1,279 research outputs found

    Electrodynamics of an omega-band as deduced from optical and magnetometer data

    Get PDF
    We investigate an omega-band event that took place above northern Scandinavia around 02:00–02:30 UT on 9 March 1999. In our analysis we use ground based magnetometer, optical and riometer measurements together with satellite based optical images. The optical and riometer data are used to estimate the ionospheric Hall and Pedersen conductances, while ionospheric equivalent currents are obtained from the magnetometer measurements. These data sets are used as input in a local KRM calculation, which gives the ionospheric potential electric field as output, thus giving us a complete picture of the ionospheric electrodynamic state during the omega-band event. <br><br> The overall structure of the electric field and field-aligned current (FAC) provided by the local KRM method are in good agreement with previous studies. Also the <I><B>E</B></I>&times;<I><B>B</B></I> drift velocity calculated from the local KRM solution is in good qualitative agreement with the plasma velocity measured by the Finnish CUTLASS radar, giving further support for the new local KRM method. The high-resolution conductance estimates allow us to discern the detailed structure of the omega-band current system. The highest Hall and Pedersen conductances, ~50 and ~25 S, respectively, are found at the edges of the bright auroral tongue. Inside the tongue, conductances are somewhat smaller, but still significantly higher than typical background values. The electric field shows a converging pattern around the tongues, and the field strength drops from ~40 mV/m found at optically dark regions to ~10 mV/m inside the areas of enhanced conductivity. Downward FAC flow in the dark regions, while upward currents flow inside the auroral tongue. Additionally, sharp conductance gradients at the edge of an auroral tongue are associated with narrow strips of intense FACs, so that a strip of downward current flows at the eastern (leading) edge and a similar strip of upward current is present at the western (trailing) edge. The Joule heating follows the electric field pattern, so that it is diminished inside the bright auroral tongue

    Competency and empowerment of project managers in China

    Get PDF
    The Agent Construction Management (ACM) system is one of the new measures adopted in government funded projects in China. The main characteristic of the ACM system is the introduction of an independent professional project management firm into the project management process. The ACM system is still in its trial stage in China and there is no unified qualification assessment system for agent construction organizations. While the importance of the project manager’s competence is recognized, previous research also shows that project manager’s empowerment is conducive to project performance. The definition of competency is confusing as several terms such as competency/competencies, competence/competences, capability and ability are used interchangeably and inconsistently. Competence is the state or quality of being adequately qualified -- the ability to perform a specific role (e.g. PMI’s project manager’s competency development framework). While empowerment can be viewed as a relational construct and considered within a more general concept of power, it is also a motivational (or psychological) construct. These two perspectives of empowerment are not independent and motivational empowerment may be an outcome of relational empowerment. This research aims to analyze the relationships of motivational empowerment and competency on job performance of the project managers in the ACM organisations. Regression modelling is adopted to analyze the data collected from 203 project managers involved in projects adopting ACM system. Findings support the relationships of competency and empowerment and their effect on project manager’s job performance.postprin

    Procurement innovation: perspectives from Chinese international construction companies

    Get PDF
    The international construction business is witnessing a trend that companies deliver projects through the adoption of innovative procurement systems (e.g. Building Operate Transfer, Public Private Partnership). By devising innovative procurement systems, it is possible to realise construction projects that are difficult for traditional procurement methods, to develop competitive advantages for companies, and ultimately, to deliver value to the society. Notably, Chinese companies are making impressive inroads into the international construction market through enhancing their competitiveness. However, little we know about how Chinese international construction companies (CICCs) perceive procurement innovation and how it relates to their recent success. This research aims to capture their perspectives towards procurement innovation by interviewing nine key decision-makers of CICCs and experts in this area. It is found that CICCs are gradually adopting procurement innovation as a competitive strategy. Unlike the traditional life-or-death competition, competing through procurement innovation can make more projects possible; the emergence of CICCs, in particular their strengths, can be encouraged to deliver more projects and value in the international construction market. This research not only provides CICCs with insights into the procurement innovations in the construction sector, but also enables other companies to know CICCs with which they might compete or collaborate in the near future.published_or_final_versio

