University of California, Santa Barbara

About: University of California, Santa Barbara is a education organization based out in Santa Barbara, California, United States. It is known for research contribution in the topics: Population & Galaxy. The organization has 30281 authors who have published 80852 publications receiving 4626827 citations. The organization is also known as: UC Santa Barbara & UCSB.

Advanced Transport Phenomena: Fluid Mechanics and Convective Transport Processes

Abstract: Advanced Transport Phenomena is ideal as a graduate textbook. It contains a detailed discussion of modern analytic methods for the solution of fluid mechanics and heat and mass transfer problems, focusing on approximations based on scaling and asymptotic methods, beginning with the derivation of basic equations and boundary conditions and concluding with linear stability theory. Also covered are unidirectional flows, lubrication and thin-film theory, creeping flows, boundary layer theory, and convective heat and mass transport at high and low Reynolds numbers. The emphasis is on basic physics, scaling and nondimensionalization, and approximations that can be used to obtain solutions that are due either to geometric simplifications, or large or small values of dimensionless parameters. The author emphasizes setting up problems and extracting as much information as possible short of obtaining detailed solutions of differential equations. The book also focuses on the solutions of representative problems. This reflects the book's goal of teaching readers to think about the solution of transport problems.

THE STRUCTURE AND KINEMATICS OF THE CIRCUMGALACTIC MEDIUM FROM FAR-ULTRAVIOLET SPECTRA OF z ≃ 2-3 GALAXIES*

Abstract: We present new results on the kinematics and spatial distribution of metal-enriched gas within ~125 kpc of star-forming ("Lyman break") galaxies at redshifts 2 ≲ z ≲ 3 In particular, we focus on constraints provided by the rest-frame far-ultraviolet (far-UV) spectra of faint galaxies, and demonstrate how galaxy spectra can be used to obtain key spatial and spectral information more efficiently than possible with QSO sightlines Using a sample of 89 galaxies with z = 23 ± 03 and with both rest-frame far-UV and Hα spectra, we re-calibrate the measurement of accurate galaxy systemic redshifts using only survey-quality rest-UV spectra We use the velocity-calibrated sample to investigate the kinematics of the galaxy-scale outflows via the strong interstellar (IS) absorption lines and Lyα emission (when present), as well as their dependence on other physical properties of the galaxies We construct a sample of 512 close (1"-15") angular pairs of z ~ 2-3 galaxies with redshift differences indicating a lack of physical association Sightlines to the background galaxies provide new information on the spatial distribution of circumgalactic gas surrounding the foreground galaxies The close pairs sample galactocentric impact parameters 3-125 kpc (physical) at = 22, providing for the first time a robust map of cool gas as a function of galactocentric distance for a well-characterized population of galaxies We propose a simple model of circumgalactic gas that simultaneously matches the kinematics, depth, and profile shape of IS absorption and Lyα emission lines, as well as the observed variation of absorption line strength (H I and several metallic species) versus galactocentric impact parameter Within the model, cool gas is distributed symmetrically around every galaxy, accelerating radially outward with v_(out)(r) increasing with r (ie, the highest velocities are located at the largest galactocentric distances r) The inferred radial dependence of the covering fraction of cool gas (which modulates the absorption line strength) is f_c(r) ∝ r^(–γ) with 02 ≲ γ ≲ 06 depending on transition We discuss the results of the observations in the context of "cold accretion," in which cool gas is accreting via filamentary streams directly onto the central regions of galaxies At present, we find little observational evidence for cool infalling material, while evidence supporting the large-scale effects of superwind outflows is strong This "pilot" study using faint galaxy spectra demonstrates the potential of using galaxies to trace baryons within galaxies, in the circumgalactic medium, and ultimately throughout the intergalactic medium

Morphological Control of Highly Ordered Mesoporous Silica SBA-15

Abstract: Highly ordered hexagonal mesoporous silica SBA-15 with fiber, rope, donut, sphere, gyroid, and discoid-like morphology have been synthesized.

Ordered macroporous materials by emulsion templating

Abstract: Ordered macroporous materials with pore diameters comparable to optical wavelengths are predicted to have unique and highly useful optical properties such as photonic bandgaps1,2,3 and optical stop-bands4. Tight control over the pore size distribution might also lead to improved macroporous materials (those with pores greater than approximately 50 nm) for application as catalytic surfaces and supports5, adsorbents, chromatographic materials, filters6, light-weight structural materials7, and thermal, acoustic8 and electrical insulators9. Although methods exist for producing ordered porous materials with pore diameters less than 10 nm (refs 10, 11), there is no general method for producing such materials with uniform pore sizes at larger length scales. Here we report a new method for producing highly monodisperse macroporous materials with pore sizes ranging from 50 nm to several micrometres. Starting with an emulsion of equally sized droplets (produced through a repeated fractionation procedure12), we form macroporous materials of titania, silica and zirconia by using the emulsion droplets as templates around which material is deposited through a sol–gel process13. Subsequent drying and heat treatment yields solid materials with spherical pores left behind by the emulsion droplets. These pores are highly ordered, reflecting the self-assembly of the original monodisperse emulsion droplets into a nearly crystalline array14. We show that the pore size can be accurately controlled, and that the technique should be applicable to a wide variety of metal oxides and even organic polymer gels.