spectroscopy techniques and DFT calculations. - Highlights: • Three electronically tuned sulfonamide-based probes (probes 1, 2, and 3) were developed for metal ion-sensing. • Probes 2 and 3 exhibited AIE behavior with increasing water-content. • Probes 2 and 3 displayed a

Analysis of the tuning characteristics of microwave plasma source

International Nuclear Information System (INIS)

Miotk, Robert; Jasiński, Mariusz; Mizeraczyk, Jerzy

2016-01-01

In this paper, we present an analysis of the tuning characteristics of waveguide-supplied metal-cylinder-based nozzleless microwave plasma source. This analysis has enabled to estimate the electron concentration n_e and electron frequency collisions ν in the plasma generated in nitrogen and in a mixture of nitrogen and ethanol vapour. The parameters n_e and ν are the basic quantities that characterize the plasma. The presented new plasma diagnostic method is particularly useful, when spectroscopic methods are useless. The presented plasma source is currently used in research of a hydrogen production from liquids.

Electronic tuning of the transport properties of off-stoichiometric Pb{sub x}Sn{sub 1−x}Te thermoelectric alloys by Bi{sub 2}Te{sub 3} doping

Energy Technology Data Exchange (ETDEWEB)

Guttmann, Gilad M. [The Unit of Energy Engineering, Ben-Gurion University of the Negev, Beer-Sheva (Israel); Dadon, David [Department of Materials Engineering, Ben-Gurion University of the Negev, Beer-Sheva (Israel); Gelbstein, Yaniv [The Unit of Energy Engineering, Ben-Gurion University of the Negev, Beer-Sheva (Israel); Department of Materials Engineering, Ben-Gurion University of the Negev, Beer-Sheva (Israel)

2015-08-14

The recent energy demands affected by the dilution of conventional energy resources and the growing awareness of environmental considerations had motivated many researchers to seek for novel renewable energy conversion methods. Thermoelectric direct conversion of thermal into electrical energies is such a method, in which common compositions include IV-VI semiconducting compounds (e.g., PbTe and SnTe) and their alloys. For approaching practical thermoelectric devices, the current research is focused on electronic optimization of off-stoichiometric p-type Pb{sub x}Sn{sub 1−x}Te alloys by tuning of Bi{sub 2}Te{sub 3} doping and/or SnTe alloying levels, while avoiding the less mechanically favorable Na dopant. It was shown that upon such doping/alloying, higher ZTs, compared to those of previously reported undoped Pb{sub 0.5}Sn{sub 0.5}Te alloy, were obtained at temperatures lower than 210–340 °C, depending of the exact doping/alloying level. It was demonstrated that upon optimal grading of the carrier concentration, a maximal thermoelectric efficiency enhancement of ∼38%, compared to that of an undoped material, is expected.

iTunes music

CERN Document Server

Katz, Bob

2013-01-01

Apple's exciting new Mastered for iTunes (MFiT) initiative, introduced in early 2012, introduces new possibilities for delivering high-quality audio. For the first time, record labels and program producers are encouraged to deliver audio materials to iTunes in a high resolution format, which can produce better-sounding masters. In iTunes Music, author and world-class mastering engineer Bob Katz starts out with the basics, surveys the recent past, and brings you quickly up to the present-where the current state of digital audio is bleak. Katz explains the evolution of

Towards an Automatic Parameter-Tuning Framework for Cost Optimization on Video Encoding Cloud

Directory of Open Access Journals (Sweden)

Xiaowei Li

2012-01-01

Full Text Available The emergence of cloud encoding services facilitates many content owners, such as the online video vendors, to transcode their digital videos without infrastructure setup. Such service provider charges the customers only based on their resource consumption. For both the service provider and customers, lowering the resource consumption while maintaining the quality is valuable and desirable. Thus, to choose a cost-effective encoding parameter, configuration is essential and challenging due to the tradeoff between bitrate, encoding speed, and resulting quality. In this paper, we explore the feasibility of an automatic parameter-tuning framework, based on which the above objective can be achieved. We introduce a simple service model, which combines the bitrate and encoding speed into a single value: encoding cost. Then, we conduct an empirical study to examine the relationship between the encoding cost and various parameter settings. Our experiment is based on the one-pass Constant Rate Factor method in x264, which can achieve relatively stable perceptive quality, and we vary each parameter we choose to observe how the encoding cost changes. The experiment results show that the tested parameters can be independently tuned to minimize the encoding cost, which makes the automatic parameter-tuning framework feasible and promising for optimizing the cost on video encoding cloud.

Low-emittance tuning of storage rings using normal mode beam position monitor calibration

Science.gov (United States)

Wolski, A.; Rubin, D.; Sagan, D.; Shanks, J.

2011-07-01

We describe a new technique for low-emittance tuning of electron and positron storage rings. This technique is based on calibration of the beam position monitors (BPMs) using excitation of the normal modes of the beam motion, and has benefits over conventional methods. It is relatively fast and straightforward to apply, it can be as easily applied to a large ring as to a small ring, and the tuning for low emittance becomes completely insensitive to BPM gain and alignment errors that can be difficult to determine accurately. We discuss the theory behind the technique, present some simulation results illustrating that it is highly effective and robust for low-emittance tuning, and describe the results of some initial experimental tests on the CesrTA storage ring.

Uranium resource processing. Secondary resources

International Nuclear Information System (INIS)

Gupta, C.K.; Singh, H.

2003-01-01

This book concentrates on the processing of secondary sources for recovering uranium, a field which has gained in importance in recent years as it is environmental-friendly and economically in tune with the philosophy of sustainable development. Special mention is made of rock phosphate, copper and gold tailings, uranium scrap materials (both natural and enriched) and sea water. This volume includes related area of ore mineralogy, resource classification, processing principles involved in solubilization followed by separation and safety aspects

Java performance tuning

CERN Document Server

Shirazi, Jack

2003-01-01

Performance has been an important issue for Java developers ever since the first version hit the streets. Over the years, Java performance has improved dramatically, but tuning is essential to get the best results, especially for J2EE applications. You can never have code that runs too fast. Java Peformance Tuning, 2nd edition provides a comprehensive and indispensable guide to eliminating all types of performance problems. Using many real-life examples to work through the tuning process in detail, JPT shows how tricks such as minimizing object creation and replacing strings with arrays can

An Auto Tuning Substation Peak Shaving Controller for Congestion Management Using Flexible Demand

DEFF Research Database (Denmark)

Sossan, Fabrizio; Marinelli, Mattia

2013-01-01

A closed loop substation peak shaving/congestion management controller for radial distribution networks is presented. The controller it uses an individual control signal in order to shift the consumption of a population of demand side resources, DSRs. The controller auto tunes its parameters on...

Remote tuning of NMR probe circuits.

Science.gov (United States)

Kodibagkar, V D; Conradi, M S

2000-05-01

There are many circumstances in which the probe tuning adjustments cannot be located near the rf NMR coil. These may occur in high-temperature NMR, low-temperature NMR, and in the use of magnets with small diameter access bores. We address here circuitry for connecting a fixed-tuned probe circuit by a transmission line to a remotely located tuning network. In particular, the bandwidth over which the probe may be remotely tuned while keeping the losses in the transmission line acceptably low is considered. The results show that for all resonant circuit geometries (series, parallel, series-parallel), overcoupling of the line to the tuned circuit is key to obtaining a large tuning bandwidth. At equivalent extents of overcoupling, all resonant circuit geometries have nearly equal remote tuning bandwidths. Particularly for the case of low-loss transmission line, the tuning bandwidth can be many times the tuned circuit's bandwidth, f(o)/Q. Copyright 2000 Academic Press.

Pair-Wise and Many-Body Dispersive Interactions Coupled to an Optimally Tuned Range-Separated Hybrid Functional.

Science.gov (United States)

Agrawal, Piyush; Tkatchenko, Alexandre; Kronik, Leeor

2013-08-13

We propose a nonempirical, pair-wise or many-body dispersion-corrected, optimally tuned range-separated hybrid functional. This functional retains the advantages of the optimal-tuning approach in the prediction of the electronic structure. At the same time, it gains accuracy in the prediction of binding energies for dispersively bound systems, as demonstrated on the S22 and S66 benchmark sets of weakly bound dimers.

GUIDELINES FOR EVALUATION OF PSYCHOLOGICAL AND PEDAGOGICAL QUALITY CHARACTERISTICS OF ELECTRONIC EDUCATIONAL RESOURCES

Directory of Open Access Journals (Sweden)

Galina P. Lavrentieva

2014-05-01

Full Text Available The article highlights the causes of insufficient effective use of electronic learning resources and sets out the guidelines on ways to solve the aforementioned problems. The set of didactic, methodical, psychological, pedagogical, design and ergonomic quality requirements is considered for evaluation, selection and application of information and communication technologies in the educational process. The most appropriate mechanisms for the ICT introduction into the learning process are disclosed as it should meet the specific learning needs of the student and the objectives of the educational process. The guidance for psycho-educational assessment of quality of electronic educational resources is provided. It is argued that the effectiveness of the ICT use is to be improved by means of quality evaluation mechanisms involved into the educational process.

Analysis of the tuning characteristics of microwave plasma source

Energy Technology Data Exchange (ETDEWEB)

Miotk, Robert, E-mail: rmiotk@imp.gda.pl; Jasiński, Mariusz [Centre for Plasma and Laser Engineering, The Szewalski Institute of Fluid-Flow Machinery, Polish Academy of Sciences, Fiszera 14, 80-231 Gdańsk (Poland); Mizeraczyk, Jerzy [Department of Marine Electronics, Gdynia Maritime University, Morska 81-87, 81-225 Gdynia (Poland)

2016-04-15

In this paper, we present an analysis of the tuning characteristics of waveguide-supplied metal-cylinder-based nozzleless microwave plasma source. This analysis has enabled to estimate the electron concentration n{sub e} and electron frequency collisions ν in the plasma generated in nitrogen and in a mixture of nitrogen and ethanol vapour. The parameters n{sub e} and ν are the basic quantities that characterize the plasma. The presented new plasma diagnostic method is particularly useful, when spectroscopic methods are useless. The presented plasma source is currently used in research of a hydrogen production from liquids.

Availability, Use and Constraints to Use of Electronic Information Resources by Postgraduates Students at the University of Ibadan

Directory of Open Access Journals (Sweden)

Dare Samuel Adeleke

2017-12-01

Full Text Available Availability, awareness and use of electronic resources provide access to authoritative, reliable, accurate and timely access to information. The use of electronic information resources (EIRs can enable innovation in teaching and increase timeliness in research of postgraduate students which will eventual result into encouragement of the expected research-led enquiry in this digital age. The study adopted a descriptive survey design. Samples of 300 of postgraduate students within seven out 13 Faculties were randomly selected. Data were collected using questionnaire designed to elicit response from respondents and data were analyzed using descriptive statistics methods percentages, mean, and standard deviation. Results indicated that internet was ranked most available and used in the university. Low level of usage of electronic resources, in particular, full texts data bases is linked to a number of constraints: Interrupted power supply was ranked highest among other factors as speed and capacity of computers, retrieval of records with high recall and low precision, retrieving records relevant to information need, lack of knowledge of search techniques to retrieve information effectively, non possession of requisite IT skills and problems accessing the internet. The study recommended that usage of electronic resources be made compulsory, intensifying awareness campaigns concerning the availability, training on use of electronic resources and the problem of power outage be addressed.

A Study on Developing Evaluation Criteria for Electronic Resources in Evaluation Indicators of Libraries

Science.gov (United States)

Noh, Younghee

2010-01-01

This study aimed to improve the current state of electronic resource evaluation in libraries. While the use of Web DB, e-book, e-journal, and other e-resources such as CD-ROM, DVD, and micro materials is increasing in libraries, their use is not comprehensively factored into the general evaluation of libraries and may diminish the reliability of…

Low-emittance tuning of storage rings using normal mode beam position monitor calibration

Directory of Open Access Journals (Sweden)

A. Wolski

2011-07-01

Full Text Available We describe a new technique for low-emittance tuning of electron and positron storage rings. This technique is based on calibration of the beam position monitors (BPMs using excitation of the normal modes of the beam motion, and has benefits over conventional methods. It is relatively fast and straightforward to apply, it can be as easily applied to a large ring as to a small ring, and the tuning for low emittance becomes completely insensitive to BPM gain and alignment errors that can be difficult to determine accurately. We discuss the theory behind the technique, present some simulation results illustrating that it is highly effective and robust for low-emittance tuning, and describe the results of some initial experimental tests on the CesrTA storage ring.

Measure Guideline. Steam System Balancing and Tuning for Multifamily Residential Buildings

Energy Technology Data Exchange (ETDEWEB)

Choi, Jayne [Partnership for Advanced Residential Retrofit (PARR), Chicago, IL (United States); Ludwig, Peter [Partnership for Advanced Residential Retrofit (PARR), Chicago, IL (United States); Brand, Larry [Partnership for Advanced Residential Retrofit (PARR), Chicago, IL (United States)

2013-04-01

This guideline provides building owners, professionals involved in multifamily audits, and contractors insights for improving the balance and tuning of steam systems. It provides readers an overview of one-pipe steam heating systems, guidelines for evaluating steam systems, typical costs and savings, and guidelines for ensuring quality installations. It also directs readers to additional resources for details not included here. Measures for balancing a distribution system that are covered include replacing main line vents and upgrading radiator vents. Also included is a discussion on upgrading boiler controls and the importance of tuning the settings on new or existing boiler controls. The guideline focuses on one-pipe steam systems, though many of the assessment methods can be generalized to two-pipe steam systems.

Tuning the cathodoluminescence of porous silicon films

International Nuclear Information System (INIS)

Biaggi-Labiosa, A.; Fonseca, L.F.; Resto, O.; Balberg, I.

2008-01-01

We have obtained intense cathodoluminescence (CL) emission from electron beam modified porous silicon films by excitation with electrons with kinetic energies below 2 keV. Two types of CL emissions were observed, a stable one and a non-stable one. The first type is obtained in well-oxidized samples and is characterized by a spectral peak that is red shifted with respect to the photoluminescence (PL) peak. The physically interesting and technologically promising CL is however the CL that correlates closely with the PL. Tuning of this CL emission was achieved by controlling the average size of the nanostructure thus showing that the origin of this CL emission is associated with the quantum confinement and the surface chemistry effects that are known to exist in the porous silicon system. We also found that the electron bombardment causes microscale morphological modifications of the films, but the nanoscale features appear to be unchanged. The structural changes are manifested by the increase in the density of the nanoparticles which explains the significant enhancement of the PL that follows the electron irradiation

Design, construction and tuning of S-band coupler for electron linear accelerator of institute for research in fundamental sciences (IPM E-linac)

International Nuclear Information System (INIS)

Ghasemi, F.; Abbasi Davani, F.; Lamehi Rachti, M.; Shaker, H.; Ahmadiannamin, S.

2015-01-01

Design and construction of an electron linear accelerator by Institute for Research in Fundamental Science (IPM) is considered as Iran’s first attempt to construct such an accelerator. In order to design a linear accelerating tube, after defining the accelerating tube and buncher geometries, RF input and output couplers must be designed. In this article, firstly, a brief report on the specifications of an S-band electron linear accelerator which is in progress in the school of particles and accelerators is presented and then, the design process and construction reports of the couplers required for this accelerator are described. Through performing necessary calculations and tuning the coupling factor and resonant frequency, couplers with desired specification have been fabricated by shrinking method. The final obtained coupling factor and resonant frequency have been respectively 1.05 and 2997 MHz for the first coupler, and 0.98 and 2996.9 MHz for the second one that are close to calculation results

Tuning the band gap of silicene by functionalisation with naphthyl and anthracyl groups

Energy Technology Data Exchange (ETDEWEB)

Brennan, Mathew D.; Spencer, Michelle J. S., E-mail: t-morishita@aist.go.jp, E-mail: michelle.spencer@rmit.edu.au [School of Science, RMIT University, GPO Box 2476, Melbourne, Victoria 3001 (Australia); Morishita, Tetsuya, E-mail: t-morishita@aist.go.jp, E-mail: michelle.spencer@rmit.edu.au [Research Center for Computational Design of Advanced Functional Materials, National Institute of Advanced Industrial Science and Technology (AIST), Central 2, 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568 (Japan)

2016-03-21

Silicene is a relatively new material consisting of a two-dimensional sheet of silicon atoms. Functionalisation of silicene with different chemical groups has been suggested as a way to tune its electronic properties. In this work, density functional theory calculations and ab initio molecular dynamics simulations are used to examine the effects of functionalisation with naphthyl or anthracyl groups, which are two examples of small polycyclic aromatic hydrocarbons (PAHs). Different attachment positions on the naphthyl and anthracyl groups were compared, as well as different thicknesses of the silicene nanosheet. It was found that the carbon attachment position farthest from the bond fusing the aromatic rings gave the more stable structures for both functional groups. All structures showed direct band gaps, with tuning of the band gap being achievable by increasing the length of the PAH or the thickness of the silicene. Hence, modifying the functional group or thickness of the silicene can both be used to alter the electronic properties of silicene making it a highly promising material for use in future electronic devices and sensors.

Simultaneous gains tuning in boiler/turbine PID-based controller clusters using iterative feedback tuning methodology.

Science.gov (United States)

Zhang, Shu; Taft, Cyrus W; Bentsman, Joseph; Hussey, Aaron; Petrus, Bryan

2012-09-01

Tuning a complex multi-loop PID based control system requires considerable experience. In today's power industry the number of available qualified tuners is dwindling and there is a great need for better tuning tools to maintain and improve the performance of complex multivariable processes. Multi-loop PID tuning is the procedure for the online tuning of a cluster of PID controllers operating in a closed loop with a multivariable process. This paper presents the first application of the simultaneous tuning technique to the multi-input-multi-output (MIMO) PID based nonlinear controller in the power plant control context, with the closed-loop system consisting of a MIMO nonlinear boiler/turbine model and a nonlinear cluster of six PID-type controllers. Although simplified, the dynamics and cross-coupling of the process and the PID cluster are similar to those used in a real power plant. The particular technique selected, iterative feedback tuning (IFT), utilizes the linearized version of the PID cluster for signal conditioning, but the data collection and tuning is carried out on the full nonlinear closed-loop system. Based on the figure of merit for the control system performance, the IFT is shown to deliver performance favorably comparable to that attained through the empirical tuning carried out by an experienced control engineer. Copyright © 2012 ISA. Published by Elsevier Ltd. All rights reserved.

THE MODEL OF LINGUISTIC TEACHERS’ COMPETENCY DEVELOPMENT ON DESIGNING MULTIMEDIA ELECTRONIC EDUCATIONAL RESOURCES IN THE MOODLE SYSTEM

OpenAIRE

Anton M. Avramchuk

2017-01-01

The article is devoted to the problem of developing the competency of teachers of language disciplines on designing multimedia electronic educational resources in the Moodle system. The concept of "the competence of teachers of language disciplines on designing multimedia electronic educational resources in the Moodle system" is justified and defined. Identified and characterized the components by which the levels of the competency development of teachers of language disciplines on designing ...

Adaptive Self-Tuning Networks

Science.gov (United States)

Knox, H. A.; Draelos, T.; Young, C. J.; Lawry, B.; Chael, E. P.; Faust, A.; Peterson, M. G.

2015-12-01

The quality of automatic detections from seismic sensor networks depends on a large number of data processing parameters that interact in complex ways. The largely manual process of identifying effective parameters is painstaking and does not guarantee that the resulting controls are the optimal configuration settings. Yet, achieving superior automatic detection of seismic events is closely related to these parameters. We present an automated sensor tuning (AST) system that learns near-optimal parameter settings for each event type using neuro-dynamic programming (reinforcement learning) trained with historic data. AST learns to test the raw signal against all event-settings and automatically self-tunes to an emerging event in real-time. The overall goal is to reduce the number of missed legitimate event detections and the number of false event detections. Reducing false alarms early in the seismic pipeline processing will have a significant impact on this goal. Applicable both for existing sensor performance boosting and new sensor deployment, this system provides an important new method to automatically tune complex remote sensing systems. Systems tuned in this way will achieve better performance than is currently possible by manual tuning, and with much less time and effort devoted to the tuning process. With ground truth on detections in seismic waveforms from a network of stations, we show that AST increases the probability of detection while decreasing false alarms.

Determining the level of awareness of the physicians in using the variety of electronic information resources and the effecting factors.

Science.gov (United States)

Papi, Ahmad; Ghazavi, Roghayeh; Moradi, Salimeh

2015-01-01

Understanding of the medical society's from the types of information resources for quick and easy access to information is an imperative task in medical researches and management of the treatment. The present study was aimed to determine the level of awareness of the physicians in using various electronic information resources and the factors affecting it. This study was a descriptive survey. The data collection tool was a researcher-made questionnaire. The study population included all the physicians and specialty physicians of the teaching hospitals affiliated to Isfahan University of Medical Sciences and numbered 350. The sample size based on Morgan's formula was set at 180. The content validity of the tool was confirmed by the library and information professionals and the reliability was 95%. Descriptive statistics were used including the SPSS software version 19. On reviewing the need of the physicians to obtain the information on several occasions, the need for information in conducting the researches was reported by the maximum number of physicians (91.9%) and the usage of information resources, especially the electronic resources, formed 65.4% as the highest rate with regard to meeting the information needs of the physicians. Among the electronic information databases, the maximum awareness was related to Medline with 86.5%. Among the various electronic information resources, the highest awareness (43.3%) was related to the E-journals. The highest usage (36%) was also from the same source. The studied physicians considered the most effective deterrent in the use of electronic information resources as being too busy and lack of time. Despite the importance of electronic information resources for the physician's community, there was no comprehensive knowledge of these resources. This can lead to less usage of these resources. Therefore, careful planning is necessary in the hospital libraries in order to introduce the facilities and full capabilities of the

Managing Selection for Electronic Resources: Kent State University Develops a New System to Automate Selection

Science.gov (United States)

Downey, Kay

2012-01-01

Kent State University has developed a centralized system that manages the communication and work related to the review and selection of commercially available electronic resources. It is an automated system that tracks the review process, provides selectors with price and trial information, and compiles reviewers' feedback about the resource. It…

The ATLAS Monte Carlo tuning system

CERN Document Server

Wahrmund, S

2012-01-01

The ATLAS experiment moved the tuning of the underlying event and minimum bias event shape modeling, previously done in a manual fashion, to the automated Professor tuning tool, employed in connection with the Rivet analysis framework, when the first corresponding experimental analysis from LHC became available. The tuning effort for the Pythia 8 generator, which includes improved models for diffraction, has been started in this automated way in ATLAS, with the aim of getting a good description of the pile-up generated by multiple minimum bias interactions. The first results for these Pythia 8 tunes, as well as Pythia 6 shower tunes are presented, including a study of tunes for various PDFs.

End-of-life resource recovery from emerging electronic products

DEFF Research Database (Denmark)

Parajuly, Keshav; Habib, Komal; Cimpan, Ciprian

2016-01-01

Integrating product design with appropriate end-of-life (EoL) processing is widely recognized to have huge potentials in improving resource recovery from electronic products. In this study, we investigate both the product characteristics and EoL processing of robotic vacuum cleaner (RVC), as a case...... of emerging electronic product, in order to understand the recovery fate of different materials and its linkage to product design. Ten different brands of RVC were dismantled and their material composition and design profiles were studied. Another 125 RVCs (349 kg) were used for an experimental trial...... at a conventional ‘shred-and-separate’ type preprocessing plant in Denmark. A detailed material flow analysis was performed throughout the recycling chain. The results show a mismatch between product design and EoL processing, and the lack of practical implementation of ‘Design for EoL’ thinking. In the best...

Use of electronic sales data to tailor nutrition education resources for an ethnically diverse population.

Science.gov (United States)

Eyles, H; Rodgers, A; Ni Mhurchu, C

2010-02-01

Nutrition education may be most effective when personally tailored. Individualised electronic supermarket sales data offer opportunities to tailor nutrition education using shopper's usual food purchases. The present study aimed to use individualised electronic supermarket sales data to tailor nutrition resources for an ethnically diverse population in a large supermarket intervention trial in New Zealand. Culturally appropriate nutrition education resources (i.e. messages and shopping lists) were developed with the target population (through two sets of focus groups) and ethnic researchers. A nutrient database of supermarket products was developed using retrospective sales data and linked to participant sales to allow tailoring by usual food purchases. Modified Heart Foundation Tick criteria were used to identify 'healthier' products in the database suitable for promotion in the resources. Rules were developed to create a monthly report listing the tailored and culturally targeted messages to be sent to each participant, and to produce automated, tailored shopping lists. Culturally targeted nutrition messages (n = 864) and shopping lists (n = 3 formats) were developed. The food and nutrient database (n = 3000 top-selling products) was created using 12 months of retrospective sales data, and comprised 60%'healthier' products. Three months of baseline sales data were used to determine usual food purchases. Tailored resources were successfully mailed to 123 Māori, 52 Pacific and 346 non-Māori non-Pacific participants over the 6-month trial intervention period. Electronic supermarket sales data can be used to tailor nutrition education resources for a large number of ethnically diverse supermarket shoppers.

SC tuning fork

CERN Document Server

The tuning fork used to modulate the radiofrequency system of the synchro cyclotron (SC) from 1957 to 1973. This piece is an unused spare part. The SC was the 1st accelerator built at CERN. It operated from August 1957 until it was closed down at the end of 1990. In the SC the magnetic field did not change with time, and the particles were accelerated in successive pulses by a radiofrequency voltage of some 20kV which varied in frequency as they spiraled outwards towards the extraction radius. The frequency varied from 30MHz to about 17Mz in each pulse. The tuning fork vibrated at 55MHz in vacuum in an enclosure which formed a variable capacitor in the tuning circuit of the RF system, allowing the RF to vary over the appropriate range to accelerate protons from the centre of the macine up to 600Mev at extraction radius. In operation the tips of the tuning fork blade had an amplitude of movement of over 1 cm. The SC accelerator underwent extensive improvements from 1973 to 1975, including the installation of a...

Availability, Level of Use and Constraints to Use of Electronic Resources by Law Lecturers in Public Universities in Nigeria

Science.gov (United States)

Amusa, Oyintola Isiaka; Atinmo, Morayo

2016-01-01

(Purpose) This study surveyed the level of availability, use and constraints to use of electronic resources among law lecturers in Nigeria. (Methodology) Five hundred and fifty-two law lecturers were surveyed and four hundred and forty-two responded. (Results) Data analysis revealed that the level of availability of electronic resources for the…

Tuning the Schottky rectification in graphene-hexagonal boron nitride-molybdenum disulfide heterostructure.

Science.gov (United States)

Liu, Biao; Zhao, Yu-Qing; Yu, Zhuo-Liang; Wang, Lin-Zhi; Cai, Meng-Qiu

2018-03-01

It was still a great challenge to design high performance of rectification characteristic for the rectifier diode. Lately, a new approach was proposed experimentally to tune the Schottky barrier height (SBH) by inserting an ultrathin insulated tunneling layer to form metal-insulator-semiconductor (MIS) heterostructures. However, the electronic properties touching off the high performance of these heterostructures and the possibility of designing more efficient applications for the rectifier diode were not presently clear. In this paper, the structural, electronic and interfacial properties of the novel MIS diode with the graphene/hexagonal boron nitride/monolayer molybdenum disulfide (GBM) heterostructure had been investigated by first-principle calculations. The calculated results showed that the intrinsic properties of graphene and MoS 2 were preserved due to the weak van der Waals contact. The height of interfacial Schottky barrier can be tuned by the different thickness of hBN layers. In addition, the GBM Schottky diode showed more excellent rectification characteristic than that of GM Schottky diode due to the interfacial band bending caused by the epitaxial electric field. Based on the electronic band structure, we analyzed the relationship between the electronic structure and the nature of the Schottky rectifier, and revealed the potential of utilizing GBM Schottky diode for the higher rectification characteristic devices. Copyright © 2017 Elsevier Inc. All rights reserved.

A systematic review of portable electronic technology for health education in resource-limited settings.

Science.gov (United States)

McHenry, Megan S; Fischer, Lydia J; Chun, Yeona; Vreeman, Rachel C

2017-08-01

The objective of this study is to conduct a systematic review of the literature of how portable electronic technologies with offline functionality are perceived and used to provide health education in resource-limited settings. Three reviewers evaluated articles and performed a bibliography search to identify studies describing health education delivered by portable electronic device with offline functionality in low- or middle-income countries. Data extracted included: study population; study design and type of analysis; type of technology used; method of use; setting of technology use; impact on caregivers, patients, or overall health outcomes; and reported limitations. Searches yielded 5514 unique titles. Out of 75 critically reviewed full-text articles, 10 met inclusion criteria. Study locations included Botswana, Peru, Kenya, Thailand, Nigeria, India, Ghana, and Tanzania. Topics addressed included: development of healthcare worker training modules, clinical decision support tools, patient education tools, perceptions and usability of portable electronic technology, and comparisons of technologies and/or mobile applications. Studies primarily looked at the assessment of developed educational modules on trainee health knowledge, perceptions and usability of technology, and comparisons of technologies. Overall, studies reported positive results for portable electronic device-based health education, frequently reporting increased provider/patient knowledge, improved patient outcomes in both quality of care and management, increased provider comfort level with technology, and an environment characterized by increased levels of technology-based, informal learning situations. Negative assessments included high investment costs, lack of technical support, and fear of device theft. While the research is limited, portable electronic educational resources present promising avenues to increase access to effective health education in resource-limited settings, contingent

Tuning intermetallic electronic coupling in polyruthenium systems ...

Indian Academy of Sciences (India)

molecular architecture. SANDEEP GHUMAAN and GOUTAM KUMAR LAHIRI ... complexes encompassing selective combinations of spacer (bridging ligand, BL) and ancillary (AL) functionalities have been designed. ... plications in designing molecular electronic devices3 such as molecular wires, semi-conductors, rods etc.

Tetronic Star Block Copolymer Micelles: Photophysical Characterisation of Microenvironments and Applicability for Tuning Electron Transfer Reactions.

Science.gov (United States)

Samanta, Papu; Rane, Sonal; Bahadur, Pratap; Dutta Choudhury, Sharmistha; Pal, Haridas

2018-05-10

Detailed photophysical investigations have been carried out using a probe dye, Coumarin-153 (C153), to understand the microenvironments of micelles formed by the newly introduced Tetronic star block copolymers, T1304 and T1307, having the same polypropylene oxide (PPO) block size but different polyethylene oxide (PEO) block sizes. Ground state absorption, steady-state fluorescence and time-resolved fluorescence measurements have been used to estimate the micropolarity, microviscosity and solvation dynamics within the two micelles. To the best of our knowledge this is the first report on these important physicochemical parameters for this new class of the star block copolymer micelles. Our results indicate that T1307 micelle offers a relatively more polar and less viscous microenvironment in the corona region, compared to T1304. The effect of the two micellar systems has subsequently been investigated on the bimolecular photoinduced electron transfer (ET) reactions between coumarin dyes (electron acceptors) and aromatic amines (electron donors). On correlating the energetics and kinetics of the ET reactions, clear Marcus Inversion (MI) behavior is observed in both the micellar media. Interestingly, the ET rates for all the donor-acceptor pairs are much higher in T1307 than in T1304, and the onset of MI also appears at a relatively higher exergenocity (-Δ G 0 ) in the former micelle (~0.45 eV for T1307) than the latter (~0.37 eV for T1304). Effect of added NaCl salt studied selectively in T1307 micelle, shows that the ET rate decreases significantly along with a shift in the onset of MI toward lower exergenocity region, so that in the presence of 2 M NaCl the system becomes quite comparable to T1304. Based on the observed results, it is realized that the micropolarity and hence the dynamics of ET process can be tuned very effectively either by changing the constitution of the star block copolymer or by using a suitable additive as a modifier of the micellar

Data Driven Tuning of Inventory Controllers

DEFF Research Database (Denmark)

Huusom, Jakob Kjøbsted; Santacoloma, Paloma Andrade; Poulsen, Niels Kjølstad

2007-01-01

A systematic method for criterion based tuning of inventory controllers based on data-driven iterative feedback tuning is presented. This tuning method circumvent problems with modeling bias. The process model used for the design of the inventory control is utilized in the tuning...... as an approximation to reduce time required on experiments. The method is illustrated in an application with a multivariable inventory control implementation on a four tank system....

Imaging and tuning polarity at SrTiO3 domain walls

Science.gov (United States)

Frenkel, Yiftach; Haham, Noam; Shperber, Yishai; Bell, Christopher; Xie, Yanwu; Chen, Zhuoyu; Hikita, Yasuyuki; Hwang, Harold Y.; Salje, Ekhard K. H.; Kalisky, Beena

2017-12-01

Electrostatic fields tune the ground state of interfaces between complex oxide materials. Electronic properties, such as conductivity and superconductivity, can be tuned and then used to create and control circuit elements and gate-defined devices. Here we show that naturally occurring twin boundaries, with properties that are different from their surrounding bulk, can tune the LaAlO3/SrTiO3 interface 2DEG at the nanoscale. In particular, SrTiO3 domain boundaries have the unusual distinction of remaining highly mobile down to low temperatures, and were recently suggested to be polar. Here we apply localized pressure to an individual SrTiO3 twin boundary and detect a change in LaAlO3/SrTiO3 interface current distribution. Our data directly confirm the existence of polarity at the twin boundaries, and demonstrate that they can serve as effective tunable gates. As the location of SrTiO3 domain walls can be controlled using external field stimuli, our findings suggest a novel approach to manipulate SrTiO3-based devices on the nanoscale.

Bandgap tuning with thermal residual stresses induced in a quantum dot.

Science.gov (United States)

Kong, Eui-Hyun; Joo, Soo-Hyun; Park, Hyun-Jin; Song, Seungwoo; Chang, Yong-June; Kim, Hyoung Seop; Jang, Hyun Myung

2014-09-24

Lattice distortion induced by residual stresses can alter electronic and mechanical properties of materials significantly. Herein, a novel way of the bandgap tuning in a quantum dot (QD) by lattice distortion is presented using 4-nm-sized CdS QDs grown on a TiO2 particle as an application example. The bandgap tuning (from 2.74 eV to 2.49 eV) of a CdS QD is achieved by suitably adjusting the degree of lattice distortion in a QD via the tensile residual stresses which arise from the difference in thermal expansion coefficients between CdS and TiO2. The idea of bandgap tuning is then applied to QD-sensitized solar cells, achieving ≈60% increase in the power conversion efficiency by controlling the degree of thermal residual stress. Since the present methodology is not limited to a specific QD system, it will potentially pave a way to unexplored quantum effects in various QD-based applications. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

HIL Tuning of UAV for Exploration of Risky Environments

Directory of Open Access Journals (Sweden)

C. D. Melita

2008-11-01

Full Text Available In this paper the latest results of an HIL architecture, optimized to develop and test UAV platforms are presented. This architecture has been used to realize the different devices involved in the navigation and stability control of the Volcan UAV, a plane designed to operate in volcanic environments. The proposed architecture is strongly modular and flexible and allows the development of avionic hardware and software, testing and tuning the involved algorithms with non-destructive trials. A flight simulator (X-Plane with a suitable plane model and plug-in, has been adopted to simulate the UAV dynamics. The flight simulator, interfaced with the real electronic boards, allows an easy tuning of all the control parameters and data collecting for test and validation. The effectiveness of adopted methodology was confirmed by several flight tests performed subsequently by using the designed avionic modules on the real UAV.

Size-dependent single electron transfer and semi-metal-to-insulator transitions in molecular metal oxide electronics

Science.gov (United States)

Balliou, Angelika; Bouroushian, Mirtat; Douvas, Antonios M.; Skoulatakis, George; Kennou, Stella; Glezos, Nikos

2018-07-01

All-inorganic self-arranged molecular transition metal oxide hyperstructures based on polyoxometalate molecules (POMs) are fabricated and tested as electronically tunable components in emerging electronic devices. POM hyperstructures reveal great potential as charging nodes of tunable charging level for molecular memories and as enhancers of interfacial electron/hole injection for photovoltaic stacks. STM, UPS, UV–vis spectroscopy and AFM measurements show that this functionality stems from the films’ ability to structurally tune their HOMO–LUMO levels and electron localization length at room temperature. By adapting POM nanocluster size in solution, self-doping and current modulation of four orders of magnitude is monitored on a single nanocluster on SiO2 at voltages as low as 3 Volt. Structurally driven insulator-to-semi-metal transitions and size-dependent current regulation through single electron tunneling are demonstrated and examined with respect to the stereochemical and electronic structure of the molecular entities. This extends the value of self-assembly as a tool for correlation length and electronic properties tuning and demonstrate POM hyperstructures’ plausibility for on-chip molecular electronics operative at room temperature.

Size-dependent single electron transfer and semi-metal-to-insulator transitions in molecular metal oxide electronics.

Science.gov (United States)

Balliou, Angelika; Bouroushian, Mirtat; Douvas, Antonios M; Skoulatakis, George; Kennou, Stella; Glezos, Nikos

2018-07-06

All-inorganic self-arranged molecular transition metal oxide hyperstructures based on polyoxometalate molecules (POMs) are fabricated and tested as electronically tunable components in emerging electronic devices. POM hyperstructures reveal great potential as charging nodes of tunable charging level for molecular memories and as enhancers of interfacial electron/hole injection for photovoltaic stacks. STM, UPS, UV-vis spectroscopy and AFM measurements show that this functionality stems from the films' ability to structurally tune their HOMO-LUMO levels and electron localization length at room temperature. By adapting POM nanocluster size in solution, self-doping and current modulation of four orders of magnitude is monitored on a single nanocluster on SiO 2 at voltages as low as 3 Volt. Structurally driven insulator-to-semi-metal transitions and size-dependent current regulation through single electron tunneling are demonstrated and examined with respect to the stereochemical and electronic structure of the molecular entities. This extends the value of self-assembly as a tool for correlation length and electronic properties tuning and demonstrate POM hyperstructures' plausibility for on-chip molecular electronics operative at room temperature.

SAGES: a suite of freely-available software tools for electronic disease surveillance in resource-limited settings.

Directory of Open Access Journals (Sweden)

Sheri L Lewis

Full Text Available Public health surveillance is undergoing a revolution driven by advances in the field of information technology. Many countries have experienced vast improvements in the collection, ingestion, analysis, visualization, and dissemination of public health data. Resource-limited countries have lagged behind due to challenges in information technology infrastructure, public health resources, and the costs of proprietary software. The Suite for Automated Global Electronic bioSurveillance (SAGES is a collection of modular, flexible, freely-available software tools for electronic disease surveillance in resource-limited settings. One or more SAGES tools may be used in concert with existing surveillance applications or the SAGES tools may be used en masse for an end-to-end biosurveillance capability. This flexibility allows for the development of an inexpensive, customized, and sustainable disease surveillance system. The ability to rapidly assess anomalous disease activity may lead to more efficient use of limited resources and better compliance with World Health Organization International Health Regulations.

