19,331 research outputs found
Erratum: Noninvasive Measurements and FEM Analyses for Estimating the Rotor Bar-Lamination Contact Resistance (IEEE Trans. Ind. Appl. (2021) 57: 1 (208-217) DOI: 10.1109/tia.2020.3028347)
No full textIn [1], the correct author affiliations should read: Z. Gmyrek is with the Institute of Mechatronics and Information Systems, Lodz University of Technology, Lodz 90-924, Poland (e-mail: [email protected]). S. Vaschetto, M. Ahmadi Darmani, and A. Cavagnino are with the Politecnico di Torino, Dipartimento Energia, Turin 10129, Italy (e-mail: [email protected]; [email protected]; andrea. [email protected])
Lyman break galaxies and the star formation rate of the Universe at z ~ 6
No full textWe determine the space density of UV-luminous starburst galaxies at z≈ 6 using deep HST ACS SDSS-i′ (F775W) and SDSS-z′ (F850LP) and VLT ISAAC J and Ks band imaging of the Chandra Deep Field South. We find eight galaxies and one star with (i′−z′) > 1.5 to a depth of z′AB= 25.6 (an 8σ detection in each of the 3 available ACS epochs). This corresponds to an unobscured star formation rate of ≈15 h−270 M⊙ yr−1 at z= 5.9, equivalent to L* for the Lyman-break population at z= 3–4 (ΩΛ= 0.7, ΩM= 0.3). We are sensitive to star-forming galaxies at 5.6 ≲z≲ 7.0 with an effective comoving volume of ≈1.8 × 105h−370 Mpc3 after accounting for incompleteness at the higher redshifts due to luminosity bias. This volume should encompass the primeval subgalactic-scale fragments of the progenitors of about a thousand L* galaxies at the current epoch. We determine a volume-averaged global star formation rate of (6.7 ± 2.7) × 10−4h70 M⊙ yr−1 Mpc−3 at z∼ 6 from rest-frame UV selected starbursts at the bright end of the luminosity function: this is a lower limit because of dust obscuration and galaxies below our sensitivity limit. This measurement shows that at z∼ 6 the star formation density at the bright end is a factor of ∼6 times less than that determined by Steidel et al. for a comparable sample of UV-selected galaxies at z= 3–4, and so extends our knowledge of the star formation history of the Universe to earlier times than previous work and into the epoch where reionization may have occurred
Transition to turbulence in a qblique shock-wave/boundary-layer interaction at M=15
No full textDirect numerical simulations are carried out for different forcing techniques to trigger transition during the interaction between an oblique shock-wave and a laminar boundary-layer at M = 1.5. Three forcing methods are used: a) forcing of oblique unstable modes, whose shape and behaviour are determined by the local linear stability theory, b) broadband free-stream acoustic disturbances, and c) a cold plasma flow control device. While the oblique-mode breakdown is dominant for low-amplitude forcing, long streaky structures drive the transition process in a high-amplitude disturbance environment. LES are also performed on the experimental setup by the Institute of Theoretical and Applied Mechanics (ITAM) from Novosibirsk State University with cold plasma actuation. As well as the disturbance type, the effect of Reynolds number and forcing amplitude will be investigated
Tuning the band gap of Bismuth Vanadate via Z-scheme heterojunction
No full textAccess to thesis permanently restricted to Ball State community only.Metal oxide semiconductors such as TiO2 and ZnO have been exploited many times in
photocatalysis and photoelectrochemical applications under UV light irradiation. Alternatively,
new sets of metal oxide semiconductors such as Cu2O, Fe2O3, and BiVO4 have attracted
widespread attention because of their ability to absorb light in the visible region. However, most
of this category of photocatalyst is impacted by electron-hole recombination, slow charge
transportation, and photo-corrosion. Furthermore, the bandgap of most metal oxides is not
positioned to allow the reduction of water to hydrogen. Creating a Z-scheme heterojunction is a
practical approach to total photoelectrochemical water splitting by combining a photoanode and a
photocathode in one photocatalyst. This architecture allows spatial separation between the H2 and
the O2 generation processes and improves the electron/hole separation. In this thesis, we describe
a new approach to enhance the photocatalytic activity of BiVO4 with other bismuth-based metal
oxides, namely Bi2Ru2O7, and BixGayOz to produce the Z-scheme photocatalyst Bi2Ru2O7/BiVO4,
and BixGayOz/BiVO4, respectively. These heterogeneous Z-scheme architectures are constructed
by temperature-controlled hydrothermal synthetic methods. A relatively low-temperature
hydrothermal synthesis at 80 °C and high-temperature hydrothermal synthesis at temperatures ranging from 140 to 180 °C have been followed to tune the composition of the BiVO4-based Z-scheme photocatalysts. These materials are further characterized by transmission electron microscopy, x-ray crystallographic diffraction, x-ray photoelectron spectroscopy, and UV-vis diffuse reflectance spectroscopy. Among all the nano-heterojunction materials, the Bi2Ru2O7/BiVO4 Z-scheme heterojunction displayed an improved photocatalytic activity in the degradation of the organic dye, rhodamine B. The Bi2Ru2O7/BiVO4 heterojunction degrades rhodamine B completely in 80 min compared to 300 min and 120 min for the single oxides Bi2Ru2O7 and BiVO4, respectively. The photoelectrochemical characterization indicated that the Z-scheme heterojunction improved the charge transfer and enhanced the electron/hole separation in Bi2Ru2O7/BiVO4 photocatalyst compared to the single catalyst. This novel bismuth vanadate/bismuth heterometal composite is a promising photocatalyst for photoelectrochemical water splitting and photodegradation of persistent organic contaminants.Thesis (M.S.
