Characteristics, secondary transformation and odor activity evaluation of VOCs emitted from municipal solid waste incineration power plant.

Volatile organic compounds (VOCs) emitted from municipal solid waste incineration power plant (MSWIPP) plays a significant role in the formation of O3 and PM2.5 and odor pollution. Field test was performed on four MSWIPPs in an area of the North China Plain. Nonmethane hydrocarbons (NMHCs) and 102 VOCs were identified and quantified. Ozone formation potential (OFP), secondary organic aerosol formation potential (SOAFP), and odor activity of the detected VOCs were evaluated. Results showed that the average concentration of NMHCs and VOCs were 1648.6 ± 1290.4 µg/m3 and 635.3 ± 588.8 µg/m3, respectively. Aromatics (62.1%), O-VOCs (16.0%), and halo hydrocarbons (10.0%) were the main VOCs groups in the MSWIPP exhaust gas. VOCs emission factor of MSWIPP was 2.43 × 103 ± 2.27 × 103 ng/g-waste. The OFP and SOAFP of MSWIPP were 960.18 ± 2158.17 µg/m3 and 1.57 ± 3.38 µg/m3, respectively. Acrolein as the dominant VOC species was the major odor contributor with a percentage of odor contribution of 65.9%. Benzene and 1,2,4-trimethylbenzene as the dominant VOC species were the main contributors of O3 formation potentials, in which 1,2,4-trimethylbenzene was also the main contributors of SOA formation potential.

A Miniaturized and Highly Stable Frequency-Selective Rasorber Incorporating an Embedded Transmission Window.

In this article, a miniaturized and highly stable frequency-selective rasorber (FSR) incorporating an embedded transmission window is designed. This FSR consists of a lossy layer loaded with resistors, an air layer, and a bandpass layer. The lossy layer is provided with a rectangular, square ring structure loaded with four 180 Ω resistors and four quadrilateral metal plates. The four metal plates are connected to the four corners of the inner ring around the square ring and are radially distributed along the diagonal. The bandpass layer is a square metal patch that a cross-ring slot structure is loaded inside of, and the cross points lie in the direction along the diagonal of the unit. The inner boundary of the cross-ring is composed of two mutually perpendicular and long rectangular elements. This FSR shows an embedded transmission window from 3.63 GHz to 3.80 GHz and has a transmission rate of 93% at 3.72 GHz. Moreover, both sides of the transmission band, namely, 1.86-3.35 GHz and 3.99-8.28 GHz, have an absorption rate of more than 80% and bilateral relative bandwidth of more than 50%. In addition, this structure exhibits excellent miniaturization performance, polarization insensitivity, and angular stability. Finally, a prototype of the designed FSR is processed and measured. The measured results are basically consistent with the simulation results.

Relativistic DFT and experimental studies of mono- and bis-actinyl complexes of an expanded Schiff-base polypyrrole macrocycle.

The computationally- and experimentally-determined molecular structures of a bis-uranyl(vi) complex of an expanded Schiff-base polypyrrolic macrocycle [(UO2)2(L)] are in close agreement only if the pyridine in the fifth equatorial donor site on the uranium is included in the calculations. The relativistic density functional theory (DFT) calculations presented here are augmented from those on previously reported simpler frameworks, and demonstrate that other augmentations, such as the incorporation of condensed-phase media and the changes in the peripheral groups of the ligand, have only a slight effect. Synthetic routes to pure samples of the bis- and mono-uranyl(vi) complexes have been developed using pyridine and arene solvents, respectively, allowing the experimental determination of the molecular structures by X-ray single crystal diffraction; these agree well with the calculated structures. A comprehensive set of calculations has been performed on a series of actinyl AnO2n+ complexes of this macrocyclic ligand. These include both bis- and mono-actinyl adducts for the metals U, Np and Pu, and formal oxidation states VI and V. The reduction potentials of the complexes for U, Np, and Pu, incorporating both solvation and spin-orbit coupling considerations, show the order Np > Pu > U. The agreement between experimental and computed data for U is excellent, suggesting that at this level of computation predictions made about the significantly more radiotoxic Np and Pu molecules should be accurate. A particularly unusual structure of the mononuclear plutonyl(v) complex was predicted by quantum chemical calculations, in which a twist in the macrocycle allows one of the two endo-oxo groups to form a hydrogen bond to one pyrrole group of the opposite side of the macrocycle, in accordance with this member of the set containing the most Lewis basic oxo groups.