Boiling of Immiscible Mixtures for Cooling of Electronics

To satisfy the requirements for the cooling of small and large semiconductors operated at high heat flux density, an innovative cooling method using boiling heat transfer to immiscible liquid mixtures is proposed. Immiscible liquid mixtures discussed here are composed of more-volatile liquid with higher density and less-volatile liquid with lower density, and appropriate volumetric ratios become a key to realize high-performance cooling. The chapter reviews the experimental results obtained by the present authors, where critical heat flux accompanied by the catastrophic surface temperature excursion is increased up to 300 W/cm2 for FC72/water by using a flat heating surface of 40 mm in diameter facing upwards under the pressure 0.1 MPa

Duality cascade of softly broken supersymmetric theories

We study the duality cascade of softly broken supersymmetric theories. We investigate the renormalization group (RG) flow of SUSY breaking terms as well as supersymmetric couplings. It is found that the magnitudes of SUSY breaking terms are suppressed in most regimes of the RG flow through the duality cascade. At one stage of cascading, the gaugino mass of the strongly coupled sector and scalar masses converge to certain values, which are determined by the gauge coupling and the gaugino mass of the weakly coupled sector. At the next stage, the strongly and weakly coupled sectors are interchanged with each other. We also show the possibility that cascading would be terminated by the gauge symmetry breaking, which is induced by the so-called B-term.Comment: 25 pages, 5 figure

Boiling heat transfer characteristics of immiscible liquid mixtures

Paper presented at the 9th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Malta, 16-18 July, 2012.Cooling technology becomes more important because of the increase in heat generation density of semiconductor chips. Boiling and two-phase flow is expected as one of the most effective methods to cool the electronic devices because of its superior heat transfer characteristics. Because the boiling heat transfer depends on the selection of coolant, the development of liquid mixtures and their components optimized for the individual cooling systems becomes very important. Most of the existing researches on nucleate boiling of binary mixtures clarify the heat transfer characteristics peculiar to the miscible ones, while the studies for immiscible mixtures were very limited. Pool boiling experiments on nucleate boiling of immiscible mixture FC72/Water are performed in a closed vessel at 0.1MPa. The experimental data is acquired under the steady-state conditions at heat flux ranging from those for the boiling incipience to CHF or to the highest possible value under the restriction of the available cooling. Before the experiments, the height of liquid layers on the horizontal heating surface is kept at a constant value of 100mm, and the thickness of FC72 layer above the heating surface is varied at three different values of 5mm, 10mm and 50mm. A new phenomena of “intermediate burnout” due to the evaporation of FC72 is observed provided that the layer thickness of FC72 is not large. At heat flux higher than that for intermediate burnout, the immiscible mixture decreases the surface temperature from that for pure water and simultaneously increases CHF. The immiscible mixture has a potential to realize high performance heat exchange systems by the self-sustaining subcooling of components under the constant system pressure.dc201

Prevention of Cognitive Decline in Alzheimer's Disease by Novel Antioxidative Supplements

Oxidative stress plays a crucial role in Alzheimer's disease (AD) from its prodromal stage of mild cognitive impairment. There is an interplay between oxidative stress and the amyloid beta (A beta) cascade via various mechanisms including mitochondrial dysfunction, lipid peroxidation, protein oxidation, glycoxidation, deoxyribonucleotide acid damage, altered antioxidant defense, impaired amyloid clearance, inflammation and chronic cerebral hypoperfusion. Based on findings that indicate that oxidative stress plays a major role in AD, oxidative stress has been considered as a therapeutic target of AD. In spite of favorable preclinical study outcomes, previous antioxidative components, including a single antioxidative supplement such as vitamin C, vitamin E or their mixtures, did not clearly show any therapeutic effect on cognitive decline in AD. However, novel antioxidative supplements can be beneficial for AD patients. In this review, we summarize the interplay between oxidative stress and the A beta cascade, and introduce novel antioxidative supplements expected to prevent cognitive decline in AD

IL-18 with IL-2 protects against Strongyloides venezuelensis infection by activating mucosal mast cell–dependent type 2 innate immunity

C57BL/6 (B6) and B6 background STAT6−/− mice pretreated with IL-18 plus IL-2 showed prominent intestinal mastocytosis and rapidly expelled implanted adult worms of the gastrointestinal nematode Strongyloides venezuelensis. In contrast, identically pretreated mast cell–deficient W/Wv mice failed to do so. Thus, activated mucosal mast cells (MMC) are crucial for parasite expulsion. B6 mice infected with S. venezuelensis third-stage larvae (L3) completed parasite expulsion by day 12 after infection, whereas IL-18−/− or IL-18Rα−/− B6 mice exhibited marked impairment in parasite expulsion, suggesting a substantial contribution of IL-18–dependent MMC activation to parasite expulsion. Compared with IL-18−/− or IL-18Rα−/− mice, S. venezuelensis L3–infected STAT6−/− mice have poorly activated MMC and sustained infection; although their IL-18 production is normal. Neutralization of IL-18 and IL-2 further reduces expulsion in infected STAT6−/− mice. These results suggest that collaboration between IL-18–dependent and Th2 cell–dependent mastocytosis is important for prompt parasite expulsion

