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1. The 9‐Borataphenanthrene Anion

   https://doi.org/10.1002/anie.202002125  

   Bartholome, Tyler A.; Kaur, Aishvaryadeep; Wilson, David J. D.; Dutton, Jason L.; Martin, Caleb D. (May 2020, Angewandte Chemie International Edition)

   Abstract The 9‐borataphenanthrene anion is easily accessed by deprotonation of a 9,10‐dihydro‐9‐boraphenanthrene and its diverse reactivity is investigated. Alkylation occurs at the carbon atom adjacent to boron, and room temperature hydroboration occurs across the B=C bond. The π‐manifold of the central BC₅ring coordinates to chromium in an η⁶fashion while only the B=C unit binds η²to gold, indicating versatility of the 9‐borataphenanthrene anion as a ligand. Supporting calculations rationalize the reactivity and aromaticity is corroborated by nucleus‐independent chemical shift (NICS) indices. 

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2. Synthesis of 9-borafluorene analogues featuring a three-dimensional 1,1′-bis( o -carborane) backbone

   https://doi.org/10.1039/c8cc10087j  

   Yruegas, Sam; Axtell, Jonathan C.; Kirlikovali, Kent O.; Spokoyny, Alexander M.; Martin, Caleb D. (January 2019, Chemical Communications)

   The synthesis of [1,1′-bis( o -carboranyl)]boranes was achieved through the deprotonation of 1,1′-bis( o -carborane) reagents followed by salt metathesis with ( i Pr) 2 NBCl 2 . X-ray crystallography confirms planar central BC 4 rings and Gutmann–Beckett studies reveal an increase in Lewis acidity at the boron center in comparison to their biphenyl congener, 9-borafluorene. 

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3. Study the Use of Activated Carbon and Bone Char on the Performance of Gravity Sand-Bag Water Filter

   https://doi.org/10.3390/membranes11110868  

   Fung, Eric; Johnson, Ken I.; Li, Wenqi; Borges, William; Chi, Kai; Sharma, Sunil K.; Madan, Yogita; Sharma, Priyanka R.; Hsiao, Benjamin S. (November 2021, Membranes)

   In this study, granulated activated charcoal (GAC) and bio charcoal (BC) is used as a filler in P3 biosand bag filter to study their filtration performance against a range of fluoride impurities from 1–1400 mg/L. A set of experiments are done to analyze the filtration efficiency of the sandbag filter against fluoride impurities after incorporating different amounts (e.g., 0.2, 2 kg) and a combination of GAC and BC. A combination of filler GAC and BC (1 kg each) have exhibited excellent results with 100% fluoride removal efficiency against 5 mg/L fluoride impurities for an entire experimental time of 165 min. It is because of the synergetic effect of adsorption caused by the high surface area (739 m2/g) of GAC and hydroxyapatite groups in BC. The data from remediation experiments using individual GAC and BC are fitted into the Langmuir and Freundlich Isotherm Models to check their adsorption mechanism and determine GAC and BC’s maximum adsorption capacity (Qm). The remediation data for both GAC and BC have shown the better fitting to the Langmuir Isotherm Model with a high R2 value of 0.994 and 0.970, respectively, showing the excellent conformity with monolayer adsorption. While the GAC and BC have presented negative Kf values of −1.08 and −0.72, respectively, for Freundlich Model, showing the non-conformity to multilayer adsorption. The Qm values obtained from Langmuir Model for GAC is 6.23 mg/g, and for BC, it is 9.13 mg/g. The pH study on adsorption efficiency of individual GAC and BC against 5 mg/L of fluoride impurities indicates the decrease in removal efficiency with an increase in pH from 3 to 9. For example, BC has shown removal efficiency of 99.8% at pH 3 and 99.5% at pH 9, while GAC has exhibited removal efficiency of 96.1% at pH 3 and 95.9% at pH 9. Importantly, this study presents the significance of the synergetic application of GAC and BC in the filters, where GAC and BC are different in their origin, functionalities, and surface characteristics. 

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4. The Atacama Cosmology Telescope: A Search for Planet 9

   https://doi.org/10.3847/1538-4357/ac2307  

   Naess, Sigurd; Aiola, Simone; Battaglia, Nick; Bond, Richard J.; Calabrese, Erminia; Choi, Steve K.; Cothard, Nicholas F.; Halpern, Mark; Hill, J. Colin; Koopman, Brian J.; et al (December 2021, The Astrophysical Journal)

   Abstract We use Atacama Cosmology Telescope (ACT) observations at 98 GHz (2015–2019), 150 GHz (2013–2019), and 229 GHz (2017–2019) to perform a blind shift-and-stack search for Planet 9. The search explores distances from 300 au to 2000 au and velocities up to 6.′3 per year, depending on the distance ( r ). For a 5 Earth-mass Planet 9 the detection limit varies from 325 au to 625 au, depending on the sky location. For a 10 Earth-mass planet the corresponding range is 425 au to 775 au. The predicted aphelion and most likely location of the planet corresponds to the shallower end of these ranges. The search covers the whole 18,000 square degrees of the ACT survey. No significant detections are found, which is used to place limits on the millimeter-wave flux density of Planet 9 over much of its orbit. Overall we eliminate roughly 17% and 9% of the parameter space for a 5 and 10 Earth-mass Planet 9, respectively. These bounds approach those of a recent INPOP19a ephemeris-based analysis, but do not exceed it. We also provide a list of the 10 strongest candidates from the search for possible follow-up. More generally, we exclude (at 95% confidence) the presence of an unknown solar system object within our survey area brighter than 4–12 mJy (depending on position) at 150 GHz with current distance 300 au < r < 600 au and heliocentric angular velocity 1 .′ 5 yr − 1 < v · 500 au r < 2 .″ 3 yr − 1 , corresponding to low-to-moderate eccentricities. These limits worsen gradually beyond 600 au, reaching 5–15 mJy by 1500 au. 

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5. Mobile Monitoring of Air Pollution Reveals Spatial and Temporal Variation in an Urban Landscape

   https://doi.org/10.3389/fbuil.2021.648620  

   Cummings, Lucas E.; Stewart, Justin D.; Reist, Radley; Shakya, Kabindra M.; Kremer, Peleg (May 2021, Frontiers in Built Environment)

   null (Ed.)

   Urban air pollution poses a major threat to human health. Understanding where and when urban air pollutant concentrations peak is essential for effective air quality management and sustainable urban development. To this end, we implement a mobile monitoring methodology to determine the spatiotemporal distribution of particulate matter (PM) and black carbon (BC) throughout Philadelphia, Pennsylvania and use hot spot analysis and heatmaps to determine times and locations where pollutant concentrations are highest. Over the course of 12 days between June 27 and July 29, 2019, we measured air pollution concentrations continuously across two 150 mile (241.4 km) long routes. Average daily mean concentrations were 11.55 ± 5.34 μg/m 3 (PM 1 ), 13.48 ± 5.59 μg/m 3 (PM 2.5 ), 16.13 ± 5.80 μg/m 3 (PM 10 ), and 1.56 ± 0.39 μg/m 3 (BC). We find that fine PM size fractions (PM 2.5 ) constitute approximately 84% of PM 10 and that BC comprises 11.6% of observed PM 2.5 . Air pollution hotspots across three size fractions of PM (PM 1 , PM 2.5 , and PM 10 ) and BC had similar distributions throughout Philadelphia, but were most prevalent in the North Delaware, River Wards, and North planning districts. A plurality of detected hotspots found throughout the data collection period (30.19%) occurred between the hours of 8:00 AM–9:00 AM. 

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