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RADIO JET FEEDBACK AND STAR FORMATION IN HEAVILY OBSCURED, HYPERLUMINOUS QUASARS AT REDSHIFTS ∼ 0.5-3. I. ALMA OBSERVATIONS

Lonsdale, Carol J.,Lacy, M.,Kimball, A. E.,Blain, A.,Whittle, M.,Wilkes, B.,Stern, D.,Condon, J.,Kim, M.,Assef, R. J.,Tsai, C.-W.,Efstathiou, A.,Jones, S.,Eisenhardt, P.,Bridge, C.,Wu, J.,Lonsdale, Co IOP Publishing 2015 The Astrophysical journal Vol.813 No.1
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<P>We present Atacama Large Millimeter/submillimeter Array (ALMA) 870 mu m (345 GHz) data for 49 high-redshift (0.47 < z < 2.85), luminous (11.7 < log(L-bol/L-circle dot) < 14.2) radio-powerful active galactic nuclei (AGNs), obtained to constrain cool dust emission from starbursts concurrent with highly obscured radiative-mode black hole (BH) accretion in massive galaxies that possess a small radio jet. The sample was selected from the Wide-field Infrared Survey Explorer with extremely steep (red) mid-infrared colors and with compact radio emission from NVSS/FIRST. Twenty-six sources are detected at 870 mu m, and we find that the sample has large mid- to far-infrared luminosity ratios, consistent with a dominant and highly obscured quasar. The rest-frame 3 GHz radio powers are 24.7 < log P-3.0 GHz/W Hz(-1)) < 27.3, and all sources are radio-intermediate or radio-loud. BH mass estimates are 7.7 < log(M-BH/M-circle dot) < 10.2. The rest-frame 1-5 mu m spectral energy distributions are very similar to the 'Hot DOGs' (hot dust-obscured galaxies), and steeper (redder) than almost any other known extragalactic sources. ISM masses estimated for the ALMA-detected sources are 9.9 < log (M-ISM/M-circle dot) < 11.75 assuming a dust temperature of 30 K. The cool dust emission is consistent with star formation rates reaching several thousand M-circle dot yr(-1), depending on the assumed dust temperature, but we cannot rule out the alternative that the AGN powers all the emission in some cases. Our best constrained source has radiative transfer solutions with approximately equal contributions from an obscured AGN and a young (10-15 Myr) compact starburst.</P>
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Impact of Precipitating Ice on the Simulation of a Heavy Rainfall Event with Advanced Research WRF Using Two Bulk Microphysical Schemes

G. A. Efstathiou,N. M. Zoumakis,D. Melas,P. Kassomenos 한국기상학회 2012 Asia-Pacific Journal of Atmospheric Sciences Vol.48 No.4
In this study, the Weather Research and Forecasting (WRF) model version 3.2 is used to examine the impact of precipitating ice and especially snow-graupel partitioning in the simulation of a heavy rainfall event over Chalkidiki peninsula in Northern Greece. This major precipitation event, associated with a case of cyclogenesis over the Aegean Sea, occurred on the 8th of October 2006 causing severe flooding and damage. Two widely used microphysical parameterizations, the Purdue Lin (PLIN) and WRF Single-Moment 6-class scheme (WSM6) are compared with available raingauge measurements over the complex topography of Chalkidiki. To further investigate the importance of snow and graupel relative mass content and the treatment of precipitating ice sedimentation velocity, two older versions of the WSM6 scheme were compiled and run with the current model. The verification results indicate that all simulations were found to match raingauge data more closely over the eastern mountainous Chalkidiki peninsula where maximum accumulations were observed. In other stations all schemes overestimate 24h accumulated rainfall except a station situated at the western part of the peninsula, where none of the simulations was able to reproduce observed rainfall. Graupel dominance in PLIN generates rapid precipitation fallout at the point of maximum predicted 24h accumulation. Similar behavior is shown in WSM6from WRF version 2, but with significant less rainfall. Increasing snow amounts aloft, due to the unified treatment of precipitating ice in WSM6 from WRF version 3, modifies rain dynamics which decrease rainfall rates, but increases 24h accumulations. A sensitivity experiment where PLIN is used with snow accretion by graupel turned off, indicated that this process seems to be the most important factor controlling the differences in surface precipitation between PLIN and WSM6 from WRF version 3, determining the spatial and temporal distribution of this heavy precipitation event. The results also revealed that snow overestimation can lead to high rainfall accumulations,even though rain is more evenly distributed over the 24h period, deteriorating precipitation forecast.
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Computer-aided approach of parameters influencing concrete service life and field validation

V. G. Papadakis,M. P. Efstathiou,C. A. Apostolopoulos 한국계산역학회 2007 Computers and Concrete, An International Journal Vol.4 No.1
Over the past decades, an enormous amount of effort has been expended in laboratory and field studies on concrete durability estimation. The results of this research are still either widely scattered in the journal literature or mentioned briefly in the standard textbooks. Moreover, the theoretical approaches of deterioration mechanisms with a predictive character are limited to some complicated mathematical models not widespread in practice. A significant step forward could be the development of appropriate software for computer-based estimation of concrete service life, including reliable mathematical models and adequate experimental data. In the present work, the basis for the development of a computer estimation of the concrete service life is presented. After the definition of concrete mix design and structure characteristics, as well as the consideration regarding the environmental conditions where the structure will be found, the concrete service life can be reliably predicted using fundamental mathematical models that simulate the deterioration mechanisms. The prediction is focused on the basic deterioration phenomena of reinforced concrete, such as carbonation and chloride penetration, that initiate the reinforcing bars corrosion. Aspects on concrete strength and the production cost are also considered. Field observations and data collection from existing structures are compared with predictions of service life using the above model. A first attempt to develop a database of service lives of different types of reinforced concrete structure exposed to varying environments is finally included.