1,579 research outputs found

    An Investigation of Void Fraction in the Stratified/Annular Flow Regions in Smooth, Horizontal Tubes

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    Refrigerants R134a and R410A have been used for void fraction measurements in smooth horizontal tubes with diameters between 4mm and 7mm. Quality and mass flux were varied from 5% to 90% and 75 kglm2-s to 700 kglm2-s, respectively. Two test loops, one for condensing flows at 35C and the other for evaporating flows at 5C, were used in the investigation. Results show that near the transition from annular to stratified flow void fraction changed from viscousinertial dependence to gravitational-inertial dominated dependence. An important feature observed is the annular flow region's relative insensitivity to mass flux while the border region between annular and stratified flows is characterized by strong mass flux dependence.Air Conditioning and Refrigeration Project 7

    Electronic damping of molecular motion at metal surfaces

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    A method for the calculation of the damping rate due to electron-hole pair excitation for atomic and molecular motion at metal surfaces is presented. The theoretical basis is provided by Time Dependent Density Functional Theory (TDDFT) in the quasi-static limit and calculations are performed within a standard plane-wave, pseudopotential framework. The artificial periodicity introduced by using a super-cell geometry is removed to derive results for the motion of an isolated atom or molecule, rather than for the coherent motion of an ordered over-layer. The algorithm is implemented in parallel, distributed across both k{\bf k} and g{\bf g} space, and in a form compatible with the CASTEP code. Test results for the damping of the motion of hydrogen atoms above the Cu(111) surface are presented.Comment: 10 pages, 3 figure

    PCN162 The Cost-Effectiveness of Second-Line Crizotinib in Eml4-Alk Rearranged Advanced Non-Small Cell Lung Cancer

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    Background: Snoring / sleep apnea are potentially life threatening breathing occurs during sleep. Little attention is being giving to this clinical condition. Objective: To determine the prevalence of snoring and risk factors associated with obstructive sleep apnea (OSA) among adults workers in two local governments of state, Nigeria Methodology: A cross - sectional survey of 121 young adult and adults working in two local governments of Ekiti state, south western Nigeria was carried out. A self administered questionnaire that was incorporated with Epworth Sleepiness Scale and Berlin Score was used to collect data on socio-demographic characteristics, information related to snoring, sleep related problems and their anthropometric. The Body Mass Index (BMI) and blood pressure of each participant were also measured. Results: Snoring was reported in forty nine (40.5%) of the participants. Their age ranges from 23 to 65 years, mean of 43.89 ± 8.53 SD. The proportion of males and Berlin score (high risk) were significantly (p < 0.001) higher among snores than non regression found sex (OR=7.791, 95% CI =2.971- 20.429), Berlin Score (high risk) (OR= 8.642, 95% CI= 3.159 - 23.639) as significant (P< 0.001) independent risk factors for OSA. Excessive day time sleepiness as determined by ESS score of the participants. Conclusion: The overall prevalence of snoring in this study was 40.5%. Snoring was found to increase with age, body mass index, male sex and those with high risk for Berlin score with high risk of developing Obstructive sleep apne

    Symmetric-Asymmetric transition in mixtures of Bose-Einstein condensates

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    We propose a new kind of quantum phase transition in phase separated mixtures of Bose-Einstein condensates. In this transition, the distribution of the two components changes from a symmetric to an asymmetric shape. We discuss the nature of the phase transition, the role of interface tension and the phase diagram. The symmetric to asymmetric transition is the simplest quantum phase transition that one can imagine. Careful study of this problem should provide us new insight into this burgeoning field of discovery.Comment: 6 pages, 3 eps figure

    Boundary of two mixed Bose-Einstein condensates

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    The boundary of two mixed Bose-Einstein condensates interacting repulsively was considered in the case of spatial separation at zero temperature. Analytical expressions for density distribution of condensates were obtained by solving two coupled nonlinear Gross-Pitaevskii equations in cases corresponding weak and strong separation. These expressions allow to consider excitation spectrum of a particle confined in the vicinity of the boundary as well as surface waves associated with surface tension.Comment: 6 pages, 3 figures, submitted to Phys.Rev.

    Constructing our identities: Identity Expression amongst lesbian women attending university

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    Issues of marginalisation have been central to studies on lesbian women, and can affect the expression of sexuality. The university is a site that can potentially provide a physical and relational space that facilitates the negotiation of identities within the context of institutional policies that protect LGBTI people. This article examines data collected from 3 focus group discussions with 11 lesbian women attending university. Using queer theory, this article explores how policy shifts have affected identity expression; identification with ‘categories’ of lesbianism; the intersections of sexual identity with other social markers; and the interplay of space and identity expression. The results of the study indicated new emerging ways of viewing and expressing lesbian identity. The intersection of identity with policies, Westernisation, privilege, and power, as well as an increase in LGBTI consciousness and access to information, has allowed for wider expressions of sexuality that attempt to break gender binaries

    Geometry and material effects in Casimir physics - Scattering theory

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    We give a comprehensive presentation of methods for calculating the Casimir force to arbitrary accuracy, for any number of objects, arbitrary shapes, susceptibility functions, and separations. The technique is applicable to objects immersed in media other than vacuum, to nonzero temperatures, and to spatial arrangements in which one object is enclosed in another. Our method combines each object's classical electromagnetic scattering amplitude with universal translation matrices, which convert between the bases used to calculate scattering for each object, but are otherwise independent of the details of the individual objects. This approach, which combines methods of statistical physics and scattering theory, is well suited to analyze many diverse phenomena. We illustrate its power and versatility by a number of examples, which show how the interplay of geometry and material properties helps to understand and control Casimir forces. We also examine whether electrodynamic Casimir forces can lead to stable levitation. Neglecting permeabilities, we prove that any equilibrium position of objects subject to such forces is unstable if the permittivities of all objects are higher or lower than that of the enveloping medium; the former being the generic case for ordinary materials in vacuum.Comment: 44 pages, 11 figures, to appear in upcoming Lecture Notes in Physics volume in Casimir physic

    Morphologies of AGN host galaxies using HST/ACS in the CDFS-GOODS field

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    Using HST/ACS images in four bands F435W, F606W, F775W and F850LP, we identify optical counterparts to the X-ray sources in the Chandra Deep Field South in the GOODS South field. A detailed study has been made of these sources to study their morphological types. We use methods like decomposition of galaxy luminosity profiles, color maps and visual inspection of 192 galaxies which are identified as possible optical counterparts of Chandra X-ray sources in the CDFS-GOODS field. We find that most moderate luminosity AGN hosts are bulge dominated in the redshift range (z \approx 0.4-1.3), but not merging/interacting galaxies. This implies probable fueling of the moderate luminosity AGN by mechanisms other than those merger driven.Comment: pdflatex, accepted in ApSS. revisions in tex

    Nonequilibrium wetting

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    When a nonequilibrium growing interface in the presence of a wall is considered a nonequilibrium wetting transition may take place. This transition can be studied trough Langevin equations or discrete growth models. In the first case, the Kardar-Parisi-Zhang equation, which defines a very robust universality class for nonequilibrium moving interfaces, with a soft-wall potential is considered. While in the second, microscopic models, in the corresponding universality class, with evaporation and deposition of particles in the presence of hard-wall are studied. Equilibrium wetting is related to a particular case of the problem, it corresponds to the Edwards-Wilkinson equation with a potential in the continuum approach or to the fulfillment of detailed balance in the microscopic models. In this review we present the analytical and numerical methods used to investigate the problem and the very rich behavior that is observed with them.Comment: Review, 36 pages, 16 figure
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