EFFECTS OF AL(2)O(3) NANOPARTICLES DEPOSITION ON CRITICAL HEAT FLUX OF R-123 IN FLOW BOILING HEAT TRANSFER

In this study, R-123 flow boiling experiments were carried out to investigate the effects of nanoparticle deposition on heater surfaces on flow critical heat flux (CHF) and boiling heat transfer. It is known that CHF enhancement by nanoparticles results from porous structures that are very similar to layers of Chalk River unidentified deposit formed on nuclear fuel rod surfaces during the reactor operation period. Although previous studies have investigated the surface effects through surface modifications, most studies are limited to pool boiling conditions, and therefore, the effects of porous surfaces on flow boiling heat transfer are still unclear. In addition, there have been only few reports on suppression of wetting for decoupled approaches of reasoning. In this study, bare and Al2O3 nanoparticle-coated surfaces were prepared for the study experiments. The CHF of each surface was measured with different mass fluxes of 1,600 kg/m(2)s, 1,800 kg/m(2)s, 2,100 kg/m(2)s, 2,400 kg/m(2)s, and 2,600 kg/m(2)s. The nanoparticle-coated tube showed CHF enhancement up to 17% at a mass flux of 2,400 kg/m(2)s compared with the bare tube. The factors for CHF enhancement are related to the enhanced rewetting process derived from capillary action through porous structures built-up by nanoparticles while suppressing relative wettability effects between two sample surfaces as a highly wettable R-123 refrigerant was used as a working fluid. Copyright (C) 2015, Published by Elsevier Korea LLC on behalf of Korean Nuclear Societyclose0

PALS/PRISM Software Design Description (SDD): Ver. 0.51

This Software Design Description (SDD) provides detailed information on the architecture and coding for the PRISM C++ library (version 0.51). The PRISM C++ library supports consistent information sharing and in- teractions between distributed components of networked embedded systems, e.g. avionics. It is designed to reduce the complexity of the networked sys- tem by employing synchronous semantics provided by the architectural pat- tern called a Physically-Asynchronous Logically-Synchronous (PALS) system.unpublishednot peer reviewe

Visualizing Atomic-Scale Negative Differential Resistance in Bilayer Graphene

We investigate the atomic-scale tunneling characteristics of bilayer graphene on silicon carbide using the scanning tunneling microscopy. The high-resolution tunneling spectroscopy reveals an unexpected negative differential resistance (NDR) at the Dirac energy, which spatially varies within the single unit cell of bilayer graphene. The origin of NDR is explained by two near-gap van Hove singularities emerging in the electronic spectrum of bilayer graphene under a transverse electric field, which are strongly localized on two sublattices in different layers. Furthermore, defects near the tunneling contact are found to strongly impact on NDR through the electron interference. Our result provides an atomic-level understanding of quantum tunneling in bilayer graphene, and constitutes a useful step towards graphene-based tunneling devices. DOI: 10.1103/PhysRevLett.110.036804X11109sciescopu

Country background report for Korea

노트 : OECD Review on Evaluation and Assessment Frameworks for Improving School Outcome

Gaming with Mr. Slot or gaming the slot machine? Power, anthropomorphism, and risk perception

We propose that risk perceptions are systematically influenced by anthropomorphism. Anthropomorphism effects, however, are moderated by the individual's feelings of social power. People with low power perceive higher risk in playing a slot machine (study 1) and in getting skin cancer (study 2) when the risk-bearing entities (the slot machine and skin cancer) are highly anthropomorphized. In contrast, those with high power perceive greater risk when the entities are less anthropomorphized. We hypothesize these effects occur because those with high (low) power perceived a greater (lesser) degree of control over the anthropomorphized entity. In study 3, we investigate the reverse effect that higher perceived risk may increase anthropomorphism for people with low power but decrease anthropomorphism for people with high power. © 2010 by JOURNAL OF CONSUMER RESEARCH, Inc.published_or_final_versio