Tuning Optoelectronic Properties of Ambipolar Organic Light-Emitting Transistors Using a Bulk-Heterojunction Approach

NARCIS (Netherlands)

Loi, Maria Antonietta; Rost-Bietsch, Constance; Murgia, Mauro; Karg, Siegfried; Riess, Walter; Muccini, Michele

2006-01-01

Bulk-heterojunction engineering is demonstrated as an approach to producing ambipolar organic light-emitting field-effect transistors with tunable electrical and optoelectronic characteristics. The electron and hole mobilities, as well as the electroluminescence intensity, can be tuned over a large

Use and Cost of Electronic Resources in Central Library of Ferdowsi University Based on E-metrics

Directory of Open Access Journals (Sweden)

Mohammad Reza Davarpanah

2012-07-01

Full Text Available The purpose of this study was to investigate the usage of electronic journals in Ferdowsi University, Iran based on e-metrics. The paper also aimed to emphasize the analysis of cost-benefit and the correlation between the journal impact factors and the usage data. In this study experiences of Ferdowsi University library on licensing and usage of electronic resources was evaluated by providing a cost-benefit analysis based on the cost and usage statistics of electronic resources. Vendor-provided data were also compared with local usage data. The usage data were collected by tracking web-based access locally, and by collecting vender-provided usage data. The data sources were one-year of vendor-supplied e-resource usage data such as Ebsco, Elsevier, Proquest, Emerald, Oxford and Springer and local usage data collected from the Ferdowsi university web server. The study found that actual usage values differ for vendor-provided data and local usage data. Elsevier has got the highest usage degree in searches, sessions and downloads. Statistics also showed that a small number of journals satisfy significant amount of use while the majority of journals were used less frequent and some were never used at all. The users preferred the PDF rather than HTML format. The data in subject profile suggested that the provided e-resources were best suited to certain subjects. There was no correlation between IF and electronic journal use. Monitoring the usage of e-resources gained increasing importance for acquisition policy and budget decisions. The article provided information about local metrics for the six surveyed vendors/publishers, e.g. usage trends, requests per package, cost per use as related to the scientific specialty of the university.

Transverse betatron tune measurements

International Nuclear Information System (INIS)

Serio, M.

1989-01-01

In this paper the concept of the betatron tune and the techniques to measure it are discussed. The smooth approximation is introduced along with the terminology of betatron oscillations, phase advance and tune. Single particle and beam spectra in the presence of synchro-betatron oscillations are treated with emphasis on the consequences of sampling the beam position. After a general presentation of various kinds of beam position monitors and transverse kickers, the time domain and frequency domain analysis of the beam response to a transverse excitation are discussed and several methods and applications of the tune measurements are listed

The ATLAS Monte Carlo tuning system

CERN Document Server

Wahrmund, S; The ATLAS collaboration

2011-01-01

The ATLAS experiment moved the tuning of the underlying event and minimum bias event shape modeling, previously done in a manual fashion, to the automated Professor tuning tool, employed in connection with the Rivet analysis framework, when the first corresponding experimental analysis from LHC became available. The tuning effort for the Pythia 8 generator, which includes improved models for diffraction, has been started in this automated way in ATLAS, with the aim of getting a good description of the pile-up generated by multiple minimum bias interactions. The first results for these Pythia 8 tunes are presented, including a study of tunes for various PDFs.

Tuning of PI/PID controllers by developing an Android application

International Nuclear Information System (INIS)

Wu Wu, Steven

2013-01-01

The guidelines are defined for the implementation of the tuning rules uSORT_1 and uSORT_2, to an Android application. This is based on the parameters of a process model, which has allowed to perform the calculation of PI/PID type controllers of 1GdL and 2GdL respectively. The tuning rule mentioned above was revised, its functionality was checked calculating and analyzing the results for the various values of the relation of time constants. The use on the linear interpolation of the normalized parameters of the controllers has allowed to observe for the extreme cases of the chosen 'a' value, values that have fulfilled the own characteristics of the tuning rules. Eclipse ADT was used for the development of the application, as it has turned out to be a very functional tool that has facilitated the execution and debugging of the application, as well as the management of libraries and Android resources. The functionality of the parameters of the controller product of the application was verified, since it was possible to control a real process, obtaining congruent and very successful results to the expected product of the simulations performed, both in the operation of servo control and in regulatory control. (author) [es

Tuning magnet power supply

International Nuclear Information System (INIS)

Han, B.M.; Karady, G.G.; Thiessen, H.A.

1989-01-01

The particles in a Rapid Cycling Accelerator are accelerated by rf cavities, which are tuned by dc biased ferrite cores. The tuning is achieved by the regulation of bias current, which is produced by a power supply. The tuning magnet power supply utilizes a bridge circuit, supplied by a three phase rectifier. During the rise of the current, when the particles are accelerated, the current is controlled with precision by the bridge which operates a power amplifier. During the fall of the current, the bridge operates in a switching mode and recovers the energy stored in the ferrites. The recovered energy is stored in a capacitor bank. The bridge circuit is built with 150 power transistors. The drive, protection and control circuit were designed and built from commercial component. The system will be used for a rf cavity experiment in Los Alamos and will serve as a prototype tuning power supply for future accelerators. 1 ref., 7 figs

Building and Managing Electronic Resources in Digital Era in India with Special Reference to IUCAA and NIV, Pune: A Comparative Case Study

Science.gov (United States)

Sahu, H. K.; Singh, S. N.

2015-04-01

This paper discusses and presents a comparative case study of two libraries in Pune, India, Inter-University Centre for Astronomy and Astrophysics and Information Centre and Library of National Institute of Virology (Indian Council of Medical Research). It compares how both libraries have managed their e-resource collections, including acquisitions, subscriptions, and consortia arrangements, while also developing a collection of their own resources, including pre-prints and publications, video lectures, and other materials in an institutional repository. This study illustrates how difficult it is to manage electronic resources in a developing country like India, even though electronic resources are used more than print resources. Electronic resource management can be daunting, but with a systematic approach, various problems can be solved, and use of the materials will be enhanced.

Enhanced emission of encaged-OH--free Ca12(1-x)Sr12xAl14O33:0.1%Gd3+ conductive phosphors via tuning the encaged-electron concentration for low-voltage FEDs.

Science.gov (United States)

Zhang, Meng; Liu, Yuxue; Yang, Jian; Zhu, Hancheng; Yan, Duanting; Zhang, Xinyang; Liu, Chunguang; Xu, Changshan; Zhang, Hong

2017-05-24

Encaged-OH - -free Ca 12(1-x) Sr 12x Al 14 O 33 :0.1%Gd 3+ conductive phosphors were prepared through a melt-solidification process in combination with a subsequent heat treatment. Absorption spectra showed that the maximum encaged-electron concentration was increased to 1.08 × 10 21 cm -3 through optimizing the doping amount of Sr 2+ (x = 0.005). Meanwhile, FTIR and Raman spectra indicated that pure Ca 11.94 Sr 0.06 Al 14 O 33 :0.1%Gd 3+ conductive phosphor without encaged OH - and C 2 2- anions was acquired. For the conductive powders heat-treated in air for different times, the encaged-electron concentrations were tuned from 1.02 × 10 21 to 8.3 × 10 20 cm -3 . ESR, photoluminescence, and luminescence kinetics analyses indicated that the emission at 312 nm mainly originated from Gd 3+ ions surrounded by encaged O 2- anions, while Gd 3+ ions surrounded by encaged electrons had a negative contribution to the UV emission due to the existence of an energy transfer process. Under low-voltage electron-beam excitation (3 kV), enhanced cathodoluminescence (CL) of the conductive phosphors could be achieved by tuning the encaged-electron concentrations. In particular, for the encaged-OH - -free conductive phosphor, the emission intensity of the CL was about one order of magnitude higher than that of the conductive phosphor containing encaged OH - anions. Our results suggested that the encaged-OH - -free conductive phosphors have potential application in low-voltage FEDs.

ATLAS Run 1 Pythia8 tunes

CERN Document Server

The ATLAS collaboration

2014-01-01

We present tunes of the Pythia8 Monte~Carlo event generator's parton shower and multiple parton interaction parameters to a range of data observables from ATLAS Run 1. Four new tunes have been constructed, corresponding to the four leading-order parton density functions, CTEQ6L1, MSTW2008LO, NNPDF23LO, and HERAPDF15LO, each simultaneously tuning ten generator parameters. A set of systematic variations is provided for the NNPDF tune, based on the eigentune method. These tunes improve the modeling of observables that can be described by leading-order + parton shower simulation, and are primarily intended for use in situations where next-to-leading-order and/or multileg parton-showered simulations are unavailable or impractical.

Robust Self Tuning Controllers

DEFF Research Database (Denmark)

Poulsen, Niels Kjølstad

1985-01-01

The present thesis concerns robustness properties of adaptive controllers. It is addressed to methods for robustifying self tuning controllers with respect to abrupt changes in the plant parameters. In the thesis an algorithm for estimating abruptly changing parameters is presented. The estimator...... has several operation modes and a detector for controlling the mode. A special self tuning controller has been developed to regulate plant with changing time delay.......The present thesis concerns robustness properties of adaptive controllers. It is addressed to methods for robustifying self tuning controllers with respect to abrupt changes in the plant parameters. In the thesis an algorithm for estimating abruptly changing parameters is presented. The estimator...

Angle-dependent strong-field molecular ionization rates with tuned range-separated time-dependent density functional theory

Energy Technology Data Exchange (ETDEWEB)

Sissay, Adonay [Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803 (United States); Abanador, Paul; Mauger, François; Gaarde, Mette; Schafer, Kenneth J. [Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803 (United States); Lopata, Kenneth, E-mail: klopata@lsu.edu [Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803 (United States); Center for Computation and Technology, Louisiana State University, Baton Rouge, Louisiana 70803 (United States)

2016-09-07

Strong-field ionization and the resulting electronic dynamics are important for a range of processes such as high harmonic generation, photodamage, charge resonance enhanced ionization, and ionization-triggered charge migration. Modeling ionization dynamics in molecular systems from first-principles can be challenging due to the large spatial extent of the wavefunction which stresses the accuracy of basis sets, and the intense fields which require non-perturbative time-dependent electronic structure methods. In this paper, we develop a time-dependent density functional theory approach which uses a Gaussian-type orbital (GTO) basis set to capture strong-field ionization rates and dynamics in atoms and small molecules. This involves propagating the electronic density matrix in time with a time-dependent laser potential and a spatial non-Hermitian complex absorbing potential which is projected onto an atom-centered basis set to remove ionized charge from the simulation. For the density functional theory (DFT) functional we use a tuned range-separated functional LC-PBE*, which has the correct asymptotic 1/r form of the potential and a reduced delocalization error compared to traditional DFT functionals. Ionization rates are computed for hydrogen, molecular nitrogen, and iodoacetylene under various field frequencies, intensities, and polarizations (angle-dependent ionization), and the results are shown to quantitatively agree with time-dependent Schrödinger equation and strong-field approximation calculations. This tuned DFT with GTO method opens the door to predictive all-electron time-dependent density functional theory simulations of ionization and ionization-triggered dynamics in molecular systems using tuned range-separated hybrid functionals.

Angle-dependent strong-field molecular ionization rates with tuned range-separated time-dependent density functional theory

International Nuclear Information System (INIS)

Sissay, Adonay; Abanador, Paul; Mauger, François; Gaarde, Mette; Schafer, Kenneth J.; Lopata, Kenneth

2016-01-01

Strong-field ionization and the resulting electronic dynamics are important for a range of processes such as high harmonic generation, photodamage, charge resonance enhanced ionization, and ionization-triggered charge migration. Modeling ionization dynamics in molecular systems from first-principles can be challenging due to the large spatial extent of the wavefunction which stresses the accuracy of basis sets, and the intense fields which require non-perturbative time-dependent electronic structure methods. In this paper, we develop a time-dependent density functional theory approach which uses a Gaussian-type orbital (GTO) basis set to capture strong-field ionization rates and dynamics in atoms and small molecules. This involves propagating the electronic density matrix in time with a time-dependent laser potential and a spatial non-Hermitian complex absorbing potential which is projected onto an atom-centered basis set to remove ionized charge from the simulation. For the density functional theory (DFT) functional we use a tuned range-separated functional LC-PBE*, which has the correct asymptotic 1/r form of the potential and a reduced delocalization error compared to traditional DFT functionals. Ionization rates are computed for hydrogen, molecular nitrogen, and iodoacetylene under various field frequencies, intensities, and polarizations (angle-dependent ionization), and the results are shown to quantitatively agree with time-dependent Schrödinger equation and strong-field approximation calculations. This tuned DFT with GTO method opens the door to predictive all-electron time-dependent density functional theory simulations of ionization and ionization-triggered dynamics in molecular systems using tuned range-separated hybrid functionals.

Electron-electron attractive interaction in Maxwell-Chern-Simons QED3 at zero temperature

International Nuclear Information System (INIS)

Belich, H.; Ferreira Junior, M.M.; Helayel-Neto, J.A.; Ferreira Junior, M.M.

2001-04-01

One discusses the issue of low-energy electron-electron bound states in the Maxwell-Chern-Simons model coupled to QED 3 with spontaneous breaking of a local U(1)-symmetry. The scattering potential, in the non-relativistic limit, steaming from the electron-electron Moeller scattering, mediated by the Maxwell-Chern-Simons-Proca gauge field and the Higgs scalar, might be attractive by fine-tuning properly the physical parameters of the model. (author)

Pre-tuning of TRISTAN superconducting RF cavities

International Nuclear Information System (INIS)

Tajima, Tsuyoshi; Furuya, Takaaki; Suzuki, Toshiji; Iino, Yohsuke.

1990-01-01

Pre-tuning of thirty-two TRISTAN superconducting cavities has been done. In this paper are described the pre-tuning system and the results of all the cavities. The average field flatness was 1.4 % after pre-tuning. From our experience, the followings are important, 1) to evacuate the cavity during the process of the pre-tuning to avoid the uncertainty in evacuation, 2) pre-tuning is needed after annealing because it causes changes of the cell length and the field profile and 3) field flatness sometimes changes when expanded and 4) cells should not be expanded more than 1.5 mm after pre-tuning since inelastic deformation occurs. (author)

Magnetic and electrostatic confinement of plasma with tuning of electrostatic field

Science.gov (United States)

Rostoker, Norman [Irvine, CA; Binderbauer, Michl [Irvine, CA; Qerushi, Artan [Irvine, CA; Tahsiri, Hooshang [Irvine, CA

2008-10-21

A system and method for containing plasma and forming a Field Reversed Configuration (FRC) magnetic topology are described in which plasma ions are contained magnetically in stable, non-adiabatic orbits in the FRC. Further, the electrons are contained electrostatically in a deep energy well, created by tuning an externally applied magnetic field. The simultaneous electrostatic confinement of electrons and magnetic confinement of ions avoids anomalous transport and facilitates classical containment of both electrons and ions. In this configuration, ions and electrons may have adequate density and temperature so that upon collisions they are fused together by nuclear force, thus releasing fusion energy. Moreover, the fusion fuel plasmas that can be used with the present confinement system and method are not limited to neutronic fuels only, but also advantageously include advanced fuels.

How safe is tuning a radio?: using the radio tuning task as a benchmark for distracted driving.

Science.gov (United States)

Lee, Ja Young; Lee, John D; Bärgman, Jonas; Lee, Joonbum; Reimer, Bryan

2018-01-01

Drivers engage in non-driving tasks while driving, such as interactions entertainment systems. Studies have identified glance patterns related to such interactions, and manual radio tuning has been used as a reference task to set an upper bound on the acceptable demand of interactions. Consequently, some view the risk associated with radio tuning as defining the upper limit of glance measures associated with visual-manual in-vehicle activities. However, we have little knowledge about the actual degree of crash risk that radio tuning poses and, by extension, the risk of tasks that have similar glance patterns as the radio tuning task. In the current study, we use counterfactual simulation to take the glance patterns for manual radio tuning tasks from an on-road experiment and apply these patterns to lead-vehicle events observed in naturalistic driving studies. We then quantify how often the glance patterns from radio tuning are associated with rear-end crashes, compared to driving only situations. We used the pre-crash kinematics from 34 crash events from the SHRP2 naturalistic driving study to investigate the effect of radio tuning in crash-imminent situations, and we also investigated the effect of radio tuning on 2,475 routine braking events from the Safety Pilot project. The counterfactual simulation showed that off-road glances transform some near-crashes that could have been avoided into crashes, and glance patterns observed in on-road radio tuning experiment produced 2.85-5.00 times more crashes than baseline driving. Copyright © 2017 Elsevier Ltd. All rights reserved.

Single-particle dynamics in a nonlinear accelerator lattice: attaining a large tune spread with octupoles in IOTA

Energy Technology Data Exchange (ETDEWEB)

Antipov, S. A.; Nagaitsev, S.; Valishev, A.

2017-04-01

Fermilab is constructing the Integrable Optics Test Accelerator (IOTA) as the centerpiece of the Accelerator R&D Program towards high-intensity circular machines. One of the factors limiting the beam intensity in present circular accelerators is collective instabilities, which can be suppressed by a spread of betatron frequencies (tunes) through the Landau damping mechanism or by an external damper, if the instability is slow enough. The spread is usually created by octupole magnets, which introduce the tune dependence on the amplitude and, in some cases, by a chromatic spread (tune dependence on particle's momentum). The introduction of octupoles usually lead to a resonant behavior and a reduction of the dynamic aperture. One of the goals of the IOTA research program is to achieve a high betatron tune spread, while retaining a large dynamic aperture using conventional octupole magnets in a special but realistic accelerator configuration. In this report, we present results of computer simulations of an electron beam in the IOTA by particle tracking and the Frequency Map Analysis. The results show that the ring's octupole magnets can be configured to provide a betatron tune shift of 0.08 (for particles at large amplitudes) with the dynamical aperture of over 20 beam sigma for a 150-MeV electron beam. The influence of the synchrotron motion, lattice errors, and magnet imperfections is insignificant for the parameters and levels of tolerances set by the design of the ring. The described octupole insert could be beneficial for suppression of space-charge induced instabilities in high intensity machines.

Tuning the hysteresis voltage in 2D multilayer MoS{sub 2} FETs

Energy Technology Data Exchange (ETDEWEB)

Jiang, Jie, E-mail: jiangjie@csu.edu.cn; Zheng, Zhouming; Guo, Junjie

2016-10-01

The hysteresis tuning is of great significance before the two-dimensional (2D) molybdenum disulfide (MoS{sub 2}) field-effect transistors (FETs) can be practically used in the next-generation nanoelectronic devices. In this paper, a simple and effective annealing method was developed to tune the hysteresis voltage in 2D MoS{sub 2} transistors. It was found that high temperature (175 °C) annealing in air could increase the hysteresis voltage from 8.0 V (original device) to 28.4 V, while a next vacuum annealing would reduce the hysteresis voltage to be only 2.0 V. An energyband diagram model based on electron trapping/detrapping due to oxygen adsorption is proposed to understand the hysteresis mechanism in multilayer MoS{sub 2} FET. This simple method for tuning the hysteresis voltage of MoS{sub 2} FET can make a significant step toward 2D nanoelectronic device applications.

Tuning of electronic band gaps and optoelectronic properties of binary strontium chalcogenides by means of doping of magnesium atom(s)- a first principles based theoretical initiative with mBJ, B3LYP and WC-GGA functionals

Science.gov (United States)

Debnath, Bimal; Sarkar, Utpal; Debbarma, Manish; Bhattacharjee, Rahul; Chattopadhyaya, Surya

2018-02-01

First principle based theoretical initiative is taken to tune the optoelectronic properties of binary strontium chalcogenide semiconductors by doping magnesium atom(s) into their rock-salt unit cells at specific concentrations x = 0.0, 0.25, 0.50, 0.75 and 1.0 and such tuning is established by studying structural, electronic and optical properties of designed binary compounds and ternary alloys employing WC-GGA, B3LYP and mBJ exchange-correlation functionals. Band structure of each compound is constructed and respective band gaps under all the potential schemes are measured. The band gap bowing and its microscopic origin are calculated using quadratic fit and Zunger's approach, respectively. The atomic and orbital origins of electronic states in the band structure of any compound are explored from its density of states. The nature of chemical bonds between the constituent atoms in each compound is explored from the valence electron density contour plots. Optical properties of any specimen are explored from the computed spectra of its dielectric function, refractive index, extinction coefficient, normal incidence reflectivity, optical conductivity optical absorption and energy loss function. Several calculated results are compared with available experimental and earlier theoretical data.

Betatron tune measurement

International Nuclear Information System (INIS)

Dinev, D.

2001-01-01

On the basis of the comparative review of the methods for the betatron tune measurement in cyclic accelerators of synchrotrons type, the research of these methods is carried out from the point of view of their applicability to Nuclotron. Both methods using measurement of the statistical fluctuations of the beam current (Schottky noise) and methods using coherent beam excitation have been discussed. The emphasis is on the final results of importance for the tune measurement practice. Signal processing is briefly discussed too

Cyclic electron flow is redox-controlled but independent of state transition.

Science.gov (United States)

Takahashi, Hiroko; Clowez, Sophie; Wollman, Francis-André; Vallon, Olivier; Rappaport, Fabrice

2013-01-01

Photosynthesis is the biological process that feeds the biosphere with reduced carbon. The assimilation of CO2 requires the fine tuning of two co-existing functional modes: linear electron flow, which provides NADPH and ATP, and cyclic electron flow, which only sustains ATP synthesis. Although the importance of this fine tuning is appreciated, its mechanism remains equivocal. Here we show that cyclic electron flow as well as formation of supercomplexes, thought to contribute to the enhancement of cyclic electron flow, are promoted in reducing conditions with no correlation with the reorganization of the thylakoid membranes associated with the migration of antenna proteins towards Photosystems I or II, a process known as state transition. We show that cyclic electron flow is tuned by the redox power and this provides a mechanistic model applying to the entire green lineage including the vast majority of the cases in which state transition only involves a moderate fraction of the antenna.

[Use of internet and electronic resources among Spanish intensivist physicians. First national survey].

Science.gov (United States)

Gómez-Tello, V; Latour-Pérez, J; Añón Elizalde, J M; Palencia-Herrejón, E; Díaz-Alersi, R; De Lucas-García, N

2006-01-01

Estimate knowledge and use habits of different electronic resources in a sample of Spanish intensivists: Internet, E-mail, distribution lists, and use of portable electronic devices. Self-applied questionnaire. A 50-question questionnaire was distributed among Spanish intensivists through the hospital marketing delegates of a pharmaceutical company and of electronic forums. A total of 682 questionnaires were analyzed (participation: 74%). Ninety six percent of those surveyed used Internet individually: 67% admitted training gap. Internet was the second source of clinical consultations most used (61%), slightly behind consultation to colleagues (65%). The pages consulted most were bibliographic databases (65%) and electronic professional journals (63%), with limited use of Evidence Based Medicine pages (19%). Ninety percent of those surveyed used e-mail regularly in the practice of their profession, although 25% admitted that were not aware of its possibilities. The use of E-mail decreased significantly with increase in age. A total of 62% of the intensivists used distribution lists. Of the rest, 42% were not aware of its existence and 32% admitted they had insufficient training to handle them. Twenty percent of those surveyed had portable electronic devices and 64% considered it useful, basically due to its rapid consultation at bedside. Female gender was a negative predictive factor of its use (OR 0.35; 95% CI 0.2-0.63; p=0.0002). A large majority of the Spanish intensivists use Internet and E-mail. E-mail lists and use of portable devices are still underused resources. There are important gaps in training and infrequent use of essential pages. There are specific groups that require directed educational policies.

Upgrades to PEP-II Tune Measurements

Energy Technology Data Exchange (ETDEWEB)

Fisher, Alan S.

2002-07-30

The tune monitors for the two-ring PEP-II collider convert signals from one set of four BPM-type pickup buttons per ring into horizontal and vertical differences, which are then downconverted from 952 MHz (twice the RF) to baseband. Two-channel 10-MHz FFT spectrum analyzers show spectra in X-window displays in the Control Room, to assist PEP operators. When operating with the original system near the beam-beam limit, collisions broadened and flattened the tune peaks, often bringing them near the noise floor. We recently installed new downconverters that increase the signal-to-noise ratio by about 5 dB. In addition, we went from one to two sets of pickups per ring, near focusing and defocusing quadrupoles, so that signals for both planes originate at locations with large amplitudes. We also have just installed a tune tracker, based on a digital lock-in amplifier (one per tune plane) that is controlled by an EPICS software feedback loop. The tracker monitors the phase of the beam's response to a sinusoidal excitation, and adjusts the drive frequency to track the middle of the 1 go-degree phase transition across the tune resonance. We plan next to test an outer loop controlling the tune quadrupoles based on this tune measurement.

Upgrades to PEP-II Tune Measurements

Energy Technology Data Exchange (ETDEWEB)

Fisher, Alan S.

2002-07-30

The tune monitors for the two-ring PEP-II collider convert signals from one set of four BPM-type pickup buttons per ring into horizontal and vertical differences, which are then downconverted from 952 MHz (twice the RF) to baseband. Two-channel l0-MHz FFT spectrum analyzers show spectra in X-window displays in the Control Room, to assist PEP operators. When operating with the original system near the beam-beam limit, collisions broadened and flattened the tune peaks, often bringing them near the noise floor. We recently installed new downconverters that increase the signal-to-noise ratio by about 5 dB. In addition, we went from one to two sets of pickups per ring, near focusing and defocusing quadrupoles, so that signals for both planes originate at locations with large amplitudes. We also have just installed a tune tracker, based on a digital lock-in amplifier (one per tune plane) that is controlled by an EPICS software feedback loop. The tracker monitors the phase of the beam's response to a sinusoidal excitation, and adjusts the drive frequency to track the middle of the 180-degree phase transition across the tune resonance. We plan next to test an outer loop controlling the tune quadrupoles based on this tune measurement.

Upgrades to PEP-II tune measurements

International Nuclear Information System (INIS)

Fisher, Alan S.; Petree, Mark; Wienands, Uli; Allison, Stephanie; Laznovsky, Michael; Seeman, Michael; Robin, Jolene

2002-01-01

The tune monitors for the two-ring PEP-II collider convert signals from one set of four BPM-type pickup buttons per ring into horizontal and vertical differences, which are then downconverted from 952 MHz (twice the RF) to baseband. Two-channel 10-MHz FFT spectrum analyzers show spectra in X-window displays in the Control Room, to assist PEP operators. When operating with the original system near the beam-beam limit, collisions broadened and flattened the tune peaks, often bringing them near the noise floor. We recently installed new downconverters that increase the signal-to-noise ratio by about 5 dB. In addition, we went from one to two sets of pickups per ring, near focusing and defocusing quadrupoles, so that signals for both planes originate at locations with large amplitudes. We also have just installed a tune tracker, based on a digital lock-in amplifier (one per tune plane) that is controlled by an EPICS software feedback loop. The tracker monitors the phase of the beam's response to a sinusoidal excitation, and adjusts the drive frequency to track the middle of the 180-degree phase transition across the tune resonance. We plan next to test an outer loop controlling the tune quadrupoles based on this tune measurement

Model of e-learning with electronic educational resources of new generation

OpenAIRE

A. V. Loban; D. A. Lovtsov

2017-01-01

Purpose of the article: improving of scientific and methodical base of the theory of the е-learning of variability. Methods used: conceptual and logical modeling of the е-learning of variability process with electronic educational resource of new generation and system analysis of the interconnection of the studied subject area, methods, didactics approaches and information and communication technologies means. Results: the formalization complex model of the е-learning of variability with elec...

Enlargement of Tuning Range in a Ferrite-Tuned Cavity Through Superposed Orthogonal and Parallel Magnetic Bias

CERN Document Server

Vollinger, C

2013-01-01

Conventional ferrite-tuned cavities operate either with bias fields that are orthogonal or parallel to the magnetic RF-field. For a cavity that tunes rapidly over an overall frequency range around 100-400 MHz with high Q, we use ferrite garnets exposed to an innovative new biasing method consisting of a superposition of perpendicular and parallel magnetic fields. This method leads to a significant enlargement of the high-Q cavity tuning range by defining an operation point close to the magnetic saturation and thus improving ferrite material behaviour. A further advantage of this technique is the fast tuning speed resulting from the fact that tuning is carried out either with pure parallel biasing, or together with a very small change of operating point from perpendicular bias. In this paper, several scaled test models of ferrite-filled resonators are shown; measurements on the set-ups are compared and discussed.

Impact of Knowledge Resources Linked to an Electronic Health Record on Frequency of Unnecessary Tests and Treatments

Science.gov (United States)

Goodman, Kenneth; Grad, Roland; Pluye, Pierre; Nowacki, Amy; Hickner, John

2012-01-01

Introduction: Electronic knowledge resources have the potential to rapidly provide answers to clinicians' questions. We sought to determine clinicians' reasons for searching these resources, the rate of finding relevant information, and the perceived clinical impact of the information they retrieved. Methods: We asked general internists, family…

Electronic Document Management: A Human Resource Management Case Study

Directory of Open Access Journals (Sweden)

Thomas Groenewald

2004-11-01

Full Text Available This case study serve as exemplar regarding what can go wrong with the implementation of an electronic document management system. Knowledge agility and knowledge as capital, is outlined against the backdrop of the information society and knowledge economy. The importance of electronic document management and control is sketched thereafter. The literature review is concluded with the impact of human resource management on knowledge agility, which includes references to the learning organisation and complexity theory. The intervention methodology, comprising three phases, follows next. The results of the three phases are presented thereafter. Partial success has been achieved with improving the human efficacy of electronic document management, however the client opted to discontinue the system in use. Opsomming Die gevalle studie dien as voorbeeld van wat kan verkeerd loop met die implementering van ’n elektroniese dokumentbestuur sisteem. Teen die agtergrond van die inligtingsgemeenskap en kennishuishouding word kennissoepelheid en kennis as kapitaal bespreek. Die literatuurstudie word afgesluit met die inpak van menslikehulpbronbestuur op kennissoepelheid, wat ook die verwysings na die leerorganisasie en kompleksietydsteorie insluit. Die metodologie van die intervensie, wat uit drie fases bestaan, volg daarna. Die resultate van die drie fases word vervolgens aangebied. Slegs gedeelte welslae is behaal met die verbetering van die menslike doeltreffendheid ten opsigte van elektroniese dokumentbestuur. Die klient besluit egter om nie voort te gaan om die huidige sisteem te gebruik nie.

Electron-electron attractive interaction in Maxwell-Chern-Simons QED{sub 3} at zero temperature

Energy Technology Data Exchange (ETDEWEB)

Belich, H.; Ferreira Junior, M.M.; Helayel-Neto, J.A. [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil). E-mail: belich@cbpf.br; manojr@cbpf.br; helayel@gft.ucp.br; Ferreira Junior, M.M. [Universidade Catolica de Petropolis, RJ (Brazil). Grupo de Fisica Teorica. E-mail: delcima@gft.ucp.br

2001-04-01

One discusses the issue of low-energy electron-electron bound states in the Maxwell-Chern-Simons model coupled to QED{sub 3} with spontaneous breaking of a local U(1)-symmetry. The scattering potential, in the non-relativistic limit, steaming from the electron-electron Moeller scattering, mediated by the Maxwell-Chern-Simons-Proca gauge field and the Higgs scalar, might be attractive by fine-tuning properly the physical parameters of the model. (author)

Enhancing Photocatalytic Performance through Tuning the Interfacial Process between -Assembled and Pt-Loaded Microspheres

Directory of Open Access Journals (Sweden)

Jun Zhang

2012-01-01

Full Text Available This work reports on a simple two-step approach to rutile TiO2-assembled microspheres loaded by Pt with an aim to tune semiconductor-metal interfacial processes for enhancing the photocatalytic performance. Systematic sample characterizations and structural analysis indicate that Pt loading did not produce any significant influences on the lattice structure of TiO2-assembled microspheres. Instead, upon Pt loading, Schottky barrier was formed in the interfaces between microspheres and Pt nanoparticles, which inhabited efficiently the recombination of photo-generated electron-hole pairs essential for the photocatalytic activities. In addition, TiO2 microspheres also showed a capacity of electrons storage and releasing as represented by a high dielectric constant, which increased the utility rate of photogenerated electrons. All these structural advantages contribute to the excellent photocatalytic activity under ultraviolet light irradiation. The interfacial process between microspheres and Pt nanoparticles was further tuned through adjusting the loading Pt content of metal Pt. As a consequence, the best photocatalytic activity on TiO2 was obtained at 0.85 wt% Pt loading, above or below which photocatalytic activity was apparently decreased.

Introduction to electronics

CERN Document Server

Korneff, Theodore

1966-01-01

Introduction to Electronics focuses on the study of electronics and electronic devices. Composed of 14 chapters, the book starts with discussions on dc circuits, including resistance, voltmeter, ammeter, galvanometer, internal resistance, and positive and negative currents. This topic is followed by discussions on ac circuits, particularly addressing voltage and current, average power, resistive load, complex plane, and parallel circuits. Discussions also focus on filters and tuned circuits, diodes, and power supplies. Particularly given attention are the processes, diagrams, and analyses

Challenges in the implementation of an electronic surveillance system in a resource-limited setting: Alerta, in Peru

Directory of Open Access Journals (Sweden)

Soto Giselle

2008-11-01

Full Text Available Abstract Background Infectious disease surveillance is a primary public health function in resource-limited settings. In 2003, an electronic disease surveillance system (Alerta was established in the Peruvian Navy with support from the U.S. Naval Medical Research Center Detachment (NMRCD. Many challenges arose during the implementation process, and a variety of solutions were applied. The purpose of this paper is to identify and discuss these issues. Methods This is a retrospective description of the Alerta implementation. After a thoughtful evaluation according to the Centers for Disease Control and Prevention (CDC guidelines, the main challenges to implementation were identified and solutions were devised in the context of a resource-limited setting, Peru. Results After four years of operation, we have identified a number of challenges in implementing and operating this electronic disease surveillance system. These can be divided into the following categories: (1 issues with personnel and stakeholders; (2 issues with resources in a developing setting; (3 issues with processes involved in the collection of data and operation of the system; and (4 issues with organization at the central hub. Some of the challenges are unique to resource-limited settings, but many are applicable for any surveillance system. For each of these challenges, we developed feasible solutions that are discussed. Conclusion There are many challenges to overcome when implementing an electronic disease surveillance system, not only related to technology issues. A comprehensive approach is required for success, including: technical support, personnel management, effective training, and cultural sensitivity in order to assure the effective deployment of an electronic disease surveillance system.

Model-independent particle accelerator tuning

Directory of Open Access Journals (Sweden)

Alexander Scheinker

2013-10-01

Full Text Available We present a new model-independent dynamic feedback technique, rotation rate tuning, for automatically and simultaneously tuning coupled components of uncertain, complex systems. The main advantages of the method are: (1 it has the ability to handle unknown, time-varying systems, (2 it gives known bounds on parameter update rates, (3 we give an analytic proof of its convergence and its stability, and (4 it has a simple digital implementation through a control system such as the experimental physics and industrial control system (EPICS. Because this technique is model independent it may be useful as a real-time, in-hardware, feedback-based optimization scheme for uncertain and time-varying systems. In particular, it is robust enough to handle uncertainty due to coupling, thermal cycling, misalignments, and manufacturing imperfections. As a result, it may be used as a fine-tuning supplement for existing accelerator tuning/control schemes. We present multiparticle simulation results demonstrating the scheme’s ability to simultaneously adaptively adjust the set points of 22 quadrupole magnets and two rf buncher cavities in the Los Alamos Neutron Science Center (LANSCE Linear Accelerator’s transport region, while the beam properties and rf phase shift are continuously varying. The tuning is based only on beam current readings, without knowledge of particle dynamics. We also present an outline of how to implement this general scheme in software for optimization, and in hardware for feedback-based control/tuning, for a wide range of systems.

Tuning the Schottky contacts in the phosphorene and graphene heterostructure by applying strain.

Science.gov (United States)

Liu, Biao; Wu, Li-Juan; Zhao, Yu-Qing; Wang, Lin-Zhi; Caii, Meng-Qiu

2016-07-20

The structures and electronic properties of the phosphorene and graphene heterostructure are investigated by density functional calculations using the hybrid Heyd-Scuseria-Ernzerhof (HSE) functional. The results show that the intrinsic properties of phosphorene and graphene are preserved due to the weak van der Waals contact. But the electronic properties of the Schottky contacts in the phosphorene and graphene heterostructure can be tuned from p-type to n-type by the in-plane compressive strains from -2% to -4%. After analyzing the total band structure and density of states of P atom orbitals, we find that the Schottky barrier height (SBH) is determined by the P-pz orbitals. What is more, the variation of the work function of the phosphorene monolayer and the graphene electrode and the Fermi level shift are the nature of the transition of Schottky barrier from n-type Schottky contact to p-type Schottky contact in the phosphorene and graphene heterostructure under different in-plane strains. We speculate that these are general results of tuning of the electronic properties of the Schottky contacts in the phosphorene and graphene heterostructure by controlling the in-plane compressive strains to obtain a promising method to design and fabricate a phosphorene-graphene based field effect transistor.

Single-particle dynamics in a nonlinear accelerator lattice: attaining a large tune spread with octupoles in IOTA

Science.gov (United States)

Antipov, S. A.; Nagaitsev, S.; Valishev, A.

2017-04-01

Fermilab is constructing the Integrable Optics Test Accelerator (IOTA) as the centerpiece of the Accelerator R&D Program towards high-intensity circular machines. One of the factors limiting the beam intensity in present circular accelerators is collective instabilities, which can be suppressed by a spread of betatron frequencies (tunes) through the Landau damping mechanism or by an external damper, if the instability is slow enough. The spread is usually created by octupole magnets, which introduce the tune dependence on the amplitude and, in some cases, by a chromatic spread (tune dependence on particle's momentum). The introduction of octupoles usually has both beneficial (improved Landau damping) and harmful properties, such as a resonant behavior and a reduction of the dynamic aperture. One of the research goals at the IOTA ring is to achieve a large betatron tune spread, while retaining a large dynamic aperture, using conventional octupole magnets in a special but realistic accelerator configuration. The configuration, although not integrable by design, approximates an autonomous 2D Hamiltonian system. In this paper, we present results of computer simulations of an electron beam in the IOTA by particle tracking and the Frequency Map Analysis. The results show that the ring's octupole magnets can be configured to provide a betatron tune shift of 0.08 (for particles at large amplitudes) with the dynamical aperture of over 20 beam sigma for a 150-MeV electron beam. The influence of the synchrotron motion, lattice errors, and magnet imperfections is insignificant for the parameters and levels of tolerances set by the design of the ring. The described octupole insert could be beneficial for enhancing Landau damping in high intensity machines.

Considering Point-of-Care Electronic Medical Resources in Lieu of Traditional Textbooks for Medical Education.

Science.gov (United States)

Hale, LaDonna S; Wallace, Michelle M; Adams, Courtney R; Kaufman, Michelle L; Snyder, Courtney L

2015-09-01

Selecting resources to support didactic courses is a critical decision, and the advantages and disadvantages must be carefully considered. During clinical rotations, students not only need to possess strong background knowledge but also are expected to be proficient with the same evidence-based POC resources used by clinicians. Students place high value on “real world” learning and therefore may place more value on POC resources that they know practicing clinicians use as compared with medical textbooks. The condensed nature of PA education requires students to develop background knowledge and information literacy skills over a short period. One way to build that knowledge and those skills simultaneously is to use POC resources in lieu of traditional medical textbooks during didactic training. Electronic POC resources offer several advantages over traditional textbooks and should be considered as viable options in PA education.

Control of Fermilab Booster tunes

International Nuclear Information System (INIS)

Johnson, R.P; Meisner, K.; Sandberg, B.

