713 research outputs found
Upper limits for the photoproduction cross section for the phi(--)(1860) pentaquark state off the deuteron
We searched for the phi(--)(1860) pentaquark in the photoproduction process off the deuteron in the Xi(-)pi(-)-decay channel using CLAS. The invariant-mass spectrum of the Xi(-)pi(-) system does not indicate any statistically significant enhancement near the reported mass M = 1.860 GeV. The statistical analysis of the sideband-subtracted mass spectrum yields a 90%-confidence-level upper limit of 0.7 nb for the photoproduction cross section of phi(--)(1860) with a consecutive decay into Xi(-)pi(-) in the photon-energy range 4.5 GeV \u3c E-gamma \u3c 5.5 GeV
Energy efficiency parametric design tool in the framework of holistic ship design optimization
Recent International Maritime Organization (IMO) decisions with respect to measures to reduce the emissions from maritime greenhouse gases (GHGs) suggest that the collaboration of all major stakeholders of shipbuilding and ship operations is required to address this complex techno-economical and highly political problem efficiently. This calls eventually for the development of proper design, operational knowledge, and assessment tools for the energy-efficient design and operation of ships, as suggested by the Second IMO GHG Study (2009). This type of coordination of the efforts of many maritime stakeholders, with often conflicting professional interests but ultimately commonly aiming at optimal ship design and operation solutions, has been addressed within a methodology developed in the EU-funded Logistics-Based (LOGBASED) Design Project (2004–2007). Based on the knowledge base developed within this project, a new parametric design software tool (PDT) has been developed by the National Technical University of Athens, Ship Design Laboratory (NTUA-SDL), for implementing an energy efficiency design and management procedure. The PDT is an integral part of an earlier developed holistic ship design optimization approach by NTUA-SDL that addresses the multi-objective ship design optimization problem. It provides Pareto-optimum solutions and a complete mapping of the design space in a comprehensive way for the final assessment and decision by all the involved stakeholders. The application of the tool to the design of a large oil tanker and alternatively to container ships is elaborated in the presented paper
Atypical and Asymmetric 1,3-P,N Ligands: Synthesis, Coordination and Catalytic Performance of Cycloiminophosphanes
Enhancement of London Dispersion in Frustrated Lewis Pairs:Towards a Crystalline Encounter Complex
Exploring the application of a text-to-personality technique in job interviews
This research’s purpose was to develop a valid and transparent text-to-personality technique to fit the requirements for personnel selection assessments. In this research we developed an advanced word-counting technique, the HEXACO text-to-personality (HTTP) technique, based on prior lexical personality research to assess personality from job interviews. To evaluate the technique’s construct and criterion-related validity we conducted three studies and analysed the transcripts of asynchronous (n = 102 and 72) and face-to-face (n = 155) interviews. These studies provided four key insights. First, the HTTP technique showed small to medium correlations with self-reported and interviewer-rated personality. Second, the technique showed mixed, but generally favourable, evidence for criterion-related validity. Third, the technique produced a more construct valid personality score when the interview questions activated the predicted personality trait. Fourth, the technique’s additional features (i.e., having weighted keywords and adjusting the keywords’ weight for adjacent quantifiers) did not improve its validity; unit-weighing was approximately equally effective. Altogether, the results show that a word-count text-analysis technique can discover traces of personality in interview transcripts. Still, significant improvements are needed before these types of automatically computed text-to-personality ratings can be used to replace or supplement interviewer ratings
Applicant reactions to algorithm- versus recruiter-based evaluations of an asynchronous video interview and a personality inventory
In two studies, we examined the effects of algorithm based (vs. recruiter-based) evaluations of an asynchronous video interview and a personality inventory on applicant reactions. In line with our expectations, we found several negative applicant reactions to the use of algorithms. Specifically, in Study 1 (N = 172), informing participants that an algorithm, rather than a recruiter, had analysed their interview and personality inventory increased feelings of emotional creepiness, and reduced fairness perceptions, perceived predictive validity and feedback acceptance. In Study 2 (N = 276), we were able to replicate these effects for fairness perceptions and perceived predictive validity. Furthermore, in both studies, algorithm based evaluations negatively affected feedback acceptance, organizational attraction and job acceptance intentions through fairness perceptions. However, in contrast with our expectations, selection decision favour ability did not influence the impact of evaluation source (recruiter vs. algorithm) on applicant reactions. In Study 2, we also found some tentative evidence that applicant reactions to algorithm based evaluations are not affected by the type of information source (i.e. verbal vs. nonverbal cues) on which the algorithm is based
