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Green roof systems (GRs) provide a promising stormwater management strategy in highly urbanized areas when limited open space is available. Hydrological modeling can predict the ability of GRs to reduce runoff. This paper reviews three popular types of GR models with varying complexities, including water balance models, the U.S. EPA's Stormwater Management Model (SWMM), and Hydrus-1D. Developments and practical applications of these models are discussed, by detailing model parameter estimates, performance evaluations and application scopes. These three models are capable of replicating GR outflow. Water balance models have the smallest number of parameters (≤7) to estimate. Hydrus-1D requires substantial parameterization effort for soil hydraulic properties but can simulate unsaturated soil water flow processes. Although SWMM has a large number of parameters (>10), it can simulate water transport through the entire GR profile. In addition, SWMM GR models can be easily incorporated into SWMM's stormwater model framework, so it is widely used to simulate the watershed-scale effects of GR implementations. Four research gaps limiting GR model applications are identified and discussed: drainage mat flow simulations, soil characterization, evapotranspiration estimates, and scale effects of GRs. The literature documents promising results in GR simulations for rainfall events, however, a critical need remains for long-term monitoring and modeling of full-scale GR systems to allow interpretation of both internal (substrate) and external (meteorological characteristics) system effects on stormwater management. 

Abstract Titanium dioxide (TiO₂) has been used in numerous paintings since its creation in the early 1920s. However, due to this relatively recent adoption by the art world, we have limited knowledge about the nature and risk of degradation in museum environments. This study expands on the existing understanding of TiO₂facilitated degradation of linseed oil, by examining the effect of visible light and crystallographic phase (either anatase or rutile) on the reactivity of TiO₂. The present approach is based on a combination of experimental chemical characterization with computational calculation through Density Functional Theory (DFT) modeling of the TiO₂-oil system. Attenuated Total Reflection Fourier Transform Infrared Spectroscopy (ATR-FT-IR) enabled the identification of characteristic degradation products during UV and visible light aging of both rutile and anatase based paints in comparison to BaSO₄and linseed oil controls. In addition, cratering and cracking of the paint surface in TiO₂based paints, aged under visible and UV–vis illumination, were observed through Scanning Electron Microscopy (SEM). Finally, Density Functional Theory (DFT) modeling of interactions between anatase TiO₂and oleic acid, a fatty acid component of linseed oil, to form a charge transfer complex explains one possible mechanism for the visible light activity observed in artificial aging. Visible light excitation of this complex sensitizes TiO₂by injecting an electron into the conduction band of TiO₂to generate reactive oxygen species and subsequent degradation of the oil binder by various mechanisms (e.g., formation of an oleic acid cation radical and other oxidation products). Graphical Abstract 

Using the EXOplanet Transit Interpretation Code (EXOTIC), we reduced 52 sets of images of WASP-104 b, a Hot Jupiter-class exoplanet orbiting WASP-104, in order to obtain an updated mid-transit time (ephemeris) and orbital period for the planet. We performed this reduction on images taken with a 6-inch telescope of the Center for Astrophysics | Harvard & Smithsonian MicroObservatory. Of the reduced light curves, 13 were of sufficient accuracy to be used in updating the ephemerides for WASP-104b, meeting or exceeding the three-sigma standard for determining a significant detection. Our final mid-transit value was 2457805.170208 ± 0.000036 BJD_TBD and the final period value was 1.75540644 ± 0.00000016 days. The true significance of our results is in their derivation from image sets gathered over time by a small, ground-based telescope as part of the Exoplanet Watch citizen science initiative, and their competitive results to an ephemeris generated from data gathered by the TESS telescope. We use these results to further show how such techniques can be employed by amateur astronomers and citizen scientists to maximize the efficacy of larger telescopes by reducing the use of expensive observation time. The work done in the paper was accomplished as part of the first fully online Course-Based Undergraduate Research Experience (CURE) for astronomy majors in the only online Bachelor of Science program in Astronomical and Planetary Sciences.