390 research outputs found

    Integrating psychological and neurobiological considerations regarding the development and maintenance of specific Internet-use disorders: An Interaction of Person-Affect-Cognition-Execution (I-PACE) model

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    AbstractWithin the last two decades, many studies have addressed the clinical phenomenon of Internet-use disorders, with a particular focus on Internet-gaming disorder. Based on previous theoretical considerations and empirical findings, we suggest an Interaction of Person-Affect-Cognition-Execution (I-PACE) model of specific Internet-use disorders. The I-PACE model is a theoretical framework for the processes underlying the development and maintenance of an addictive use of certain Internet applications or sites promoting gaming, gambling, pornography viewing, shopping, or communication. The model is composed as a process model. Specific Internet-use disorders are considered to be the consequence of interactions between predisposing factors, such as neurobiological and psychological constitutions, moderators, such as coping styles and Internet-related cognitive biases, and mediators, such as affective and cognitive responses to situational triggers in combination with reduced executive functioning. Conditioning processes may strengthen these associations within an addiction process. Although the hypotheses regarding the mechanisms underlying the development and maintenance of specific Internet-use disorders, summarized in the I-PACE model, must be further tested empirically, implications for treatment interventions are suggested

    Results of the QUENCH-20 experiment with BWR test bundle [in press]

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    The experiment QUENCH-20 with BWR geometry simulation bundle was successfully conducted at KIT on 9th October 2019 in the framework of the international SAFEST project. The test bundle mock-up represented one quarter of a BWR fuel assembly with 24 electrically heated fuel rod simulators and two B4C control blades. The rod simulators were filled with Kr to an inner pressure of 5.5 bar. The pre-oxidation stage in a flowing gas mixture of steam and argon (each 3 g/s) and system pressure of 2 bar lasted 4 hours at the peak cladding temperature of 1250 K. The Zry-4 corner rod, withdrawn at the end of this stage, showed the maximal oxidation at elevations between 930 and 1020 mm with signs of breakaway. During the transient stage, the bundle was heated to a maximum temperature of 2000 K. The coolability of the bundle was decreased by its squeezing due to the shroud ductile deformation caused by an overpressure outside the shroud. The cladding radial strain and failures due to inner overpressure (about 4 bar) were observed at temperature about 1700 K and lasted about 200 s. During the period of rod failures also the first absorber melt relocation accompanied by shroud failure were registered. The interaction of B4C with the steel blade and the ZIRLO channel box were observed at elevations 650…950 mm with the formation of eutectic melt. The typical components of this melt are (Fe, Cr) borides and ZrB2 precipitated in steel or in Zr-steel eutectic melt. Massive absorber melt relocation was observed 50 s before the end of transition stage. Small fragments of the absorber melt moved down to the elevation of 50 mm. The melting point of Inconel spacer grids at 500 and 1050 mm was also reached at the end of the transition stage. The Inconel melt from the elevation 1050 mm relocated downwards through hot bundle regions to the Inconel grid spacer at 550 mm and later (during the escalation caused by quench) to 450 mm. This melt penetrated also under the damaged cladding oxide layer and formed molten eutectic mixtures between elevations 450 and 550 mm. The test was terminated by quench water injection with a flow rate of 50 g/s from the bundle bottom. Fast temperature escalation from 2000 to 2300 K during 20 s was observed due to the strongly exothermic oxidation reactions. As result, the metal part (prior β-Zr) of the claddings between 550 and 950 mm was melted, partially released into space between rods and partially relocated in the gap between pellet and outer oxide layer to 450 mm. In this case, the positive role of the oxide layer should be noted, which does not allow the melt to completely escape into the inter-rod space. It is thereby limiting the possibility of interactions of a large amount of melt with steam, which could significantly increase the exothermic oxidation processes and the escalation of temperatures. The distribution of the oxidation rate within each bundle cross section is very inhomogeneous: whereas the average outer ZrO2 layer thickness for the central rod (#1) at the elevation of 750 mm is 465 µm, the same parameter for the peripheral rod #24 is only 108 µm. The average oxidation rate of the inner cladding surface (due to interaction with steam and with ZrO2 pellets) is about 20% in comparison to the outer cladding oxidation. The bundle elevations 850 and 750 mm are mostly oxidized with average cladding ECR 33%. The oxidation of the melt relocated inside the rods was observed at elevations 550…950 mm. The mass spectrometer measured release of CO (12.6 g), CO2 (9.7 g) and CH4 (0.4 g) during the reflood as products of absorber oxidation; the corresponding B4C reacted mass was 41 g or 4.6% of the total B4C inventory. It is significantly lower than in the PWR bundle tests QUENCH-07 and QUENCH-09 containing central absorber rod with B4C pellets inserted into a thin stainless steel cladding and Zry-4 guide tubes (20% and 50% reacted B4C correspondingly). Hydrogen production during the reflood amounted to 32 g during the reflood (57.4 g during the whole test) including 10 g from B4C oxidation

    Surface-dependent properties of α-Ag2WO4: a joint experimental and theoretical investigation

