Pool Boiling Enhanced by Electric Field Distribution in Microsized Space

This paper was presented at the 4th Micro and Nano Flows Conference (MNF2014), which was held at University College, London, UK. The conference was organised by Brunel University and supported by the Italian Union of Thermofluiddynamics, IPEM, the Process Intensification Network, the Institution of Mechanical Engineers, the Heat Transfer Society, HEXAG - the Heat Exchange Action Group, and the Energy Institute, ASME Press, LCN London Centre for Nanotechnology, UCL University College London, UCL Engineering, the International NanoScience Community, www.nanopaprika.eu.In this study, the enhancement of boiling heat transfer by electrostatic pressure was experimentally and analytically investigated. A fluorinated dielectric liquid was selected as the working fluid. Pool boiling heat transfer in the saturated liquid was measured at atmospheric pressure. In order to make clear the enhancement mechanisms, three microsized slit electrodes were designed with different slit widths, electrode widths, and total slit lengths over the boiling surface. Slits of several hundred micrometers were formed in the electrode, so as to remove vapor bubbles from the boiling surface by electrostatic pressure. The boiling surface was electrically grounded, and the electrode was placed above the boiling surface at heights of 200 μm to 400 μm. The maximum heat flux was 76 W/cm2 by the application of an electric field of －7 kV/mm, which was 3.5 times over pool boiling without the electrode. The previous analytical equation of pool boiling exhibited the essential feature of the effect of the electric field on the boiling heat transfer, and showed good agreement with the experimental results

Subjects, Agents, or Collectives? The Discourse of Youth and Philosophy

The present paper argues that the term "youth", which is traditionally used to refer both to young people of a certain age bracket and to a time of life between childhood and maturity has acquired distinctive yet contradictory meanings since the 19th century, and that the category of people, individuals, or persons that the concept describes or purports to analyze (the so-called young people, teenagers, pubescents, adolescents) may be regarded as subjects in the philosophical sense of being persons capable of intentional behaviour and to whom intentional predicates (beliefs and desires) can be ascribed but not, however, as a collective agent, with the capacity for goal-directed activity (such as, for example, political, social, or national transformation), in spite of the shift in the use of the concept from a singular to a collective noun. The paper argues further that the term "youth" is a vacuous concept, and thus lacks any philosophic or analytic significance or explanatory value in social theory and, especially, in philosophy, and that the discourse of youth which deploys the concept can only sustain the "politics of collective singularity" whereby a singular or a single collective subject or a parasitic structure usurps, or feeds on, the activity and capacity of empirical subjects (young people). The paper draws out the philosophic and practical-political implications of its central arguments - namely that young people, teenagers, pubescents, or adolescents those presumably described by the collective noun, "youth", do not, and cannot, articulate a coherent group - or age-based beliefs, desires, reasons, and action; cannot represent (or be the collective agency of) definite, historically-specific political-economic interests or relations in society; and, that, to the same extent, cannot be an agency of, or for; and indeed cannot be mobilized form; any form of enduring political action or social or national transformation

Superlubricity mechanism of diamond-like carbon with glycerol. Coupling of experimental and simulation studies

We report a unique tribological system that produces superlubricity under boundary lubrication conditions with extremely little wear. This system is a thin coating of hydrogen-free amorphous Diamond-Like-Carbon (denoted as ta-C) at 353 K in a ta-C/ta-C friction pair lubricated with pure glycerol. To understand the mechanism of friction vanishing we performed ToF-SIMS experiments using deuterated glycerol and 13C glycerol. This was complemented by first-principles-based computer simulations using the ReaxFF reactive force field to create an atomistic model of ta-C. These simulations show that DLC with the experimental density of 3.24 g/cc leads to an atomistic structure consisting of a 3D percolating network of tetrahedral (sp3) carbons accounting for 71.5% of the total, in excellent agreement with the 70% deduced from our Auger spectroscopy and XANES experiments. The simulations show that the remaining carbons (with sp2 and sp1 character) attach in short chains of length 1 to 7. In sliding simulations including glycerol molecules, the surface atoms react readily to form a very smooth carbon surface containing OH-terminated groups. This agrees with our SIMS experiments. The simulations find that the OH atoms are mostly bound to surface sp1 atoms leading to very flexible elastic response to sliding. Both simulations and experiments suggest that the origin of the superlubricity arises from the formation of this OH-terminated surface

Growth, production and nutrients in coriander cultivated with biofertilizer.