    Competency and empowerment of project managers in China

    Get PDF
    The Agent Construction Management (ACM) system is one of the new measures adopted in government funded projects in China. The main characteristic of the ACM system is the introduction of an independent professional project management firm into the project management process. The ACM system is still in its trial stage in China and there is no unified qualification assessment system for agent construction organizations. While the importance of the project manager’s competence is recognized, previous research also shows that project manager’s empowerment is conducive to project performance. The definition of competency is confusing as several terms such as competency/competencies, competence/competences, capability and ability are used interchangeably and inconsistently. Competence is the state or quality of being adequately qualified -- the ability to perform a specific role (e.g. PMI’s project manager’s competency development framework). While empowerment can be viewed as a relational construct and considered within a more general concept of power, it is also a motivational (or psychological) construct. These two perspectives of empowerment are not independent and motivational empowerment may be an outcome of relational empowerment. This research aims to analyze the relationships of motivational empowerment and competency on job performance of the project managers in the ACM organisations. Regression modelling is adopted to analyze the data collected from 203 project managers involved in projects adopting ACM system. Findings support the relationships of competency and empowerment and their effect on project manager’s job performance.postprin

    Sharpening Competitive Edge through Procurement Innovation: Perspectives from Chinese International Construction Companies

    Get PDF
    The international construction business is witnessing a trend towards the delivery of projects through the adoption of innovative procurement systems, which allow companies to gain competitive advantages and to potentially deliver enhanced value to society. Notably, Chinese companies are making steady inroads into the international construction market by enhancing competitiveness. However, we know little about the extent to which Chinese international construction companies (CICCs) perceive procurement innovation and how this factor may relate to their recent success. This research aims to fill the void based on interviews with nine CICC key decision‐makers and experts in this area, and the capturing of their perspectives. It is found that CICCs are gradually adopting procurement innovation as a competitive strategy. Although procurement innovation is conducive to competitive advantage in the long run, CICCs have to pay the cost of entering the new market. Thus a “wait‐and‐see” attitude exists in respect of a long term vision. Unlike the traditional win‐lose competitive bidding system, competing through procurement innovation can lead to larger, more suitable market presence. By succinctly describing the CICC story in the international market this research not only provides CICCs themselves with insights into current procurement innovations existing within the construction sector, but also enables other companies to understand the nature of CICCs with which they might compete or collaborate in the near future.postprin

    Effect of CLIQ on training of HL-LHC quadrupole magnets

    Full text link
    The high-luminosity LHC upgrade requires stronger than LHC low-beta quadrupole magnets to reach the luminosity goals of the project. The project is well advanced and HL-LHC quadrupole magnets are currently being commissioned in US Labs (MQXFA magnets) and CERN (MQXFB magnets). Those are the first Nb3Sn magnets to be used in any large particle accelerator. At development stages, many Nb3Sn accelerator sub-scale models showed relatively slow training and MQXFA magnets were projected to have low tens of quenches before reaching operational field. Recently it was shown that dedicated capacitor-based devices can affect Nb3Sn magnet training, and it was suggested that CLIQ, a capacitor-based device intended for quench protection, can do too. The present paper investigates effects on training likely induced by CLIQ, using the base fact that only half the coils in a quadrupole experience upward current modulation at quench because of capacitor discharge. The study encompasses all MQXFA production magnets trained at BNL to date. No other high-statistics data from identical magnets (series) with CLIQ protection exist so far. Implications and opportunities stemming from data analysis are discussed and conclusions drawn.Comment: Accepted versio

    A Cognitive Ethology Study of First- and Third-Person Perspectives

    Get PDF
    The present investigation was funded by a grant awarded to AK by the Natural Sciences and Engineering Council of Canada. The funders had no role in study design, data collection, and analysis, decision to publish, or preparation of the manuscript.Peer reviewedPublisher PD

    Fundamental scaling laws of on-off intermittency in a stochastically driven dissipative pattern forming system

    Full text link
    Noise driven electroconvection in sandwich cells of nematic liquid crystals exhibits on-off intermittent behaviour at the onset of the instability. We study laser scattering of convection rolls to characterize the wavelengths and the trajectories of the stochastic amplitudes of the intermittent structures. The pattern wavelengths and the statistics of these trajectories are in quantitative agreement with simulations of the linearized electrohydrodynamic equations. The fundamental τ3/2\tau^{-3/2} distribution law for the durations τ\tau of laminar phases as well as the power law of the amplitude distribution of intermittent bursts are confirmed in the experiments. Power spectral densities of the experimental and numerically simulated trajectories are discussed.Comment: 20 pages and 17 figure

    Direct observation of twist mode in electroconvection in I52

    Full text link
    I report on the direct observation of a uniform twist mode of the director field in electroconvection in I52. Recent theoretical work suggests that such a uniform twist mode of the director field is responsible for a number of secondary bifurcations in both electroconvection and thermal convection in nematics. I show here evidence that the proposed mechanisms are consistent with being the source of the previously reported SO2 state of electroconvection in I52. The same mechanisms also contribute to a tertiary Hopf bifurcation that I observe in electroconvection in I52. There are quantitative differences between the experiment and calculations that only include the twist mode. These differences suggest that a complete description must include effects described by the weak-electrolyte model of electroconvection
    corecore