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Outgassing tests on materials used in the DIII-D magnetic fusion tokamak
In order to achieve high performance plasma discharges in the DIII-D magnetic fusion tokamak, impurity levels must be carefully controlled. Since first wall materials can desorb volatile impurities during these discharges, it is important to characterize and control the outgassing of these materials. An outgassing chamber was built to measure the outgassing properties of various materials used in the DIII-D vessel. The results of pump-down tests performed on ATJ graphite, thin Grafoil {reg_sign} gaskets, and MgO coaxial cables will be presented. In addition to pumpdown tests it was desired to study the behavior of the materials at temperatures up to 400 C, which is the maximum temperature to which the DIII-D vessel is baked. The station was modified to include independent heating control of the sample and a simple load-lock chamber
Beam spin asymmetries in deeply virtual Compton scattering (DVCS) with CLAS at 4.8 GeV
We report measurements of the beam spin asymmetry in deeply virtual Compton scattering (DVCS) at an electron beam energy of 4.8 GeV using the CLAS detector at the Thomas Jefferson National Accelerator Facility. The DVCS beam spin asymmetry has been measured in a wide range of kinematics, 1.0 \u3c Q(2) \u3c 2.8 (GeV/c)(2), 0.12 \u3c x(B) \u3c 0.48, and 0.1 \u3c -t \u3c 0.8 (GeV/c)(2), using the reaction (e) over right arrow - \u3e e\u27pX. The number of H(e, e\u27gamma p) and H(e, e\u27pi(0)p) events are separated in each (Q(2), x(B), t) bin by a fit to the line shape of the H(e, e\u27p) X M(x)(2) distribution. The validity of the method was studied in detail using experimental and simulated data. It was shown that with the achieved missing mass squared resolution and the available statistics, the separation of DVCS-Bethe-Heitler and pi(0) events can reliably be done with less than 5% uncertainty. Also, the Q(2) and t dependences of the sin phi moments of the asymmetry are extracted and compared with theoretical calculations
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Improvements to the Cryogenic Control System on Diii-D
OAK-B135 The cryogenic facility that is part of the DIII-D tokamak system supplies liquid nitrogen and liquid helium to the superconducting magnets used for electron cyclotron heating, the D{sub 2} pellet injection system, cryopumps in the DIII-D vessel, and cryopanels in the neutral beam injection system. The liquid helium is liquefied on site using a Sulzer liquefier that has a 150 l/h liquefaction rate. Control of the cryogenic facility at DIII-D was initially accomplished through the use of three different programmable logic controllers (PLCs). Recently, two of those three PLCs, a Sattcon PLC controlling the Sulzer liquefier and a Westinghouse PLC, were removed and all their control logic was merged into the remaining PLC, a Siemens T1555. This replacement was originally undertaken because the removed PLCs were obsolete and unsupported. However, there have been additional benefits from the replacement. The replacement of the RS-232 serial links between the graphical user interface and the PLCs with a high speed Ethernet link allows for real-time display and historical trending of nearly all the cryosystem's data. this has greatly increased the ability to troubleshoot problems with the system, and has permitted optimization of the cryogenic system's performance because of the increased system integration. To move the control logic of the Sattcon control loops into the T1555, an extensive modification of the basic PID control was required. These modifications allow for better control of the control loops and are now being incorporated in other control loops in the system
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Glow discharge initiation with electron gun assist
Helium glow discharge conditioning is used before every discharge in the D3-D Tokamak to desorb hydrogen and low Z impurities from the graphite and Inconel plasma facing surfaces. However high gas pressure is required to initiate each glow discharge session and this requires frequent cycling of valves to protect pressure sensitive devices. To alleviate this mechanical fatigue an electron gun assisted glow system (EAG) is being installed on the D3-D vessel to lower the initiation pressure. Through the injection of electrons the initiation pressure of the helium glow discharge has been lowered by a factor of 70, bringing the initiation pressure within a factor of 2 of the minimum sustaining pressure of the glow discharge. This might also make possible pulsed glow conditioning which would allow a lower average pressure during glow conditioning reducing the heat load on proposed cryogenic pumping panels. Experimental results of the electron assist on He glow initiation and a scaling model for the electron gun assisted glow will be presented. The electron gun can also be used as a diagnostic. Without a glow discharge, the electron gun has been pulsed into the wall and desorbed gas measured by a Residual Gas Analyzer. We are attempting to correlate the desorbed gas with recycling or vessel cleanliness
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