1977-01-01

Control of the radial and vertical tunes of the booster is implemented using ramped correction quadrupoles. Minor modifications to the power supply cards for the 48 (previously) dc correction quadrupoles allow ''the tunes'' to be continuously programmed or held constant throughout the 33 ms acceleration cycle. This capability is in addition to the usual use of these quadrupoles to be independently varied to correct for harmonic distortions in the lattice. An automatic computer program measures and displays the tunes vs. time in the cycle to monitor performance and to allow the ramps to be adjusted by the machine operator

Full-color tuning in binary polymer:perovskite nanocrystals organic-inorganic hybrid blends

Science.gov (United States)

Perulli, A.; Balena, A.; Fernandez, M.; Nedelcu, G.; Cretí, A.; Kovalenko, M. V.; Lomascolo, M.; Anni, M.

2018-04-01

The excellent optical and electronic properties of metal halide perovskites recently proposed these materials as interesting active materials for optoelectronic applications. In particular, the high color purity of perovskite colloidal nanocrystals (NCs) had recently motivated their exploration as active materials for light emitting diodes with tunable emission across the visible range. In this work, we investigated the emission properties of binary blends of conjugated polymers and perovskite NCs. We demonstrate that the emission color of the blends is determined by the superposition of the component photoluminescence spectra, allowing color tuning by acting on the blend relative composition. The use of two different polymers, two different perovskite NCs, and different blend compositions is exploited to tune the blend color in the blue-green, yellow-red, and blue-red ranges, including white light generation.

Resource conservation approached with an appropriate collection and upgrade-remanufacturing for used electronic products.

Science.gov (United States)

Zlamparet, Gabriel I; Tan, Quanyin; Stevels, A B; Li, Jinhui

2018-03-01

This comparative research represents an example for a better conservation of resources by reducing the amount of waste (kg) and providing it more value under the umbrella of remanufacturing. The three discussed cases will expose three issues already addressed separately in the literature. The generation of waste electrical and electronic equipment (WEEE) interacts with the environmental depletion. In this article, we gave the examples of addressed issues under the concept of remanufacturing. Online collection opportunity eliminating classical collection, a business to business (B2B) implementation for remanufactured servers and medical devices. The material reuse (recycling), component sustainability, reuse (part harvesting), product reuse (after repair/remanufacturing) indicates the recovery potential using remanufacturing tool for a better conservation of resources adding more value to the products. Our findings can provide an overview of new system organization for the general collection, market potential and the technological advantages using remanufacturing instead of recycling of WEEE or used electrical and electronic equipment. Copyright © 2017. Published by Elsevier Ltd.

Selective enhancement of orientation tuning before saccades.

Science.gov (United States)

Ohl, Sven; Kuper, Clara; Rolfs, Martin

2017-11-01

Saccadic eye movements cause a rapid sweep of the visual image across the retina and bring the saccade's target into high-acuity foveal vision. Even before saccade onset, visual processing is selectively prioritized at the saccade target. To determine how this presaccadic attention shift exerts its influence on visual selection, we compare the dynamics of perceptual tuning curves before movement onset at the saccade target and in the opposite hemifield. Participants monitored a 30-Hz sequence of randomly oriented gratings for a target orientation. Combining a reverse correlation technique previously used to study orientation tuning in neurons and general additive mixed modeling, we found that perceptual reports were tuned to the target orientation. The gain of orientation tuning increased markedly within the last 100 ms before saccade onset. In addition, we observed finer orientation tuning right before saccade onset. This increase in gain and tuning occurred at the saccade target location and was not observed at the incongruent location in the opposite hemifield. The present findings suggest, therefore, that presaccadic attention exerts its influence on vision in a spatially and feature-selective manner, enhancing performance and sharpening feature tuning at the future gaze location before the eyes start moving.

Effects of the Use of Electronic Human Resource Management (EHRM Within Human Resource Management (HRM Functions at Universities

Directory of Open Access Journals (Sweden)

Chux Gervase Iwu

2016-09-01

Full Text Available This study set out to examine the effect of e-hrm systems in assisting human resource practitioners to execute their duties and responsibilities. In comparison to developed economies of the world, information technology adoption in sub-Saharan Africa has not been without certain glitches. Some of the factors that are responsible for these include poor need identification, sustainable funding, and insufficient skills. Besides these factors, there is also the issue of change management and users sticking to what they already know. Although, the above factors seem negative, there is strong evidence that information systems such as electronic human resource management present benefits to an organization. To achieve this, a dual research approach was utilized. Literature assisted immensely in both the development of the conceptual framework upon which the study hinged as well as in the development of the questionnaire items. The study also made use of an interview checklist to guide the participants. The findings reveal a mix of responses that indicate that while there are gains in adopting e-hrm systems, it is wiser to consider supporting resources as well as articulate the needs of the university better before any investment is made.

Electronic human resource management: Enhancing or entrancing?

Directory of Open Access Journals (Sweden)

Paul Poisat

2017-07-01

Full Text Available Orientation: This article provides an investigation into the current level of development of the body of knowledge related to electronic human resource management (e-HRM by means of a qualitative content analysis. Several aspects of e-HRM, namely definitions of e-HRM, the theoretical perspectives around e-HRM, the role of e-HRM, the various types of e-HRM and the requirements for successful e-HRM, are examined. Research purpose: The purpose of the article was to determine the status of e-HRM and examine the studies that report on the link between e-HRM and organisational productivity. Motivation for the study: e-HRM has the capacity to improve organisational efficiency and leverage the role of human resources (HR as a strategic business partner. Main findings: The notion that the implementation of e-HRM will lead to improved organisational productivity is commonly assumed; however, empirical evidence in this regard was found to be limited. Practical/managerial implications: From the results of this investigation it is evident that more research is required to gain a greater understanding of the influence of e-HRM on organisational productivity, as well as to develop measures for assessing this influence. Contribution: This article proposes additional areas to research and measure when investigating the effectiveness of e-HRM. It provides a different lens from which to view e-HRM assessment whilst keeping it within recognised HR measurement parameters (the HR value chain. In addition, it not only provides areas for measuring e-HRM’s influence but also provides important clues as to how the measurements may be approached.

Widespread auditory deficits in tune deafness.

Science.gov (United States)

Jones, Jennifer L; Zalewski, Christopher; Brewer, Carmen; Lucker, Jay; Drayna, Dennis

2009-02-01

The goal of this study was to investigate auditory function in individuals with deficits in musical pitch perception. We hypothesized that such individuals have deficits in nonspeech areas of auditory processing. We screened 865 randomly selected individuals to identify those who scored poorly on the Distorted Tunes test (DTT), a measure of musical pitch recognition ability. Those who scored poorly were given a comprehensive audiologic examination, and those with hearing loss or other confounding audiologic factors were excluded from further testing. Thirty-five individuals with tune deafness constituted the experimental group. Thirty-four individuals with normal hearing and normal DTT scores, matched for age, gender, handedness, and education, and without overt or reported psychiatric disorders made up the normal control group. Individual and group performance for pure-tone frequency discrimination at 1000 Hz was determined by measuring the difference limen for frequency (DLF). Auditory processing abilities were assessed using tests of pitch pattern recognition, duration pattern recognition, and auditory gap detection. In addition, we evaluated both attention and short- and long-term memory as variables that might influence performance on our experimental measures. Differences between groups were evaluated statistically using Wilcoxon nonparametric tests and t-tests as appropriate. The DLF at 1000 Hz in the group with tune deafness was significantly larger than that of the normal control group. However, approximately one-third of participants with tune deafness had DLFs within the range of performance observed in the control group. Many individuals with tune deafness also displayed a high degree of variability in their intertrial frequency discrimination performance that could not be explained by deficits in memory or attention. Pitch and duration pattern discrimination and auditory gap-detection ability were significantly poorer in the group with tune deafness

Electrical tuning of mechanical characteristics in qPlus sensor: Active Q and resonance frequency control

Energy Technology Data Exchange (ETDEWEB)

Lee, Manhee; Hwang, Jong Geun; Jahng, Junghoon; Kim, QHwan; Noh, Hanaul; An, Sangmin; Jhe, Wonho, E-mail: whjhe@snu.ac.kr [Department of Physics and Astronomy, Institute of Applied Physics and Centre for THz-Bio Application Systems, Seoul National University, Seoul 151-747 (Korea, Republic of)

2016-08-21

We present an electrical feedback method for independent and simultaneous tuning of both the resonance frequency and the quality factor of a harmonic oscillator, the so called “qPlus” configuration of quartz tuning forks. We incorporate a feedback circuit with two electronic gain parameters into the original actuation-detection system, and systematically demonstrate the control of the original resonance frequency of 32 592 Hz from 32 572 Hz to 32 610 Hz and the original quality factor 952 from 408 up to 20 000. This tunable module can be used for enhancing and optimizing the oscillator performance in compliance with specifics of applications.

Electrical tuning of mechanical characteristics in qPlus sensor: Active Q and resonance frequency control

International Nuclear Information System (INIS)

Lee, Manhee; Hwang, Jong Geun; Jahng, Junghoon; Kim, QHwan; Noh, Hanaul; An, Sangmin; Jhe, Wonho

2016-01-01

We present an electrical feedback method for independent and simultaneous tuning of both the resonance frequency and the quality factor of a harmonic oscillator, the so called “qPlus” configuration of quartz tuning forks. We incorporate a feedback circuit with two electronic gain parameters into the original actuation-detection system, and systematically demonstrate the control of the original resonance frequency of 32 592 Hz from 32 572 Hz to 32 610 Hz and the original quality factor 952 from 408 up to 20 000. This tunable module can be used for enhancing and optimizing the oscillator performance in compliance with specifics of applications.

Tune splitting in the presence of linear coupling

International Nuclear Information System (INIS)

Parzen, G.

1991-01-01

The presence of random skew quadrupole field errors will couple the x and y motions. The x and y motions are then each given by the sum of 2 normal modes with the tunes v 1 and v 2 , which may differ appreciably from v x and v y , the unperturbed tunes. This is often called tune splitting since |v 1 - v 2 | is usually larger than |v x - v y |. This tune splitting may be large in proton accelerators using superconducting magnets, because of the relatively large random skew quadrupole field errors that are expected in these magnets. This effect is also increased by the required insertions in proton colliders which generate large β-functions in the insertion region. This tune splitting has been studied in the RHIC accelerator. For RHIC, a tune splitting as large as 0.2 was found in one worse case. A correction system has been developed for correcting this large tune splitting which uses two families of skew quadrupole correctors. It has been found that this correction system corrects most of the large tune splitting, but a residual tune splitting remains that is still appreciable. This paper discusses the corrections to this residual time

Single-particle dynamics in a nonlinear accelerator lattice: attaining a large tune spread with octupoles in IOTA

International Nuclear Information System (INIS)

Antipov, S.A.; Nagaitsev, S.; Valishev, A.

2017-01-01

Fermilab is constructing the Integrable Optics Test Accelerator (IOTA) as the centerpiece of the Accelerator R and D Program towards high-intensity circular machines. One of the factors limiting the beam intensity in present circular accelerators is collective instabilities, which can be suppressed by a spread of betatron frequencies (tunes) through the Landau damping mechanism or by an external damper, if the instability is slow enough. The spread is usually created by octupole magnets, which introduce the tune dependence on the amplitude and, in some cases, by a chromatic spread (tune dependence on particle's momentum). The introduction of octupoles usually has both beneficial (improved Landau damping) and harmful properties, such as a resonant behavior and a reduction of the dynamic aperture. One of the research goals at the IOTA ring is to achieve a large betatron tune spread, while retaining a large dynamic aperture, using conventional octupole magnets in a special but realistic accelerator configuration. The configuration, although not integrable by design, approximates an autonomous 2D Hamiltonian system. In this paper, we present results of computer simulations of an electron beam in the IOTA by particle tracking and the Frequency Map Analysis. The results show that the ring's octupole magnets can be configured to provide a betatron tune shift of 0.08 (for particles at large amplitudes) with the dynamical aperture of over 20 beam sigma for a 150-MeV electron beam. The influence of the synchrotron motion, lattice errors, and magnet imperfections is insignificant for the parameters and levels of tolerances set by the design of the ring. The described octupole insert could be beneficial for enhancing Landau damping in high intensity machines.

Telling in-tune from out-of-tune: widespread evidence for implicit absolute intonation.

Science.gov (United States)

Van Hedger, Stephen C; Heald, Shannon L M; Huang, Alex; Rutstein, Brooke; Nusbaum, Howard C

2017-04-01

Absolute pitch (AP) is the rare ability to name or produce an isolated musical note without the aid of a reference note. One skill thought to be unique to AP possessors is the ability to provide absolute intonation judgments (e.g., classifying an isolated note as "in-tune" or "out-of-tune"). Recent work has suggested that absolute intonation perception among AP possessors is not crystallized in a critical period of development, but is dynamically maintained by the listening environment, in which the vast majority of Western music is tuned to a specific cultural standard. Given that all listeners of Western music are constantly exposed to this specific cultural tuning standard, our experiments address whether absolute intonation perception extends beyond AP possessors. We demonstrate that non-AP listeners are able to accurately judge the intonation of completely isolated notes. Both musicians and nonmusicians showed evidence for absolute intonation recognition when listening to familiar timbres (piano and violin). When testing unfamiliar timbres (triangle and inverted sine waves), only musicians showed weak evidence of absolute intonation recognition (Experiment 2). Overall, these results highlight a previously unknown similarity between AP and non-AP possessors' long-term musical note representations, including evidence of sensitivity to frequency.

Identifying and evaluating electronic learning resources for use in adult-gerontology nurse practitioner education.

Science.gov (United States)

Thompson, Hilaire J; Belza, Basia; Baker, Margaret; Christianson, Phyllis; Doorenbos, Ardith; Nguyen, Huong

2014-01-01

Enhancing existing curricula to meet newly published adult-gerontology advanced practice registered nurse (APRN) competencies in an efficient manner presents a challenge to nurse educators. Incorporating shared, published electronic learning resources (ELRs) in existing or new courses may be appropriate in order to assist students in achieving competencies. The purposes of this project were to (a) identify relevant available ELR for use in enhancing geriatric APRN education and (b) to evaluate the educational utility of identified ELRs based on established criteria. A multilevel search strategy was used. Two independent team members reviewed identified ELR against established criteria to ensure utility. Only resources meeting all criteria were retained. Resources were found for each of the competency areas and included formats such as podcasts, Web casts, case studies, and teaching videos. In many cases, resources were identified using supplemental strategies and not through traditional search or search of existing geriatric repositories. Resources identified have been useful to advanced practice educators in improving lecture and seminar content in a particular topic area and providing students and preceptors with additional self-learning resources. Addressing sustainability within geriatric APRN education is critical for sharing of best practices among educators and for sustainability of teaching and related resources. © 2014.

Systematic review of electronic surveillance of infectious diseases with emphasis on antimicrobial resistance surveillance in resource-limited settings.

Science.gov (United States)

Rattanaumpawan, Pinyo; Boonyasiri, Adhiratha; Vong, Sirenda; Thamlikitkul, Visanu

2018-02-01

Electronic surveillance of infectious diseases involves rapidly collecting, collating, and analyzing vast amounts of data from interrelated multiple databases. Although many developed countries have invested in electronic surveillance for infectious diseases, the system still presents a challenge for resource-limited health care settings. We conducted a systematic review by performing a comprehensive literature search on MEDLINE (January 2000-December 2015) to identify studies relevant to electronic surveillance of infectious diseases. Study characteristics and results were extracted and systematically reviewed by 3 infectious disease physicians. A total of 110 studies were included. Most surveillance systems were developed and implemented in high-income countries; less than one-quarter were conducted in low-or middle-income countries. Information technologies can be used to facilitate the process of obtaining laboratory, clinical, and pharmacologic data for the surveillance of infectious diseases, including antimicrobial resistance (AMR) infections. These novel systems require greater resources; however, we found that using electronic surveillance systems could result in shorter times to detect targeted infectious diseases and improvement of data collection. This study highlights a lack of resources in areas where an effective, rapid surveillance system is most needed. The availability of information technology for the electronic surveillance of infectious diseases, including AMR infections, will facilitate the prevention and containment of such emerging infectious diseases. Copyright © 2018 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.

Apple iTunes music store

OpenAIRE

Lenzi, R.; Schmucker, M.; Spadoni, F.

2003-01-01

This technical report analyses the Apple iTunes Music Store and its success factors. Besides the technical aspects, user and customer aspects as well as content aspects are considered. Furthermore, iTunes Music Store's impact to online music distribution services is analysed and a short outlook to future music online distribution is given.

From Millennium ERM to Proquest 360 Resource Manager: Implementing a new Electronic Resources Management System ERMS in an International Graduate Research University in Saudi Arabia

KAUST Repository

Ramli, Rindra M.

2017-01-01

An overview of the Recommendation Study and the subsequent Implementation of a new Electronic Resources Management system ERMS in an international graduate research university in the Kingdom of Saudi Arabia. It covers the timeline, deliverables

Plasma Wave Electronic Terahertz Technology

National Research Council Canada - National Science Library

Shur, Michael

2003-01-01

Plasma waves are oscillations of electron density in time and space. In deep submicron field effect transistors plasma wave frequencies lie in the terahertz range and can be tuned by applied gate bias...

'Electron compression' of beam-beam footprint in the Tevatron

International Nuclear Information System (INIS)

Shiltsev, V.; Finley, D.A.

1997-08-01

The beam-beam interaction in the Tevatron collider sets some limits on bunch intensity and luminosity. These limits are caused by a tune spread in each bunch which is mostly due to head-on collisions, but there is also a bunch-to-bunch tune spread due to parasitic collisions in multibunch operation. We describe a counter-traveling electron beam which can be used to eliminate these effects, and present general considerations and physics limitations of such a device which provides 'electron compression' of the beam-beam footprint in the Tevatron

Duo gating on a 3D topological insulator - independent tuning of both topological surface states

Science.gov (United States)

Li, Chuan; de Ronde, Bob; Snelder, Marieke; Stehno, Martin; Huang, Yingkai; Golden, Mark; Brinkman, Alexander; ICE Team; IOP Collaboration

ABSTRACT: Topological insulators are associated with a trove of exciting physics, such as the ability to host robust anyons, Majorana Bound States, which can be used for quantum computation. For future Majorana devices it is desirable to have the Fermi energy tuned as close as possible to the Dirac point of the topological surface state. Based on previous work on gating BSTS, we report the experimental progress towards gate-tuning of the top and bottom topological surface states of BiSbTeSe2 crystal flakes. When the Fermi level is moved across the Dirac point conduction is shown to change from electron dominated transport to hole dominated transport independently for either surface. In the high magnetic field, one can tune the system precisely between the different landau levels of both surfaces, thus a full gating map of the possible landau levels combination is established. In addition, we provide a simple capacitance model to explain the general hysteresis behaviors in topological insulator systems.

The minimally tuned minimal supersymmetric standard model

International Nuclear Information System (INIS)

Essig, Rouven; Fortin, Jean-Francois

2008-01-01

The regions in the Minimal Supersymmetric Standard Model with the minimal amount of fine-tuning of electroweak symmetry breaking are presented for general messenger scale. No a priori relations among the soft supersymmetry breaking parameters are assumed and fine-tuning is minimized with respect to all the important parameters which affect electroweak symmetry breaking. The superpartner spectra in the minimally tuned region of parameter space are quite distinctive with large stop mixing at the low scale and negative squark soft masses at the high scale. The minimal amount of tuning increases enormously for a Higgs mass beyond roughly 120 GeV

Tuning the electronic structure of SrTiO3/SrFeO3−x superlattices via composition and vacancy control

Directory of Open Access Journals (Sweden)

Robert F. Berger

2014-04-01

Full Text Available Using density functional theory-based calculations, we explore the effects of oxygen vacancies and epitaxial layering on the atomic, magnetic, and electronic structure of (SrTiO3n(SrFeO3−x1 superlattices. While structures without oxygen vacancies (x = 0 possess small or non-existent band gaps and ferromagnetic ordering in their iron layers, those with large vacancy concentrations (x = 0.5 have much larger gaps and antiferromagnetic ordering. Though the computed gaps depend numerically on the delicate energetic balance of vacancy ordering and on the value of Hubbard U eff used in the calculations, we demonstrate that changes in layering can tune the band gaps of these superlattices below that of SrTiO3 (3.2 eV by raising their valence band maxima. This suggests the possibility that these superlattices could absorb in the solar spectrum, and could serve as water-splitting photocatalysts.

Feedback-tuned, noise resilient gates for encoded spin qubits

Science.gov (United States)

Bluhm, Hendrik

Spin 1/2 particles form native two level systems and thus lend themselves as a natural qubit implementation. However, encoding a single qubit in several spins entails benefits, such as reducing the resources necessary for qubit control and protection from certain decoherence channels. While several varieties of such encoded spin qubits have been implemented, accurate control remains challenging, and leakage out of the subspace of valid qubit states is a potential issue. Optimal performance typically requires large pulse amplitudes for fast control, which is prone to systematic errors and prohibits standard control approaches based on Rabi flopping. Furthermore, the exchange interaction typically used to electrically manipulate encoded spin qubits is inherently sensitive to charge noise. I will discuss all-electrical, high-fidelity single qubit operations for a spin qubit encoded in two electrons in a GaAs double quantum dot. Starting from a set of numerically optimized control pulses, we employ an iterative tuning procedure based on measured error syndromes to remove systematic errors.Randomized benchmarking yields an average gate fidelity exceeding 98 % and a leakage rate into invalid states of 0.2 %. These gates exhibit a certain degree of resilience to both slow charge and nuclear spin fluctuations due to dynamical correction analogous to a spin echo. Furthermore, the numerical optimization minimizes the impact of fast charge noise. Both types of noise make relevant contributions to gate errors. The general approach is also adaptable to other qubit encodings and exchange based two-qubit gates.

Electronic Structure Approach to Tunable Electronic Properties of Hybrid Organic-Inorganic Perovskites

Science.gov (United States)

Liu, Garnett; Huhn, William; Mitzi, David B.; Kanai, Yosuke; Blum, Volker

We present a study of the electronic structure of layered hybrid organic-inorganic perovskite (HOIP) materials using all-electron density-functional theory. Varying the nature of the organic and inorganic layers should enable systematically fine-tuning the carrier properties of each component. Using the HSE06 hybrid density functional including spin-orbit coupling (SOC), we validate the principle of tuning subsystem-specific parts of the electron band structures and densities of states in CH3NH3PbX3 (X=Cl, Br, I) compared to a modified organic component in layered (C6H5C2H4NH3) 2PbX4 (X=Cl, Br, I) and C20H22S4N2PbX4 (X=Cl, Br, I). We show that tunable shifts of electronic levels indeed arise by varying Cl, Br, I as the inorganic components, and CH3NH3+ , C6H5C2H4NH3+ , C20H22S4N22 + as the organic components. SOC is found to play an important role in splitting the conduction bands of the HOIP compounds investigated here. The frontier orbitals of the halide shift, increasing the gap, when Cl is substituted for Br and I.

Application of genetic algorithms to tuning fuzzy control systems

Science.gov (United States)

Espy, Todd; Vombrack, Endre; Aldridge, Jack

1993-01-01

Real number genetic algorithms (GA) were applied for tuning fuzzy membership functions of three controller applications. The first application is our 'Fuzzy Pong' demonstration, a controller that controls a very responsive system. The performance of the automatically tuned membership functions exceeded that of manually tuned membership functions both when the algorithm started with randomly generated functions and with the best manually-tuned functions. The second GA tunes input membership functions to achieve a specified control surface. The third application is a practical one, a motor controller for a printed circuit manufacturing system. The GA alters the positions and overlaps of the membership functions to accomplish the tuning. The applications, the real number GA approach, the fitness function and population parameters, and the performance improvements achieved are discussed. Directions for further research in tuning input and output membership functions and in tuning fuzzy rules are described.

Open-Source Electronic Health Record Systems for Low-Resource Settings: Systematic Review.

Science.gov (United States)

Syzdykova, Assel; Malta, André; Zolfo, Maria; Diro, Ermias; Oliveira, José Luis

2017-11-13

Despite the great impact of information and communication technologies on clinical practice and on the quality of health services, this trend has been almost exclusive to developed countries, whereas countries with poor resources suffer from many economic and social issues that have hindered the real benefits of electronic health (eHealth) tools. As a component of eHealth systems, electronic health records (EHRs) play a fundamental role in patient management and effective medical care services. Thus, the adoption of EHRs in regions with a lack of infrastructure, untrained staff, and ill-equipped health care providers is an important task. However, the main barrier to adopting EHR software in low- and middle-income countries is the cost of its purchase and maintenance, which highlights the open-source approach as a good solution for these underserved areas. The aim of this study was to conduct a systematic review of open-source EHR systems based on the requirements and limitations of low-resource settings. First, we reviewed existing literature on the comparison of available open-source solutions. In close collaboration with the University of Gondar Hospital, Ethiopia, we identified common limitations in poor resource environments and also the main requirements that EHRs should support. Then, we extensively evaluated the current open-source EHR solutions, discussing their strengths and weaknesses, and their appropriateness to fulfill a predefined set of features relevant for low-resource settings. The evaluation methodology allowed assessment of several key aspects of available solutions that are as follows: (1) integrated applications, (2) configurable reports, (3) custom reports, (4) custom forms, (5) interoperability, (6) coding systems, (7) authentication methods, (8) patient portal, (9) access control model, (10) cryptographic features, (11) flexible data model, (12) offline support, (13) native client, (14) Web client,(15) other clients, (16) code

Revisiting fine-tuning in the MSSM

Energy Technology Data Exchange (ETDEWEB)

Ross, Graham G. [Oxford Univ. (United Kingdom). Rudolf Peierls Centre for Theoretical Physics; Schmidt-Hoberg, Kai [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Staub, Florian [Karlsruher Institut fuer Technologie (KIT), Karlsruhe (Germany). Inst. fuer Theoretische Physik; Karlsruher Institut fuer Technologie (KIT), Eggenstein-Leopoldshafen (Germany). Inst. fuer Experimentelle Kernphysik

2017-03-15

We evaluate the amount of fine-tuning in constrained versions of the minimal supersymmetric standard model (MSSM), with different boundary conditions at the GUT scale. Specifically we study the fully constrained version as well as the cases of non-universal Higgs and gaugino masses. We allow for the presence of additional non-holomorphic soft-terms which we show further relax the fine-tuning. Of particular importance is the possibility of a Higgsino mass term and we discuss possible origins for such a term in UV complete models. We point out that loop corrections typically lead to a reduction in the fine-tuning by a factor of about two compared to the estimate at tree-level, which has been overlooked in many recent works. Taking these loop corrections into account, we discuss the impact of current limits from SUSY searches and dark matter on the fine-tuning. Contrary to common lore, we find that the MSSM fine-tuning can be as small as 10 while remaining consistent with all experimental constraints. If, in addition, the dark matter abundance is fully explained by the neutralino LSP, the fine-tuning can still be as low as ∝20 in the presence of additional non-holomorphic soft-terms. We also discuss future prospects of these models and find that the MSSM will remain natural even in the case of a non-discovery in the foreseeable future.

Revisiting fine-tuning in the MSSM

Energy Technology Data Exchange (ETDEWEB)

Ross, Graham G. [Rudolf Peierls Centre for Theoretical Physics, University of Oxford, 1 Keble Road, Oxford OX1 3NP (United Kingdom); Schmidt-Hoberg, Kai [DESY, Notkestraße 85, D-22607 Hamburg (Germany); Staub, Florian [Institute for Theoretical Physics (ITP), Karlsruhe Institute of Technology, Engesserstraße 7, D-76128 Karlsruhe (Germany); Institute for Nuclear Physics (IKP), Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen (Germany)

2017-03-06

We evaluate the amount of fine-tuning in constrained versions of the minimal supersymmetric standard model (MSSM), with different boundary conditions at the GUT scale. Specifically we study the fully constrained version as well as the cases of non-universal Higgs and gaugino masses. We allow for the presence of additional non-holomorphic soft-terms which we show further relax the fine-tuning. Of particular importance is the possibility of a Higgsino mass term and we discuss possible origins for such a term in UV complete models. We point out that loop corrections typically lead to a reduction in the fine-tuning by a factor of about two compared to the estimate at tree-level, which has been overlooked in many recent works. Taking these loop corrections into account, we discuss the impact of current limits from SUSY searches and dark matter on the fine-tuning. Contrary to common lore, we find that the MSSM fine-tuning can be as small as 10 while remaining consistent with all experimental constraints. If, in addition, the dark matter abundance is fully explained by the neutralino LSP, the fine-tuning can still be as low as ∼20 in the presence of additional non-holomorphic soft-terms. We also discuss future prospects of these models and find that the MSSM will remain natural even in the case of a non-discovery in the foreseeable future.

A mechanism for tuning 5 GHz HTS filters

Energy Technology Data Exchange (ETDEWEB)

Ohsaka, M.; Takeuchi, S.; Ono, S.; Lee, J.H.; Saito, A. [Department of Electrical Engineering, Yamagata University, 4-3-16 Johnan, Yonezawa 992-8510 (Japan); Akasegawa, A.; Yamanaka, K.; Kurihara, K. [Fujitsu LTD., 10-1 Wakamiya, Morinosato, Atsugi, Kanagawa 243-0197 (Japan); Ohshima, S. [Department of Electrical Engineering, Yamagata University, 4-3-16 Johnan, Yonezawa 992-8510 (Japan)], E-mail: ohshima@yz.yamagata-u.ac.jp

2008-09-15

We developed a tuning mechanism of HTS filter with a dielectric tuning plate, dielectric trimming rods, and conducting trimming rods. The tuning plate has windows through which the dielectric and conducting trimming rods pass. The tuning plate was designed for a 3-pole filter with 5 GHz center frequency (f{sub c}) and 100 MHz bandwidth (BW) using a 3-dimensional electromagnetic simulator. We were able to shift the f{sub c} to frequencies below 500 MHz using the tuning plate with a dielectric constant of 45. However, the insertion loss (IL) and the pass-band ripple of the filter became more severe and the BW of the filter was narrower after tuning. We tried to improve the filter properties after tuning using the dielectric and conducting trimming rods. We decreased the IL and the pass-band ripple by adjusting the height of the dielectric trimming rods to above the resonators. Also, the BW was improved by using copper (Cu) trimming rods above the spaces between the resonators. The tuning plate and the trimming rods did not affect the IL. So, we simulated 500 MHz tuning without the filter properties deteriorating at f{sub c} = 5 GHz. Also, we experimentally evaluated that the f{sub c} could be shifted to 340 MHz using the dielectric plate, the pass-band ripple could be decreased by ripple trimming using the dielectric rods, and the BW could be increased 31 MHz by BW trimming using the Cu rods.

Summary of ATLAS Pythia 8 tunes

CERN Document Server

The ATLAS collaboration

2012-01-01

We summarize the latest ATLAS Pythia 8 minimum bias and underlying event tunes. The Pythia 8 MPI tunes in this note have been constructed for nine different PDFs, making use of a new x-dependent hadronic matter distribution model.

Tuning resistance states by thickness control in an electroforming-free nanometallic complementary resistance random access memory

Science.gov (United States)

Yang, Xiang; Lu, Yang; Lee, Jongho; Chen, I.-Wei

2016-01-01

Tuning low resistance state is crucial for resistance random access memory (RRAM) that aims to achieve optimal read margin and design flexibility. By back-to-back stacking two nanometallic bipolar RRAMs with different thickness into a complementary structure, we have found that its low resistance can be reliably tuned over several orders of magnitude. Such high tunability originates from the exponential thickness dependence of the high resistance state of nanometallic RRAM, in which electron wave localization in a random network gives rise to the unique scaling behavior. The complementary nanometallic RRAM provides electroforming-free, multi-resistance-state, sub-100 ns switching capability with advantageous characteristics for memory arrays.

Tuning resistance states by thickness control in an electroforming-free nanometallic complementary resistance random access memory

International Nuclear Information System (INIS)

Yang, Xiang; Lu, Yang; Lee, Jongho; Chen, I-Wei

2016-01-01

Tuning low resistance state is crucial for resistance random access memory (RRAM) that aims to achieve optimal read margin and design flexibility. By back-to-back stacking two nanometallic bipolar RRAMs with different thickness into a complementary structure, we have found that its low resistance can be reliably tuned over several orders of magnitude. Such high tunability originates from the exponential thickness dependence of the high resistance state of nanometallic RRAM, in which electron wave localization in a random network gives rise to the unique scaling behavior. The complementary nanometallic RRAM provides electroforming-free, multi-resistance-state, sub-100 ns switching capability with advantageous characteristics for memory arrays

Metal nitride cluster as a template to tune the electronic and magnetic properties of rare-earth metal containing endohedral fullerenes

International Nuclear Information System (INIS)

Zhang, Yang

2013-01-01

Rare-earth metal containing endohedral fullerenes have attracted much attention due to the feasibility of encaging metal atom, atoms or cluster inside of carbon cages. By switching the metal atom or cluster entrapped inside of the carbon cage the physical and chemical properties of the fullerene compounds can be tuned. The understanding of magnetic and electrochemical properties of endohedral fullerenes plays an essential role in fundamental scientific researches and potential applications in materials science. In this thesis, synthesizing novel rare-earth metal containing endohedral fullerene structures, studying the properties of these isolated endohedral fullerenes and the strategies of tuning the electronic and magnetic properties of endohedral fullerenes were introduced. The DC-arc discharging synthesis of different lanthanide metal-based (Ho, Ce and Pr) mixed metal nitride clusterfullerenes was achieved. Those rare-earth metal containing endohedral fullerenes were isolated by multi-step HPLC. The isolated samples were characterized by spectroscopic techniques included UV-vis-NIR, FTIR, Raman, LDI-TOF mass spectrometry, NMR and electrochemistry. The Ho-based mixed metal nitride clusterfullerenes Ho x M 3-x N rate at C 80 (M= Sc, Lu, Y; x=1, 2) were synthesized by ''reactive gas atmosphere'' method or ''selective organic solid'' route. The isolated samples were characterized by LDI-TOF mass spectrometry, UV-vis-NIR, FTIR, Raman and NMR spectroscopy. The 13 C NMR spectroscopic studies demonstrated exceptional NMR behaviors that resulted from switching the second metal inside of the mixed metal nitride cluster Ho x M 3-x N from Sc to Lu and further to Y. The LnSc 2 N rate at C 80 (Ln= Ce, Pr, Nd, Tb, Dy, Ho, Lu) MMNCFs were characterized by 13 C and 45 Sc NMR study respectively. According to Bleaney's theory and Reilley method, the separation of δ PC and δ con from δ para was achieved by the primary 13 C and 45 Sc NMR analysis of LnSc 2 N rate at C 80 (I). The

Frequency Tuning of Vibration Absorber Using Topology Optimization

Science.gov (United States)

Harel, Swapnil Subhash

A tuned mass absorber is a system for reducing the amplitude in one oscillator by coupling it to a second oscillator. If tuned correctly, the maximum amplitude of the first oscillator in response to a periodic driver will be lowered, and much of the vibration will be 'transferred' to the second oscillator. The tuned vibration absorber (TVA) has been utilized for vibration control purposes in many sectors of Civil/Automotive/Aerospace Engineering for many decades since its inception. Time and again we come across a situation in which a vibratory system is required to run near resonance. In the past, approaches have been made to design such auxiliary spring mass tuned absorbers for the safety of the structures. This research focuses on the development and optimization of continuously tuned mass absorbers as a substitute to the discretely tuned mass absorbers (spring- mass system). After conducting the study of structural behavior, the boundary condition and frequency to which the absorber is to be tuned are determined. The Modal analysis approach is used to determine mode shapes and frequencies. The absorber is designed and optimized using the topology optimization tool, which simultaneously designs, optimizes and tunes the absorber to the desired frequency. The tuned, optimized absorber, after post processing, is attached to the target structure. The number of the absorbers are increased to amplify bandwidth and thereby upgrade the safety of structure for a wide range of frequency. The frequency response analysis is carried out using various combinations of structure and number of absorber cell.

Simple force balance accelerometer/seismometer based on a tuning fork displacement sensor

International Nuclear Information System (INIS)

Stuart-Watson, D.; Tapson, J.

2004-01-01

Seismometers and microelectromechanical system accelerometers use the force-balance principle to obtain measurements. In these instruments the displacement of a mass object by an unknown force is sensed using a very high-resolution displacement sensor. The position of the object is then stabilized by applying an equal and opposite force to it. The magnitude of the stabilizing force is easily measured, and is assumed to be equivalent to the unknown force. These systems are critically dependent on the displacement sensor. In this article we use a resonant quartz tuning fork as the sensor. The tuning fork is operated so that its oscillation is lightly damped by the proximity of the movable mass object. Changes in the position of the mass object cause changes in the phase of the fork's resonance; this is used as the feedback variable in controlling the mass position. We have developed an acceleration sensor using this principle. The mass object is a piezoelectric bimorph diaphragm which is anchored around its perimeter, allowing direct electronic control of the displacement of its center. The tuning fork is brought very close to the diaphragm center, and is connected into a self-oscillating feedback circuit which has phase and amplitude as outputs. The diaphragm position is adjusted by a feedback loop, using phase as the feedback variable, to keep it in a constant position with respect to the tuning fork. The measured noise for this sensor is approximately 10.0 mg in a bandwidth of 100 Hz, which is substantially better than commercial systems of equivalent cost and size

Efficient tuning in supervised machine learning

NARCIS (Netherlands)

Koch, Patrick

2013-01-01

The tuning of learning algorithm parameters has become more and more important during the last years. With the fast growth of computational power and available memory databases have grown dramatically. This is very challenging for the tuning of parameters arising in machine learning, since the

Dynamic Performance Tuning Supported by Program Specification

Directory of Open Access Journals (Sweden)

Eduardo César

2002-01-01

Full Text Available Performance analysis and tuning of parallel/distributed applications are very difficult tasks for non-expert programmers. It is necessary to provide tools that automatically carry out these tasks. These can be static tools that carry out the analysis on a post-mortem phase or can tune the application on the fly. Both kind of tools have their target applications. Static automatic analysis tools are suitable for stable application while dynamic tuning tools are more appropriate to applications with dynamic behaviour. In this paper, we describe KappaPi as an example of a static automatic performance analysis tool, and also a general environment based on parallel patterns for developing and dynamically tuning parallel/distributed applications.

Evaluation of three electronic report processing systems for preparing hydrologic reports of the U.S Geological Survey, Water Resources Division

Science.gov (United States)

Stiltner, G.J.

