1Urban trees can help mitigate some of the environmental degradation linked to the rapid 2 urbanization of humanity. Many municipalities are implementing ambitious tree planting 3 programs to help remove air pollution, mitigate urban heat island effects, and provide other 4 ecosystem services and benefits but lack quantitative tools to explore priority planting locations 5 and potential tradeoffs between services. This work demonstrates a quantitative method for 6 exploring priority planting and ecosystem service tradeoffs in Baltimore, Maryland using 7 spatially explicit biophysical iTree models. Several planting schemes were created based on the 8 individual optimization of a number of metrics related to services and benefits of air pollution 9 and heat mitigation ecosystem services. The results demonstrate that different tree planting 10 schemes would be pursued based on the ecosystem service or benefit maximized, revealing 11 tradeoffs between services and priority planting locations. With further development including 12 consideration of additional ecosystem services, disservices, user input, and costs of tree planting 13 and maintenance, this approach could provide city planners, urban foresters, and members of the 14 public with a powerful tool to better manage urban forest systems.

A perfluorinated monomer, perfluoro-2-methylene-4-methyl-1,3-dioxolane (PFMMD), was synthesized by various methods. The monomer was polymerized in bulk and/or in the solution by a free radical mechanism using perfluorodibenzoyl peroxide and/or perfluorodi-tert-butyl peroxide as an initiators. The polymers obtained (poly(PFMMD)) were colorless and transparent. However, a polymer rod exposed to the atmosphere turned hazy. When the polymers were purified by precipitating the polymer solution into chloroform, they did not turn hazy when exposed to air for a long period of time and remained clear with a high UV-vis light transmittance. The glass transition temperature of the purified polymer was 130-134 °C. NMR measurements indicate that the purified polymers have mostly vinyl addition polymer structure. Nevertheless, we suppose that the pristine polymers contain structural units formed by ringopening polymerization. The molecular weight of poly(PFMMD) samples can be regulated using carbon tetrachloride, carbon tetrabromide, and sulfuryl chloride as chain transfer agents. Polymerization in the presence of these regulators is characterized by nondegradative chain transfer. The intrinsic viscosity of poly(PFMMD) samples was determined in hexafluorobenzene. Hexafluorobenzene is a thermodynamically good solvent for poly(PFMMD). The molecular weights of poly(PFMMD)s were characterized by the intrinsic viscosity and dynamic light scattering (DLS). The refractive index of poly(PFMMD) between 400 and 1550 nm was between 1.3360 and 1.3270. The material dispersion of poly(PFMMD) is superior to that of a commercial poly (1,1,2,4,4,5,5,6,7,7-decafluoro-3-oxa-1,6-heptadiene) (Cytop).

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Laser-induced breakdown spectroscopy (LIBS) combined with support vector machine (SVM) algorithm was used to identify 11 kinds of plastics. For each plastic, 100 spectra recorded by the spectrometer system were divided equally into training set and test set, and the former was used to train SVM model while the latter was used to validate SVM model created by the training set. Result shows that 543 of 550 test set spectra are identified correctly with the average correct identification rate 98.73%. However, there are six spectra of PU misidentified as PMMA. This is because the difference of nitrogen content in 11 plastics cannot be reflected by the intensities of N I 746.87 nm and C-N (0,0) 388.3 nm due to the influence of ambient air. Methods and reference data are provided for further study of plastics identification by laser-induced breakdown spectroscopy technique.

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