Crescimento, produção e nutrientes no coentro cultivado com biofertilizante. Objetivou-se avaliar o efeito de doses de um biofertilizante de materiais vegetais (BMV) sobre o crescimento, produção e nutrientes no coentro "Verdão"

Plasticity of microvascular oxygenation control in rat fast-twitch muscle: effects of experimental creatine depletion

Aging, heart failure and diabetes each compromise the matching of O2 delivery (QO2)-to-metabolic requirements (O2 uptake, VO2) in skeletal muscle such that the O2 pressure driving blood-myocyte O2 flux (microvascular PO2, PmvO2) is reduced and contractile function impaired. In contrast, β-guanidinopropionic acid (β-GPA) treatment improves muscle contractile function, primarily in fast-twitch muscle (Moerland and Kushmerick, 1994). We tested the hypothesis that β-GPA (2% wt/BW in rat chow, 8 wk; n=14) would improve QO2-to-VO2 matching (elevated PmvO2) during contractions (4.5 V @ 1 Hz) in mixed (MG) and white (WG) portions of the gastrocnemius, both predominantly fast-twitch). Compared with control (CON), during contractions PmvO2 fell less following β-GPA (MG -54%, WG -26%, p<0.05), elevating steady-state PmvO2 (CON, MG: 10±2, WG: 9±1; β-GPA, MG 16±2, WG 18±2 mmHg, P<0.05). This reflected an increased QO2/VO2 ratio due primarily to a reduced VO2 in β-GPA muscles. It is likely that this adaptation helps facilitate the β-GPA-induced enhancement of contractile function in fast-twitch muscles

The Continuing Debate on Deep Molluscan Phylogeny: Evidence for Serialia (Mollusca, Monoplacophora + Polyplacophora)

Molluscs are a diverse animal phylum with a formidable fossil record. Although there is little doubt about the monophyly of the eight extant classes, relationships between these groups are controversial. We analysed a comprehensive multilocus molecular data set for molluscs, the first to include multiple species from all classes, including five monoplacophorans in both extant families. Our analyses of five markers resolve two major clades: the first includes gastropods and bivalves sister to Serialia (monoplacophorans and chitons), and the second comprises scaphopods sister to aplacophorans and cephalopods. Traditional groupings such as Testaria, Aculifera, and Conchifera are rejected by our data with significant Approximately Unbiased (AU) test values. A new molecular clock indicates that molluscs had a terminal Precambrian origin with rapid divergence of all eight extant classes in the Cambrian. The recovery of Serialia as a derived, Late Cambrian clade is potentially in line with the stratigraphic chronology of morphologically heterogeneous early mollusc fossils. Serialia is in conflict with traditional molluscan classifications and recent phylogenomic data. Yet our hypothesis, as others from molecular data, implies frequent molluscan shell and body transformations by heterochronic shifts in development and multiple convergent adaptations, leading to the variable shells and body plans in extant lineages

Pressure Evolution of a Field Induced Fermi Surface Reconstruction and of the Neel Critical Field in CeIn3

We report high-pressure skin depth measurements on the heavy fermion material CeIn3 in magnetic fields up to 64 T using a self-resonant tank circuit based on a tunnel diode oscillator. At ambient pressure, an anomaly in the skin depth is seen at 45 T. The field where this anomaly occurs decreases with applied pressure until approximately 1.0 GPa, where it begins to increase before merging with the antiferromagnetic phase boundary. Possible origins for this transport anomaly are explored in terms of a Fermi surface reconstruction. The critical magnetic field at which the Neel ordered phase is suppressed is also mapped as a function of pressure and extrapolates to the previous ambient pressure measurements at high magnetic fields and high pressure measurements at zero magnetic field.Comment: 15 pages, 5 figure

Complex-Temperature Properties of the Ising Model on 2D Heteropolygonal Lattices

Using exact results, we determine the complex-temperature phase diagrams of the 2D Ising model on three regular heteropolygonal lattices, $(3 \cdot 6 \cdot 3 \cdot 6)$ (kagom\'{e}), $(3 \cdot 12^2)$, and $(4 \cdot 8^2)$ (bathroom tile), where the notation denotes the regular $n$-sided polygons adjacent to each vertex. We also work out the exact complex-temperature singularities of the spontaneous magnetisation. A comparison with the properties on the square, triangular, and hexagonal lattices is given. In particular, we find the first case where, even for isotropic spin-spin exchange couplings, the nontrivial non-analyticities of the free energy of the Ising model lie in a two-dimensional, rather than one-dimensional, algebraic variety in the $z=e^{-2K}$ plane.Comment: 31 pages, latex, postscript figure

Observation and Modeling of the Solar Transition Region: II. Solutions of the Quasi-Static Loop Model

In the present work we undertake a study of the quasi-static loop model and the observational consequences of the various solutions found. We obtain the most general solutions consistent with certain initial conditions. Great care is exercised in choosing these conditions to be physically plausible (motivated by observations). We show that the assumptions of previous quasi-static loop models, such as the models of Rosner, Tucker and Vaiana (1978) and Veseckey, Antiochos and Underwood (1979), are not necessarily valid for small loops at transition region temperatures. We find three general classes of solutions for the quasi-static loop model, which we denote, radiation dominated loops, conduction dominated loops and classical loops. These solutions are then compared with observations. Departures from the classical scaling law of RTV are found for the solutions obtained. It is shown that loops of the type that we model here can make a significant contribution to lower transition region emission via thermal conduction from the upper transition region.Comment: 30 pages, 3 figures, Submitted to ApJ, Microsoft Word File 6.0/9