1990-01-01

In 1987, the Water Resources Division of the U.S. Geological Survey undertook three pilot projects to evaluate electronic report processing systems as a means to improve the quality and timeliness of reports pertaining to water resources investigations. The three projects selected for study included the use of the following configuration of software and hardware: Ventura Publisher software on an IBM model AT personal computer, PageMaker software on a Macintosh computer, and FrameMaker software on a Sun Microsystems workstation. The following assessment criteria were to be addressed in the pilot studies: The combined use of text, tables, and graphics; analysis of time; ease of learning; compatibility with the existing minicomputer system; and technical limitations. It was considered essential that the camera-ready copy produced be in a format suitable for publication. Visual improvement alone was not a consideration. This report consolidates and summarizes the findings of the electronic report processing pilot projects. Text and table files originating on the existing minicomputer system were successfully transformed to the electronic report processing systems in American Standard Code for Information Interchange (ASCII) format. Graphics prepared using a proprietary graphics software package were transferred to all the electronic report processing software through the use of Computer Graphic Metafiles. Graphics from other sources were entered into the systems by scanning paper images. Comparative analysis of time needed to process text and tables by the electronic report processing systems and by conventional methods indicated that, although more time is invested in creating the original page composition for an electronically processed report , substantial time is saved in producing subsequent reports because the format can be stored and re-used by electronic means as a template. Because of the more compact page layouts, costs of printing the reports were 15% to 25

A tuning method for nonuniform traveling-wave accelerating structures

International Nuclear Information System (INIS)

Gong Cunkui; Zheng Shuxin; Shao Jiahang; Jia Xiaoyu; Chen Huaibi

2013-01-01

The tuning method of uniform traveling-wave structures based on non-resonant perturbation field distribution measurement has been widely used in tuning both constant-impedance and constant-gradient structures. In this paper, the method of tuning nonuniform structures is proposed on the basis of the above theory. The internal reflection coefficient of each cell is obtained from analyzing the normalized voltage distribution. A numerical simulation of tuning process according to the coupled cavity chain theory has been done and the result shows each cell is in right phase advance after tuning. The method will be used in the tuning of a disk-loaded traveling-wave structure being developed at the Accelerator Laboratory, Tsinghua University. (authors)

An optimal tuning strategy for tidal turbines

Science.gov (United States)

2016-01-01

Tuning wind and tidal turbines is critical to maximizing their power output. Adopting a wind turbine tuning strategy of maximizing the output at any given time is shown to be an extremely poor strategy for large arrays of tidal turbines in channels. This ‘impatient-tuning strategy’ results in far lower power output, much higher structural loads and greater environmental impacts due to flow reduction than an existing ‘patient-tuning strategy’ which maximizes the power output averaged over the tidal cycle. This paper presents a ‘smart patient tuning strategy’, which can increase array output by up to 35% over the existing strategy. This smart strategy forgoes some power generation early in the half tidal cycle in order to allow stronger flows to develop later in the cycle. It extracts enough power from these stronger flows to produce more power from the cycle as a whole than the existing strategy. Surprisingly, the smart strategy can often extract more power without increasing maximum structural loads on the turbines, while also maintaining stronger flows along the channel. This paper also shows that, counterintuitively, for some tuning strategies imposing a cap on turbine power output to limit loads can increase a turbine’s average power output. PMID:27956870

An optimal tuning strategy for tidal turbines.

Science.gov (United States)

Vennell, Ross

2016-11-01

Tuning wind and tidal turbines is critical to maximizing their power output. Adopting a wind turbine tuning strategy of maximizing the output at any given time is shown to be an extremely poor strategy for large arrays of tidal turbines in channels. This 'impatient-tuning strategy' results in far lower power output, much higher structural loads and greater environmental impacts due to flow reduction than an existing 'patient-tuning strategy' which maximizes the power output averaged over the tidal cycle. This paper presents a 'smart patient tuning strategy', which can increase array output by up to 35% over the existing strategy. This smart strategy forgoes some power generation early in the half tidal cycle in order to allow stronger flows to develop later in the cycle. It extracts enough power from these stronger flows to produce more power from the cycle as a whole than the existing strategy. Surprisingly, the smart strategy can often extract more power without increasing maximum structural loads on the turbines, while also maintaining stronger flows along the channel. This paper also shows that, counterintuitively, for some tuning strategies imposing a cap on turbine power output to limit loads can increase a turbine's average power output.

Tuning of band gap due to fluorination of graphyne and graphdiyne

International Nuclear Information System (INIS)

Bhattacharya, B; Singh, N B; Sarkar, U

2014-01-01

The electronic properties of graphyne and graphdiyne consisting of sp and sp 2 hybridized carbon atom have been investigated within the density functional theory (DFT) method. The corresponding changes in the electronic properties due to systematic functionalization by fluorine at different possible sites are reported. Our band structure calculations clearly infer that all fluorographyne are wide band gap semiconductor and the band gap can be tuned by fluorination and the possibility of modulating the band gap provides flexibility for its use in nanoelectronic devices. Projected density of state (PDOS) analysis provides the clear idea about the bonding nature of these novel materials in details and Crystal Orbital Hamilton Population (-COHP) analysis shed insight on the orbital participating in bonding and antibonding

Iterative Feedback Tuning in district heating systems; Iterative Feedback Tuning i vaermeproduktionsanlaeggningar

Energy Technology Data Exchange (ETDEWEB)

Raaberg, Martin; Velut, Stephane; Bari, Siavosh Amanat

2010-10-15

The project goal is to evaluate and describe how Iterative Feedback Tuning (IFT) can be used to tune controllers in the typical control loops in heat- and power plants. There are only a few practical studies carried out for IFT and they are not really relevant for power and heat processes. It is the practical problems in implementing the IFT and the result of trimming that is the focus of this project. The project will start with theoretical studies of the IFT-method, then realization and simple simulations in scilab. The IFT equations are then implemented in Freelance 2000, an ABB control system, for practical tests on a SISO- and a MIMO-process. By performing reproducible experiments on the process and analyze the results IFT can adjust the controller parameters to minimize a cost function that represents the control goal. The project selected for SISO experiments a pressure controller in an oil transportation system. By controlling the valve position of a control valve for the reversal to the supply tank, the pressure in the oil transport system is regulated. A disturbance in oil pressure can be achieved by changing the position of a valve that lets oil through to the day tank. The selected MIMO-process is a pre-heater in a degassing process. In this process, a valve on the secondary side is utilized to control the flow in the secondary system. A valve on the primary side is utilized to control the district heating water flow through the heat exchanger to control the temperature on the secondary side. An increased secondary flow increases the heat demand and thus requiring an increase in primary flow to maintain the secondary side outlet temperature. This is the cross-coupling responsible for why it is an advantage to consider the process as multi-variable. Using the IFT method, the two original PID-controllers and a feed-forward controller is tuned simultaneously. IFT-method was difficult to implement but worked well in both simulations and in real processes

Small Commercial Building Re-tuning: A Primer

Energy Technology Data Exchange (ETDEWEB)

Cort, Katherine A.; Hostick, Donna J.; Underhill, Ronald M.; Fernandez, Nicholas; Katipamula, Srinivas

2013-09-30

To help building owners and managers address issues related to energy-efficient operation of small buildings, DOE has developed a Small Building Re-tuning training curriculum. This "primer" provides additional background information to understand some of the concepts presented in the Small Building Re-tuning training. The intent is that those who are less familiar with the buidling energy concepts will review this material before taking the building re-tuning training class.

Oracle SQL Tuning pocket Reference

CERN Document Server

Gurry, Mark

2002-01-01

One of the most important challenges faced by Oracle database administrators and Oracle developers is the need to tune SQL statements so that they execute efficiently. Poorly tuned SQL statements are one of the leading causes of substandard database performance and poor response time. SQL statements that perform poorly result in frustration for users, and can even prevent a company from serving its customers in a timely manner

Use and User Perception of Electronic Information Resources: A Case Study of Siva Institute of Frontier Technology, India

Directory of Open Access Journals (Sweden)

Velmurugan Chandran

2013-12-01

Full Text Available The present study aims to explore the use and user perception of electronic resources in Siva Institute of Frontier Technology, India. A total number of 123 users were taken into account for the study through a questionnaire-based survey method. A well-structured questionnaire was designed and distributed to the selected 200 students and staff members. 123 copies of the questionnaires were returned dully filled in and the overall response rate was 61.50 percent. The questionnaire contained both open- and close-ended questions. The collected data were classified, analyzed, and tabulated by using simple statistical methods. This study covers the impact of electronic resources on students and faculty in their academic pursuit.

A preliminary categorization of end-of-life electrical and electronic equipment as secondary metal resources

International Nuclear Information System (INIS)

Oguchi, Masahiro; Murakami, Shinsuke; Sakanakura, Hirofumi; Kida, Akiko; Kameya, Takashi

2011-01-01

Highlights: → End-of-life electrical and electronic equipment (EEE) as secondary metal resources. → The content and the total amount of metals in specific equipment are both important. → We categorized 21 EEE types from contents and total amounts of various metals. → Important equipment types as secondary resources were listed for each metal kind. → Collectability and possible collection systems of various EEE types were discussed. - Abstract: End-of-life electrical and electronic equipment (EEE) has recently received attention as a secondary source of metals. This study examined characteristics of end-of-life EEE as secondary metal resources to consider efficient collection and metal recovery systems according to the specific metals and types of EEE. We constructed an analogy between natural resource development and metal recovery from end-of-life EEE and found that metal content and total annual amount of metal contained in each type of end-of-life EEE should be considered in secondary resource development, as well as the collectability of the end-of-life products. We then categorized 21 EEE types into five groups and discussed their potential as secondary metal resources. Refrigerators, washing machines, air conditioners, and CRT TVs were evaluated as the most important sources of common metals, and personal computers, mobile phones, and video games were evaluated as the most important sources of precious metals. Several types of small digital equipment were also identified as important sources of precious metals; however, mid-size information and communication technology (ICT) equipment (e.g., printers and fax machines) and audio/video equipment were shown to be more important as a source of a variety of less common metals. The physical collectability of each type of EEE was roughly characterized by unit size and number of end-of-life products generated annually. Current collection systems in Japan were examined and potentially appropriate collection

Noncovalent Intermolecular Interactions in Organic Electronic Materials: Implications for the Molecular Packing vs Electronic Properties of Acenes

KAUST Repository

Sutton, Christopher; Risko, Chad; Bredas, Jean-Luc

2015-01-01

Noncovalent intermolecular interactions, which can be tuned through the toolbox of synthetic chemistry, determine not only the molecular packing but also the resulting electronic, optical, and mechanical properties of materials derived from π

Tuning spin transport across two-dimensional organometallic junctions

Science.gov (United States)

Liu, Shuanglong; Wang, Yun-Peng; Li, Xiangguo; Fry, James N.; Cheng, Hai-Ping

2018-01-01

We study via first-principles modeling and simulation two-dimensional spintronic junctions made of metal-organic frameworks consisting of two Mn-phthalocyanine ferromagnetic metal leads and semiconducting Ni-phthalocyanine channels of various lengths. These systems exhibit a large tunneling magnetoresistance ratio; the transmission functions of such junctions can be tuned using gate voltage by three orders of magnitude. We find that the origin of this drastic change lies in the orbital alignment and hybridization between the leads and the center electronic states. With physical insight into the observed on-off phenomenon, we predict a gate-controlled spin current switch based on two-dimensional crystallines and offer general guidelines for designing spin junctions using 2D materials.

Stress-tuned conductor-polymer composite for use in sensors

Science.gov (United States)

Martin, James E; Read, Douglas H

2013-10-22

A method for making a composite polymeric material with electrical conductivity determined by stress-tuning of the conductor-polymer composite, and sensors made with the stress-tuned conductor-polymer composite made by this method. Stress tuning is achieved by mixing a miscible liquid into the polymer precursor solution or by absorbing into the precursor solution a soluble compound from vapor in contact with the polymer precursor solution. The conductor may or may not be ordered by application of a magnetic field. The composite is formed by polymerization with the stress-tuning agent in the polymer matrix. The stress-tuning agent is removed following polymerization to produce a conductor-polymer composite with a stress field that depends on the amount of stress-tuning agent employed.

Principles of formation of the content of an educational electronic resource on the basis of general and didactic patterns of learning

Directory of Open Access Journals (Sweden)

Ольга Юрьевна Заславская

2018-12-01

Full Text Available The article considers the influence of the development of technical means of teaching on the effectiveness of educational and methodical resources. Modern opportunities of information and communication technologies allow creating electronic educational resources that represent educational information that automates the learning process, provide information assistance, if necessary, collect and process statistical information on the degree of development of the content of the school material by schoolchildren, set an individual trajectory of learning, and so on. The main principle of data organization is the division of the training course into separate sections on the thematic elements and components of the learning process. General regularities include laws that encompass the entire didactic system, and in specific (particular cases, those whose actions extend to a separate component (aspect of the system. From the standpoint of the existence of three types of electronic training modules in the aggregate content of the electronic learning resource - information, control and module of practical classes - the principles of the formation of the electronic learning resource, in our opinion, should regulate all these components. Each of the certain principles is considered in the groups: scientific orientation, methodological orientation, systemic nature, accounting of interdisciplinary connections, fundamentalization, systematic and dosage sequence, rational use of study time, accessibility, minimization, operationalization of goals, unified identification diagnosis.

New ATLAS event generator tunes to 2010 data

CERN Document Server

The ATLAS collaboration

2011-01-01

This note describes the Monte Carlo event generator tunings for the Pythia 6 and Herwig/Jimmy generators in the ATLAS MC11 simulation production. New tunes have been produced for these generators, making maximal use of available published data from ATLAS and from the Tevatron and LEP experiments. Particular emphasis has been placed on improvement of the description of e+ e− event shape and jet rate data, and on description of hadron collider event shape observables in Pythia, as well as the established procedure of tuning the multiple parton interactions of both models to describe underlying event and minimum bias data. The tuning of Pythia is provided at this time for the MRST LO∗∗ PDF, while the purely MPI tune of Herwig/Jimmy is performed for ten different PDFs.

Electronic thermal conductivity of 2-dimensional circular-pore metallic nanoporous materials

International Nuclear Information System (INIS)

Huang, Cong-Liang; Lin, Zi-Zhen; Luo, Dan-Chen; Huang, Zun

2016-01-01

The electronic thermal conductivity (ETC) of 2-dimensional circular-pore metallic nanoporous material (MNM) was studied here for its possible applications in thermal cloaks. A simulation method based on the free-electron-gas model was applied here without considering the quantum effects. For the MNM with circular nanopores, there is an appropriate nanopore size for thermal conductivity tuning, while a linear relationship exists for this size between the ETC and the porosity. The appropriate nanopore diameter size will be about one times that of the electron mean free path. The ETC difference along different directions would be less than 10%, which is valuable when estimating possible errors, because the nanoscale-material direction could not be controlled during its application. Like nanoparticles, the ETC increases with increasing pore size (diameter for nanoparticles) while the porosity was fixed, until the pore size reaches about four times that of electron mean free path, at which point the ETC plateaus. The specular coefficient on the surface will significantly impact the ETC, especially for a high-porosity MNM. The ETC can be decreased by 30% with a tuning specular coefficient. - Highlights: • For metallic nanoporous materials, there is an appropriate pore size for thermal conductivity tuning. • ETC increases with increasing pore size until pore size reaches about four times EMFP. • The ETC difference between different directions will be less than 10%. • The ETC can be decreased by 30% with tuning specular coefficient.

From Millennium ERM to Proquest 360 Resource Manager: Implementing a new Electronic Resources Management System ERMS in an International Graduate Research University in Saudi Arabia

KAUST Repository

Ramli, Rindra M.

2017-05-17

An overview of the Recommendation Study and the subsequent Implementation of a new Electronic Resources Management system ERMS in an international graduate research university in the Kingdom of Saudi Arabia. It covers the timeline, deliverables and challenges as well as lessons learnt by the Project Team.

Tuning and History: A Personal Overview

Science.gov (United States)

Isaacs, Ann Katherine

2017-01-01

The text places Tuning History in the context of the rapidly developing international collaboration among historians which began in Europe in 1989, with the ECTS Pilot project, and continued, from 2000 on, with the European History Networks (for research and for curriculum development) working in parallel and in collaboration with Tuning, in…

Linear beam-beam tune shift calculations for the Tevatron Collider

International Nuclear Information System (INIS)

Johnson, D.

1989-01-01

A realistic estimate of the linear beam-beam tune shift is necessary for the selection of an optimum working point in the tune diagram. Estimates of the beam-beam tune shift using the ''Round Beam Approximation'' (RBA) have over estimated the tune shift for the Tevatron. For a hadron machine with unequal lattice functions and beam sizes, an explicit calculation using the beam size at the crossings is required. Calculations for various Tevatron lattices used in Collider operation are presented. Comparisons between the RBA and the explicit calculation, for elliptical beams, are presented. This paper discusses the calculation of the linear tune shift using the program SYNCH. Selection of a working point is discussed. The magnitude of the tune shift is influenced by the choice of crossing points in the lattice as determined by the pbar ''cogging effects''. Also discussed is current cogging procedures and presents results of calculations for tune shifts at various crossing points in the lattice. Finally, a comparison of early pbar tune measurements with the present linear tune shift calculations is presented. 17 refs., 13 figs., 3 tabs

Characterization and tuning of ultrahigh gradient permanent magnet quadrupoles

Directory of Open Access Journals (Sweden)

S. Becker

2009-10-01

Full Text Available The application of quadrupole devices with high field gradients and small apertures requires precise control over higher order multipole field components. We present a new scheme for performance control and tuning, which allows the illumination of most of the quadrupole device aperture because of the reduction of higher order field components. Consequently, the size of the aperture can be minimized to match the beam size achieving field gradients of up to 500  T m^{-1} at good imaging quality. The characterization method based on a Hall probe measurement and a Fourier analysis was confirmed using the high quality electron beam at the Mainz Microtron MAMI.

Metal nitride cluster as a template to tune the electronic and magnetic properties of rare-earth metal containing endohedral fullerenes

Energy Technology Data Exchange (ETDEWEB)

Zhang, Yang

2013-10-16

Rare-earth metal containing endohedral fullerenes have attracted much attention due to the feasibility of encaging metal atom, atoms or cluster inside of carbon cages. By switching the metal atom or cluster entrapped inside of the carbon cage the physical and chemical properties of the fullerene compounds can be tuned. The understanding of magnetic and electrochemical properties of endohedral fullerenes plays an essential role in fundamental scientific researches and potential applications in materials science. In this thesis, synthesizing novel rare-earth metal containing endohedral fullerene structures, studying the properties of these isolated endohedral fullerenes and the strategies of tuning the electronic and magnetic properties of endohedral fullerenes were introduced. The DC-arc discharging synthesis of different lanthanide metal-based (Ho, Ce and Pr) mixed metal nitride clusterfullerenes was achieved. Those rare-earth metal containing endohedral fullerenes were isolated by multi-step HPLC. The isolated samples were characterized by spectroscopic techniques included UV-vis-NIR, FTIR, Raman, LDI-TOF mass spectrometry, NMR and electrochemistry. The Ho-based mixed metal nitride clusterfullerenes Ho{sub x}M{sub 3-x}N rate at C{sub 80} (M= Sc, Lu, Y; x=1, 2) were synthesized by ''reactive gas atmosphere'' method or ''selective organic solid'' route. The isolated samples were characterized by LDI-TOF mass spectrometry, UV-vis-NIR, FTIR, Raman and NMR spectroscopy. The {sup 13}C NMR spectroscopic studies demonstrated exceptional NMR behaviors that resulted from switching the second metal inside of the mixed metal nitride cluster Ho{sub x}M{sub 3-x}N from Sc to Lu and further to Y. The LnSc{sub 2}N rate at C{sub 80} (Ln= Ce, Pr, Nd, Tb, Dy, Ho, Lu) MMNCFs were characterized by {sup 13}C and {sup 45}Sc NMR study respectively. According to Bleaney's theory and Reilley method, the separation of δ{sup PC} and δ{sup con

Tuning of Clic accelerating structure prototypes at CERN

CERN Document Server

Shi, J; Olyunin, A; Wuensch, W

2010-01-01

An RF measurement system has been set up at CERN for use in the X-band accelerating structure development program of the CLIC study. Using the system, S-parameters are measured and the field distribution is obtained automatically using a bead-pull technique. The corrections for tuning the structure are calculated from an initial measurement and cell-by-cell tuning is applied to obtain the correct phase advance and minimum reflection at the operation frequency. The detailed tuning procedure is presented and explained along with an example of measurement and tuning of CLIC accelerating structure prototypes.

The Synthesis of the Hierarchical Structure of Information Resources for Management of Electronic Commerce Entities

Directory of Open Access Journals (Sweden)

Krutova Anzhelika S.

2017-06-01

Full Text Available The aim of the article is to develop the theoretical bases for the classification and coding of economic information and the scientific justification of the content of information resources of an electronic commerce enterprise. The essence of information resources for management of electronic business entities is investigated. It is proved that the organization of accounting in e-commerce systems is advisable to be built on the basis of two circuits: accounting for financial flows and accounting associated with transformation of business factors in products and services as a result of production activities. There presented a sequence of accounting organization that allows to combine the both circuits in a single information system, which provides a possibility for the integrated replenishment and distributed simultaneous use of the e-commerce system by all groups of users. It is proved that the guarantee of efficient activity of the information management system of electronic commerce entities is a proper systematization of the aggregate of information resources on economic facts and operations of an enterprise in accordance with the management tasks by building the hierarchy of accounting nomenclatures. It is suggested to understand nomenclature as an objective, primary information aggregate concerning a certain fact of the economic activity of an enterprise, which is characterized by minimum requisites, is entered into the database of the information system and is to be reflected in the accounting system. It is proposed to build a database of e-commerce systems as a part of directories (constants, personnel, goods / products, suppliers, buyers and the hierarchy of accounting nomenclatures. The package of documents regulating the organization of accounting at an enterprise should include: the provision on the accounting services, the order on the accounting policy, the job descriptions, the schedules of information exchange, the report card and

Tuning electronic properties in graphene quantum dots by chemical functionalization: Density functional theory calculations

Science.gov (United States)

Abdelsalam, Hazem; Elhaes, Hanan; Ibrahim, Medhat A.

2018-03-01

The energy gap and dipole moment of chemically functionalized graphene quantum dots are investigated by density functional theory. The energy gap can be tuned through edge passivation by different elements or groups. Edge passivation by oxygen considerably decreases the energy gap in hexagonal nanodots. Edge states in triangular quantum dots can also be manipulated by passivation with fluorine. The dipole moment depends on: (a) shape and edge termination of the quantum dot, (b) attached group, and (c) position to which the groups are attached. Depending on the position of attached groups, the total dipole can be increased, decreased, or eliminated.

Spin tune dependence on closed orbit in RHIC

International Nuclear Information System (INIS)

Ptitsyn, V.; Bai, M.; Roser, T.

2010-01-01

Polarized proton beams are accelerated in RHIC to 250 GeV energy with the help of Siberian Snakes. The pair of Siberian Snakes in each RHIC ring holds the design spin tune at 1/2 to avoid polarization loss during acceleration. However, in the presence of closed orbit errors, the actual spin tune can be shifted away from the exact 1/2 value. It leads to a corresponding shift of locations of higher-order ('snake') resonances and limits the available betatron tune space. The largest closed orbit effect on the spin tune comes from the horizontal orbit angle between the two snakes. During RHIC Run in 2009 dedicated measurements with polarized proton beams were taken to verify the dependence of the spin tune on the local orbits at the Snakes. The experimental results are presented along with the comparison with analytical predictions.

Integrated unaligned resonant modulator tuning

Energy Technology Data Exchange (ETDEWEB)

Zortman, William A.; Lentine, Anthony L.

2017-10-03

Methods and systems for tuning a resonant modulator are disclosed. One method includes receiving a carrier signal modulated by the resonant modulator with a stream of data having an approximately equal number of high and low bits, determining an average power of the modulated carrier signal, comparing the average power to a predetermined threshold, and operating a tuning device coupled to the resonant modulator based on the comparison of the average power and the predetermined threshold. One system includes an input structure, a plurality of processing elements, and a digital control element. The input structure is configured to receive, from the resonant modulator, a modulated carrier signal. The plurality of processing elements are configured to determine an average power of the modulated carrier signal. The digital control element is configured to operate a tuning device coupled to the resonant modulator based on the average power of the modulated carrier signal.

Genetic algorithm parameters tuning for resource-constrained project scheduling problem

Science.gov (United States)

Tian, Xingke; Yuan, Shengrui

2018-04-01

Project Scheduling Problem (RCPSP) is a kind of important scheduling problem. To achieve a certain optimal goal such as the shortest duration, the smallest cost, the resource balance and so on, it is required to arrange the start and finish of all tasks under the condition of satisfying project timing constraints and resource constraints. In theory, the problem belongs to the NP-hard problem, and the model is abundant. Many combinatorial optimization problems are special cases of RCPSP, such as job shop scheduling, flow shop scheduling and so on. At present, the genetic algorithm (GA) has been used to deal with the classical RCPSP problem and achieved remarkable results. Vast scholars have also studied the improved genetic algorithm for the RCPSP problem, which makes it to solve the RCPSP problem more efficiently and accurately. However, for the selection of the main parameters of the genetic algorithm, there is no parameter optimization in these studies. Generally, we used the empirical method, but it cannot ensure to meet the optimal parameters. In this paper, the problem was carried out, which is the blind selection of parameters in the process of solving the RCPSP problem. We made sampling analysis, the establishment of proxy model and ultimately solved the optimal parameters.

Efficient Thermal Tuning Employing Metallic Microheater With Slow Light Effect

DEFF Research Database (Denmark)

Yan, Siqi; Chen, Hao; Gao, Shengqian

2018-01-01

Thermal tuning acts as one of the most fundamental roles in integrated silicon photonics since it can provide flexibility and reconfigurability. Low tuning power and fast tuning speed are long-term pursuing goals in terms of the performance of the thermal tuning. Here we propose and experimentall...

Online control loop tuning in Pickering Nuclear Generating Stations

International Nuclear Information System (INIS)

Yu, K.X.; Harrington, S.

2008-01-01

Most analog controllers in the Pickering B Nuclear Generating Stations adopted PID control scheme. In replacing the analog controllers with digital controllers, the PID control strategies, including the original tuning parameters were retained. The replacement strategy resulted in minimum effort on control loop tuning. In a few cases, however, it was found during commissioning that control loop tuning was required as a result of poor control loop performance, typically due to slow response and controlled process oscillation. Several factors are accounted for the necessities of control loop re-tuning. Our experience in commissioning the digital controllers showed that online control tuning posted some challenges in nuclear power plant. (author)

Overhead-Aware-Best-Fit (OABF) Resource Allocation Algorithm for Minimizing VM Launching Overhead

Energy Technology Data Exchange (ETDEWEB)

Wu, Hao [IIT; Garzoglio, Gabriele [Fermilab; Ren, Shangping [IIT, Chicago; Timm, Steven [Fermilab; Noh, Seo Young [KISTI, Daejeon

2014-11-11

FermiCloud is a private cloud developed in Fermi National Accelerator Laboratory to provide elastic and on-demand resources for different scientific research experiments. The design goal of the FermiCloud is to automatically allocate resources for different scientific applications so that the QoS required by these applications is met and the operational cost of the FermiCloud is minimized. Our earlier research shows that VM launching overhead has large variations. If such variations are not taken into consideration when making resource allocation decisions, it may lead to poor performance and resource waste. In this paper, we show how we may use an VM launching overhead reference model to minimize VM launching overhead. In particular, we first present a training algorithm that automatically tunes a given refer- ence model to accurately reflect FermiCloud environment. Based on the tuned reference model for virtual machine launching overhead, we develop an overhead-aware-best-fit resource allocation algorithm that decides where and when to allocate resources so that the average virtual machine launching overhead is minimized. The experimental results indicate that the developed overhead-aware-best-fit resource allocation algorithm can significantly improved the VM launching time when large number of VMs are simultaneously launched.

Reflectors and tuning elements for widely-tunable GaAs-based sampled grating DBR lasers

Science.gov (United States)

Brox, O.; Wenzel, H.; Della Case, P.; Tawfieq, M.; Sumpf, B.; Weyers, M.; Knigge, A.

2018-02-01

Widely-tunable lasers without moving parts are attractive light sources for sensors in industry and biomedicine. In contrast to InP based sampled grating (SG) distributed Bragg reflector (DBR) diode lasers which are commercially available, shorter wavelength GaAs SG-DBR lasers are still under development. One reason is the difficulty to integrate gratings with coupling coefficients that are high enough for functional grating bursts with lengths below 10 μm. Recently we have demonstrated > 20 nm wide quasi-continuous tuning with a GaAs based SG-DBR laser emitting around 975 nm. Wavelength selective reflectors are realized with SGs having different burst periods for the front and back mirrors. Thermal tuning elements (resistors) which are placed on top of the SG allow the control of the spectral positions of the SG reflector combs and hence to adjust the Vernier mode. In this work we characterize subsections of the developed SG-DBR laser to further improve its performance. We study the impact of two different vertical structures (with vertical far field FWHMs of 41° and 24°) and two grating orders on the coupling coefficient. Gratings with coupling coefficients above 350 cm-1 have been integrated into SG-DBR lasers. We also examine electronic tuning elements (a technique which is typically applied in InP based SG-DBR lasers and allows tuning within nanoseconds) and discuss the limitations in the GaAs material system

Chemically modulated graphene quantum dot for tuning the photoluminescence as novel sensory probe

Science.gov (United States)

Hwang, Eunhee; Hwang, Hee Min; Shin, Yonghun; Yoon, Yeoheung; Lee, Hanleem; Yang, Junghee; Bak, Sora; Lee, Hyoyoung

2016-12-01

A band gap tuning of environmental-friendly graphene quantum dot (GQD) becomes a keen interest for novel applications such as photoluminescence (PL) sensor. Here, for tuning the band gap of GQD, a hexafluorohydroxypropanyl benzene (HFHPB) group acted as a receptor of a chemical warfare agent was chemically attached on the GQD via the diazonium coupling reaction of HFHPB diazonium salt, providing new HFHPB-GQD material. With a help of the electron withdrawing HFHPB group, the energy band gap of the HFHPB-GQD was widened and its PL decay life time decreased. As designed, after addition of dimethyl methyl phosphonate (DMMP), the PL intensity of HFHPB-GQD sensor sharply increased up to approximately 200% through a hydrogen bond with DMMP. The fast response and short recovery time was proven by quartz crystal microbalance (QCM) analysis. This HFHPB-GQD sensor shows highly sensitive to DMMP in comparison with GQD sensor without HFHPB and graphene. In addition, the HFHPB-GQD sensor showed high selectivity only to the phosphonate functional group among many other analytes and also stable enough for real device applications. Thus, the tuning of the band gap of the photoluminescent GQDs may open up new promising strategies for the molecular detection of target substrates.

Application of Stark Tuned Laser for Interferometry and Polarimetry in Plasmas

International Nuclear Information System (INIS)

H.K. Park; K.C. Lee; B. Deng; C.W. Domier; M. Johnson; B. Nathan; N.C. Luhmann, Jr.

2001-01-01

A Stark-tuned optically pumped far-infrared CH(subscript ''3'')OH laser at 119 mm has been successfully applied in the Far Infrared Tangential Interferometer/Polarimeter (FIReTIP) system for the National Spherical Torus Experiment (NSTX). The system will provide temporally and radially resolved 2-D electron density profile [n(subscript ''e'')(r,t)] and toroidal field profile [B(subscript ''T'')(r,t)] data. In the 2001 campaign, a single channel interferometer system has been operated and tested for the Faraday rotation measurement. A plan for improvement and upgrading of the FIReTIP is discussed

Spectrally tuned structural and pigmentary coloration of birdwing butterfly wing scales.

Science.gov (United States)

Wilts, Bodo D; Matsushita, Atsuko; Arikawa, Kentaro; Stavenga, Doekele G

2015-10-06

The colourful wing patterns of butterflies play an important role for enhancing fitness; for instance, by providing camouflage, for interspecific mate recognition, or for aposematic display. Closely related butterfly species can have dramatically different wing patterns. The phenomenon is assumed to be caused by ecological processes with changing conditions, e.g. in the environment, and also by sexual selection. Here, we investigate the birdwing butterflies, Ornithoptera, the largest butterflies of the world, together forming a small genus in the butterfly family Papilionidae. The wings of these butterflies are marked by strongly coloured patches. The colours are caused by specially structured wing scales, which act as a chirped multilayer reflector, but the scales also contain papiliochrome pigments, which act as a spectral filter. The combined structural and pigmentary effects tune the coloration of the wing scales. The tuned colours are presumably important for mate recognition and signalling. By applying electron microscopy, (micro-)spectrophotometry and scatterometry we found that the various mechanisms of scale coloration of the different birdwing species strongly correlate with the taxonomical distribution of Ornithoptera species. © 2015 The Author(s).

Controlling user access to electronic resources without password

Science.gov (United States)

Smith, Fred Hewitt

2015-06-16

Described herein are devices and techniques for remotely controlling user access to a restricted computer resource. The process includes pre-determining an association of the restricted computer resource and computer-resource-proximal environmental information. Indicia of user-proximal environmental information are received from a user requesting access to the restricted computer resource. Received indicia of user-proximal environmental information are compared to associated computer-resource-proximal environmental information. User access to the restricted computer resource is selectively granted responsive to a favorable comparison in which the user-proximal environmental information is sufficiently similar to the computer-resource proximal environmental information. In at least some embodiments, the process further includes comparing user-supplied biometric measure and comparing it with a predetermined association of at least one biometric measure of an authorized user. Access to the restricted computer resource is granted in response to a favorable comparison.

Heavy superpartners with less tuning from hidden sector renormalisation

International Nuclear Information System (INIS)

Hardy, Edward

2014-01-01

In supersymmetric extensions of the Standard Model, superpartner masses consistent with collider bounds typically introduce significant tuning of the electroweak scale. We show that hidden sector renormalisation can greatly reduce such a tuning if the supersymmetry breaking, or mediating, sector runs through a region of strong coupling not far from the weak scale. In the simplest models, only the tuning due to the gaugino masses is improved, and a weak scale gluino mass in the region of 5 TeV may be obtained with an associated tuning of only one part in ten. In models with more complex couplings between the visible and hidden sectors, the tuning with respect to sfermions can also be reduced. We give an example of a model, with low scale gauge mediation and superpartner masses allowed by current LHC bounds, that has an overall tuning of one part in twenty

Electronic theses and dissertations: a review of this valuable resource for nurse scholars worldwide.

Science.gov (United States)

Goodfellow, L M

2009-06-01

A worldwide repository of electronic theses and dissertations (ETDs) could provide worldwide access to the most up-to-date research generated by masters and doctoral students. Until that international repository is established, it is possible to access some of these valuable knowledge resources. ETDs provide a technologically advanced medium with endless multimedia capabilities that far exceed the print and bound copies of theses and dissertations housed traditionally in individual university libraries. CURRENT USE: A growing trend exists for universities worldwide to require graduate students to submit theses or dissertations as electronic documents. However, nurse scholars underutilize ETDs, as evidenced by perusing bibliographic citation lists in many of the research journals. ETDs can be searched for and retrieved through several digital resources such as the Networked Digital Library of Theses and Dissertations (http://www.ndltd.org), ProQuest Dissertations and Theses (http://www.umi.com), the Australasian Digital Theses Program (http://adt.caul.edu.au/) and through individual university web sites and online catalogues. An international repository of ETDs benefits the community of nurse scholars in many ways. The ability to access recent graduate students' research electronically from anywhere in the world is advantageous. For scholars residing in developing countries, access to these ETDs may prove to be even more valuable. In some cases, ETDs are not available for worldwide access and can only be accessed through the university library from which the student graduated. Public access to university library ETD collections is not always permitted. Nurse scholars from both developing and developed countries could benefit from ETDs.

Challenges of communicating integrated water resource management in Zimbabwe

NARCIS (Netherlands)

Marimbe, S.; Manzungu, E.

2003-01-01

With the promulgation of the 1998 Water Act the Government of Zimbabwe took a decisive step to reform the country's water sector, to bring it in line with contemporary socio-political realities obtaining in the country, and in tune with the philosophy of integrated water resources management.

Mammalian odorant receptor tuning breadth persists across distinct odorant panels.

Directory of Open Access Journals (Sweden)

Devin Kepchia

Full Text Available The molecular receptive range (MRR of a mammalian odorant receptor (OR is the set of odorant structures that activate the OR, while the distribution of these odorant structures across odor space is the tuning breadth of the OR. Variation in tuning breadth is thought to be an important property of ORs, with the MRRs of these receptors varying from narrowly to broadly tuned. However, defining the tuning breadth of an OR is a technical challenge. For practical reasons, a screening panel that broadly covers odor space must be limited to sparse coverage of the many potential structures in that space. When screened with such a panel, ORs with different odorant specificities, but equal tuning breadths, might appear to have different tuning breadths due to chance. We hypothesized that ORs would maintain their tuning breadths across distinct odorant panels. We constructed a new screening panel that was broadly distributed across an estimated odor space and contained compounds distinct from previous panels. We used this new screening panel to test several murine ORs that were previously characterized as having different tuning breadths. ORs were expressed in Xenopus laevis oocytes and assayed by two-electrode voltage clamp electrophysiology. MOR256-17, an OR previously characterized as broadly tuned, responded to nine novel compounds from our new screening panel that were structurally diverse and broadly dispersed across an estimated odor space. MOR256-22, an OR previously characterized as narrowly tuned, responded to a single novel compound that was structurally similar to a previously known ligand for this receptor. MOR174-9, a well-characterized receptor with a narrowly tuned MRR, did not respond to any novel compounds in our new panel. These results support the idea that variation in tuning breadth among these three ORs is not an artifact of the screening protocol, but is an intrinsic property of the receptors.

Library resources on the Internet

Science.gov (United States)

Buchanan, Nancy L.

1995-07-01

Library resources are prevalent on the Internet. Library catalogs, electronic books, electronic periodicals, periodical indexes, reference sources, and U.S. Government documents are available by telnet, Gopher, World Wide Web, and FTP. Comparatively few copyrighted library resources are available freely on the Internet. Internet implementations of library resources can add useful features, such as full-text searching. There are discussion lists, Gophers, and World Wide Web pages to help users keep up with new resources and changes to existing ones. The future will bring more library resources, more types of library resources, and more integrated implementations of such resources to the Internet.

Electron cloud dynamics in the Cornell Electron Storage Ring Test Accelerator wiggler

Directory of Open Access Journals (Sweden)

C. M. Celata

2011-04-01

Full Text Available The interference of stray electrons (also called “electron clouds” with accelerator beams is important in modern intense-beam accelerators, especially those with beams of positive charge. In magnetic wigglers, used, for instance, for transverse emittance damping, the intense synchrotron radiation produced by the beam can generate an electron cloud of relatively high density. In this paper the complicated dynamics of electron clouds in wigglers is examined using the example of a wiggler in the Cornell Electron Storage Ring Test Accelerator experiment at the Cornell Electron Storage Ring. Three-dimensional particle-in-cell simulations with the WARP-POSINST computer code show different density and dynamics for the electron cloud at locations near the maxima of the vertical wiggler field when compared to locations near the minima. Dynamics in these regions, the electron cloud distribution vs longitudinal position, and the beam coherent tune shift caused by the wiggler electron cloud will be discussed.

Development of a Magnetron Resonance Frequency Auto Tuning System for Medical Xband [9300 MHz] RF Linear Accelerator

Energy Technology Data Exchange (ETDEWEB)

Cha, Sung Su; Lee, Byung Cheol [University of Science and Technology, Daejeon (Korea, Republic of); Kim, Yujong; Park, Hyung Dal; Lee, Byeong-No; Joo, Youngwoo; Cha, Hyungki; Lee, Soo Min; Song, Ki Baek [KAERI, Daejeon (Korea, Republic of); Lee, Seung Hyun [Sungkyunkwan University, Suwon (Korea, Republic of)

2015-05-15

The total components of the accelerator are the magnetron, electron gun, accelerating structure, a set of solenoid magnets, four sets of steering coils, a modulator, and a circulator. One of the accelerator components of the accelerating structure is made of oxygen-free high-conductivity copper (OFHC), and its volume is changed according to the ambient temperature. As the volume changes, the resonant frequency of the accelerating structure is changed. Accordingly, the resonance frequency is mismatched between the source of the magnetron and the accelerating structure. An automatic frequency tuning system is automatically matched with the resonant frequency of the magnetron and accelerating structure, which allows a high output power and reliable accelerator operation. An automatic frequency tuning system is composed of a step motor control part for correcting the frequency of the source and power measuring parts, i.e., the forward and reflected power between the magnetron and accelerating structure. In this paper, the design, fabrication, and RF power test of the automatic frequency tuning system for the X-band linac are presented. A frequency tuning system was developed to overcome an unstable accelerator operation owing to the frequency mismatch between the magnetron and accelerating structure. The frequency measurement accuracy is 100 kHz and 0.72 degree per pulse.

