Computer program for analysis of coupled-cavity traveling wave tubes

A flexible, accurate, large signal computer program was developed for the design of coupled cavity traveling wave tubes. The program is written in FORTRAN IV for an IBM 360/67 time sharing system. The beam is described by a disk model and the slow wave structure by a sequence of cavities, or cells. The computational approach is arranged so that each cavity may have geometrical or electrical parameters different from those of its neighbors. This allows the program user to simulate a tube of almost arbitrary complexity. Input and output couplers, severs, complicated velocity tapers, and other features peculiar to one or a few cavities may be modeled by a correct choice of input data. The beam-wave interaction is handled by an approach in which the radio frequency fields are expanded in solutions to the transverse magnetic wave equation. All significant space harmonics are retained. The program was used to perform a design study of the traveling-wave tube developed for the Communications Technology Satellite. Good agreement was obtained between the predictions of the program and the measured performance of the flight tube

The extraordinary mid-infrared spectral properties of FeLoBAL Quasars

We present mid-infrared spectra of six FeLoBAL QSOs at 1<z<1.8, taken with the Spitzer space telescope. The spectra span a range of shapes, from hot dust dominated AGN with silicate emission at 9.7 microns, to moderately obscured starbursts with strong Polycyclic Aromatic Hydrocarbon (PAH) emission. The spectrum of one object, SDSS 1214-0001, shows the most prominent PAHs yet seen in any QSO at any redshift, implying that the starburst dominates the mid-IR emission with an associated star formation rate of order 2700 solar masses per year. With the caveats that our sample is small and not robustly selected, we combine our mid-IR spectral diagnostics with previous observations to propose that FeLoBAL QSOs are at least largely comprised of systems in which (a) a merger driven starburst is ending, (b) a luminous AGN is in the last stages of burning through its surrounding dust, and (c) which we may be viewing over a restricted line of sight range.Comment: ApJ, accepte

From Jacobs to the Just City: A foundation for challenging the green planning orthodoxy

Unidad de excelencia María de Maeztu MdM-2015-0552Now that Jane Jacobs' ideas are seen as urban planning orthodoxy, it is unclear how her institutional goal of progressive change for the field will carry forward. In the 1960s, Jacobs created the conditions for institutional change by offering a thorough critique of the "Radiant Garden City Beautiful" orthodoxy of urban planning and presenting a solution for the problems that she saw with this approach. She argued that the top-down, design-oriented planning of her time hurt the lives of individual residents and diminished society as a whole. Her solution was a new way of seeing the city: as a functional and efficient social system. Since the 1990s, a global planning orthodoxy - of which Jacobs' ideas are part - developed around the "Smart Sustainable Resilient City." This orthodoxy has been subject to critique, but Susan Fainstein's Just City theory offers tools for comprehensively challenging the approach and a solution for addressing the problems. In order to demonstrate the need for institutional change within the Smart Sustainable Resilient City orthodoxy, I use the Just City theoretical perspective to interpret the results of an analysis of green gentrification in New York City between 1990 and 2014. I argue that the over-valuation of Jacobsian diversity within the current urban planning orthodoxy generates unjust outcomes. The just green city, then, requires de-emphasizing Jacobs' intellectual project in favor of her far more important institutional project

From Systems Thinking to Systemic Action : Social Vulnerability and the Institutional Challenge of Urban Resilience

Unidad de excelencia María de Maeztu MdM-2015-055

Computer-assisted Structure Elucidation of Humulene Epoxide and Caryophyllene Epoxide Mixture of Turraea Brownii

An experiment was carried out to isolate active material from Turraea brownli for biological insectislde. The isolated component obtained by using TLC was elucidated with iH NMR, and 13C NMR techniques. It was found that the compound was unknown triterpenoid (C30H48O). Further elucidation using 2D NMR with COSY, HMBC, and HMQC combined with computer techniques showed that the component was an approximately equimolar mixture of two sesqulterpenes (C15H24O) which were identified as humulene epoxide and B-caryophyllene epoxide

Reconstructing Galaxy Spectral Energy Distributions from Broadband Photometry

We present a novel approach to photometric redshifts, one that merges the advantages of both the template fitting and empirical fitting algorithms, without any of their disadvantages. This technique derives a set of templates, describing the spectral energy distributions of galaxies, from a catalog with both multicolor photometry and spectroscopic redshifts. The algorithm is essentially using the shapes of the templates as the fitting parameters. From simulated multicolor data we show that for a small training set of galaxies we can reconstruct robustly the underlying spectral energy distributions even in the presence of substantial errors in the photometric observations. We apply these techniques to the multicolor and spectroscopic observations of the Hubble Deep Field building a set of template spectra that reproduced the observed galaxy colors to better than 10%. Finally we demonstrate that these improved spectral energy distributions lead to a photometric-redshift relation for the Hubble Deep Field that is more accurate than standard template-based approaches.Comment: 23 pages, 8 figures, LaTeX AASTeX, accepted for publication in A

Three Histories of Greening and Whiteness in American Cities

Unidad de excelencia María de Maeztu CEX2019-000940-MHow has urban greening related to the degree of whiteness in neighborhoods? The answer to this question provides an essential "historical diagnostic" that can be used to develop an approach to urban ecology which integrates racial and ethnic change into the planning for proposed interventions. In this paper we employ state sequence analysis to analyze the historical trend of greening (including the implementation of new parks, greenways, community gardens, green recreation areas, and nature preserves) between 1975 and 2014 in a sample of nine cities in the United States relative to concentrations of white and non-white residents. We divide the nine cities into three common growth trajectories and separately examine the trends for each growth trajectory. We further illustrate these trends by mobilizing qualitative data from field work in selected neighborhoods to help explain the processes that generate certain key findings in the quantitative data. We find that the relationship between greening and race/ethnicity differs according to city-level growth trajectory. Cities with continuous high and rapid levels of growth in the postwar period have the strongest link between increased greening and whiter populations. Meanwhile, in cities that contracted or had a punctuated growth pattern, non-white areas had a uniformly low level of greening that occurred mostly in recent years. In all, we show how urban growth, greening, and whiteness are inextricably associated qualities of American cities. We argue that understanding this association is essential for development of a race-conscious model for enhancing urban ecosystems

Microwave monolithic integrated circuit development for future spaceborne phased array antennas

The development of fully monolithic gallium arsenide (GaAs) receive and transmit modules suitable for phased array antenna applications in the 30/20 gigahertz bands is presented. Specifications and various design approaches to achieve the design goals are described. Initial design and performance of submodules and associated active and passive components are presented. A tradeoff study summary is presented highlighting the advantages of distributed amplifier approach compared to the conventional single power source designs