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    Alpha-silver tungstate (α-Ag2WO4) has attracted much attention in recent years due to its unique crystal and electronic structures, which are suitable for a wide range of applications. This work presents a more realistic study, based on frst-principles calculations and experimental results, of the potential of α-Ag2WO4 for antibacterial and photocatalytic activity. α-Ag2WO4 material has been successfully synthesized by a coprecipitation method and subjected to microwave irradiation for diferent times. The as-synthesized microcrystals were structurally characterized by X-ray difraction, while the morphological aspects were investigated by feld emission scanning electron microscopy. The experimental studies and theoretical simulations of α-Ag2WO4, based on density functional theory calculations, have highlighted several key parameters (surface dependent) that determine the antibacterial (against Staphylococcus aureus) and photocatalytic activity (for the degradation of rhodamine B) and provided some general principles for material design. We believe that our results ofer new insights regarding the local coordination of superfcial Ag and W atoms (i.e. clusters) on each exposed surface of the corresponding morphology, that dictate the antibacterial and photocatalytic activities of α-Ag2WO4, a feld that has so far remained unexplored

    Latest Developments from the S-DALINAC*

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    The S-DALINAC is a 130 MeV superconducting recirculating electron accelerator serving several nuclear and radiation physics experiments as well as driving an infrared free-electron laser. A system of normal conducting rf resonators for noninvasive beam position and current measurement was established. For the measurement of gamma-radiation inside the accelerator cave a system of Compton diodes has been developed and tested. Detailed investigations of the transverse phasespace were carried out with a tomographical reconstruction method of optical transition radiation spots. The method can be applied also to non-Gaussian phasespace distributions. The results are in good accordance with simulations. To improve the quality factor of the superconducting 3 GHz cavities, an external 2K testcryostat was commissioned. The influence of electro-chemical polishing and magnetic shielding is currently under investigation. A digital rf-feedback-system for the accelerator cavities is being developed in order to improve the energy spread of the beam of the S-DALINAC. * Supported by the BMBF under contract no. 06 DA 820, the DFG under contract no. Ri 242/12-1 and -2 and the DFG Graduiertenkolleg 'Physik und Technik von Beschleunigern

    A Systematic Review of Online Sex Addiction and Clinical Treatments Using CONSORT Evaluation

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    Researchers have suggested that the advances of the Internet over the past two decades have gradually eliminated traditional offline methods of obtaining sexual material. Additionally, research on cybersex and/or online sex addictions has increased alongside the development of online technology. The present study extended the findings from Griffiths’ (2012) systematic empirical review of online sex addiction by additionally investigating empirical studies that implemented and/or documented clinical treatments for online sex addiction in adults. A total of nine studies were identified and then each underwent a CONSORT evaluation. The main findings of the present review provide some evidence to suggest that some treatments (both psychological and/or pharmacological) provide positive outcomes among those experiencing difficulties with online sex addiction. Similar to Griffiths’ original review, this study recommends that further research is warranted to establish the efficacy of empirically driven treatments for online sex addiction

    Precise verification of phase and amplitude calibration by means of a debunching experiment in SIS18

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    Several new rf cavity systems have to be realized for the FAIR synchrotrons and for the upgrade of the existing GSI synchrotron SIS18 [1]. For this purpose, a completely new low-level rf (LLRF) system architecture [2] has been developed, which is now used in SIS18 operation. Closedloop control systems stabilize the amplitude and the phase of the rf gap voltages. Due to component imperfections the transmission and the detection of the actual values lead to systematic errors without countermeasures. These errors prohibit the operation of the rf systems over the whole amplitude and frequency range within the required accuracy. To compensate the inevitable errors, the target values provided by the central control system are modified by socalled calibration electronics (CEL, [3]) modules. The calibration curves can be measured without the beam, but the desired beam behaviour has to be verified by experiments. For this purpose, a debunching scenario was selected as a SIS18 beam experiment that proved to be very sensitive to inaccuracies. In this contribution the results of this experiment are presented, showing for the first time at GSI by beam observation that the accuracy requirements are met based on predefined calibration curves

    Generation of RF Frequency and Phase References on the FAIR Site

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    Based on the Bunch Phase Timing System (BuTiS) local analog radio frequency reference signals (RF references) like the particle revolution frequency and their multiple harmonics will be generated. These references are used to control the phase of the accelerator cavities to altering harmonics of the bunch revolution frequency. Delay or phase shifts from the FAIR-Center to references at the BuTiS endpoints are already compensated by the BuTiS receivers. Phase shifts from the RF reference generators to LLRF electronics can be compensated by controlling the output phases of the DDS modules of the RF references. However phase shift delays of multiple harmonics at the same interconnecting electrical path are not identical at the same time. Configurable electronics manage phase calibration of the RF references to their endpoints. Calibration may depend on frequency and harmonic of the RF reference, aging as well as on thermal effects. The electrical length and impedance of interconnecting cables for phase control loops can be compensated. This is an important feature, in particular if control loops are switched between different harmonic frequencies
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