Conductance with stochastic resonance in Mn{sub 12} redox network without tuning

Energy Technology Data Exchange (ETDEWEB)

Hirano, Yoshiaki [Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama-cho, Toyonaka, Osaka 560-0043 (Japan); Graduate School of Engineering, University of Fukui, 3-9-1 Bunkyo, Fukui 910-8507 (Japan); Segawa, Yuji; Kawai, Tomoji [Institute of Scientific and Industrial Research (ISIR), Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047 (Japan); Kuroda-Sowa, Takayoshi [Department of Chemistry, Faculty of Science and Engineering, Kinki University, 3-4-1 Kowakae, Higashi-Osaka, Osaka 577-8502 (Japan); Matsumoto, Takuya, E-mail: matsumoto-t@chem.sci.osaka-u.ac.jp [Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama-cho, Toyonaka, Osaka 560-0043 (Japan)

2014-06-09

Artificial neuron-based information processing is one of the attractive approaches of molecular-scale electronics, which can exploit the ability of molecular system for self-assembling or self-organization. The self-organized Mn{sub 12}/DNA redox network shows nonlinear current-voltage characteristics that can be described by the Coulomb blockade network model. As a demonstration of the nonlinear network system, we have observed stochastic resonance without tuning for weak periodic input signals and thermal noise, which suggests a route to neural network composed of molecular materials.

Double Relativistic Electron Accelerating Mirror

Directory of Open Access Journals (Sweden)

Saltanat Sadykova

2013-02-01

Full Text Available In the present paper, the possibility of generation of thin dense relativistic electron layers is shown using the analytical and numerical modeling of laser pulse interaction with ultra-thin layers. It was shown that the maximum electron energy can be gained by optimal tuning between the target width, intensity and laser pulse duration. The optimal parameters were obtained from a self-consistent system of Maxwell equations and the equation of motion of electron layer. For thin relativistic electron layers, the gaining of maximum electron energies requires a second additional overdense plasma layer, thus cutting the laser radiation off the plasma screen at the instant of gaining the maximum energy (DREAM-schema.

70 MeV injector auto tuning system handbook

International Nuclear Information System (INIS)

Ellis, J.E.; Munn, R.W.; Sandels, E.G.

1976-06-01

The handbook is in three sections: (1) description and location; (2) operating instructions; and (3) design notes on the tank and debuncher auto tuning systems for the 70 MeV injector. The purpose of the auto tuning system is to maintain the 'tune' of the four tanks and debuncher to within a few Hz, stabilizing against changes of temperature and other physical factors affecting the resonant frequency of the tanks. (U.K.)

Broader visual orientation tuning in patients with schizophrenia

Directory of Open Access Journals (Sweden)

Ariel eRokem

2011-11-01

Full Text Available Reduced gamma-aminobutyric acid (GABA levels in cerebral cortex are thought to contribute to information processing deficits in patients with schizophrenia (SZ, and we have previously reported lower in vivo GABA levels in the visual cortex of patients with SZ. GABA-mediated inhibition plays a role in sharpening orientation tuning of visual cortical neurons. Therefore, we predicted that tuning for visual stimulus orientation would be wider in SZ. We measured orientation tuning with a psychophysical procedure in which subjects performed a target detection task of a low-contrast oriented grating, following adaptation to a high-contrast grating. Contrast detection thresholds were determined for a range of adapter-target orientation offsets. For both SZ and healthy controls, contrast thresholds decreased as orientation offset increased, suggesting that this tuning curve reflects the selectivity of visual cortical neurons for stimulus orientation. After accounting for generalized deficits in task performance in SZ, there was no difference between patients and controls for detection of target stimuli having either the same orientation as the adapter or orientations far from the adapter. However, patients’ thresholds were significantly higher for intermediate adapter-target offsets. In addition, the mean width parameter of a Gaussian fit to the psychophysical orientation tuning curves was significantly larger for the patient group. We also present preliminary data relating visual cortical GABA levels, as measured with magnetic resonance spectroscopy, and orientation tuning width. These results suggest that our finding of broader orientation tuning in SZ may be due to diminished visual cortical GABA levels.

ATLAS tunes of PYTHIA 6 and Pythia 8 for MC11

CERN Document Server

The ATLAS collaboration

2011-01-01

We present the latest developments of the ATLAS MC generator tuning project for the Pythia family of event generators, including the C++ Pythia 8 code for the first time. The PYTHIA 6 tunes presented here, titled AMBT2B and AUET2B and constructed for a variety of PDFs, constitute alternatives to the AMBT2/AUET2 tunes previously presented as a candidate for MC11 event simulation. They systematically differ from the AMBT2/AUET2 PYTHIA 6 tunes in the treatment of alpha_S, to address concerns with those tunes. Systematic tune variations are also presented. The Pythia 8 tunes have been constructed for two different PDFs, and are aimed at an optimal description of minimum bias, for use in pile-up simulation. PDF-sensitive effects are observed and discussed in the MPI tunings of both generators.

Self-tuning control studies of the plasma vertical position problem

International Nuclear Information System (INIS)

Zheng, Guang Lin; Wellstead, P.E.; Browne, M.L.

1993-01-01

The plasma vertical position system in a tokamak device can be open-loop unstable with time-varying dynamics, such that the instability increases with system dynamical changes. Time-varying unstable dynamics makes the plasma vertical position a particularly difficult one to control with traditional fixed-coefficient controllers. A self-tuning technique offers a new solution of the plasma vertical position control problem by an adaptive control approach. Specifically, the self-tuning controller automatically tunes the controller parameters without an a priori knowledge of the system dynamics and continuously tracks dynamical changes within the system, thereby providing the system with auto-tuning and adaptive tuning capabilities. An overview of the self-tuning methods is given, and their applicability to a simulation of the Joint European Torus (JET) vertical plasma positions system is illustrated. Specifically, the applicability of pole-assignment and generalized predictive control self-tuning methods to the vertical plasma position system is demonstrated. 26 refs., 16 figs., 1 tab

ELECTRONIC EDUCATIONAL RESOURCES FOR ONLINE SUPPORT OF MODERN CHEMISTRY CLASSES IN SPECIALIZED SCHOOL

Directory of Open Access Journals (Sweden)

Maria D. Tukalo

2013-09-01

Full Text Available This article contains material of some modern electronic educational resources that can be used via the Internet to support the modern chemistry classes in specialized school. It was drawn attention to the educational chemical experiments as means of knowledge; simulated key motivational characteristics to enhance students interest for learning subjects, their cognitive and practical activity in the formation of self-reliance and self-creative; commented forecasts for creating of conditions to enhance the creative potential of students in a modern learning environment.

Selection and Evaluation of Electronic Resources

Directory of Open Access Journals (Sweden)

Doğan Atılgan

2013-11-01

Full Text Available Publication boom and issues related to controlling and accession of printed sources have created some problems after World War II. Consequently, publishing industry has encountered the problem of finding possible solution for emerged situation. Industry of electronic publishing has started to improve with the rapid increase of the price of printed sources as well as the problem of publication boom. The first effects of electronic publishing were appeared on the academic and scholarly publications then electronic publishing became a crucial part of all types of publications. As a result of these developments, collection developments and service policies of information centers were also significantly changed. In this article, after a general introduction about selection and evaluation processes of electronic publications, the subscribed databases by a state and a privately owned university in Turkey and their usage were examined.

A frequency domain approach for MPC tuning

NARCIS (Netherlands)

Özkan, L.; Meijs, J.B.; Backx, A.C.P.M.; Karimi, I.A.; Srinivasan, R.

2012-01-01

This paper presents a frequency domain based approach to tune the penalty weights in the model predictive control (MPC) formulation. The two-step tuning method involves the design of a favourite controller taking into account the model-plant mismatch followed by the controller matching. We implement

Accumulative job demands and support for strength use : Fine-tuning the job demands-resources model using conservation of resources theory

NARCIS (Netherlands)

van Woerkom, M.; Bakker, A.B.; Nishii, L.H.

2016-01-01

Absenteeism associated with accumulated job demands is a ubiquitous problem. We build on prior research on the benefits of counteracting job demands with resources by focusing on a still untapped resource for buffering job demands—that of strengths use. We test the idea that employees who are

Natural tuning: towards a proof of concept

Science.gov (United States)

Dubovsky, Sergei; Gorbenko, Victor; Mirbabayi, Mehrdad

2013-09-01

The cosmological constant problem and the absence of new natural physics at the electroweak scale, if confirmed by the LHC, may either indicate that the nature is fine-tuned or that a refined notion of naturalness is required. We construct a family of toy UV complete quantum theories providing a proof of concept for the second possibility. Low energy physics is described by a tuned effective field theory, which exhibits relevant interactions not protected by any symmetries and separated by an arbitrary large mass gap from the new "gravitational" physics, represented by a set of irrelevant operators. Nevertheless, the only available language to describe dynamics at all energy scales does not require any fine-tuning. The interesting novel feature of this construction is that UV physics is not described by a fixed point, but rather exhibits asymptotic fragility. Observation of additional unprotected scalars at the LHC would be a smoking gun for this scenario. Natural tuning also favors TeV scale unification.

Accurate guitar tuning by cochlear implant musicians.

Directory of Open Access Journals (Sweden)

Thomas Lu

Full Text Available Modern cochlear implant (CI users understand speech but find difficulty in music appreciation due to poor pitch perception. Still, some deaf musicians continue to perform with their CI. Here we show unexpected results that CI musicians can reliably tune a guitar by CI alone and, under controlled conditions, match simultaneously presented tones to <0.5 Hz. One subject had normal contralateral hearing and produced more accurate tuning with CI than his normal ear. To understand these counterintuitive findings, we presented tones sequentially and found that tuning error was larger at ∼ 30 Hz for both subjects. A third subject, a non-musician CI user with normal contralateral hearing, showed similar trends in performance between CI and normal hearing ears but with less precision. This difference, along with electric analysis, showed that accurate tuning was achieved by listening to beats rather than discriminating pitch, effectively turning a spectral task into a temporal discrimination task.

An Exploratory study on the use of LibAnswers to Resolve, Track and Monitor Electronic Resources Issues: The KAUST Library experience

KAUST Repository

Ramli, Rindra M.

2017-01-01

An Exploratory study on KAUST library use of LibAnswers in resolving electronic resources questions received in LibAnswers. It describes the findings of the questions received in LibAnswers. The author made suggestions based on the findings to improve the reference services in responding to e-resources questions.

An Exploratory study on the use of LibAnswers to Resolve, Track and Monitor Electronic Resources Issues: The KAUST Library experience

KAUST Repository

Ramli, Rindra M.

2017-05-03

An Exploratory study on KAUST library use of LibAnswers in resolving electronic resources questions received in LibAnswers. It describes the findings of the questions received in LibAnswers. The author made suggestions based on the findings to improve the reference services in responding to e-resources questions.

An express method for optimally tuning an analog controller with respect to integral quality criteria

Science.gov (United States)

Golinko, I. M.; Kovrigo, Yu. M.; Kubrak, A. I.

2014-03-01

An express method for optimally tuning analog PI and PID controllers is considered. An integral quality criterion with minimizing the control output is proposed for optimizing control systems. The suggested criterion differs from existing ones in that the control output applied to the technological process is taken into account in a correct manner, due to which it becomes possible to maximally reduce the expenditure of material and/or energy resources in performing control of industrial equipment sets. With control organized in such manner, smaller wear and longer service life of control devices are achieved. A unimodal nature of the proposed criterion for optimally tuning a controller is numerically demonstrated using the methods of optimization theory. A functional interrelation between the optimal controller parameters and dynamic properties of a controlled plant is numerically determined for a single-loop control system. The results obtained from simulation of transients in a control system carried out using the proposed and existing functional dependences are compared with each other. The proposed calculation formulas differ from the existing ones by a simple structure and highly accurate search for the optimal controller tuning parameters. The obtained calculation formulas are recommended for being used by specialists in automation for design and optimization of control systems.

Further ATLAS tunes of PYTHIA6 and Pythia 8

CERN Document Server

The ATLAS collaboration

2011-01-01

We present the latest developments of the ATLAS MC generator tuning project for the Pythia family of event generators, including the C++ Pythia 8 code. The PYTHIA 6 tunes presented here complete the ``AUET2B'' set by addition of parton shower and multi-parton interaction model tunings with three next-to-leading order (NLO) PDFs in addition to the leading-order and MC-adapted PDFs previously presented. This note also presents systematic variation ``eigentunes'' for the parton shower configurations in the AMBT2B/AUET2B tune series. The Pythia 8 MPI tunes in this note have been constructed for six different PDFs, making use of a new $x$-dependent hadronic matter distribution model. MPI eigentunes are constructed for the PDFs intended for use in ATLAS bulk MC production.

The level of the usage of the human resource information system and electronic recruitment in Croatian companies

Directory of Open Access Journals (Sweden)

Snježana Pivac

2014-12-01

Full Text Available Performing business according to contemporary requirements influences companies for continuous usage of modern managerial tools, such as a human resource information system (HRIS and electronic recruitment (ER. Human resources have been recognised as curtail resources and the main source of a competitive advantage in creation of successful business performance. In order to attract and select the top employees, companies use quality information software for attracting internal ones, and electronic recruitment for attracting the best possible external candidates. The main aim of this paper is to research the level of the usage of HRIS and ER within medium-size and large Croatian companies. Moreover, the additional aim of this paper is to evaluate the relationship among the usage of these modern managerial tools and the overall success of human resource management within these companies. For the purpose of this paper, primary and secondary research has been conducted in order to reveal the level of the usage of HRIS and ER as well as the overall success of human resource management in Croatian companies. The companies’ classification (HRIS and ER is done by using the non-hierarchical k-means cluster method as well as the nonparametric Kruskal Wallis test. Further, the companies are ranked by the multicriteria PROMETHEE method. Relevant nonparametric tests are used for testing the overall companies’ HRM. Finally, binary logistic regression is estimated, relating binary variable HRM and HRIS development. After detailed research, it can be concluded that large Croatian companies apply HRIS in majority (with a positive relation to HRM performance, but still require certain degrees of its development.

Kernel Tuning and Nonuniform Influence on Optical and Electrochemical Gaps of Bimetal Nanoclusters.

Science.gov (United States)

He, Lizhong; Yuan, Jinyun; Xia, Nan; Liao, Lingwen; Liu, Xu; Gan, Zibao; Wang, Chengming; Yang, Jinlong; Wu, Zhikun

2018-03-14

Fine tuning nanoparticles with atomic precision is exciting and challenging and is critical for tuning the properties, understanding the structure-property correlation and determining the practical applications of nanoparticles. Some ultrasmall thiolated metal nanoparticles (metal nanoclusters) have been shown to be precisely doped, and even the protecting staple metal atom could be precisely reduced. However, the precise addition or reduction of the kernel atom while the other metal atoms in the nanocluster remain the same has not been successful until now, to the best of our knowledge. Here, by carefully selecting the protecting ligand with adequate steric hindrance, we synthesized a novel nanocluster in which the kernel can be regarded as that formed by the addition of two silver atoms to both ends of the Pt@Ag 12 icosohedral kernel of the Ag 24 Pt(SR) 18 (SR: thiolate) nanocluster, as revealed by single crystal X-ray crystallography. Interestingly, compared with the previously reported Ag 24 Pt(SR) 18 nanocluster, the as-obtained novel bimetal nanocluster exhibits a similar absorption but a different electrochemical gap. One possible explanation for this result is that the kernel tuning does not essentially change the electronic structure, but obviously influences the charge on the Pt@Ag 12 kernel, as demonstrated by natural population analysis, thus possibly resulting in the large electrochemical gap difference between the two nanoclusters. This work not only provides a novel strategy to tune metal nanoclusters but also reveals that the kernel change does not necessarily alter the optical and electrochemical gaps in a uniform manner, which has important implications for the structure-property correlation of nanoparticles.

Progress in Studies of Electron-Cloud-Induced Optics Distortions at CesrTA

International Nuclear Information System (INIS)

Crittenden, James; Penn, Gregory; Venturini, Marco; Harkay, Katherine; Holtzapple, Robert; Pivi, Mauro; Wang, Lanfa

2012-01-01

The Cornell Electron Storage Ring Test Accelerator (CesrTA) program has included extensive measurements of coherent betatron tune shifts for a variety of electron and positron beam energies, bunch population levels, and bunch train configurations. The tune shifts have been shown to result primarily from the interaction of the beam with the space-charge field of the beam-induced low-energy electron cloud in the vacuum chamber. Comparison to several advanced electron cloud simulation codes has allowed determination of the sensitivity of these measurements to physical parameters characterizing the synchrotron radiation flux, the production of photo-electrons on the vacuum chamber wall, the beam emittance, lattice optics, and the secondary-electron yield model. We report on progress in understanding the cloud buildup and decay mechanisms in magnetic fields and in field-free regions, addressing quantitatively the precise determination of the physical parameters of the modeling. Validation of these models will serve as essential input in the design of damping rings for future high-energy linear colliders.

The electronic encapsulation of knowledge in hydraulics, hydrology and water resources

Science.gov (United States)

Abbott, Michael B.

The rapidly developing practice of encapsulating knowledge in electronic media is shown to lead necessarily to the restructuring of the knowledge itself. The consequences of this for hydraulics, hydrology and more general water-resources management are investigated in particular relation to current process-simulation, real-time control and advice-serving systems. The generic properties of the electronic knowledge encapsulator are described, and attention is drawn to the manner in which knowledge 'goes into hiding' through encapsulation. This property is traced in the simple situations of pure mathesis and in the more complex situations of taxinomia using one example each from hydraulics and hydrology. The consequences for systems architectures are explained, pointing to the need for multi-agent architectures for ecological modelling and for more general hydroinformatics systems also. The relevance of these developments is indicated by reference to ongoing projects in which they are currently being realised. In conclusion, some more general epistemological aspects are considered within the same context. As this contribution is so much concerned with the processes of signification and communication, it has been partly shaped by the theory of semiotics, as popularised by Eco ( A Theory of Semiotics, Indiana University, Bloomington, 1977).

Progress in studies of Electron-Cloud-Induced Optics Distortions at CESRTA

International Nuclear Information System (INIS)

Crittenden, J.A.; Calvey, J.R.; Dugan, G.F.; Kreinick, D.L.; Leong, Z.; Livezey, J.A.; Palmer, M.A.; Rubin, D.L.; Sagan, D.C.; Holtzapple, R.L.; Furman, M.A.; Penn, G.; Venturini, M.; Pivi, M.; Wang, L.; Harkay, K.

2010-01-01

The Cornell Electron Storage Ring Test Accelerator (CesrTA) program has included extensive measurements of coherent betatron tune shifts for a variety of electron and positron beam energies, bunch population levels, and bunch train configurations. The tune shifts have been shown to result primarily from the interaction of the beam with the space-charge field of the beam-induced low energy electron cloud in the vacuum chamber. Comparison to several advanced electron cloud simulation program packages has allowed determination of the sensitivity of these measurements to physical parameters characterizing the synchrotron radiation flux, the production of photoelectrons on the vacuum chamberwall, the beam emittance, lattice optics, and the secondary-electron yield model. We report on progress in understanding the cloud buildup and decay mechanisms in magnetic fields and in field-free regions, addressing quantitatively the precise determination of the physical parameters of the modeling. Validation of these models will serve as essential input in the design of damping rings for future high-energy linear colliders.

Molecular self-assembly approaches for supramolecular electronic and organic electronic devices

Science.gov (United States)

Yip, Hin-Lap

Molecular self-assembly represents an efficient bottom-up strategy to generate structurally well-defined aggregates of semiconducting pi-conjugated materials. The capability of tuning the chemical structures, intermolecular interactions and nanostructures through molecular engineering and novel materials processing renders it possible to tailor a large number of unprecedented properties such as charge transport, energy transfer and light harvesting. This approach does not only benefit traditional electronic devices based on bulk materials, but also generate a new research area so called "supramolecular electronics" in which electronic devices are built up with individual supramolecular nanostructures with size in the sub-hundred nanometers range. My work combined molecular self-assembly together with several novel materials processing techniques to control the nucleation and growth of organic semiconducting nanostructures from different type of pi-conjugated materials. By tailoring the interactions between the molecules using hydrogen bonds and pi-pi stacking, semiconducting nanoplatelets and nanowires with tunable sizes can be fabricated in solution. These supramolecular nanostructures were further patterned and aligned on solid substrates through printing and chemical templating methods. The capability to control the different hierarchies of organization on surface provides an important platform to study their structural-induced electronic properties. In addition to using molecular self-assembly to create different organic nanostructures, functional self-assembled monolayer (SAM) formed by spontaneous chemisorption on surfaces was used to tune the interfacial property in organic solar cells. Devices showed dramatically improved performance when appropriate SAMs were applied to optimize the contact property for efficiency charge collection.

Predictive Performance Tuning of OpenACC Accelerated Applications

KAUST Repository

Siddiqui, Shahzeb

2014-05-04

Graphics Processing Units (GPUs) are gradually becoming mainstream in supercomputing as their capabilities to significantly accelerate a large spectrum of scientific applications have been clearly identified and proven. Moreover, with the introduction of high level programming models such as OpenACC [1] and OpenMP 4.0 [2], these devices are becoming more accessible and practical to use by a larger scientific community. However, performance optimization of OpenACC accelerated applications usually requires an in-depth knowledge of the hardware and software specifications. We suggest a prediction-based performance tuning mechanism [3] to quickly tune OpenACC parameters for a given application to dynamically adapt to the execution environment on a given system. This approach is applied to a finite difference kernel to tune the OpenACC gang and vector clauses for mapping the compute kernels into the underlying accelerator architecture. Our experiments show a significant performance improvement against the default compiler parameters and a faster tuning by an order of magnitude compared to the brute force search tuning.

Beam-Beam Interaction, Electron Cloud and Intrabeam Scattering for Proton Super-bunches

CERN Document Server

Ruggiero, F; Rumolo, Giovanni; Papaphilippou, Y

2003-01-01

Super-bunches are long bunches with a flat longitudinal profile, which could potentially increase the LHC luminosity in a future upgrade. We present example parameters and discuss a variety of issues related to such superbunches, including beam-beam tune shift, tune footprints, crossing schemes, luminosity, intrabeam scattering, and electron cloud. We highlight the benefits, disadvantages and open questions.

RESEARCH OF INFLUENCE OF QUALITY OF ELECTRONIC EDUCATIONAL RESOURCES ON QUALITY OF TRAINING WITH USE OF DISTANCE TECHNOLOGIES

Directory of Open Access Journals (Sweden)

H. M. Kravtsov

2013-03-01

Full Text Available Communication improving of educational processes requires today new approaches to the management arrangements and forming of educational policy in the field of distance learning, which is based on the use of modern information and communication technologies. An important step in this process is the continuous monitoring of the development and implementation of information technology and, in particular, the distance learning systems in higher educational establishments. The main objective of the monitoring is the impact assessment on the development of distance learning following the state educational standards, curricula, methodical and technical equipment and other factors; factors revelation that influence the implementation and outcomes of distance learning; results comparison of educational institution functioning and distance education systems in order to determine the most efficient ways of its development. The paper presents the analysis results of the dependence of the quality of educational services on the electronic educational resources. Trends in educational services development was studied by comparing the quality influence of electronic educational resources on the quality of educational services of higher pedagogical educational institutions of Ukraine as of 2009-2010 and 2012-2013. Generally, the analysis of the survey results allows evaluating quality of the modern education services as satisfactory and it can be said that almost 70% of the success of their future development depends on the quality of the used electronic educational resources and distance learning systems in particular.

Tracking the Flow of Resources in Electronic Waste - The Case of End-of-Life Computer Hard Disk Drives.

Science.gov (United States)

Habib, Komal; Parajuly, Keshav; Wenzel, Henrik

2015-10-20

Recovery of resources, in particular, metals, from waste flows is widely seen as a prioritized option to reduce their potential supply constraints in the future. The current waste electrical and electronic equipment (WEEE) treatment system is more focused on bulk metals, where the recycling rate of specialty metals, such as rare earths, is negligible compared to their increasing use in modern products, such as electronics. This study investigates the challenges in recovering these resources in the existing WEEE treatment system. It is illustrated by following the material flows of resources in a conventional WEEE treatment plant in Denmark. Computer hard disk drives (HDDs) containing neodymium-iron-boron (NdFeB) magnets were selected as the case product for this experiment. The resulting output fractions were tracked until their final treatment in order to estimate the recovery potential of rare earth elements (REEs) and other resources contained in HDDs. The results further show that out of the 244 kg of HDDs treated, 212 kg comprising mainly of aluminum and steel can be finally recovered from the metallurgic process. The results further demonstrate the complete loss of REEs in the existing shredding-based WEEE treatment processes. Dismantling and separate processing of NdFeB magnets from their end-use products can be a more preferred option over shredding. However, it remains a technological and logistic challenge for the existing system.

Reducing the fine-tuning of gauge-mediated SUSY breaking

Energy Technology Data Exchange (ETDEWEB)

Casas, J.A.; Moreno, Jesus M. [Universidad Autonoma de Madrid, Instituto de Fisica Teorica, IFT-UAM/CSIC, Madrid (Spain); Robles, Sandra [Universidad Autonoma de Madrid, Instituto de Fisica Teorica, IFT-UAM/CSIC, Madrid (Spain); Universidad Autonoma de Madrid, Departamento de Fisica Teorica, Madrid (Spain); Rolbiecki, Krzysztof [Universidad Autonoma de Madrid, Instituto de Fisica Teorica, IFT-UAM/CSIC, Madrid (Spain); University of Warsaw, Faculty of Physics, Warsaw (Poland)

2016-08-15

Despite their appealing features, models with gauge-mediated supersymmetry breaking (GMSB) typically present a high degree of fine-tuning, due to the initial absence of the top trilinear scalar couplings, A{sub t} = 0. In this paper, we carefully evaluate such a tuning, showing that is worse than per mil in the minimal model. Then, we examine some existing proposals to generate A{sub t} ≠ 0 term in this context. We find that, although the stops can be made lighter, usually the tuning does not improve (it may be even worse), with some exceptions, which involve the generation of A{sub t} at one loop or tree level. We examine both possibilities and propose a conceptually simplified version of the latter; which is arguably the optimum GMSB setup (with minimal matter content), concerning the fine-tuning issue. The resulting fine-tuning is better than one per mil, still severe but similar to other minimal supersymmetric standard model constructions. We also explore the so-called ''little A{sub t}{sup 2}/m{sup 2} problem'', i.e. the fact that a large A{sub t}-term is normally accompanied by a similar or larger sfermion mass, which typically implies an increase in the fine-tuning. Finally, we find the version of GMSB for which this ratio is optimized, which, nevertheless, does not minimize the fine-tuning. (orig.)

Tuning magnetotransport in a compensated semimetal at the atomic scale

Science.gov (United States)

Wang, Lin; Gutiérrez-Lezama, Ignacio; Barreteau, Céline; Ubrig, Nicolas; Giannini, Enrico; Morpurgo, Alberto F.

2015-11-01

Either in bulk form, or in atomically thin crystals, layered transition metal dichalcogenides continuously reveal new phenomena. The latest example is 1T'-WTe2, a semimetal found to exhibit the largest known magnetoresistance in the bulk, and predicted to become a topological insulator in strained monolayers. Here we show that reducing the thickness through exfoliation enables the electronic properties of WTe2 to be tuned, which allows us to identify the mechanisms responsible for the observed magnetotransport down to the atomic scale. The longitudinal resistance and the unconventional magnetic field dependence of the Hall resistance are reproduced quantitatively by a classical two-band model for crystals as thin as six monolayers, whereas a crossover to an Anderson insulator occurs for thinner crystals. Besides establishing the origin of the magnetoresistance of WTe2, our results represent a complete validation of the classical theory for two-band electron-hole transport, and indicate that atomically thin WTe2 layers remain gapless semimetals.

Tuning electronic transport via hepta-alanine peptides junction by tryptophan doping.

Science.gov (United States)

Guo, Cunlan; Yu, Xi; Refaely-Abramson, Sivan; Sepunaru, Lior; Bendikov, Tatyana; Pecht, Israel; Kronik, Leeor; Vilan, Ayelet; Sheves, Mordechai; Cahen, David

2016-09-27

Charge migration for electron transfer via the polypeptide matrix of proteins is a key process in biological energy conversion and signaling systems. It is sensitive to the sequence of amino acids composing the protein and, therefore, offers a tool for chemical control of charge transport across biomaterial-based devices. We designed a series of linear oligoalanine peptides with a single tryptophan substitution that acts as a "dopant," introducing an energy level closer to the electrodes' Fermi level than that of the alanine homopeptide. We investigated the solid-state electron transport (ETp) across a self-assembled monolayer of these peptides between gold contacts. The single tryptophan "doping" markedly increased the conductance of the peptide chain, especially when its location in the sequence is close to the electrodes. Combining inelastic tunneling spectroscopy, UV photoelectron spectroscopy, electronic structure calculations by advanced density-functional theory, and dc current-voltage analysis, the role of tryptophan in ETp is rationalized by charge tunneling across a heterogeneous energy barrier, via electronic states of alanine and tryptophan, and by relatively efficient direct coupling of tryptophan to a Au electrode. These results reveal a controlled way of modulating the electrical properties of molecular junctions by tailor-made "building block" peptides.

Towards automatic parameter tuning of stream processing systems

KAUST Repository

Bilal, Muhammad; Canini, Marco

2017-01-01

for automating parameter tuning for stream-processing systems. Our framework supports standard black-box optimization algorithms as well as a novel gray-box optimization algorithm. We demonstrate the multiple benefits of automated parameter tuning in optimizing

Compensation of head-on beam-beam induced resonance driving terms and tune spread in the Relativistic Heavy Ion Collider

Directory of Open Access Journals (Sweden)

W. Fischer

2017-09-01

Full Text Available A head-on beam-beam compensation scheme was implemented for operation in the Relativistic Heavy Ion Collider (RHIC at Brookhaven National Laboratory [Phys. Rev. Lett. 115, 264801 (2015PRLTAO0031-900710.1103/PhysRevLett.115.264801]. The compensation consists of electron lenses for the reduction of the beam-beam induced tune spread, and a lattice for the minimization of beam-beam generated resonance driving terms. We describe the implementations of the lattice and electron lenses, and report on measurements of lattice properties and the effect of the electron lenses on the hadron beam.

Electronically Tunable Current-Mode Quadrature Oscillator Using Single MCDTA

Directory of Open Access Journals (Sweden)

Y. Li

2010-12-01

Full Text Available This paper presents a modified current differencing transconductance amlpifier (MCDTA and the MCDTA based quadrature oscillator. The oscillator is current-mode and provides current output from high output impedance terminals. The circuit uses only one MCDTA and two grounded capacitors, and is easy to be integrated. Its oscillation frequency can be tuned electronically by tuning bias currents of MCDTA. Finally, frequency error is analyzed. The results of circuit simulations are in agreement with theory.

Tuning and backreaction in F-term axion monodromy inflation

Directory of Open Access Journals (Sweden)

Arthur Hebecker

2015-05-01

Full Text Available We continue the development of axion monodromy inflation, focusing in particular on the backreaction of complex structure moduli. In our setting, the shift symmetry comes from a partial large complex structure limit of the underlying type IIB orientifold or F-theory fourfold. The coefficient of the inflaton term in the superpotential has to be tuned small to avoid conflict with Kähler moduli stabilisation. To allow such a tuning, this coefficient necessarily depends on further complex structure moduli. At large values of the inflaton field, these moduli are then in danger of backreacting too strongly. To avoid this, further tunings are necessary. In weakly coupled type IIB theory at the orientifold point, implementing these tunings appears to be difficult if not impossible. However, fourfolds or models with mobile D7-branes provide enough structural freedom. We calculate the resulting inflaton potential and study the feasibility of the overall tuning given the limited freedom of the flux landscape. Our preliminary investigations suggest that, even imposing all tuning conditions, the remaining choice of flux vacua can still be large enough for such models to provide a promising path to large-field inflation in string theory.

Self tuning fuzzy PID type load and frequency controller

International Nuclear Information System (INIS)

Yesil, E.; Guezelkaya, M.; Eksin, I.

2004-01-01

In this paper, a self tuning fuzzy PID type controller is proposed for solving the load frequency control (LFC) problem. The fuzzy PID type controller is constructed as a set of control rules, and the control signal is directly deduced from the knowledge base and the fuzzy inference. Moreover, there exists a self tuning mechanism that adjusts the input scaling factor corresponding to the derivative coefficient and the output scaling factor corresponding to the integral coefficient of the PID type fuzzy logic controller in an on-line manner. The self tuning mechanism depends on the peak observer idea, and this idea is modified and adapted to the LFC problem. A two area interconnected system is assumed for demonstrations. The proposed self tuning fuzzy PID type controller has been compared with the fuzzy PID type controller without a self tuning mechanism and the conventional integral controller through some performance indices

Non-parametric Tuning of PID Controllers A Modified Relay-Feedback-Test Approach

CERN Document Server

Boiko, Igor

2013-01-01

The relay feedback test (RFT) has become a popular and efficient  tool used in process identification and automatic controller tuning. Non-parametric Tuning of PID Controllers couples new modifications of classical RFT with application-specific optimal tuning rules to form a non-parametric method of test-and-tuning. Test and tuning are coordinated through a set of common parameters so that a PID controller can obtain the desired gain or phase margins in a system exactly, even with unknown process dynamics. The concept of process-specific optimal tuning rules in the nonparametric setup, with corresponding tuning rules for flow, level pressure, and temperature control loops is presented in the text.   Common problems of tuning accuracy based on parametric and non-parametric approaches are addressed. In addition, the text treats the parametric approach to tuning based on the modified RFT approach and the exact model of oscillations in the system under test using the locus of a perturbedrelay system (LPRS) meth...

Comparison of the Efficiency of Tuned Mass and Tuned Liquid Dampers at High-Rise Structures under Near and Far Fault Earthquakes

Directory of Open Access Journals (Sweden)

Hamed Rahman Shokrgozar

2017-02-01

Full Text Available Tuned mass and tuned liquid dampers are most common passive control systems that used for decrease of seismic responses of buildings. In this study, the performance of high-rise buildings with TM and TL dampers are evaluated under seven near-fault and seven far-fault earthquakes. For this purpose, a twenty-four stories steel moment frame building has been considered and the time history dynamic analyses are performed for both of controlled and uncontrolled states. Moreover, this building has been also modelled with five various mass, stiffness and damping ratios.The results have been shown that decreasing the structural responses at tall buildings against near-fault earthquakes are more than far-fault earthquakes due to the effect of higher modes. Furthermore, the tuned mass damper has better performance at decreasing of the responses in comparison of tuned liquid dampers.

Broad electrical tuning of plasmonic nanoantennas at visible frequencies

Energy Technology Data Exchange (ETDEWEB)

Hoang, Thang B. [Department of Physics, Duke University, Durham, North Carolina 27708 (United States); Center for Metamaterials and Integrated Plasmonics, Duke University, Durham, North Carolina 27708 (United States); Mikkelsen, Maiken H., E-mail: m.mikkelsen@duke.edu [Department of Physics, Duke University, Durham, North Carolina 27708 (United States); Center for Metamaterials and Integrated Plasmonics, Duke University, Durham, North Carolina 27708 (United States); Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27708 (United States)

2016-05-02

We report an experimental demonstration of electrical tuning of plasmon resonances of optical nanopatch antennas over a wide wavelength range. The antennas consist of silver nanocubes separated from a gold film by a thin 8 nm polyelectrolyte spacer layer. By using ionic liquid and indium tin oxide coated glass as a top electrode, we demonstrate dynamic and reversible tuning of the plasmon resonance over 100 nm in the visible wavelength range using low applied voltages between −3.0 V and 2.8 V. The electrical potential is applied across the nanoscale gap causing changes in the gap thickness and dielectric environment which, in turn, modifies the plasmon resonance. The observed tuning range is greater than the full-width-at-half-maximum of the plasmon resonance, resulting in a tuning figure of merit of 1.05 and a tuning contrast greater than 50%. Our results provide an avenue to create active and reconfigurable integrated nanophotonic components for applications in optoelectronics and sensing.

Tuning the Wettability of Halloysite Clay Nanotubes by Surface Carbonization for Optimal Emulsion Stabilization.

Science.gov (United States)

Owoseni, Olasehinde; Zhang, Yueheng; Su, Yang; He, Jibao; McPherson, Gary L; Bose, Arijit; John, Vijay T

2015-12-29

The carbonization of hydrophilic particle surfaces provides an effective route for tuning particle wettability in the preparation of particle-stabilized emulsions. The wettability of naturally occurring halloysite clay nanotubes (HNT) is successfully tuned by the selective carbonization of the negatively charged external HNT surface. The positively charge chitosan biopolymer binds to the negatively charged external HNT surface by electrostatic attraction and hydrogen bonding, yielding carbonized halloysite nanotubes (CHNT) on pyrolysis in an inert atmosphere. Relative to the native HNT, the oil emulsification ability of the CHNT at intermediate levels of carbonization is significantly enhanced due to the thermodynamically more favorable attachment of the particles at the oil-water interface. Cryogenic scanning electron microscopy (cryo-SEM) imaging reveals that networks of CHNT attach to the oil-water interface with the particles in a side-on orientation. The concepts advanced here can be extended to other inorganic solids and carbon sources for the optimal design of particle-stabilized emulsions.

Modification of anisotropic plasma diffusion via auxiliary electrons emitted by a carbon nanotubes-based electron gun in an electron cyclotron resonance ion source.

Science.gov (United States)

Malferrari, L; Odorici, F; Veronese, G P; Rizzoli, R; Mascali, D; Celona, L; Gammino, S; Castro, G; Miracoli, R; Serafino, T

2012-02-01

The diffusion mechanism in magnetized plasmas is a largely debated issue. A short circuit model was proposed by Simon, assuming fluxes of lost particles along the axial (electrons) and radial (ions) directions which can be compensated, to preserve the quasi-neutrality, by currents flowing throughout the conducting plasma chamber walls. We hereby propose a new method to modify Simon's currents via electrons injected by a carbon nanotubes-based electron gun. We found this improves the source performances, increasing the output current for several charge states. The method is especially sensitive to the pumping frequency. Output currents for given charge states, at different auxiliary electron currents, will be reported in the paper and the influence of the frequency tuning on the compensation mechanism will be discussed.

PbCl2-tuned inorganic cubic CsPbBr3(Cl) perovskite solar cells with enhanced electron lifetime, diffusion length and photovoltaic performance

Science.gov (United States)

Li, Bo; Zhang, Yanan; Zhang, Luyuan; Yin, Longwei

2017-08-01

Inorganic CsPbBr3 perovskite is arousing great interest following after organic-inorganic hybrid halide perovskites, and is found as a good candidate for photovoltaic devices for its prominent photoelectric property and stability. Herein, we for the first time report on PbCl2-tuned inorganic Cl-doped CsPbBr3(Cl) perovskite solar cells with adjustable crystal structure and Cl doping for enhanced carrier lifetime, extraction rate and photovoltaic performance. The effect of PbCl2 on the morphologies, structures, optical, and photovoltaic performance of CsPbBr3 perovskite solar cells is investigated systemically. Compared with orthorhombic CsPbBr3, cubic CsPbBr3 demonstrates a significant improvement for electron lifetime (from 6.7 ns to 12.3 ns) and diffusion length (from 69 nm to 197 nm), as well as the enhanced electron extraction rate from CsPbBr3 to TiO2. More importantly, Cl doping benefits the further enhancement of carrier lifetime (14.3 ns) and diffusion length (208 nm). The Cl doped cubic CsPbBr3(Cl) perovskite solar cell exhibits a Jsc of 8.47 mA cm-2 and a PCE of 6.21%, superior to that of pure orthorhombic CsPbBr3 (6.22 mA cm-2 and 3.78%). The improvement of photovoltaic performance can be attributed to enhanced carrier lifetime, diffusion length and extraction rates, as well as suppressed nonradiative recombination.