The role of B-cells in immunity against adult Strongyloides venezuelensis

BACKGROUND: Strongyloides venezuelensis has been used as a tool and model for strongyloidiasis research. Elimination of S. venezuelensis adult worms from mice has been particularly associated with proliferation and activation of intestinal mast cells and eosinophils. To date, the role of B-cells in the protective mechanism against adult Strongyloides infection in experimental animals has not been reported in the literature. Therefore, the present study was carried to investigate the role of B-lymphocytes in immunity against adult S. venezuelensis infection using mice with a targeted deletion of the JH locus. METHODS: JHD knockout mice with its wild-type Balb/c mice were infected by intra-duodenal implantation of adult S. venezuelensis. Fecal egg count, intestinal worm recovery, mucosal mast cells and eosinophils were counted. RESULTS: At day 11 post infection, parasites in wild-type mice stopped egg laying, while in JHD knockout mice parasites continued to excrete eggs until the end of the observation period, day 107. The higher number of parasite eggs expelled in the feces of JHD knockout infected mice was a consequence of higher worm burdens, which established in the small intestine of these animals. On the other hand worm fecundity was comparable in both groups of mice. Both B-cell-deficient mice and wild-type mice, showed an influx of mucosal mast cells and eosinophils. The absolute numbers in JHD knockout mice were lower than those seen in wild-type mice at day 11, but not to a level of significance. JHD knockout mice could not recover from infection despite the recruitment of both types of cells. CONCLUSION: Our findings highlight a role of B cells in mucosal immunity against invasion of adult S. venezuelensis and in its expulsion. Therefore, we conclude that B-cells together with mucosal mast cells and eosinophils, contribute to immunity against adult S. venezuelensis by mechanism(s) to be investigated

Development of Heated Narrow Channels with Enhanced Liquid Supply in Forced Convective Boiling

Abstract Heat generation density from semiconductor devices increases with the rapid development of electronic technology. The cooling system using boiling two-phase phenomena attracts much attention because of its high heat removal potential. Most of heat transfer researches concerning the development of electronic devices are conducted for the cooling of small semiconductor chips, while there are limited numbers of innovative investigations for the cooling of a large area at extremely high heat flux larger than 2×10 6 W/m 2 . The technology can be applied to the cooling systems in space, e.g., cooling of laser medium in solar power satellites when solar energy is converted to laser power. To develop compact and high-performance cooling systems, a structure of narrow heated channel between parallel plates with auxiliary unheated channel was devised and tested by using water in three different kinds of experimental conditions. One of liquid supply method, where liquid is supplied to both of the main heated and the auxiliary unheated channel keeping the exit of the auxiliary channel closed, gives the highest CHF value at total volumetric flow rates more than 3.0×10 -5 m 3 /s and 2mm gap size of main heated channel

CP, Charge Fractionalizations and Low Energy Effective Actions in the SU(2) Seiberg-Witten Theories with Quarks

Several dynamical aspects of the SU(2) Seiberg-Witten models with N_f quark hypermultiplets are explored. We first clarify the meaning of the number of the singularities of the space of vacua. CP invariance of the theories are then studied and periodicities of theories in \theta with and without bare quark masses are obtained ((4-N_f)\pi and \pi, respectively). CP noninvariance at a generic point of QMS manifests itself as the electric and quark-number charge fractionalizations for the dyons; we show that the exact Seiberg-Witten solution contains such effects correctly, in agreement with the semiclassical analysis recently made by F.Ferrari. Upon N=1 perturbation the low energy effective theories at the singularities display confinement, and in most cases chiral symmetry breaking as a consequence. In one of the vacua for N_f=3 confinement is not accompanied by chiral symmetry breaking: we interpret it as an example of oblique confinement of 't Hooft. We discuss further the consistency of the physical picture found here by studying the effects of soft supersymmetry breaking as well as the behavior of the theory in the N=1 limit.Comment: 38 pages, LaTex file with 3 PostScript figure

PREFACE: DROPS, BUBBLES, AND THIN FILMS, SPECIAL ISSUE HONORING PROFESSOR OLEG KABOV

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