The Benefits of Being Economics Professor A (and not Z)
No full textAlphabetic name ordering on multi-authored academic papers, which is the convention in the economics discipline and various other disciplines, is to the advantage of people whose last name initials are placed early in the alphabet. As it turns out, Professor A, who has been a first author more often than Professor Z, will have published more articles and experienced afaster growth rate over the course of her career as a result of reputation and visibility. Moreover, authors know that name ordering matters and indeed take ordering seriously: Several characteristics of an author group composition determine the decision to deviate from the default alphabetic name order to a significant extent.performance measurement, incentives, economists, name ordering
Logarithmic variance profiles and the corresponding f-1 spectra of temperature fluctuations in turbulent Rayleigh-Bénard convection
No full textWe report experimental results for the temperature variance 2(z) and the corresponding frequency spectra P(f) in turbulent Rayleigh-Bénard convection (RBC) in a cylindrical sample of aspect ratioT= D/L = 1:00 (D = 1:12 m is the diameter and L = 1:12 m the height). The measurements were conducted in the Rayleigh-number range 1011 < Ra < 1:35 1014 and Pr ' 0:8. For Ra = 1:35x1014, 2(z) could be described well by a logarithmic dependence on the vertical position z in a range of z 1 < z < z 2 with z 1 ' 70 and z 2 = 0:1L. Here L=(2Nu) is the thickness of a thin thermal sublayer adjacent to the horizontal plate where the heat flux (denoted by the Nusselt number Nu) is carried mostly by thermal diffusion. In the log layer, we found that the temperature spectra had a significant frequency range over which P(f) f with close to 1. As Ra decreased, increased so that the log layer became thinner. At Ra = 2:05 1011, z 2 < z 1 and therefore there was no range for a log layer. Correspondingly, the temperature spectrum near the horizontal plate did not have the f1 scaling form either
Triangular Constellations in Flows
No full textParticles advected on the surface of a fluid can exhibit fractal clustering. The local structure of a fractal set is described by its dimension , which is the exponent of a power-law relating the mass in a ball to its radius : . It is desirable to characterise the {\em shapes} of constellations of points sampling a fractal measure, as well as their masses. The simplest example is the distribution of shapes of triangles formed by triplets of points, which we investigate for fractals generated by chaotic dynamical systems. The most significant parameter describing the triangle shape is the ratio of its area to the radius of gyration squared. We show that the probability density of has a phase transition: is independent of and approximately uniform below a critical flow compressibility , which we estimate. For the distribution appears to be described by two power laws: when , and when
Self-archiving practice and the influence of publisher policies in the social sciences
No full textAuthors in different disciplines exhibit very different behaviours on the so-called ‘green’ road to open access, i.e. self-archiving. This study looks at the self-archiving behaviour of authors publishing in leading journals in six social science disciplines. It tests the hypothesis that authors are self-archiving according to the norms of their respective disciplines rather than following self-archiving policies of publishers, and that, as a result, they are self-archiving significant numbers of publisher PDF versions. It finds significant levels of
self-archiving, as well as significant self-archiving of
the publisher PDF version, in all the disciplines
investigated. Publishers’ self-archiving policies have
no influence on author self-archiving practice
Large eddy simulations of weakly heated stratocumulus top boudary layer
No full textPerforming Large Eddy Simulations (LES) of marine stratocumulus in the weakly heated boundary layer is an opportunity to evaluate the relative importance of radiative cooling and of a wind shear in cloud top region on cloud structure. It is shown that cooling due to longwave radiation influences the convective circulation in the atmospheric boundary layer and counteracts dilution caused by the wind shear
Drought and famine relationships in Sudan: policy implications
No full textSudan is one of the few countries where famine still persists. Why? What are the determinants of famine in Sudan? What is the role of drought, especially in the context of economic policy failure and war? Who is affected by famine? What needs to be done to mitigate and prevent famine? These are some of the questions addressed in Drought and Famine Relationships in Sudan: Policy Implications, Research Report 88, by Tesfaye Teklu, Joachim von Braun, and Elsayed Zaki. The research is particularly concerned with quantitatively tracing the drought-production-consumption-nutrition linkages under famine conditions at the household level in order to identify effective means of alleviating and preventing famine.... while famine is often strongly linked to drought, this research finds that even under the severe economic constraints of Sudan, suitable government planning and action can forestall that linkage.Famines Sudan., Droughts Sudan., Food relief Government policy Sudan., Drought relief Government policy Sudan.,
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