Measurement of Beam Tunes in the Tevatron Using the BBQ System

Energy Technology Data Exchange (ETDEWEB)

Edstrom, Dean R.; /Indiana U.

2009-04-01

Measuring the betatron tunes in any synchrotron is of critical importance to ensuring the stability of beam in the synchrotron. The Base Band Tune, or BBQ, measurement system was developed by Marek Gasior of CERN and has been installed at Brookhaven and Fermilab as a part of the LHC Accelerator Research Program, or LARP. The BBQ was installed in the Tevatron to evaluate its effectiveness at reading proton and antiproton tunes at its flattop energy of 980 GeV. The primary objectives of this thesis are to examine the methods used to measure the tune using the BBQ tune measurement system, to incorporate the system into the Fermilab accelerator controls system, ACNET, and to compare the BBQ to existing tune measurement systems in the Tevatron.

Measurement of Beam Tunes in the Tevatron Using the BBQ System

International Nuclear Information System (INIS)

Edstrom, Dean R.

2009-01-01

Measuring the betatron tunes in any synchrotron is of critical importance to ensuring the stability of beam in the synchrotron. The Base Band Tune, or BBQ, measurement system was developed by Marek Gasior of CERN and has been installed at Brookhaven and Fermilab as a part of the LHC Accelerator Research Program, or LARP. The BBQ was installed in the Tevatron to evaluate its effectiveness at reading proton and antiproton tunes at its flattop energy of 980 GeV. The primary objectives of this thesis are to examine the methods used to measure the tune using the BBQ tune measurement system, to incorporate the system into the Fermilab accelerator controls system, ACNET, and to compare the BBQ to existing tune measurement systems in the Tevatron

An efficient automated parameter tuning framework for spiking neural networks.

Science.gov (United States)

Carlson, Kristofor D; Nageswaran, Jayram Moorkanikara; Dutt, Nikil; Krichmar, Jeffrey L

2014-01-01

As the desire for biologically realistic spiking neural networks (SNNs) increases, tuning the enormous number of open parameters in these models becomes a difficult challenge. SNNs have been used to successfully model complex neural circuits that explore various neural phenomena such as neural plasticity, vision systems, auditory systems, neural oscillations, and many other important topics of neural function. Additionally, SNNs are particularly well-adapted to run on neuromorphic hardware that will support biological brain-scale architectures. Although the inclusion of realistic plasticity equations, neural dynamics, and recurrent topologies has increased the descriptive power of SNNs, it has also made the task of tuning these biologically realistic SNNs difficult. To meet this challenge, we present an automated parameter tuning framework capable of tuning SNNs quickly and efficiently using evolutionary algorithms (EA) and inexpensive, readily accessible graphics processing units (GPUs). A sample SNN with 4104 neurons was tuned to give V1 simple cell-like tuning curve responses and produce self-organizing receptive fields (SORFs) when presented with a random sequence of counterphase sinusoidal grating stimuli. A performance analysis comparing the GPU-accelerated implementation to a single-threaded central processing unit (CPU) implementation was carried out and showed a speedup of 65× of the GPU implementation over the CPU implementation, or 0.35 h per generation for GPU vs. 23.5 h per generation for CPU. Additionally, the parameter value solutions found in the tuned SNN were studied and found to be stable and repeatable. The automated parameter tuning framework presented here will be of use to both the computational neuroscience and neuromorphic engineering communities, making the process of constructing and tuning large-scale SNNs much quicker and easier.

Application of Evolutionary Computation in Automotive Powertrain Mount Tuning

Directory of Open Access Journals (Sweden)

Anab Akanda

2006-01-01

Full Text Available Engine mount tuning is a multi-disciplinary exercise since it affects Idle-shake, Road-shake and power-train noise response. Engine inertia is often used as a tuned absorber for controlling suspension resonance related road-shake issues. Last but not least, vehicle ride and handling may also be affected by mount tuning. In this work, Torque-Roll-Axis (TRA decoupling of the rigid powertrain was used as a starting point for mount tuning. Nodal point of flexible powertrain bending was used to define the envelop for transmission mount locations. The frequency corresponding to the decoupled roll mode of the rigid powertrain was then adjusted for idle-shake and road-shake response management.

Fine-tuning and the stability of recurrent neural networks.

Directory of Open Access Journals (Sweden)

David MacNeil

Full Text Available A central criticism of standard theoretical approaches to constructing stable, recurrent model networks is that the synaptic connection weights need to be finely-tuned. This criticism is severe because proposed rules for learning these weights have been shown to have various limitations to their biological plausibility. Hence it is unlikely that such rules are used to continuously fine-tune the network in vivo. We describe a learning rule that is able to tune synaptic weights in a biologically plausible manner. We demonstrate and test this rule in the context of the oculomotor integrator, showing that only known neural signals are needed to tune the weights. We demonstrate that the rule appropriately accounts for a wide variety of experimental results, and is robust under several kinds of perturbation. Furthermore, we show that the rule is able to achieve stability as good as or better than that provided by the linearly optimal weights often used in recurrent models of the integrator. Finally, we discuss how this rule can be generalized to tune a wide variety of recurrent attractor networks, such as those found in head direction and path integration systems, suggesting that it may be used to tune a wide variety of stable neural systems.

Integrating magnetism into semiconductor electronics

Energy Technology Data Exchange (ETDEWEB)

Zakharchenya, Boris P; Korenev, Vladimir L [A.F. Ioffe Physico-Technical Institute, Russian Academy of Sciences, St. Petersburg (Russian Federation)

2005-06-30

The view of a ferromagnetic-semiconducting hybrid structure as a single tunable system is presented. Based on an analysis of existing experiments it is shown that, contrary to a 'common sense', a nonmagnetic semiconductor is capable of playing an important role in controlling ferromagnetism. Magnetic properties of a hybrid (the hysteresis loop and the spatial orientation of magnetization) can be tuned both optically and electrically by utilizing semiconductor-making the hybrid an electronic-write-in and electronic-read-out elementary storage unit. (methodological notes)

Integrating magnetism into semiconductor electronics

International Nuclear Information System (INIS)

Zakharchenya, Boris P; Korenev, Vladimir L

2005-01-01

The view of a ferromagnetic-semiconducting hybrid structure as a single tunable system is presented. Based on an analysis of existing experiments it is shown that, contrary to a 'common sense', a nonmagnetic semiconductor is capable of playing an important role in controlling ferromagnetism. Magnetic properties of a hybrid (the hysteresis loop and the spatial orientation of magnetization) can be tuned both optically and electrically by utilizing semiconductor-making the hybrid an electronic-write-in and electronic-read-out elementary storage unit. (methodological notes)

Generation and application of bessel beams in electron microscopy

Energy Technology Data Exchange (ETDEWEB)

Grillo, Vincenzo, E-mail: vincenzo.grillo@cnr.it [CNR-Istituto Nanoscienze, Centro S3, Via G Campi 213/a, I-41125 Modena (Italy); CNR-IMEM, Parco Area delle Scienze 37/A, I-43124 Parma (Italy); Harris, Jérémie [Department of Physics, University of Ottawa, 25 Templeton St., Ottawa, Ontario, Canada K1N 6N5 (Canada); Gazzadi, Gian Carlo [CNR-Istituto Nanoscienze, Centro S3, Via G Campi 213/a, I-41125 Modena (Italy); Balboni, Roberto [CNR-IMM Bologna, Via P. Gobetti 101, 40129 Bologna (Italy); Mafakheri, Erfan [Dipartimento di Fisica Informatica e Matematica, Università di Modena e Reggio Emilia, via G Campi 213/a, I-41125 Modena (Italy); Dennis, Mark R. [H.H. Wills Physics Laboratory, University of Bristol, Bristol BS8 1TL (United Kingdom); Frabboni, Stefano [CNR-Istituto Nanoscienze, Centro S3, Via G Campi 213/a, I-41125 Modena (Italy); Dipartimento di Fisica Informatica e Matematica, Università di Modena e Reggio Emilia, via G Campi 213/a, I-41125 Modena (Italy); Boyd, Robert W.; Karimi, Ebrahim [Department of Physics, University of Ottawa, 25 Templeton St., Ottawa, Ontario, Canada K1N 6N5 (Canada)

2016-07-15

We report a systematic treatment of the holographic generation of electron Bessel beams, with a view to applications in electron microscopy. We describe in detail the theory underlying hologram patterning, as well as the actual electron-optical configuration used experimentally. We show that by optimizing our nanofabrication recipe, electron Bessel beams can be generated with relative efficiencies reaching 37±3%. We also demonstrate by tuning various hologram parameters that electron Bessel beams can be produced with many visible rings, making them ideal for interferometric applications, or in more highly localized forms with fewer rings, more suitable for imaging. We describe the settings required to tune beam localization in this way, and explore beam and hologram configurations that allow the convergences and topological charges of electron Bessel beams to be controlled. We also characterize the phase structure of the Bessel beams generated with our technique, using a simulation procedure that accounts for imperfections in the hologram manufacturing process. - Highlights: • Bessel beams with different convergence, topological charge, visible fringes are demonstrated. • The relation between the Fresnel hologram and the probe shape is explained by detailed calculations and experiments. • Among the holograms here presented the highest relative efficiency is 37%, the best result ever reached for blazed holograms.

Generation and application of bessel beams in electron microscopy

International Nuclear Information System (INIS)

Grillo, Vincenzo; Harris, Jérémie; Gazzadi, Gian Carlo; Balboni, Roberto; Mafakheri, Erfan; Dennis, Mark R.; Frabboni, Stefano; Boyd, Robert W.; Karimi, Ebrahim

2016-01-01

We report a systematic treatment of the holographic generation of electron Bessel beams, with a view to applications in electron microscopy. We describe in detail the theory underlying hologram patterning, as well as the actual electron-optical configuration used experimentally. We show that by optimizing our nanofabrication recipe, electron Bessel beams can be generated with relative efficiencies reaching 37±3%. We also demonstrate by tuning various hologram parameters that electron Bessel beams can be produced with many visible rings, making them ideal for interferometric applications, or in more highly localized forms with fewer rings, more suitable for imaging. We describe the settings required to tune beam localization in this way, and explore beam and hologram configurations that allow the convergences and topological charges of electron Bessel beams to be controlled. We also characterize the phase structure of the Bessel beams generated with our technique, using a simulation procedure that accounts for imperfections in the hologram manufacturing process. - Highlights: • Bessel beams with different convergence, topological charge, visible fringes are demonstrated. • The relation between the Fresnel hologram and the probe shape is explained by detailed calculations and experiments. • Among the holograms here presented the highest relative efficiency is 37%, the best result ever reached for blazed holograms.

Improving Convergence of Iterative Feedback Tuning using Optimal External Perturbations

DEFF Research Database (Denmark)

Huusom, Jakob Kjøbsted; Hjalmarsson, Håkon; Poulsen, Niels Kjølstad

2008-01-01

Iterative feedback tuning constitutes an attractive control loop tuning method for processes in the absence of sufficient process insight. It is a purely data driven approach to optimization of the loop performance. The standard formulation ensures an unbiased estimate of the loop performance cost...... function gradient, which is used in a search algorithm. A slow rate of convergence of the tuning method is often experienced when tuning for disturbance rejection. This is due to a poor signal to noise ratio in the process data. A method is proposed for increasing the information content in data...

Evaluation of Controller Tuning Methods Applied to Distillation Column Control

DEFF Research Database (Denmark)

Nielsen, Kim; W. Andersen, Henrik; Kümmel, Professor Mogens

A frequency domain approach is used to compare the nominal performance and robustness of dual composition distillation column control tuned according to Ziegler-Nichols (ZN) and Biggest Log Modulus Tuning (BLT) for three binary distillation columns, WOBE, LUVI and TOFA. The scope of this is to ex......A frequency domain approach is used to compare the nominal performance and robustness of dual composition distillation column control tuned according to Ziegler-Nichols (ZN) and Biggest Log Modulus Tuning (BLT) for three binary distillation columns, WOBE, LUVI and TOFA. The scope...

Tuning of PID load frequency controller for power systems

International Nuclear Information System (INIS)

Tan Wen

2009-01-01

PID tuning of load frequency controllers for power systems is discussed in this paper. The tuning method is based on a two-degree-of-freedom internal model control (IMC) design method, and the performance of the resulting PID controller is related to two tuning parameters thus detuning is easy when necessary. Then an anti-GRC scheme is proposed to overcome the generation rate constraints. Finally, the method is extended to two-area cases.

A Tuned Single Parameter for Representing Conjunction Risk

Science.gov (United States)

Plakaloic, D.; Hejduk, M. D.; Frigm, R. C.; Newman, L. K.

2011-01-01

Satellite conjunction assessment risk analysis is a subjective enterprise that can benefit from quantitative aids and, to this end, NASA/GSFC has developed a fuzzy logic construct - called the F-value - to attempt to provide a statement of conjunction risk that amalgamates multiple indices and yields a more stable intra-event assessment. This construct has now sustained an extended tuning procedure against heuristic analyst assessment of event risk. The tuning effort has resulted in modifications to the calculation procedure and the adjustment of tuning coefficients, producing a construct with both more predictive force and a better statement of its error.

Utilization of Short-Simulations for Tuning High-Resolution Climate Model

Science.gov (United States)

Lin, W.; Xie, S.; Ma, P. L.; Rasch, P. J.; Qian, Y.; Wan, H.; Ma, H. Y.; Klein, S. A.

2016-12-01

Many physical parameterizations in atmospheric models are sensitive to resolution. Tuning the models that involve a multitude of parameters at high resolution is computationally expensive, particularly when relying primarily on multi-year simulations. This work describes a complementary set of strategies for tuning high-resolution atmospheric models, using ensembles of short simulations to reduce the computational cost and elapsed time. Specifically, we utilize the hindcast approach developed through the DOE Cloud Associated Parameterization Testbed (CAPT) project for high-resolution model tuning, which is guided by a combination of short (tests have been found to be effective in numerous previous studies in identifying model biases due to parameterized fast physics, and we demonstrate that it is also useful for tuning. After the most egregious errors are addressed through an initial "rough" tuning phase, longer simulations are performed to "hone in" on model features that evolve over longer timescales. We explore these strategies to tune the DOE ACME (Accelerated Climate Modeling for Energy) model. For the ACME model at 0.25° resolution, it is confirmed that, given the same parameters, major biases in global mean statistics and many spatial features are consistent between Atmospheric Model Intercomparison Project (AMIP)-type simulations and CAPT-type hindcasts, with just a small number of short-term simulations for the latter over the corresponding season. The use of CAPT hindcasts to find parameter choice for the reduction of large model biases dramatically improves the turnaround time for the tuning at high resolution. Improvement seen in CAPT hindcasts generally translates to improved AMIP-type simulations. An iterative CAPT-AMIP tuning approach is therefore adopted during each major tuning cycle, with the former to survey the likely responses and narrow the parameter space, and the latter to verify the results in climate context along with assessment in

A precision study of the fine tuning in the DiracNMSSM

International Nuclear Information System (INIS)

Kaminska, Anna; Ross, Graham G.; Staub, Florian; Bonn Univ.

2014-01-01

Recently the DiracNMSSM has been proposed as a possible solution to reduce the fine tuning in supersymmetry. We determine the degree of fine tuning needed in the DiracNMSSM with and without non-universal gaugino masses and compare it with the fine tuning in the GNMSSM. To apply reasonable cuts on the allowed parameter regions we perform a precise calculation of the Higgs mass. In addition, we include the limits from direct SUSY searches and dark matter abundance. We find that both models are comparable in terms of fine tuning, with the minimal fine tuning in the GNMSSM slightly smaller.

Tune space manipulations in jumping depolarizing resonances

International Nuclear Information System (INIS)

Ratner, L.G.; Ahrens, L.A.

1987-01-01

In February 1986, the AGS polarized beam reached a momentum of 22 GeV/c with a 45% polarization and an intensity of 1 to 2 x 10 10 polarized protons per pulse at a repetition rate of 2.1 seconds. In order to achieve this, one had to overcome the effect of some 40 depolarizing resonances. In our first commissioning run in 1984, we had reached 16.5 GeV/c using, with suitable modifications, the conventional techniques first used at the Argonne ZGS. This worked well, but we found that the fast tune shifts required to cross the intrinsic depolarizing resonances were causing an increase in beam emittance which led to the need for stronger corrections later in the cycle and to diminished extraction efficiency. For the 1986 run, we were prepared to minimize this emittance growth by the application of slow quadrupole pulses to change the region in tune space in which we operated the first tune quads. In this paper we give a brief description of the conventional corrections, but our main emphasis is on the descriptions of tune space manipulations

A novel tuning approach for offset-free MPC

DEFF Research Database (Denmark)

Waschl, Harald; Jørgensen, John Bagterp; Huusom, Jakob Kjøbsted

2015-01-01

, if a nominal plant and overall objective are known, the tuning can become straightforward. However, as soon as disturbances have to be taken into account, the tuning effort increases and becomes less intuitive. Against this background, a novel strategy to address the issues with unknown disturbances...

Accurate automatic tuning circuit for bipolar integrated filters

NARCIS (Netherlands)

de Heij, Wim J.A.; de Heij, W.J.A.; Hoen, Klaas; Hoen, Klaas; Seevinck, Evert; Seevinck, E.

1990-01-01

An accurate automatic tuning circuit for tuning the cutoff frequency and Q-factor of high-frequency bipolar filters is presented. The circuit is based on a voltage controlled quadrature oscillator (VCO). The frequency and the RMS (root mean square) amplitude of the oscillator output signal are

Tuning the band structure of graphene nanoribbons through defect-interaction-driven edge patterning

Science.gov (United States)

Du, Lin; Nguyen, Tam N.; Gilman, Ari; Muniz, André R.; Maroudas, Dimitrios

2017-12-01

We report a systematic analysis of pore-edge interactions in graphene nanoribbons (GNRs) and their outcomes based on first-principles calculations and classical molecular-dynamics simulations. We find a strong attractive interaction between nanopores and GNR edges that drives the pores to migrate toward and coalesce with the GNR edges, which can be exploited to form GNR edge patterns that impact the GNR electronic band structure and tune the GNR band gap. Our analysis introduces a viable physical processing strategy for modifying GNR properties by combining defect engineering and thermal annealing.

Automatic Tuning of Control Parameters for Single Speed Engines

OpenAIRE

Olsson, Johan

2004-01-01

In Scania’s single speed engines for industrial and marine use, the engine speed is controlled by a PI-controller. This controller is tuned independent of engine type and application. This brings certain disadvantages since the engines are used in a wide range of applications where the dynamics may differ. In this thesis, the possibility to tune the controller automatically for a specific engine installation has been investigated. The work shows that automatic tuning is possible. By performin...

Neural Tuning Functions Underlie Both Generalization and Interference.

Directory of Open Access Journals (Sweden)

Ian S Howard

Full Text Available In sports, the role of backswing is considered critical for generating a good shot, even though it plays no direct role in hitting the ball. We recently demonstrated the scientific basis of this phenomenon by showing that immediate past movement affects the learning and recall of motor memories. This effect occurred regardless of whether the past contextual movement was performed actively, passively, or shown visually. In force field studies, it has been shown that motor memories generalize locally and that the level of compensation decays as a function of movement angle away from the trained movement. Here we examine if the contextual effect of past movement exhibits similar patterns of generalization and whether it can explain behavior seen in interference studies. Using a single force-field learning task, the directional tuning curves of both the prior contextual movement and the subsequent force field adaptive movements were measured. The adaptation movement direction showed strong directional tuning, decaying to zero by 90° relative to the training direction. The contextual movement direction exhibited a similar directional tuning, although the effect was always above 60%. We then investigated the directional tuning of the passive contextual movement using interference tasks, where the contextual movements that uniquely specified the force field direction were separated by ±15° or ±45°. Both groups showed a pronounced tuning effect, which could be well explained by the directional tuning functions for single force fields. Our results show that contextual effect of past movement influences predictive force compensation, even when adaptation does not require contextual information. However, when such past movement contextual information is crucial to the task, such as in an interference study, it plays a strong role in motor memory learning and recall. This work demonstrates that similar tuning responses underlie both generalization of

Required accuracy of tune measurement and parametrization of chromaticity control

International Nuclear Information System (INIS)

Maas, R.

1991-02-01

The betatron tunes v x and v y will be measured by Fourier-analyzing a BPM signal generated by a beam which received a fast ( kick /f rev ) equals the fractional part of the tune, a beam blow-up can be observed. In this note the required accuracy of such a tune measurement is discussed. (author). 6 schemes

Performance-based parameter tuning method of model-driven PID control systems.

Science.gov (United States)

Zhao, Y M; Xie, W F; Tu, X W

2012-05-01

In this paper, performance-based parameter tuning method of model-driven Two-Degree-of-Freedom PID (MD TDOF PID) control system has been proposed to enhance the control performances of a process. Known for its ability of stabilizing the unstable processes, fast tracking to the change of set points and rejecting disturbance, the MD TDOF PID has gained research interest recently. The tuning methods for the reported MD TDOF PID are based on internal model control (IMC) method instead of optimizing the performance indices. In this paper, an Integral of Time Absolute Error (ITAE) zero-position-error optimal tuning and noise effect minimizing method is proposed for tuning two parameters in MD TDOF PID control system to achieve the desired regulating and disturbance rejection performance. The comparison with Two-Degree-of-Freedom control scheme by modified smith predictor (TDOF CS MSP) and the designed MD TDOF PID tuned by the IMC tuning method demonstrates the effectiveness of the proposed tuning method. Copyright © 2012 ISA. Published by Elsevier Ltd. All rights reserved.

Using mobile electronic devices to deliver educational resources in developing countries.

Science.gov (United States)

Mazal, Jonathan Robert; Ludwig, Rebecca

2015-01-01

Developing countries have far fewer trained radiography professionals than developed countries, which exacerbates the limited access to imaging services. The lack of trained radiographers reflects, in part, limited availability of radiographer-specific educational resources. Historically, organizations that provided such resources in the developing world faced challenges related to the limited stock of current materials as well as expenses associated with shipping and delivery. Four mobile electronic devices (MEDs) were loaded with educational content (e-books, PDFs, and digital applications) spanning major radiography topics. The MEDs were distributed to 4 imaging departments in Ghana, India, Nepal, and Nigeria based on evidence of need for radiography-specific resources, as revealed by survey responses. A cost comparison of postal delivery vs digital delivery of educational content was performed. The effectiveness of delivering additional content via Wi-Fi transmission also was evaluated. Feedback was solicited on users' experience with the MEDs as a delivery tool for educational content. An initial average per e-book expense of $30.05, which included the cost of the device, was calculated for the MED delivery method compared with $15.56 for postal delivery of printed materials. The cost of the MED delivery method was reduced to an average of $10.05 for subsequent e-book deliveries. Additional content was successfully delivered via Wi-Fi transmission to all recipients during the 3-month follow-up period. Overall user feedback on the experience was positive, and ideas for enhancing the MED-based method were identified. Using MEDs to deliver radiography-specific educational content appears to be more cost effective than postal delivery of printed materials on a long-term basis. MEDs are more efficient for providing updates to educational materials. Customization of content to department needs, and using projector devices could enhance the usefulness of MEDs for

Self-Tuning Speed Regulator for CVC Induction Motor Drive

DEFF Research Database (Denmark)

Bidstrup, N.; Rasmussen, Henrik; Knudsen, Torben

1994-01-01

A self-tuning speed regulator for a current vector controlled induction motor drive has been designed.......A self-tuning speed regulator for a current vector controlled induction motor drive has been designed....

Tune modulation due to synchrotron oscillations and chromaticity, and the dynamic aperture

International Nuclear Information System (INIS)

Parzen, G.

1995-01-01

A tracking study was done of the effects of a tune modulations, due to synchrotron oscillations and the tune dependence on momentum (chromaticity), on the dynamic aperture. The studies were done using several RHIC lattices and tracking runs of about 1 x 10 6 turns. The dynamic aperture was found to decrease roughly linearly with the amplitude of the tune modulation. Lower order non-linear resonances, like the 1/3 and 1/4 resonance are not crossed because of the tune modulation. Three different cases were studied, corresponding to RHIC lattices with different β*, and with different synchrotron oscillation amplitudes. In each case, the tune modulation amplitude was varied by changing the chromaticity. In each case, roughly the same result, was found. The result found here for the effect of a tune modulation due to chromaticity may be compared with the result found for the effect of a tune modulation due to a gradient ripple in the quadrupoles. The effect of a tune modulation due to a gradient ripple appears to be about 4 times stronger than the effect of a tune modulation due to chromaticity and synchrotron oscillations

Mechanical design of a RF electron gun

International Nuclear Information System (INIS)

Woodle, M.H.; Batchelor, K.; Sheehan, J.

1989-01-01

Brookhaven National Laboratory is building an Accelerator Test Facility at which we plan to study laser acceleration of electrons, inverse free electron lasers and the production of X-rays by non-linear Compton scattering. The facility contains an electron gun, linac, lasers and ancillary systems which will enable the production of 6 ps duration pulses of 50-100 MeV electrons. The electron source is an one and one half cell RF Electron gun which utilizes either a thermionic or photoemissive cathode to produce 5 MeV electrons. This paper discusses how gun mechanical design considerations such as material, vacuum maintenance, surface finish, fabrication methods, cavity tuning, and cathode replacement were reconciled to arrive at the final design. 9 refs., 2 figs., 2 tabs

Mechanical design of a rf electron gun

International Nuclear Information System (INIS)

Woodle, M.H.; Batchelor, K.; Sheehan, J.

1988-01-01

Brookhaven National Laboratory is building an Accelerator Test Facility at which we plan to study laser acceleration of electrons inverse free electron lasers and the production of X-rays by non- linear Compton scattering. The facility contains an electron gun, linac, lasers and ancillary systems which will enable the production of 6 ps duration pulses of 50--100 MeV electrons. The electron source is an one and one half cell RF Electron gun which utilizes either a thermionic or photoemissive cathode to produce 5 MeV electrons. This paper discusses how gun mechanical design considerations such as material, vacuum maintenance, surface finish, fabrication methods, cavity tuning, and cathode replacement were reconciled to arrive at the final design. 9 refs., 2 figs., 2 tabs

Driving the Power of AIX Performance Tuning on IBM Power

CERN Document Server

Milberg, Ken

2009-01-01

A concise reference for IT professionals, this book goes beyond the rules and contains the best practices and strategies for solid tuning methodology. Tips based on years of experience from an AIX tuning master show specific steps for monitoring and tuning CPU, virtual memory, disk I/O, and network components. Also offering techniques for tuning Oracle and Linux structures that run on an IBM power system-as well as for the new AIX 6.1-this manual discusses what tools are available, how to best use them to collect historical data, and when to analyze trends and results. The only comprehensive,

Historic Learning Approach for Auto-tuning OpenACC Accelerated Scientific Applications

KAUST Repository

Siddiqui, Shahzeb

2015-04-17

The performance optimization of scientific applications usually requires an in-depth knowledge of the hardware and software. A performance tuning mechanism is suggested to automatically tune OpenACC parameters to adapt to the execution environment on a given system. A historic learning based methodology is suggested to prune the parameter search space for a more efficient auto-tuning process. This approach is applied to tune the OpenACC gang and vector clauses for a better mapping of the compute kernels onto the underlying architecture. Our experiments show a significant performance improvement against the default compiler parameters and drastic reduction in tuning time compared to a brute force search-based approach.

POLARIZED BEAMS: 1 - Longitudinal electron spin polarization at HERA

Energy Technology Data Exchange (ETDEWEB)

Anon.

1994-09-15

Wednesday 4 May marked a turning point in the art of the manipulation of spins in electron storage rings: longitudinal electron spin polarization (with the spins oriented along the electrons' direction of motion) was established in the electron ring of HERA, the electronproton collider at DESY in Hamburg. A polarization level of about 55% was obtained and polarizations of over 60% were reproducibly obtained in the following days. The beam energy was 27.52 GeV, corresponding to half integer spin tune of 62.5.

Success criteria for electronic medical record implementations in low-resource settings: a systematic review.

Science.gov (United States)

Fritz, Fleur; Tilahun, Binyam; Dugas, Martin

2015-03-01

Electronic medical record (EMR) systems have the potential of supporting clinical work by providing the right information at the right time to the right people and thus make efficient use of resources. This is especially important in low-resource settings where reliable data are also needed to support public health and local supporting organizations. In this systematic literature review, our objectives are to identify and collect literature about success criteria of EMR implementations in low-resource settings and to summarize them into recommendations. Our search strategy relied on PubMed queries and manual bibliography reviews. Studies were included if EMR implementations in low-resource settings were described. The extracted success criteria and measurements were summarized into 7 categories: ethical, financial, functionality, organizational, political, technical, and training. We collected 381 success criteria with 229 measurements from 47 articles out of 223 articles. Most papers were evaluations or lessons learned from African countries, published from 1999 to 2013. Almost half of the EMR systems served a specific disease area like human immunodeficiency virus (HIV). The majority of criteria that were reported dealt with the functionality, followed by organizational issues, and technical infrastructures. Sufficient training and skilled personnel were mentioned in roughly 10%. Political, ethical, and financial considerations did not play a predominant role. More evaluations based on reliable frameworks are needed. Highly reliable data handling methods, human resources and effective project management, as well as technical architecture and infrastructure are all key factors for successful EMR implementation. © The Author 2015. Published by Oxford University Press on behalf of the American Medical Informatics Association. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Classical Causal Models for Bell and Kochen-Specker Inequality Violations Require Fine-Tuning

Directory of Open Access Journals (Sweden)

Eric G. Cavalcanti

2018-04-01

Full Text Available Nonlocality and contextuality are at the root of conceptual puzzles in quantum mechanics, and they are key resources for quantum advantage in information-processing tasks. Bell nonlocality is best understood as the incompatibility between quantum correlations and the classical theory of causality, applied to relativistic causal structure. Contextuality, on the other hand, is on a more controversial foundation. In this work, I provide a common conceptual ground between nonlocality and contextuality as violations of classical causality. First, I show that Bell inequalities can be derived solely from the assumptions of no signaling and no fine-tuning of the causal model. This removes two extra assumptions from a recent result from Wood and Spekkens and, remarkably, does not require any assumption related to independence of measurement settings—unlike all other derivations of Bell inequalities. I then introduce a formalism to represent contextuality scenarios within causal models and show that all classical causal models for violations of a Kochen-Specker inequality require fine-tuning. Thus, the quantum violation of classical causality goes beyond the case of spacelike-separated systems and already manifests in scenarios involving single systems.

[Laser Tuning Performance Testing and Optimization in TDLAS Oxygen Measuring Systems].

Science.gov (United States)

He, Jun-feng; Hu, Jun; Kan, Rui-feng; Xu, Zhen-yu; Wang, Tao

2015-03-01

TDLAS (tunable diode laser absorption spectroscopy) technology, with its unmatched advantages such as high selectivity molecular spectra, fast response, high sensitivity, non-contact measuring, become the preferred scheme for combustion process diagnosis, and can be effectively used for oxygen measuring. DFB (distributed feedback) laser diode with its small size, low power consumption, long service life, narrow linewidth, tunable wavelength has become the main choice of the TDLAS system. Performance of laser tuning characteristics is a key factor restricting TDLAS's measuring performance. According to TDLAS oxygen measuring system's working requirements, a simple experimental method was used to test and analyze tuning characteristics such as wavelength current, power current and wavelength temperature of a 764 nm DFB laser diode in the system. Nonlinear distortion of tuning curves was obvious, which affects oxygen measuring accuracy. The laser spectra's characteristics such as narrow linewidth, high side mode suppression ratio and wide wavelength tuning range are obvious, while its wavelength-current tuning curve with a tuning rate of about 0.023 nm x mA(-1) is not strictly linear. The higher the temperature the greater the threshold current, the PI curve is not strictly linear either. Temperature tuning curve is of good linearity, temperature-wave-length tuning rate keeps constant of about 0.056 nm/DEG C. Temperature tuning nonlinearity can be improved by high temperature control accuracy, and current power nonlinearity can be improved by setting the reference light path. In order to solve the wavelength current tuning nonlinear problems, the method of DA controlling injection current was considered to compensate for non-linear wavelength current tuning according to DFB laser diode tuning mechanism and polynomial fitting of test results. In view of different type of lasers, this method needs only one polynomial fitting process before the system's initial work. The

Impact of electronic modification of the chelating benzylidene ligand in cis-dichloro-configured second-generation olefin metathesis catalysts on their activity

KAUST Repository

Pump, Eva; Poater, Albert; Zirngast, Michaela; Torvisco, Ana; Fischer, Roland C.; Cavallo, Luigi; Slugovc, Christian

2014-01-01

A series of electronically modified second-generation cis-dichloro ruthenium ester chelating benzylidene complexes was prepared, characterized, and benchmarked in a typical ring-opening metathesis polymerization (ROMP) experiment. The electronic tuning of the parent chelating benzylidene ligand (2-ethyl ester benzylidene) was achieved by substitution at the 4- and 5-positions with electron-withdrawing nitro or electron-donating methoxy groups. The effect of the electronic tuning on the cis-trans isomerization process was studied experimentally and theoretically. Density functional theory calculations clearly revealed the influence of electronic modification on the relative stability between the cis and trans isomers, which is decisive for the activity of the studied compounds as initiators in ROMP. © 2014 American Chemical Society.

Impact of electronic modification of the chelating benzylidene ligand in cis-dichloro-configured second-generation olefin metathesis catalysts on their activity

KAUST Repository

Pump, Eva

2014-06-09

A series of electronically modified second-generation cis-dichloro ruthenium ester chelating benzylidene complexes was prepared, characterized, and benchmarked in a typical ring-opening metathesis polymerization (ROMP) experiment. The electronic tuning of the parent chelating benzylidene ligand (2-ethyl ester benzylidene) was achieved by substitution at the 4- and 5-positions with electron-withdrawing nitro or electron-donating methoxy groups. The effect of the electronic tuning on the cis-trans isomerization process was studied experimentally and theoretically. Density functional theory calculations clearly revealed the influence of electronic modification on the relative stability between the cis and trans isomers, which is decisive for the activity of the studied compounds as initiators in ROMP. © 2014 American Chemical Society.

Demonstration of Bias-Controlled Algorithmic Tuning of Quantum Dots in a Well (DWELL) MidIR Detectors

Science.gov (United States)

2009-06-01

imaging, as well as imaging and nonimaging active laser and radar systems. Dr. Tyo is a Fellow of the International Society for Optical Engineers (SPIE...possible to reconstruct the spec- tral content of a target electronically without using any disper- sive optical elements for tuning, thereby...chtm.unm.edu; skr- ishna@chtm.unm.edu). J. S. Tyo is with the College of Optical Sciences, University of Arizona, Tucson, AZ 85721 USA (e-mail: tyo

On-Chip Electrolytic Chemistry for the Tuning of Graphene Devices

Science.gov (United States)

Schmucker, Scott; Ruppalt, Laura; Culbertson, James; Do, Jae Won; Lyding, Joseph; Robinson, Jeremy; Cress, Cory

2015-03-01

The inherent interfacial nature of two-dimensional materials has motivated the tuning of these films by choice of substrate or chemical functionalization. Such parameters are generally selected during fabrication, and therefore remain static during device operation. However, the possibility of dynamic chemistry in a tunable solid-state system will enable the development of new devices which fully leverage the rich chemistry of graphenic materials. Here, we fabricate a novel device for localized, dynamic doping and functionalization of graphene that is compatible with CMOS processing. The device is enabled by a top-gated, solid electrochemical cell designed with calcium fluoride (CaF2) substituting the oxide of a traditional MOSFET. When the CaF2 is gated, F flows from cathode to anode, segregating Ca and F. In this work, one electrode is graphene. When saturated with fluorine, graphene undergoes covalent modification, becoming a wide-bandgap semiconductor. In contrast, when functionalized with calcium or dilute fluorine, graphene is electron or hole doped, respectively. With transport, Raman, and XPS, we demonstrate this lithographically localized and reversible modulation of graphene's electronic and chemical character.

Accumulative job demands and support for strength use: Fine-tuning the job demands-resources model using conservation of resources theory.

Science.gov (United States)

van Woerkom, Marianne; Bakker, Arnold B; Nishii, Lisa H

2016-01-01

Absenteeism associated with accumulated job demands is a ubiquitous problem. We build on prior research on the benefits of counteracting job demands with resources by focusing on a still untapped resource for buffering job demands-that of strengths use. We test the idea that employees who are actively encouraged to utilize their personal strengths on the job are better positioned to cope with job demands. Based on conservation of resources (COR) theory, we hypothesized that job demands can accumulate and together have an exacerbating effect on company registered absenteeism. In addition, using job demands-resources theory, we hypothesized that perceived organizational support for strengths use can buffer the impact of separate and combined job demands (workload and emotional demands) on absenteeism. Our sample consisted of 832 employees from 96 departments (response rate = 40.3%) of a Dutch mental health care organization. Results of multilevel analyses indicated that high levels of workload strengthen the positive relationship between emotional demands and absenteeism and that support for strength use interacted with workload and emotional job demands in the predicted way. Moreover, workload, emotional job demands, and strengths use interacted to predict absenteeism. Strengths use support reduced the level of absenteeism of employees who experienced both high workload and high emotional demands. We conclude that providing strengths use support to employees offers organizations a tool to reduce absenteeism, even when it is difficult to redesign job demands. (c) 2016 APA, all rights reserved).

Double-tuned radiofrequency coil for (19)F and (1)H imaging.

Science.gov (United States)

Otake, Yosuke; Soutome, Yoshihisa; Hirata, Koji; Ochi, Hisaaki; Bito, Yoshitaka

2014-01-01

We developed a double-tuned radiofrequency (RF) coil using a novel circuit method to double tune for fluorine-19 (19F) and 1H magnetic resonance imaging, whose frequencies are very close to each other. The RF coil consists of 3 parallel-connected series inductor capacitor circuits. A computer simulation for our double-tuned RF coil with a phantom demonstrated that the coil has tuned resonant frequency and high sensitivity for both 19F and 1H. Drug distribution was visualized at 7 tesla using this RF coil and a rat administered perfluoro 15-crown-5-ether emulsion. The double-tune RF coil we developed may be a powerful tool for 19F and 1H imaging.

AUTOMOTIVE DIESEL MAINTENANCE 1. UNIT VII, ENGINE TUNE-UP--DETROIT DIESEL ENGINE.

Science.gov (United States)

Human Engineering Inst., Cleveland, OH.

THIS MODULE OF A 30-MODULE COURSE IS DESIGNED TO DEVELOP AN UNDERSTANDING OF TUNE-UP PROCEDURES FOR DIESEL ENGINES. TOPICS ARE SCHEDULING TUNE-UPS, AND TUNE-UP PROCEDURES. THE MODULE CONSISTS OF A SELF-INSTRUCTIONAL BRANCH PROGRAMED TRAINING FILM "ENGINE TUNE-UP--DETROIT DIESEL ENGINE" AND OTHER MATERIALS. SEE VT 005 655 FOR FURTHER INFORMATION.…

High-Q perpendicular-biased ferrite-tuned cavity

International Nuclear Information System (INIS)

Carlini, R.D.; Thiessen, H.A.; Potter, J.M.

1983-01-01

Rapid-cycling proton synchrotrons, such as the proposed LAMPF II accelerator, require approximately 10 MV per turn rf with 17% tuning range near 50 MHz. The traditional approach to ferrite-tuned cavities uses a ferrite which is longitudinally biased (rf magnetic field parallel to bias field). This method leads to unacceptably high losses in the ferrite. At Los Alamos, we are developing a cavity with transverse bias (rf magnetic field perpendicular to the bias field) that makes use of the tensor permeability of the ferrite. Modest power tests of a small (10-cm-dia) quarter-wave singly re-entrant cavity tuned by nickel-zinc ferrites and aluminum-doped garnets indicate that the losses in the ferrite can be made negligible compared with the losses due to the surface resistivity of the copper cavity at power levels from 2 to 200 watts

Application of digital beam position processor Libera on tune measurement

International Nuclear Information System (INIS)

Zhang Chunhui; Sun Baogen; Cao Yong; Lu Ping; Li Jihao

2006-01-01

Digital signal processing (DSP) is widely used in the field of beam diagnostics. Especially, DSP achieves very good performance in beam position signal analysis and betatron tune measurement. In Hefei light source, when beam was excited by narrow-band Gaussian white nose, Libera, a digital beam position processor, was used to process the signals from beam position monitor (BPM), which contained betatron oscillation. Fast Fourier transform (FFT) was applied to finding out betatron resonance frequency, from which the decimal part of betatron oscillation tune was calculated. By this means, the measure of horizontal tune was 3.5352 and the measure of vertical tune is 2.6299. (authors)

Magnetic electron focusing and tuning of the electron current with a pn-junction

Energy Technology Data Exchange (ETDEWEB)

Milovanović, S. P., E-mail: slavisa.milovanovic@uantwerpen.be; Ramezani Masir, M., E-mail: mrmphys@gmail.com; Peeters, F. M., E-mail: francois.peeters@uantwerpen.be [Departement Fysica, Universiteit Antwerpen, Groenenborgerlaan 171, B-2020 Antwerpen (Belgium)

2014-01-28

Transverse magnetic focusing properties of graphene using a ballistic four terminal structure are investigated. The electric response is obtained using the semiclassical billiard model. The transmission exhibits pronounced peaks as a consequence of skipping orbits at the edge of the structure. When we add a pn-junction between the two probes, snake states along the pn-interface appear. Injected electrons are guided by the pn-interface to one of the leads depending on the value of the applied magnetic field. Oscillations in the resistance are found depending on the amount of particles that end up in each lead.

Optimal Self-Tuning PID Controller Based on Low Power Consumption for a Server Fan Cooling System.

Science.gov (United States)

Lee, Chengming; Chen, Rongshun

2015-05-20

Recently, saving the cooling power in servers by controlling the fan speed has attracted considerable attention because of the increasing demand for high-density servers. This paper presents an optimal self-tuning proportional-integral-derivative (PID) controller, combining a PID neural network (PIDNN) with fan-power-based optimization in the transient-state temperature response in the time domain, for a server fan cooling system. Because the thermal model of the cooling system is nonlinear and complex, a server mockup system simulating a 1U rack server was constructed and a fan power model was created using a third-order nonlinear curve fit to determine the cooling power consumption by the fan speed control. PIDNN with a time domain criterion is used to tune all online and optimized PID gains. The proposed controller was validated through experiments of step response when the server operated from the low to high power state. The results show that up to 14% of a server's fan cooling power can be saved if the fan control permits a slight temperature response overshoot in the electronic components, which may provide a time-saving strategy for tuning the PID controller to control the server fan speed during low fan power consumption.

Optimal Self-Tuning PID Controller Based on Low Power Consumption for a Server Fan Cooling System

Directory of Open Access Journals (Sweden)

Chengming Lee

2015-05-01

Full Text Available Recently, saving the cooling power in servers by controlling the fan speed has attracted considerable attention because of the increasing demand for high-density servers. This paper presents an optimal self-tuning proportional-integral-derivative (PID controller, combining a PID neural network (PIDNN with fan-power-based optimization in the transient-state temperature response in the time domain, for a server fan cooling system. Because the thermal model of the cooling system is nonlinear and complex, a server mockup system simulating a 1U rack server was constructed and a fan power model was created using a third-order nonlinear curve fit to determine the cooling power consumption by the fan speed control. PIDNN with a time domain criterion is used to tune all online and optimized PID gains. The proposed controller was validated through experiments of step response when the server operated from the low to high power state. The results show that up to 14% of a server’s fan cooling power can be saved if the fan control permits a slight temperature response overshoot in the electronic components, which may provide a time-saving strategy for tuning the PID controller to control the server fan speed during low fan power consumption.

Minimization of spin tune spread by matching dispersion prime at RHIC

Energy Technology Data Exchange (ETDEWEB)

Liu, C. [Brookhaven National Lab. (BNL), Upton, NY (United States); Kewisch, J. [Brookhaven National Lab. (BNL), Upton, NY (United States); Huang, H. [Brookhaven National Lab. (BNL), Upton, NY (United States)

2017-08-31

At RHIC, the spin polarization is preserved with a pair of Siberian snakes on the oppo- site sides in each ring. The polarized proton beam with finite spin tune spread might cross spin resonances multiple times in two cases, one is when beam going through strong spin intrinsic resonances during acceleration, the other is when sweeping spin flipper’ frequency across the spin tune to flip the direction of spin polarization. The consequence is loss of spin polarization in both cases. Therefore, a scheme of min- imizing the spin tune spread by matching the dispersion primes at the two snakes was introduced based on the fact that the spin tune spread is proportional to the difference of dispersion primes at the two snakes. The scheme was implemented at fixed energies for the spin flipper study and during beam acceleration for better spin polarization transmission efficiency. The effect of minimizing the spin tune spread by matching the dispersion primes was observed and confirmed experimentally. The principle of minimizing the spin tune spread by matching the dispersion primes, the impact on the beam optics, and the effect of a narrower spin tune spread are presented in this report.

Auto-tuning systems for J-PARC LINAC RF cavities

International Nuclear Information System (INIS)

Fang, Z.; Kobayashi, T.; Fukui, Y.; Futatsukawa, K.; Michizono, S.; Yamaguchi, S.; Anami, S.; Suzuki, H.; Sato, F.; Shinozaki, S.; Chishiro, E.

2014-01-01

The 400-MeV proton linear accelerator (LINAC) at the Japan Proton Accelerator Research Complex (J-PARC) consists of 324-MHz low-β and 972-MHz high-β accelerator sections. From October 2006 to May 2013, only the 324-MHz low-β accelerator section was in operation. From the summer of 2013 the J-PARC LINAC was upgraded by installing the 972-MHz high-β accelerator section, and the proton beam was successfully accelerated to 400 MeV in January 2014. Auto-tuning systems for the J-PARC LINAC RF cavities have been successfully developed. A first generation design, an auto-tuning system using a mechanical tuner controller, was developed and operated for the first 3 years. Then the second-generation auto-tuning system was developed using a new approach to the RF cavity warm-up process, and this was applied to the accelerator operation for the subsequent 4 years. During the RF cavity warm-up process in this system, the mechanical tuner is constantly fixed and the input RF frequency is automatically tuned to the cavity resonance frequency using the FPGA (Field-Programmable Gate Array) of the digital feedback RF control system. After the input power level reaches the required value, input RF frequency tuning is stopped and it is switched to the operation frequency. Then, the mechanical tuner control begins operation. This second-generation auto-tuning system was extremely effective for the 324-MHz cavity operation. However, if we apply this approach to the 972-MHz RF cavities, an interlock due to the RF cavity reflection amplitude occasionally occurs at the end of the warm-up process. In order to solve this problem a third generation novel auto-tuning system was successfully developed in December 2013 and applied to the operation of the J-PARC LINAC, including the 972-MHz ACS RF cavities. During the warm-up process both the mechanical tuner controller and the input RF frequency tuning are in operation, and good matching between the input RF frequency and the RF cavity is

Auto-tuning systems for J-PARC LINAC RF cavities

Energy Technology Data Exchange (ETDEWEB)

Fang, Z., E-mail: fang@post.kek.jp [High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Kobayashi, T.; Fukui, Y.; Futatsukawa, K.; Michizono, S.; Yamaguchi, S.; Anami, S. [High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Suzuki, H.; Sato, F.; Shinozaki, S.; Chishiro, E. [Japan Atomic Energy Agency (JAEA), 2-4 Shirane Shirakata, Tokai-mura, Naka-gun, Ibaraki 319-1195 (Japan)

2014-12-11

The 400-MeV proton linear accelerator (LINAC) at the Japan Proton Accelerator Research Complex (J-PARC) consists of 324-MHz low-β and 972-MHz high-β accelerator sections. From October 2006 to May 2013, only the 324-MHz low-β accelerator section was in operation. From the summer of 2013 the J-PARC LINAC was upgraded by installing the 972-MHz high-β accelerator section, and the proton beam was successfully accelerated to 400 MeV in January 2014. Auto-tuning systems for the J-PARC LINAC RF cavities have been successfully developed. A first generation design, an auto-tuning system using a mechanical tuner controller, was developed and operated for the first 3 years. Then the second-generation auto-tuning system was developed using a new approach to the RF cavity warm-up process, and this was applied to the accelerator operation for the subsequent 4 years. During the RF cavity warm-up process in this system, the mechanical tuner is constantly fixed and the input RF frequency is automatically tuned to the cavity resonance frequency using the FPGA (Field-Programmable Gate Array) of the digital feedback RF control system. After the input power level reaches the required value, input RF frequency tuning is stopped and it is switched to the operation frequency. Then, the mechanical tuner control begins operation. This second-generation auto-tuning system was extremely effective for the 324-MHz cavity operation. However, if we apply this approach to the 972-MHz RF cavities, an interlock due to the RF cavity reflection amplitude occasionally occurs at the end of the warm-up process. In order to solve this problem a third generation novel auto-tuning system was successfully developed in December 2013 and applied to the operation of the J-PARC LINAC, including the 972-MHz ACS RF cavities. During the warm-up process both the mechanical tuner controller and the input RF frequency tuning are in operation, and good matching between the input RF frequency and the RF cavity is

Collective Mind: Towards Practical and Collaborative Auto-Tuning

Directory of Open Access Journals (Sweden)

Grigori Fursin

2014-01-01

Full Text Available Empirical auto-tuning and machine learning techniques have been showing high potential to improve execution time, power consumption, code size, reliability and other important metrics of various applications for more than two decades. However, they are still far from widespread production use due to lack of native support for auto-tuning in an ever changing and complex software and hardware stack, large and multi-dimensional optimization spaces, excessively long exploration times, and lack of unified mechanisms for preserving and sharing of optimization knowledge and research material. We present a possible collaborative approach to solve above problems using Collective Mind knowledge management system. In contrast with previous cTuning framework, this modular infrastructure allows to preserve and share through the Internet the whole auto-tuning setups with all related artifacts and their software and hardware dependencies besides just performance data. It also allows to gradually structure, systematize and describe all available research material including tools, benchmarks, data sets, search strategies and machine learning models. Researchers can take advantage of shared components and data with extensible meta-description to quickly and collaboratively validate and improve existing auto-tuning and benchmarking techniques or prototype new ones. The community can now gradually learn and improve complex behavior of all existing computer systems while exposing behavior anomalies or model mispredictions to an interdisciplinary community in a reproducible way for further analysis. We present several practical, collaborative and model-driven auto-tuning scenarios. We also decided to release all material at c-mind.org/repo to set up an example for a collaborative and reproducible research as well as our new publication model in computer engineering where experimental results are continuously shared and validated by the community.

Effects of graphene defect on electronic structures of its interface with organic semiconductor

Energy Technology Data Exchange (ETDEWEB)

Yang, Qing-Dan; Wang, Chundong; Mo, Hin-Wai; Lo, Ming-Fai; Yuen, Muk Fung; Ng, Tsz-Wai, E-mail: tszwaing@cityu.edu.hk, E-mail: apcslee@cityu.edu.hk; Zhang, Wen-Jun; Lee, Chun-Sing, E-mail: tszwaing@cityu.edu.hk, E-mail: apcslee@cityu.edu.hk [Department of Physics and Materials Science, Center of Super-Diamond and Advanced Films (COSDAF), City University of Hong Kong (Hong Kong); Dou, Wei-Dong [Department of Physics and Materials Science, Center of Super-Diamond and Advanced Films (COSDAF), City University of Hong Kong (Hong Kong); Physics Department, Shaoxing University, Shaoxing 312000 (China); Tsang, Sai-Wing [Department of Physics and Materials Science, City University of Hong Kong (Hong Kong)

2015-03-30

Electronic structures of copper hexadecafluorophthalocyanine (F{sub 16}CuPc)/graphene with different defect density were studied with ultra-violet photoelectron spectroscopy. We showed that the charge transfer interaction and charge flow direction can be interestingly tuned by controlling the defect density of graphene through time-controlled H{sub 2} plasma treatment. By increasing the treatment time of H{sub 2} plasma from 30 s to 5 min, both the interface surface dipole and the electron transporting barrier at F{sub 16}CuPc/graphene interface are significantly reduced from 0.86 to 0.56 eV and 0.71 to 0.29 eV, respectively. These results suggested that graphene's defect control is a simple approach for tuning electronic properties of organic/graphene interfaces.

Tuning Properties in Silver Clusters

KAUST Repository

Joshi, Chakra Prasad

2015-07-09

The properties of Ag nanoclusters are not as well understood as those of their more precious Au cousins. However, a recent surge in the exploration of strategies to tune the physicochemical characteristics of Ag clusters addresses this imbalance, leading to new insights into their optical, luminescence, crystal habit, metal-core, ligand-shell and environmental properties. In this Perspective, we provide an overview of the latest strategies along with a brief introduction of the theoretical framework necessary to understand the properties of silver nanoclusters and the basis for their tuning. The advances in cluster research and the future prospects presented in this Perspective will eventually guide the next large systematic study of nanoclusters, resulting in a single collection of data similar to the periodic table of elements.

Computation of undulator tuning curves

International Nuclear Information System (INIS)

Dejus, Roger J.

1997-01-01

Computer codes for fast computation of on-axis brilliance tuning curves and flux tuning curves have been developed. They are valid for an ideal device (regular planar device or a helical device) using the Bessel function formalism. The effects of the particle beam emittance and the beam energy spread on the spectrum are taken into account. The applicability of the codes and the importance of magnetic field errors of real insertion devices are addressed. The validity of the codes has been experimentally verified at the APS and observed discrepancies are in agreement with predicted reduction of intensities due to magnetic field errors. The codes are distributed as part of the graphical user interface XOP (X-ray OPtics utilities), which simplifies execution and viewing of the results

Tuning Properties in Silver Clusters

KAUST Repository

Joshi, Chakra Prasad; Bootharaju, Megalamane Siddaramappa; Bakr, Osman

2015-01-01

The properties of Ag nanoclusters are not as well understood as those of their more precious Au cousins. However, a recent surge in the exploration of strategies to tune the physicochemical characteristics of Ag clusters addresses this imbalance, leading to new insights into their optical, luminescence, crystal habit, metal-core, ligand-shell and environmental properties. In this Perspective, we provide an overview of the latest strategies along with a brief introduction of the theoretical framework necessary to understand the properties of silver nanoclusters and the basis for their tuning. The advances in cluster research and the future prospects presented in this Perspective will eventually guide the next large systematic study of nanoclusters, resulting in a single collection of data similar to the periodic table of elements.

Human face processing is tuned to sexual age preferences

DEFF Research Database (Denmark)

Ponseti, J; Granert, O; van Eimeren, T

2014-01-01

Human faces can motivate nurturing behaviour or sexual behaviour when adults see a child or an adult face, respectively. This suggests that face processing is tuned to detecting age cues of sexual maturity to stimulate the appropriate reproductive behaviour: either caretaking or mating....... In paedophilia, sexual attraction is directed to sexually immature children. Therefore, we hypothesized that brain networks that normally are tuned to mature faces of the preferred gender show an abnormal tuning to sexual immature faces in paedophilia. Here, we use functional magnetic resonance imaging (f......MRI) to test directly for the existence of a network which is tuned to face cues of sexual maturity. During fMRI, participants sexually attracted to either adults or children were exposed to various face images. In individuals attracted to adults, adult faces activated several brain regions significantly more...

Recommendations for the tuning of rare event probability estimators

International Nuclear Information System (INIS)

Balesdent, Mathieu; Morio, Jérôme; Marzat, Julien

2015-01-01

Being able to accurately estimate rare event probabilities is a challenging issue in order to improve the reliability of complex systems. Several powerful methods such as importance sampling, importance splitting or extreme value theory have been proposed in order to reduce the computational cost and to improve the accuracy of extreme probability estimation. However, the performance of these methods is highly correlated with the choice of tuning parameters, which are very difficult to determine. In order to highlight recommended tunings for such methods, an empirical campaign of automatic tuning on a set of representative test cases is conducted for splitting methods. It allows to provide a reduced set of tuning parameters that may lead to the reliable estimation of rare event probability for various problems. The relevance of the obtained result is assessed on a series of real-world aerospace problems

Towards automatic parameter tuning of stream processing systems

KAUST Repository

Bilal, Muhammad

2017-09-27

Optimizing the performance of big-data streaming applications has become a daunting and time-consuming task: parameters may be tuned from a space of hundreds or even thousands of possible configurations. In this paper, we present a framework for automating parameter tuning for stream-processing systems. Our framework supports standard black-box optimization algorithms as well as a novel gray-box optimization algorithm. We demonstrate the multiple benefits of automated parameter tuning in optimizing three benchmark applications in Apache Storm. Our results show that a hill-climbing algorithm that uses a new heuristic sampling approach based on Latin Hypercube provides the best results. Our gray-box algorithm provides comparable results while being two to five times faster.

Elastic and electronic tuning of magnetoresistance in MoTe2.

Science.gov (United States)

Yang, Junjie; Colen, Jonathan; Liu, Jun; Nguyen, Manh Cuong; Chern, Gia-Wei; Louca, Despina

2017-12-01

Quasi-two-dimensional transition metal dichalcogenides exhibit dramatic properties that may transform electronic and photonic devices. We report on how the anomalously large magnetoresistance (MR) observed under high magnetic field in MoTe 2 , a type II Weyl semimetal, can be reversibly controlled under tensile strain. The MR is enhanced by as much as ~30% at low temperatures and high magnetic fields when uniaxial strain is applied along the a crystallographic direction and reduced by about the same amount when strain is applied along the b direction. We show that the large in-plane electric anisotropy is coupled with the structural transition from the 1T' monoclinic to the T d orthorhombic Weyl phase. A shift of the T d -1T' phase boundary is achieved by minimal tensile strain. The sensitivity of the MR to tensile strain suggests the possibility of a nontrivial spin-orbital texture of the electron and hole pockets in the vicinity of Weyl points. Our ab initio calculations show a significant orbital mixing on the Fermi surface, which is modified by the tensile strains.

Tuning electronic transport in epitaxial graphene-based van der Waals heterostructures

Science.gov (United States)

Lin, Yu-Chuan; Li, Jun; de La Barrera, Sergio C.; Eichfeld, Sarah M.; Nie, Yifan; Addou, Rafik; Mende, Patrick C.; Wallace, Robert M.; Cho, Kyeongjae; Feenstra, Randall M.; Robinson, Joshua A.

2016-04-01

Two-dimensional tungsten diselenide (WSe2) has been used as a component in atomically thin photovoltaic devices, field effect transistors, and tunneling diodes in tandem with graphene. In some applications it is necessary to achieve efficient charge transport across the interface of layered WSe2-graphene, a semiconductor to semimetal junction with a van der Waals (vdW) gap. In such cases, band alignment engineering is required to ensure a low-resistance, ohmic contact. In this work, we investigate the impact of graphene electronic properties on the transport at the WSe2-graphene interface. Electrical transport measurements reveal a lower resistance between WSe2 and fully hydrogenated epitaxial graphene (EGFH) compared to WSe2 grown on partially hydrogenated epitaxial graphene (EGPH). Using low-energy electron microscopy and reflectivity on these samples, we extract the work function difference between the WSe2 and graphene and employ a charge transfer model to determine the WSe2 carrier density in both cases. The results indicate that WSe2-EGFH displays ohmic behavior at small biases due to a large hole density in the WSe2, whereas WSe2-EGPH forms a Schottky barrier junction.Two-dimensional tungsten diselenide (WSe2) has been used as a component in atomically thin photovoltaic devices, field effect transistors, and tunneling diodes in tandem with graphene. In some applications it is necessary to achieve efficient charge transport across the interface of layered WSe2-graphene, a semiconductor to semimetal junction with a van der Waals (vdW) gap. In such cases, band alignment engineering is required to ensure a low-resistance, ohmic contact. In this work, we investigate the impact of graphene electronic properties on the transport at the WSe2-graphene interface. Electrical transport measurements reveal a lower resistance between WSe2 and fully hydrogenated epitaxial graphene (EGFH) compared to WSe2 grown on partially hydrogenated epitaxial graphene (EGPH). Using low

Heavy vehicle pitch dynamics and suspension tuning

OpenAIRE

Cao, Dongpu; Rakheja, Subhash; Su, Chun-Yi

2008-01-01

The influence of suspension tuning of passenger cars on bounce and pitch ride performance has been explored in a number of studies, while only minimal efforts have been made for establishing similar rules for heavy vehicles. This study aims to explore pitch dynamics and suspension tunings of a two-axle heavy vehicle with unconnected suspension, which could also provide valuable information for heavy vehicles with coupled suspensions. Based on a generalised pitch-plane model of a two-axle heav...

Implementation through Innovation: A Literature-Based Analysis of the Tuning Project

Science.gov (United States)

Pálvölgyi, Krisztián

2017-01-01

Tuning Educational Structures in Europe is perhaps the most important higher education innovation platform nowadays. The main objective of the Tuning Project is to develop a tangible approach to implement the action lines of the Bologna Process; thus, implementation and innovation are closely linked in Tuning. However, during its development,…

Realtime tune measurements in slow-cycling accelerators

International Nuclear Information System (INIS)

Herrup, D.

1997-01-01

Measurement and control of the tunes, coupling, and chromaticities in storage rings is essential to efficient operation of these accelerators. Yet it has been very difficult to make reliable realtime measurements of these quantities. We have built and commissioned the microprocessor-based Generic Finite State Data Acquisition (GFSDA) system. GFSDA provides turn-by-turn data acquisition and analysis of accelerator signals in a way that can be easily related to accelerator operations. The microprocessor is capable of calculating FFTs and correlations in real time. Both the Fermilab Main Ring and Tevatron use open loop tune, chromaticity, and coupling control, and the GFSDA measurements can easily be used to improve the open loop tables. We can add realtime feedback control with simple extensions of the system. We have used this system to make tune measurements closely spaced in time over an entire Tevatron ramp cycle

Discrete PID Tuning Using Artificial Intelligence Techniques

Directory of Open Access Journals (Sweden)

Petr DOLEŽEL

2009-06-01

Full Text Available PID controllers are widely used in industry these days due to their useful properties such as simple tuning or robustness. While they are applicable to many control problems, they can perform poorly in some applications. Highly nonlinear system control with constrained manipulated variable can be mentioned as an example. The point of the paper is to string together convenient qualities of conventional PID control and progressive techniques based on Artificial Intelligence. Proposed control method should deal with even highly nonlinear systems. To be more specific, there is described new method of discrete PID controller tuning in this paper. This method tunes discrete PID controller parameters online through the use of genetic algorithm and neural model of controlled system in order to control successfully even highly nonlinear systems. After method description and some discussion, there is performed control simulation and comparison to one chosen conventional control method.

White light emission from exciplex using tris-(8-hydroxyquinoline)aluminum as chromaticity-tuning layer

International Nuclear Information System (INIS)

Feng, Jing; Li, Feng; Gao, Wenbao; Liu, Shiyong; Liu, Yu; Wang, Yue

2001-01-01

We demonstrate efficient organic white light-emitting devices (LEDs), using N,N prime-diphenyl-N,N prime-bis(1-naphthyl) - (1,1 prime-biphenyl)-4,4 prime-diamine (NPB) as the hole-transporting layer, 1,6-bis(2-hydroxyphenyl)pyridine boron complex [(dppy)BF] as the emitting layer, tris-(8-hydroxyquinoline)aluminum (Alq) as the electron-transporting and chromaticity-tuning layer. The white light comes from exciplex emission at the solid-state interface between (dppy)BF and NPB in addition to the exciton emission from NPB and (dppy)BF, respectively. The chromaticity of white emission can be tuned by adjusting the thickness of the Alq layer. The white LEDs with an Alq thickness of 15 nm exhibit a maximum luminescence of 2000 cd/m2 and efficiency of 0.58 lm/W, and the Commission Internationale De l'Eclairage coordinates of resulting emission vary from (0.29,0.33) to (0.31,0.35) with increasing forward bias from 10 to 25 V. The region is very close to the equienergy white point (0.33,0.33). [copyright] 2001 American Institute of Physics

Proportional–Integral–Derivative (PID Controller Tuning using Particle Swarm Optimization Algorithm

Directory of Open Access Journals (Sweden)

J. S. Bassi

2012-08-01

Full Text Available The proportional-integral-derivative (PID controllers are the most popular controllers used in industry because of their remarkable effectiveness, simplicity of implementation and broad applicability. However, manual tuning of these controllers is time consuming, tedious and generally lead to poor performance. This tuning which is application specific also deteriorates with time as a result of plant parameter changes. This paper presents an artificial intelligence (AI method of particle swarm optimization (PSO algorithm for tuning the optimal proportional-integral derivative (PID controller parameters for industrial processes. This approach has superior features, including easy implementation, stable convergence characteristic and good computational efficiency over the conventional methods. Ziegler- Nichols, tuning method was applied in the PID tuning and results were compared with the PSO-Based PID for optimum control. Simulation results are presented to show that the PSO-Based optimized PID controller is capable of providing an improved closed-loop performance over the Ziegler- Nichols tuned PID controller Parameters. Compared to the heuristic PID tuning method of Ziegler-Nichols, the proposed method was more efficient in improving the step response characteristics such as, reducing the steady-states error; rise time, settling time and maximum overshoot in speed control of DC motor.

Stochastic population dynamics under resource constraints

Energy Technology Data Exchange (ETDEWEB)

Gavane, Ajinkya S., E-mail: ajinkyagavane@gmail.com; Nigam, Rahul, E-mail: rahul.nigam@hyderabad.bits-pilani.ac.in [BITS Pilani Hyderabad Campus, Shameerpet, Hyd - 500078 (India)

2016-06-02

This paper investigates the population growth of a certain species in which every generation reproduces thrice over a period of predefined time, under certain constraints of resources needed for survival of population. We study the survival period of a species by randomizing the reproduction probabilities within a window at same predefined ages and the resources are being produced by the working force of the population at a variable rate. This randomness in the reproduction rate makes the population growth stochastic in nature and one cannot predict the exact form of evolution. Hence we study the growth by running simulations for such a population and taking an ensemble averaged over 500 to 5000 such simulations as per the need. While the population reproduces in a stochastic manner, we have implemented a constraint on the amount of resources available for the population. This is important to make the simulations more realistic. The rate of resource production then is tuned to find the rate which suits the survival of the species. We also compute the mean life time of the species corresponding to different resource production rate. Study for these outcomes in the parameter space defined by the reproduction probabilities and rate of resource production is carried out.

New design concepts for ferrite-tuned low-energy-booster cavities

International Nuclear Information System (INIS)

Schaffer, G.

1991-05-01

The design concepts for ferrite-tuned accelerating cavities discussed in this paper differ from conventional solutions using thick ferrite toroids for frequency tuning. Instead, tuners consisting of an array of ferrite-loaded striplines are investigated. These promise more efficient cooling and higher operational reliability. Layout examples for the SSC-LEB rf system are presented (tuning range 47.5 to 59.8 MHz, repetition frequency 10 Hz). 15 refs., 4 figs., 1 tab

Application research of tune measurement system in Hefei light source

International Nuclear Information System (INIS)

Sun Baogen; He Duohui; Xu Hongliang; Lu Ping; Wang Junhua; Gao Yunfeng; Wang Lin; Liu Jinying

2002-01-01

The author introduces the measurement and research of some beam parameters using tune measurement system for Hefei Light Source (HLS), which include the betatron tune, beta function, natural chromaticity, corrected chromaticity, and central frequency. Additionally, it also describes the measurement of the influence of DC clearing electrodes on the betatron tune shift and gives some measurement results. The measurement results are compared with the theoretical values and they are in good agreement

Efficient receiver tuning using differential evolution strategies

Science.gov (United States)

Wheeler, Caleb H.; Toland, Trevor G.

2016-08-01

Differential evolution (DE) is a powerful and computationally inexpensive optimization strategy that can be used to search an entire parameter space or to converge quickly on a solution. The Kilopixel Array Pathfinder Project (KAPPa) is a heterodyne receiver system delivering 5 GHz of instantaneous bandwidth in the tuning range of 645-695 GHz. The fully automated KAPPa receiver test system finds optimal receiver tuning using performance feedback and DE. We present an adaptation of DE for use in rapid receiver characterization. The KAPPa DE algorithm is written in Python 2.7 and is fully integrated with the KAPPa instrument control, data processing, and visualization code. KAPPa develops the technologies needed to realize heterodyne focal plane arrays containing 1000 pixels. Finding optimal receiver tuning by investigating large parameter spaces is one of many challenges facing the characterization phase of KAPPa. This is a difficult task via by-hand techniques. Characterizing or tuning in an automated fashion without need for human intervention is desirable for future large scale arrays. While many optimization strategies exist, DE is ideal for time and performance constraints because it can be set to converge to a solution rapidly with minimal computational overhead. We discuss how DE is utilized in the KAPPa system and discuss its performance and look toward the future of 1000 pixel array receivers and consider how the KAPPa DE system might be applied.

Feedback and feedforward control of frequency tuning to naturalistic stimuli.

Science.gov (United States)

Chacron, Maurice J; Maler, Leonard; Bastian, Joseph

2005-06-08

Sensory neurons must respond to a wide variety of natural stimuli that can have very different spatiotemporal characteristics. Optimal responsiveness to subsets of these stimuli can be achieved by devoting specialized neural circuitry to different stimulus categories, or, alternatively, this circuitry can be modulated or tuned to optimize responsiveness to current stimulus conditions. This study explores the mechanisms that enable neurons within the initial processing station of the electrosensory system of weakly electric fish to shift their tuning properties based on the spatial extent of the stimulus. These neurons are tuned to low frequencies when the stimulus is restricted to a small region within the receptive field center but are tuned to higher frequencies when the stimulus impinges on large regions of the sensory epithelium. Through a combination of modeling and in vivo electrophysiology, we reveal the respective contributions of the filtering characteristics of extended dendritic structures and feedback circuitry to this shift in tuning. Our results show that low-frequency tuning can result from the cable properties of an extended dendrite that conveys receptor-afferent information to the cell body. The shift from low- to high-frequency tuning, seen in response to spatially extensive stimuli, results from increased wide-band input attributable to activation of larger populations of receptor afferents, as well as the activation of parallel fiber feedback from the cerebellum. This feedback provides a cancellation signal with low-pass characteristics that selectively attenuates low-frequency responsiveness. Thus, with spatially extensive stimuli, these cells preferentially respond to the higher-frequency components of the receptor-afferent input.

Tune measurement at GSI SIS-18. Methods and applications

Energy Technology Data Exchange (ETDEWEB)

Singh, Rahul

2014-05-15

Two parallel tune measurement systems are installed at GSI SIS-18 based on different principles. The first is called the Tune, Orbit and POSition measurement system TOPOS. Its working principle involves direct digitization of BPM signals at 125 MSa/s, which is used for online bunch-by-bunch position calculation in FPGAs. In the course of this work, position calculation algorithms were developed and studied for real time implementation in the TOPOS FPGAs. The regression fit algorithm is found to be more efficient and robust in comparison to previously used weighted mean algorithm with the baseline restoration procedure. The second system is the Baseband Tune measurement system referred to as BBQ system. The operational principle of this system was conceived at the CERN Beam Instrumentation group and is based on direct diode detection. In the framework of this work, this system was optimized and brought into operation at GSI SIS-18. Front-end data from both systems are used to calculate the tune spectrum every 250-5000 beam revolutions or turns within SIS-18 based on the resolution requirement and the mode of operation. Advanced non-parametric spectrum estimation method like amplitude Capon estimator is compared to the conventional DFT based methods in terms of resolving power and computational requirements for the calculated spectrum. Further the TOPOS and BBQ systems are compared and characterized in terms of sensitivity, reliability and operational usage. The results from both systems are found to be consistent with each other and have their favoured regimes of operation. The effects on tune spectra obtained from both systems were studied with different types of excitations with excitation power levels up to 6 mW/Hz. These systems in association with other beam diagnostic devices at SIS-18 were used to conduct extensive experiments to understand the effect of high intensity beams on the tune spectrum. These careful measurements recorded all the relevant beam

Electronic Human Resources Management (e-HRM Adoption Studies: Past and Future Research

Directory of Open Access Journals (Sweden)

Winarto Winarto

2018-05-01

Full Text Available Electronic human resource management (e-HRM systems become more widely used by profit and non-profit organization. However, the field currently lacks sound theoretical frameworks that can be useful in addressing a key issue concerning the implementation of e-HRM systems, in particular to obtain a better understanding of the factors influencing the adoption of e-HRM systems. The objective of this paper is to provide a foundation towards the development of a theoretical framework for the implementation of e-HRM systems and develop a conceptual model that would reflect the nature of e-HRM systems’ adoption through systematic literature review. Adopting Crossan and Apaydin’s procedure of systematic review, this paper investigated 21 empirical papers of electronics human resources management, then categorized them into 4 characteristics which influence the adoption; System and technology characteristics; Organizational characteristics; User/individual characteristics, and Environmental and contextual characteristics. Finally, the e-HRM adoption research framework is drawn and based on the framework; avenues for future research are discussed.   Bahasa Indonesia Abstrak: Manajemen sumber daya manusia elektronik (selanjutnya disebut dengan e-HRM semakin banyak digunakan oleh organisasi profit dan nonprofit. Namun, bidang dan topik ini belum memiliki kerangka teori yang mapan, yang dapat digunakan untuk menganalisis isu-isu terkait penerapan e-HRM, terutama mengenai faktor-faktor yang mempengaruhi adopsi sistem e-HRM. Tujuan penelitian ini adalah untuk memberikan landasan bagi pengembangan kerangka teoritis untuk implementasi sistem e-HRM dan mengembangkan model konseptual yang akan menggambarkan adopsi sistem e-HRM melalui tinjauan literatur sistematis. Mengadopsi prosedur dan metode Crossan dan Apaydin untuk melakukan telaah literatur secara sistematis, paper ini menyelidiki 21 publikasi empiris manajemen sumber daya manusia elektronik dari 2

Characterization of electronic structures from CdS/Si nanoheterostructure array based on silicon nanoporous pillar array

Energy Technology Data Exchange (ETDEWEB)

Li, Yong, E-mail: liyong@pdsu.edu.cn [Department of Physics and Solar Energy Research Center, Pingdingshan University, Pingdingshan 467000 (China); Song, Xiao Yan [Department of Mathematics and Information Science, North China University of Water Resources and Electric Power, Zhengzhou 450045 (China); Song, Yue Li; Ji, Peng Fei; Zhou, Feng Qun; Tian, Ming Li; Huang, Hong Chun [Department of Physics and Solar Energy Research Center, Pingdingshan University, Pingdingshan 467000 (China); Li, Xin Jian [Department of Physics and Laboratory of Material Physics, Zhengzhou University, Zhengzhou 450052 (China)

2016-02-15

Highlights: • CdS/Si nanoheterostructure array has been fabricated through a CBD method. • The electronic properties have been investigated by the I–V and C–V techniques. • The onset voltages, characteristic frequency and built-in potential are investigated. • The electronic structures can be tuned through the annealing treatments. - Abstract: The electronic properties of heterostructures are very important to its applications in the field of optoelectronic devices. Understanding and control of electronic properties are very necessary. CdS/Si nanoheterostructure array have been fabricated through growing CdS nanocrystals on the silicon nanoporous pillar array using a chemical bath deposition method. The electronic properties of CdS nanoheterostructure array have been investigated by the current–voltage, complex impedance spectroscopy and capacitance–voltage techniques. The onset voltages, characteristic frequency and built-in potential are gradually increased with increasing the annealing temperature. It is indicated that the electronic structures of CdS/Si nanoheterostructure array can be tuned through the annealing treatments.

Characterization of electronic structures from CdS/Si nanoheterostructure array based on silicon nanoporous pillar array

International Nuclear Information System (INIS)

Li, Yong; Song, Xiao Yan; Song, Yue Li; Ji, Peng Fei; Zhou, Feng Qun; Tian, Ming Li; Huang, Hong Chun; Li, Xin Jian

2016-01-01

Highlights: • CdS/Si nanoheterostructure array has been fabricated through a CBD method. • The electronic properties have been investigated by the I–V and C–V techniques. • The onset voltages, characteristic frequency and built-in potential are investigated. • The electronic structures can be tuned through the annealing treatments. - Abstract: The electronic properties of heterostructures are very important to its applications in the field of optoelectronic devices. Understanding and control of electronic properties are very necessary. CdS/Si nanoheterostructure array have been fabricated through growing CdS nanocrystals on the silicon nanoporous pillar array using a chemical bath deposition method. The electronic properties of CdS nanoheterostructure array have been investigated by the current–voltage, complex impedance spectroscopy and capacitance–voltage techniques. The onset voltages, characteristic frequency and built-in potential are gradually increased with increasing the annealing temperature. It is indicated that the electronic structures of CdS/Si nanoheterostructure array can be tuned through the annealing treatments.

Controlling the thermoelectric effect by mechanical manipulation of the electron's quantum phase in atomic junctions.

Science.gov (United States)

Aiba, Akira; Demir, Firuz; Kaneko, Satoshi; Fujii, Shintaro; Nishino, Tomoaki; Tsukagoshi, Kazuhito; Saffarzadeh, Alireza; Kirczenow, George; Kiguchi, Manabu

2017-08-11

The thermoelectric voltage developed across an atomic metal junction (i.e., a nanostructure in which one or a few atoms connect two metal electrodes) in response to a temperature difference between the electrodes, results from the quantum interference of electrons that pass through the junction multiple times after being scattered by the surrounding defects. Here we report successfully tuning this quantum interference and thus controlling the magnitude and sign of the thermoelectric voltage by applying a mechanical force that deforms the junction. The observed switching of the thermoelectric voltage is reversible and can be cycled many times. Our ab initio and semi-empirical calculations elucidate the detailed mechanism by which the quantum interference is tuned. We show that the applied strain alters the quantum phases of electrons passing through the narrowest part of the junction and hence modifies the electronic quantum interference in the device. Tuning the quantum interference causes the energies of electronic transport resonances to shift, which affects the thermoelectric voltage. These experimental and theoretical studies reveal that Au atomic junctions can be made to exhibit both positive and negative thermoelectric voltages on demand, and demonstrate the importance and tunability of the quantum interference effect in the atomic-scale metal nanostructures.

METHODOLOGICAL NOTES: Integrating magnetism into semiconductor electronics

Science.gov (United States)

Zakharchenya, Boris P.; Korenev, Vladimir L.

2005-06-01

The view of a ferromagnetic-semiconducting hybrid structure as a single tunable system is presented. Based on an analysis of existing experiments it is shown that, contrary to a 'common sense', a nonmagnetic semiconductor is capable of playing an important role in controlling ferromagnetism. Magnetic properties of a hybrid (the hysteresis loop and the spatial orientation of magnetization) can be tuned both optically and electrically by utilizing semiconductor—making the hybrid an electronic-write-in and electronic-read-out elementary storage unit.

Structural changes in graphene oxide thin film by electron-beam irradiation

Energy Technology Data Exchange (ETDEWEB)

Tyagi, Chetna, E-mail: tchetna91@gmail.com [Materials Science Group, Inter University Accelerator Centre, New Delhi 67 (India); Lakshmi, G.B.V.S.; Kumar, Sunil; Tripathi, Ambuj [Materials Science Group, Inter University Accelerator Centre, New Delhi 67 (India); Avasthi, D.K. [Amity University, Noida 201313, Uttar Pradesh (India)

2016-07-15

Although we have a whole class of 2D materials, graphene has drawn much attention for its excellent electronic, optical, thermal and mechanical properties. Recent researches have shown its large scale production by the reduction of graphene oxide either thermally, chemically or electrochemically. Although the structure of graphene oxide is inhomogeneous and hence complicated due to the presence of organic moieties e.g. epoxy, carboxylic acid, hydroxyl groups etc., its properties can be tuned by reduction according to desired application. The aim of this work is to synthesize continuous thin film of graphene oxide using commercially available graphene oxide solution and to study its reduction by 25 keV electron beam irradiation at fluences varying from 2 × 10{sup 11} to 2 × 10{sup 13} e{sup −}/cm{sup 2}. Our studies using X-ray diffraction, Raman microscopy and UV–Vis spectroscopy showed that electron-beam irradiation is an effective tool for reduction of graphene oxide and for tuning its band gap.

Monopoly provision of tune-ins

Czech Academy of Sciences Publication Activity Database

Celik, Levent

-, č. 362 (2008), s. 1-31 ISSN 1211-3298 Institutional research plan: CEZ:MSM0021620846 Keywords : informative advertising * tune-ins * television station Subject RIV: AH - Economics http://www.cerge-ei.cz/pdf/wp/Wp362.pdf

Gain and frequency tuning within the mouse cochlear apex

Energy Technology Data Exchange (ETDEWEB)

Oghalai, John S.; Raphael, Patrick D. [Department of Otolaryngology, Stanford University School of Medicine, Stanford, California (United States); Gao, Simon [Department of Otolaryngology, Stanford University School of Medicine, Stanford, California (United States); Department of Bioengineering, Rice University, Houston, Texas (United States); Lee, Hee Yoon [Department of Otolaryngology, Stanford University School of Medicine, Stanford, California (United States); Department of Electrical Engineering, Stanford University, Stanford, California (United States); Groves, Andrew K. [Department of Neuroscience, Department of Molecular and Human Genetics, and Program in Developmental Biology, Baylor College of Medicine, Houston, Texas (United States); Zuo, Jian [Department of Developmental Neurobiology, St. Jude Children’s Research Hospital, Memphis, Tennessee (United States); Applegate, Brian E. [Department of Biomedical Engineering, Texas A& M University, College Station, Texas (United States)

2015-12-31

Normal mammalian hearing requires cochlear outer hair cell active processes that amplify the traveling wave with high gain and sharp tuning, termed cochlear amplification. We have used optical coherence tomography to study cochlear amplification within the apical turn of the mouse cochlea. We measured not only classical basilar membrane vibratory tuning curves but also vibratory responses from the rest of the tissues that compose the organ of Corti. Basilar membrane tuning was sharp in live mice and broad in dead mice, whereas other regions of the organ of Corti demonstrated phase shifts consistent with additional filtering beyond that provided by basilar membrane mechanics. We use these experimental data to support a conceptual framework of how cochlear amplification is tuned within the mouse cochlear apex. We will also study transgenic mice with targeted mutations that affect different biomechanical aspects of the organ of Corti in an effort to localize the underlying processes that produce this additional filtering.

Gain and frequency tuning within the mouse cochlear apex

International Nuclear Information System (INIS)

Oghalai, John S.; Raphael, Patrick D.; Gao, Simon; Lee, Hee Yoon; Groves, Andrew K.; Zuo, Jian; Applegate, Brian E.

2015-01-01

Normal mammalian hearing requires cochlear outer hair cell active processes that amplify the traveling wave with high gain and sharp tuning, termed cochlear amplification. We have used optical coherence tomography to study cochlear amplification within the apical turn of the mouse cochlea. We measured not only classical basilar membrane vibratory tuning curves but also vibratory responses from the rest of the tissues that compose the organ of Corti. Basilar membrane tuning was sharp in live mice and broad in dead mice, whereas other regions of the organ of Corti demonstrated phase shifts consistent with additional filtering beyond that provided by basilar membrane mechanics. We use these experimental data to support a conceptual framework of how cochlear amplification is tuned within the mouse cochlear apex. We will also study transgenic mice with targeted mutations that affect different biomechanical aspects of the organ of Corti in an effort to localize the underlying processes that produce this additional filtering

Fine tuning power diodes with irradiation

International Nuclear Information System (INIS)

Tarneja, K.S.; Bartko, J.; Johnson, J.E.

1976-01-01

Diodes of a particular type are fine tuned with irradiation to optimize the reverse recovery time while minimizing forward voltage drop and providing more uniform electrical characcteristics. The initial and desired minority carrier lifetimes in the anode region of the type are determined as a function of forward voltage drop and reverse recovery time, and the minority carrier radiation damage factor is determined for a desired type of diode and radiation source. The radiation dosage to achieve the desired carrier lifetime with the radiation source is thereafter determined from the function 1/tau = 1/tau 0 + K phi, where tau is the desired minority carrier lifetime, tau 0 is the initial minority carrier lifetime, K is the determined minority carrier radiation damage factor and phi is the radiation dosage. A major surface and preferably the major surface adjoining the anode region of the diodes is then irradiated with the radiation source to the determined radiation dosage. Preferably, the radiation dosage is between about 1 X 10 12 and 5 X 10 13 e/cm 2 , with electron radiation of intensity between 1 and 3 MeV

Electron beam lithographic modeling assisted by artificial intelligence technology

Science.gov (United States)

Nakayamada, Noriaki; Nishimura, Rieko; Miura, Satoru; Nomura, Haruyuki; Kamikubo, Takashi

2017-07-01

We propose a new concept of tuning a point-spread function (a "kernel" function) in the modeling of electron beam lithography using the machine learning scheme. Normally in the work of artificial intelligence, the researchers focus on the output results from a neural network, such as success ratio in image recognition or improved production yield, etc. In this work, we put more focus on the weights connecting the nodes in a convolutional neural network, which are naturally the fractions of a point-spread function, and take out those weighted fractions after learning to be utilized as a tuned kernel. Proof-of-concept of the kernel tuning has been demonstrated using the examples of proximity effect correction with 2-layer network, and charging effect correction with 3-layer network. This type of new tuning method can be beneficial to give researchers more insights to come up with a better model, yet it might be too early to be deployed to production to give better critical dimension (CD) and positional accuracy almost instantly.

Improving Electronic Resources through Holistic Budgeting

Science.gov (United States)

Kusik, James P.; Vargas, Mark A.

2009-01-01

To establish a more direct link between its collections and the educational goals of Saint Xavier University, the Byrne Memorial Library has adopted a "holistic" approach to collection development. This article examines how traditional budget practices influenced the library's selection of resources and describes how holistic collection…

ATLAS Monte Carlo tunes for MC09

CERN Document Server

The ATLAS collaboration

2010-01-01

This note describes the ATLAS tunes of underlying event and minimum bias description for the main Monte Carlo generators used in the MC09 production. For the main shower generators, pythia and herwig (with jimmy), the MRST LO* parton distribution functions (PDFs) were used for the first time in ATLAS. Special studies on the performance of these, conceptually new, PDFs for high pt physics processes at LHC energies are presented. In addition, a tune of jimmy for CTEQ6.6 is presented, for use with MC@NLO.

Disorder-tuned charge transport in organic semiconductors

Science.gov (United States)

Xu, Feng; Qiu, Dong; Yan, Dadong

2013-02-01

We propose that the polaron transport in organic semiconductors is remarkably tuned by the fluctuation of polarization energy. The tuning effect of energetic fluctuation not only causes a continuous transition from non-Arrhenius to Arrhenius temperature activated charge transport with increasing moderate disorder strengths but also results in a band-like conduction in the low disorder regime which benefits from the enhanced mobilities in shallow trap states. As a result, a unified description of polaron transport is obtained for a set of typical organic semiconductors.

Tuned and Balanced Redistributed Charge Scheme for Combined Quantum Mechanical and Molecular Mechanical (QM/MM) Methods and Fragment Methods: Tuning Based on the CM5 Charge Model.

Science.gov (United States)

Wang, Bo; Truhlar, Donald G

2013-02-12

Tuned and balanced redistributed charge schemes have been developed for modeling the electrostatic fields of bonds that are cut by a quantum mechanical-molecular mechanical boundary in combined quantum mechanical and molecular mechanical (QM/MM) methods. First, the charge is balanced by adjusting the charge on the MM boundary atom to conserve the total charge of the entire QM/MM system. In the balanced smeared redistributed charge (BSRC) scheme, the adjusted MM boundary charge is smeared with a smearing width of 1.0 Å and is distributed in equal portions to the midpoints of the bonds between the MM boundary atom and the MM atoms bonded to it; in the balanced redistributed charge-2 (BRC2) scheme, the adjusted MM boundary charge is distributed as point charges in equal portions to the MM atoms that are bonded to the MM boundary atom. The QM subsystem is capped by a fluorine atom that is tuned to reproduce the sum of partial atomic charges of the uncapped portion of the QM subsystem. The new aspect of the present study is a new way to carry out the tuning process; in particular, the CM5 charge model, rather than the Mulliken population analysis applied in previous studies, is used for tuning the capping atom that terminates the dangling bond of the QM region. The mean unsigned error (MUE) of the QM/MM deprotonation energy for a 15-system test suite of deprotonation reactions is 2.3 kcal/mol for the tuned BSRC scheme (TBSRC) and 2.4 kcal/mol for the tuned BRC2 scheme (TBRC2). As was the case for the original tuning method based on Mulliken charges, the new tuning method performs much better than using conventional hydrogen link atoms, which have an MUE on this test set of about 7 kcal/mol. However, the new scheme eliminates the need to use small basis sets, which can be problematic, and it allows one to be more consistent by tuning the parameters with whatever basis set is appropriate for applications. (Alternatively, since the tuning parameters and partial charges

Measurement techniques for low emittance tuning and beam dynamics at CESR

Science.gov (United States)

Billing, M. G.; Dobbins, J. A.; Forster, M. J.; Kreinick, D. L.; Meller, R. E.; Peterson, D. P.; Ramirez, G. A.; Rendina, M. C.; Rider, N. T.; Sagan, D. C.; Shanks, J.; Sikora, J. P.; Stedinger, M. G.; Strohman, C. R.; Williams, H. A.; Palmer, M. A.; Holtzapple, R. L.; Flanagan, J.

2018-03-01

After operating as a High Energy Physics electron-positron collider, the Cornell Electron-positron Storage Ring (CESR) has been converted to become a dedicated synchrotron light source for the Cornell High Energy Synchrotron Source (CHESS). Over the course of several years CESR was adapted for accelerator physics research as a test accelerator, capable of studying topics relevant to future damping rings, colliders and light sources. Initially some specific topics were targeted for accelerator physic research with the storage ring in this mode, labeled CesrTA. These topics included 1) tuning techniques to produce low emittance beams, 2) the study of electron cloud (EC) development in a storage ring and 3) intra-beam scattering effects. The complete conversion of CESR to CesrTA occurred over a several year period, described elsewhere [1–3]. A number of specific instruments were developed for CesrTA. Much of the pre-existing instrumentation was modified to accommodate the scope of these studies and these are described in a companion paper [4]. To complete this research, a number of procedures were developed or modified, often requiring coordinated measurements among different instruments [5]. This paper provides an overview of types of measurements employed for the study of beam dynamics during the operation of CesrTA.

Luminosity Tuning at the Large Hadron Collider

CERN Document Server

Wittmer, W

2006-01-01

By measuring and adjusting the beta-functions at the interaction point (IP the luminosity is being optimized. In LEP (Large Electron Positron Collider) this was done with the two closest doublet magnets. This approach is not applicable for the LHC (Large Hadron Collider) and RHIC (Relativistic Heavy Ion Collider) due to the asymmetric lattice. In addition in the LHC both beams share a common beam pipe through the inner triplet magnets (in these region changes of the magnetic field act on both beams). To control and adjust the beta-functions without perturbation of other optics functions, quadrupole groups situated on both sides further away from the IP have to be used where the two beams are already separated. The quadrupoles are excited in specific linear combinations, forming the so-called "tuning knobs" for the IP beta-functions. For a specific correction one of these knobs is scaled by a common multiplier. The different methods which were used to compute such knobs are discussed: (1) matching in MAD, (2)i...

Clinician‐selected Electronic Information Resources do not Guarantee Accuracy in Answering Primary Care Physicians’ Information Needs. A review of: McKibbon, K. Ann, and Douglas B. Fridsma. “Effectiveness of Clinician‐selected Electronic Information Resources for Answering Primary Care Physicians’ Information Needs.” Journal of the American Medical Informatics Association 13.6 (2006: 653‐9.

Directory of Open Access Journals (Sweden)

Martha Ingrid Preddie

2008-03-01

Full Text Available Objective – To determine if electronic information resources selected by primary care physicians improve their ability to answer simulated clinical questions.Design – An observational study utilizing hour‐long interviews and think‐aloud protocols.Setting – The offices and clinics of primary care physicians in Canada and the United States.Subjects – Twenty‐five primary care physicians of whom 4 were women, 17 were from Canada, 22 were family physicians,and 24 were board certified.Methods – Participants provided responses to 23 multiple‐choice questions. Each physician then chose two questions and looked for the answers utilizing information resources of their own choice. The search processes, chosen resources and search times were noted. These were analyzed along with data on the accuracy of the answers and certainties related to the answer to each clinical question prior to the search.Main results – Twenty‐three physicians sought answers to 46 simulated clinical questions. Utilizing only electronic information resources, physicians spent a mean of 13.0 (SD 5.5 minutes searching for answers to the questions, an average of 7.3(SD 4.0 minutes for the first question and 5.8 (SD 2.2 minutes to answer the second question. On average, 1.8 resources were utilized per question. Resources that summarized information, such as the Cochrane Database of Systematic Reviews, UpToDate and Clinical Evidence, were favored 39.2% of the time, MEDLINE (Ovid and PubMed 35.7%, and Internet resources including Google 22.6%. Almost 50% of the search and retrieval strategies were keyword‐based, while MeSH, subheadings and limiting were used less frequently. On average, before searching physicians answered 10 of 23 (43.5% questions accurately. For questions that were searched using clinician‐selected electronic resources, 18 (39.1% of the 46 answers were accurate before searching, while 19 (42.1% were accurate after searching. The difference of

Market-based autonomous resource and application management in private clouds

KAUST Repository

Costache, Stefania; Kortas, Samuel; Morin, Christine; Parlavantzas, Nikos

2016-01-01

High Performance Computing (HPC) clouds need to be efficiently shared between selfish tenants having applications with different resource requirements and Service Level Objectives (SLOs). The main difficulty relies on providing concurrent resource access to such tenants while maximizing the resource utilization. To overcome this challenge, we propose Merkat, a market-based SLO-driven cloud platform. Merkat relies on a market-based model specifically designed for on-demand fine-grain resource allocation to maximize resource utilization and it uses a combination of currency distribution and dynamic resource pricing to ensure proper resource distribution among tenants. To meet the tenant’s SLO, Merkat uses autonomous controllers, which apply adaptation policies that: (i) dynamically tune the application’s provisioned CPU and memory per virtual machine in contention periods, or (ii) dynamically change the number of virtual machines. Our evaluation with simulation and on the Grid’5000 testbed shows that Merkat provides flexible support for different application types and SLOs and good tenant satisfaction compared to existing centralized systems, while the infrastructure resource utilization is improved.

Market-based autonomous resource and application management in private clouds

KAUST Repository

Costache, Stefania

2016-10-12

High Performance Computing (HPC) clouds need to be efficiently shared between selfish tenants having applications with different resource requirements and Service Level Objectives (SLOs). The main difficulty relies on providing concurrent resource access to such tenants while maximizing the resource utilization. To overcome this challenge, we propose Merkat, a market-based SLO-driven cloud platform. Merkat relies on a market-based model specifically designed for on-demand fine-grain resource allocation to maximize resource utilization and it uses a combination of currency distribution and dynamic resource pricing to ensure proper resource distribution among tenants. To meet the tenant’s SLO, Merkat uses autonomous controllers, which apply adaptation policies that: (i) dynamically tune the application’s provisioned CPU and memory per virtual machine in contention periods, or (ii) dynamically change the number of virtual machines. Our evaluation with simulation and on the Grid’5000 testbed shows that Merkat provides flexible support for different application types and SLOs and good tenant satisfaction compared to existing centralized systems, while the infrastructure resource utilization is improved.

Tuning giant anomalous Hall resistance ratio in perpendicular Hall balance

Energy Technology Data Exchange (ETDEWEB)

Zhang, J. Y.; Yang, G. [Department of Materials Physics and Chemistry, University of Science and Technology Beijing, Beijing 100083 (China); State Key Laboratory of Magnetism, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Wang, S. G., E-mail: sgwang@iphy.ac.cn, E-mail: ghyu@mater.ustb.edu.cn [State Key Laboratory of Magnetism, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Liu, J. L. [State Key Laboratory of Magnetism, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Department of Physics, Beijing University of Aeronautics and Astronautics, Beijing 100191 (China); Wang, R. M. [Department of Physics, Beijing University of Aeronautics and Astronautics, Beijing 100191 (China); Amsellem, E.; Kohn, A. [Department of Materials Engineering, Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev, Beer-Sheva 84105 (Israel); Yu, G. H., E-mail: sgwang@iphy.ac.cn, E-mail: ghyu@mater.ustb.edu.cn [Department of Materials Physics and Chemistry, University of Science and Technology Beijing, Beijing 100083 (China)

2015-04-13

Anomalous Hall effect at room temperature in perpendicular Hall balance with a core structure of [Pt/Co]{sub 4}/NiO/[Co/Pt]{sub 4} has been tuned by functional CoO layers, where [Pt/Co]{sub 4} multilayers exhibit perpendicular magnetic anisotropy. A giant Hall resistance ratio up to 69 900% and saturation Hall resistance (R{sub S}{sup P}) up to 2590 mΩ were obtained in CoO/[Pt/Co]{sub 4}/NiO/[Co/Pt]{sub 4}/CoO system, which is 302% and 146% larger than that in the structure without CoO layers, respectively. Transmission electron microscopy shows highly textured [Co/Pt]{sub 4} multilayers and oxide layers with local epitaxial relations, indicating that the crystallographic structure has significant influence on spin dependent transport properties.

Automatic Monte-Carlo tuning for minimum bias events at the LHC

Energy Technology Data Exchange (ETDEWEB)

Kama, Sami

2010-06-22

The Large Hadron Collider near Geneva Switzerland will ultimately collide protons at a center-of-mass energy of 14 TeV and 40 MHz bunch crossing rate with a luminosity of L=10{sup 34} cm{sup -2}s{sup -1}. At each bunch crossing about 20 soft proton-proton interactions are expected to happen. In order to study new phenomena and improve our current knowledge of the physics these events must be understood. However, the physics of soft interactions are not completely known at such high energies. Different phenomenological models, trying to explain these interactions, are implemented in several Monte-Carlo (MC) programs such as PYTHIA, PHOJET and EPOS. Some parameters in such MC programs can be tuned to improve the agreement with the data. In this thesis a new method for tuning the MC programs, based on Genetic Algorithms and distributed analysis techniques have been presented. This method represents the first and fully automated MC tuning technique that is based on true MC distributions. It is an alternative to parametrization-based automatic tuning. This new method is used in finding new tunes for PYTHIA 6 and 8. These tunes are compared to the tunes found by alternative methods, such as the PROFESSOR framework and manual tuning, and found to be equivalent or better. Charged particle multiplicity, dN{sub ch}/d{eta}, Lorentz-invariant yield, transverse momentum and mean transverse momentum distributions at various center-of-mass energies are generated using default tunes of EPOS, PHOJET and the Genetic Algorithm tunes of PYTHIA 6 and 8. These distributions are compared to measurements from UA5, CDF, CMS and ATLAS in order to investigate the best model available. Their predictions for the ATLAS detector at LHC energies have been investigated both with generator level and full detector simulation studies. Comparison with the data did not favor any model implemented in the generators, but EPOS is found to describe investigated distributions better. New data from ATLAS and

Automatic Monte-Carlo tuning for minimum bias events at the LHC

International Nuclear Information System (INIS)

Kama, Sami

2010-01-01

The Large Hadron Collider near Geneva Switzerland will ultimately collide protons at a center-of-mass energy of 14 TeV and 40 MHz bunch crossing rate with a luminosity of L=10 34 cm -2 s -1 . At each bunch crossing about 20 soft proton-proton interactions are expected to happen. In order to study new phenomena and improve our current knowledge of the physics these events must be understood. However, the physics of soft interactions are not completely known at such high energies. Different phenomenological models, trying to explain these interactions, are implemented in several Monte-Carlo (MC) programs such as PYTHIA, PHOJET and EPOS. Some parameters in such MC programs can be tuned to improve the agreement with the data. In this thesis a new method for tuning the MC programs, based on Genetic Algorithms and distributed analysis techniques have been presented. This method represents the first and fully automated MC tuning technique that is based on true MC distributions. It is an alternative to parametrization-based automatic tuning. This new method is used in finding new tunes for PYTHIA 6 and 8. These tunes are compared to the tunes found by alternative methods, such as the PROFESSOR framework and manual tuning, and found to be equivalent or better. Charged particle multiplicity, dN ch /dη, Lorentz-invariant yield, transverse momentum and mean transverse momentum distributions at various center-of-mass energies are generated using default tunes of EPOS, PHOJET and the Genetic Algorithm tunes of PYTHIA 6 and 8. These distributions are compared to measurements from UA5, CDF, CMS and ATLAS in order to investigate the best model available. Their predictions for the ATLAS detector at LHC energies have been investigated both with generator level and full detector simulation studies. Comparison with the data did not favor any model implemented in the generators, but EPOS is found to describe investigated distributions better. New data from ATLAS and CMS show higher

Review of material recovery from used electric and electronic equipment-alternative options for resource conservation.

Science.gov (United States)

Friege, Henning

2012-09-01

For waste from electric and electronic equipment, the WEEE Directive stipulates the separate collection of electric and electronic waste. As to new electric and electronic devices, the Restriction of Hazardous Substances (RoHS) Directive bans the use of certain chemicals dangerous for man and environment. From the implementation of the WEEE directive, many unsolved problems have been documented: poor collection success, emission of dangerous substances during collection and recycling, irretrievable loss of valuable metals among others. As to RoHS, data from the literature show a satisfying success. The problems identified in the process can be reduced to some basic dilemmas at the borders between waste management, product policy and chemical safety. The objectives of the WEEE Directive and the specific targets for use and recycling of appliances are not consistent. There is no focus on scarce resources. Extended producer responsibility is not sufficient to guarantee sustainable waste management. Waste management reaches its limits due to problems of implementation but also due to physical laws. A holistic approach is necessary looking at all branch points and sinks in the stream of used products and waste from electric and electronic equipment. This may be done with respect to the general rules for sustainable management of material streams covering the three dimensions of sustainable policy. The relationships between the players in the field of electric and electronic devices have to be taken into account. Most of the problems identified in the implementation process will not be solved by the current amendment of the WEEE Directive.

Iterative Controller Tuning for Process with Fold Bifurcations

DEFF Research Database (Denmark)

Huusom, Jakob Kjøbsted; Poulsen, Niels Kjølstad; Jørgensen, Sten Bay

2007-01-01

Processes involving fold bifurcation are notoriously difficult to control in the vicinity of the fold where most often optimal productivity is achieved . In cases with limited process insight a model based control synthesis is not possible. This paper uses a data driven approach with an improved...... version of iterative feedback tuning to optimizing a closed loop performance criterion, as a systematic tool for tuning process with fold bifurcations....

Tuning and matching of the BPX ICH system

International Nuclear Information System (INIS)

Swain, D.W.

1991-01-01

Two methods of tuning and matching the ion cyclotron heating (ICH) antennas for the Burning Plasma Experiment (BPX) to the BPX plasma have been analyzed. Both appear to provide adequate tuning and matching capabilities. However, there are trade-offs between the frequency range that can be covered and the compactness of the high-voltage region of the transmission lines that makes up of the matching network. 4 refs., 5 figs

Charting a Course through CORAL: Texas A&M University Libraries' Experience Implementing an Open-Source Electronic Resources Management System

Science.gov (United States)

Hartnett, Eric; Beh, Eugenia; Resnick, Taryn; Ugaz, Ana; Tabacaru, Simona

2013-01-01

In 2010, after two previous unsuccessful attempts at electronic resources management system (ERMS) implementation, Texas A&M University (TAMU) Libraries set out once again to find an ERMS that would fit its needs. After surveying the field, TAMU Libraries selected the University of Notre Dame Hesburgh Libraries-developed, open-source ERMS,…

Elastic and electronic tuning of magnetoresistance in MoTe$_2$

OpenAIRE

Yang, Junjie; Colen, Jonathan; Liu, Jun; Nguyen, Manh Cuong; Chern, Gia-Wei; Louca, Despina

2017-01-01

Quasi-two dimensional transition metal dichalcogenides (TMD) exhibit dramatic properties that may transform electronic and photonic devices. We report on how the anomalously large magnetoresistance (MR) observed under high magnetic field in MoTe$_2$, a type II Weyl semimetal, can be reversibly controlled under tensile strain. The MR is enhanced by as much as ~ 30 % at low temperatures and high magnetic fields, when uniaxial strain is applied along the $a$-crystallographic direction and reduce...

Tuning controllers using the dual Youla parameterization

DEFF Research Database (Denmark)

Niemann, Hans Henrik; Stoustrup, Jakob

2000-01-01

This paper describes the application of the Youla parameterization of all stabilizing controllers and the dual Youla parameterization of all systems stabilized by a given controller in connection with tuning of controllers. In the uncertain case, it is shown that the use of the Youla parameteriza......This paper describes the application of the Youla parameterization of all stabilizing controllers and the dual Youla parameterization of all systems stabilized by a given controller in connection with tuning of controllers. In the uncertain case, it is shown that the use of the Youla...

Java EE 7 performance tuning and optimization

CERN Document Server

Oransa, Osama

2014-01-01

The book adopts a step-by-step approach, starting from building the basics and adding to it gradually by using different tools and examples. The book sequence is easy to follow and all topics are fully illustrated showing you how to make good use of different performance diagnostic tools. If you are an experienced Java developer, architect, team leader, consultant, support engineer, or anyone else who needs performance tuning in your Java applications, and in particular, Java enterprise applications, this book is for you. No prior experience of performance tuning is required.

A 21st Century Imperative: integrating intercultural competence in Tuning

Directory of Open Access Journals (Sweden)

Darla K. Deardorff

2015-12-01

Full Text Available Given the increasing demand for interculturally competent graduates and employees, it is incumbent upon the Tuning community to incorporate intercultural competence into Tuning Frameworks. With the growing diversity in the world today, beyond national diversity, intercultural competence cuts across disciplines, subjects, and contexts. This essay highlights the first research-based definition and framework of intercultural competence which can be translated into any subject and context and makes the case for why intercultural competence must be embedded into Tuning Frameworks around the world.

Macromolecular scaffolding: the relationship between nanoscale architecture and function in multichromophoric arrays for organic electronics.

Science.gov (United States)

Palermo, Vincenzo; Schwartz, Erik; Finlayson, Chris E; Liscio, Andrea; Otten, Matthijs B J; Trapani, Sara; Müllen, Klaus; Beljonne, David; Friend, Richard H; Nolte, Roeland J M; Rowan, Alan E; Samorì, Paolo

2010-02-23

The optimization of the electronic properties of molecular materials based on optically or electrically active organic building blocks requires a fine-tuning of their self-assembly properties at surfaces. Such a fine-tuning can be obtained on a scale up to 10 nm by mastering principles of supramolecular chemistry, i.e., by using suitably designed molecules interacting via pre-programmed noncovalent forces. The control and fine-tuning on a greater length scale is more difficult and challenging. This Research News highlights recent results we obtained on a new class of macromolecules that possess a very rigid backbone and side chains that point away from this backbone. Each side chain contains an organic semiconducting moiety, whose position and electronic interaction with neighboring moieties are dictated by the central macromolecular scaffold. A combined experimental and theoretical approach has made it possible to unravel the physical and chemical properties of this system across multiple length scales. The (opto)electronic properties of the new functional architectures have been explored by constructing prototypes of field-effect transistors and solar cells, thereby providing direct insight into the relationship between architecture and function.

The Magnetically-Tuned Transition-Edge Sensor

Science.gov (United States)

Sadleir, John E.; Lee, Sang-Jun; Smith, Stephen J.; Busch, Sarah E.; Bandler, Simon R.; Adams, Joseph S.; Eckart, Megan E.; Chevenak, James A.; Kelley, Richard L.; Kilbourne, Caroline A.;

Tuning electron transport in metal films and graphene with organic monolayers

NARCIS (Netherlands)

Ataç, Derya

2014-01-01

Introducing organic molecules into electronic devices has attracted significant research interest due to its promise in both technological development and fundamental research. Organic molecules are used for many purposes such as uniform and patterned doping of silicon with donor atoms and the

Tuning the magnetoresistance of ultrathin WTe2 sheets by electrostatic gating.

Science.gov (United States)

Na, Junhong; Hoyer, Alexander; Schoop, Leslie; Weber, Daniel; Lotsch, Bettina V; Burghard, Marko; Kern, Klaus

2016-11-10

The semimetallic, two-dimensional layered transition metal dichalcogenide WTe 2 has raised considerable interest due to its huge, non-saturating magnetoresistance. While for the origin of this effect, a close-to-ideal balance of electrons and holes has been put forward, the carrier concentration dependence of the magnetoresistance remains to be clarified. Here, we present a detailed study of the magnetotransport behaviour of ultrathin, mechanically exfoliated WTe 2 sheets as a function of electrostatic back gating. The carrier concentration and mobility, determined using the two band model and analysis of the Shubnikov-de Haas oscillations, indicate enhanced surface scattering for the thinnest sheets. By the back gate action, the magnetoresistance could be tuned by up to ∼100% for a ∼13 nm-thick WTe 2 sheet.

Basic controller tuning for large offshore wind turbines

Directory of Open Access Journals (Sweden)

K. O. Merz

2016-09-01

Full Text Available When a wind turbine operates above the rated wind speed, the blade pitch may be governed by a basic single-input–single-output PI controller, with the shaft speed as input. The performance of the wind turbine depends upon the tuning of the gains and filters of this controller. Rules of thumb, based upon pole placement, with a rigid model of the rotor, are inadequate for tuning the controller of large, flexible, offshore wind turbines. It is shown that the appropriate controller tuning is highly dependent upon the characteristics of the aeroelastic model: no single reference controller can be defined for use with all models. As an example, the ubiquitous National Renewable Energy Laboratory (NREL 5 MW wind turbine controller is unstable when paired with a fully flexible aeroelastic model. A methodical search is conducted, in order to find models with a minimum number of degrees of freedom, which can be used to tune the controller for a fully flexible aeroelastic model; this can be accomplished with a model containing 16–20 states. Transient aerodynamic effects, representing rotor-average properties, account for five of these states. A simple method is proposed to reduce the full transient aerodynamic model, and the associated turbulent wind spectra, to the rotor average. Ocean waves are also an important source of loading; it is recommended that the shaft speed signal be filtered such that wave-driven tower side-to-side vibrations do not appear in the PI controller output. An updated tuning for the NREL 5 MW controller is developed using a Pareto front technique. This fixes the instability and gives good performance with fully flexible aeroelastic models.

Interface circuit for a multiple-beam tuning-fork gyroscope with high quality factors

Science.gov (United States)

Wang, Ren

This research work presents the design, theoretical analysis, fabrication, interface electronics, and experimental results of a Silicon-On-Insulator (SOI) based Multiple-Beam Tuning-Fork Gyroscope (MB-TFG). Based on a numerical model of Thermo-Elastic Damping (TED), a Multiple-Beam Tuning-Fork Structure (MB-TFS) is designed with high Quality factors (Qs) in its two operation modes. A comprehensive theoretical analysis of the MB-TFG design is conducted to relate the design parameters to its operation parameters and further performance parameters. In conjunction with a mask that defines the device through trenches to alleviate severe fabrication effect on anchor loss, a simple one-mask fabrication process is employed to implement this MB-TFG design on SOI wafers. The fabricated MB-TFGs are tested with PCB-level interface electronics and a thorough comparison between the experimental results and a theoretical analysis is conducted to verify the MB-TFG design and accurately interpret the measured performance. The highest measured Qs of the fabricated MB-TFGs in vacuum are 255,000 in the drive-mode and 103,000 in the sense-mode, at a frequency of 15.7kHz. Under a frequency difference of 4Hz between the two modes (operation frequency is 16.8kHz) and a drive-mode vibration amplitude of 3.0um, the measured rate sensitivity is 80mVpp/°/s with an equivalent impedance of 6MQ. The calculated overall rate resolution of this device is 0.37/hrhiElz, while the measured Angle Random Walk (ARW) and bias instability are 6.67°/'vhr and 95°/hr, respectively.

Tuning the giant Rashba effect on a BiAg2 surface alloy: Two different approaches

International Nuclear Information System (INIS)

Frantzeskakis, E.; Crepaldi, A.; Pons, S.; Kern, K.; Grioni, M.

2010-01-01

We discuss two different approaches for tuning the giant spin-orbit splitting of a BiAg 2 surface alloy. The first approach consists of electron doping by alkaline metal deposition in order to shift the energy position of the spin-split surface states, while the second is based on the novel Si(1 1 1)-Ag-BiAg 2 trilayer system. In both cases the spin-polarized structure near the Fermi level can be controlled by an external parameter, while the second approach permits coupling the concept of giant spin-splitting with a semiconducting substrate.

Technical fine-tuning problem in renormalized perturbation theory

International Nuclear Information System (INIS)

Foda, O.E.

1983-01-01

The technical - as opposed to physical - fine tuning problem, i.e. the stability of tree-level gauge hierarchies at higher orders in renormalized perturbation theory, in a number of different models is studied. These include softly-broken supersymmetric models, and non-supersymmetric ones with a hierarchy of spontaneously-broken gauge symmetries. The models are renormalized using the BPHZ prescription, with momentum subtractions. Explicit calculations indicate that the tree-level hierarchy is not upset by the radiative corrections, and consequently no further fine-tuning is required to maintain it. Furthermore, this result is shown to run counter to that obtained via Dimensional Renormalization, (the only scheme used in previous literature on the subject). The discrepancy originates in the inherent local ambiguity in the finite parts of subtracted Feynman integrals. Within fully-renormalized perturbation theory the answer to the technical fine-tuning question (in the sense of whether the radiative corrections will ''readily'' respect the tree level gauge hierarchy or not) is contingent on the renormalization scheme used to define the model at the quantum level, rather than on the model itself. In other words, the need for fine-tuning, when it arises, is an artifact of the application of a certain class of renormalization schemes

Technical fine-tuning problem in renormalized perturbation theory

Energy Technology Data Exchange (ETDEWEB)

Foda, O.E.

1983-01-01

The technical - as opposed to physical - fine tuning problem, i.e. the stability of tree-level gauge hierarchies at higher orders in renormalized perturbation theory, in a number of different models is studied. These include softly-broken supersymmetric models, and non-supersymmetric ones with a hierarchy of spontaneously-broken gauge symmetries. The models are renormalized using the BPHZ prescription, with momentum subtractions. Explicit calculations indicate that the tree-level hierarchy is not upset by the radiative corrections, and consequently no further fine-tuning is required to maintain it. Furthermore, this result is shown to run counter to that obtained via Dimensional Renormalization, (the only scheme used in previous literature on the subject). The discrepancy originates in the inherent local ambiguity in the finite parts of subtracted Feynman integrals. Within fully-renormalized perturbation theory the answer to the technical fine-tuning question (in the sense of whether the radiative corrections will ''readily'' respect the tree level gauge hierarchy or not) is contingent on the renormalization scheme used to define the model at the quantum level, rather than on the model itself. In other words, the need for fine-tuning, when it arises, is an artifact of the application of a certain class of renormalization schemes.

Social cognition in autism: Face tuning.

Science.gov (United States)

Pavlova, Marina A; Guerreschi, Michele; Tagliavento, Lucia; Gitti, Filippo; Sokolov, Alexander N; Fallgatter, Andreas J; Fazzi, Elisa

2017-05-26

Faces convey valuable information for social cognition, effective interpersonal interaction, and non-verbal communication. Face perception is believed to be atypical in autism, but the origin of this deficit is controversial. Dominant featural face encoding is suggested to be responsible for face tuning scarcity. Here we used a recently developed Face-n-Food paradigm for studying face tuning in individuals with autistic spectrum disorders (ASD). The key benefit of these images is that single components do not explicitly trigger face processing. In a spontaneous recognition task, adolescents with autism and typically developing matched controls were presented with a set of Face-n-Food images in different degree resembling a face (slightly bordering on the Giuseppe Arcimboldo style). The set of images was shown in a predetermined order from the least to most resembling a face. Thresholds for recognition of the Face-n-Food images as a face in ASD individuals were substantially higher than in typically developing controls: they did not report seeing a face on the images, which controls easily recognized as a face, and gave overall fewer face responses. This outcome not only lends support to atypical face tuning, but provides novel insights into the origin of face encoding deficits in autism.

Electronic Nose and Electronic Tongue

Science.gov (United States)

Bhattacharyya, Nabarun; Bandhopadhyay, Rajib

Human beings have five senses, namely, vision, hearing, touch, smell and taste. The sensors for vision, hearing and touch have been developed for several years. The need for sensors capable of mimicking the senses of smell and taste have been felt only recently in food industry, environmental monitoring and several industrial applications. In the ever-widening horizon of frontier research in the field of electronics and advanced computing, emergence of electronic nose (E-Nose) and electronic tongue (E-Tongue) have been drawing attention of scientists and technologists for more than a decade. By intelligent integration of multitudes of technologies like chemometrics, microelectronics and advanced soft computing, human olfaction has been successfully mimicked by such new techniques called machine olfaction (Pearce et al. 2002). But the very essence of such research and development efforts has centered on development of customized electronic nose and electronic tongue solutions specific to individual applications. In fact, research trends as of date clearly points to the fact that a machine olfaction system as versatile, universal and broadband as human nose and human tongue may not be feasible in the decades to come. But application specific solutions may definitely be demonstrated and commercialized by modulation in sensor design and fine-tuning the soft computing solutions. This chapter deals with theory, developments of E-Nose and E-Tongue technology and their applications. Also a succinct account of future trends of R&D efforts in this field with an objective of establishing co-relation between machine olfaction and human perception has been included.