Characterizing Urban Household Waste Generation and Metabolism Considering Community Stratification in a Rapid Urbanizing Area of China

The relationship between social stratification and municipal solid waste generation remains uncertain under current rapid urbanization. Based on a multi-object spatial sampling technique, we selected 191 households in a rapidly urbanizing area of Xiamen, China. The selected communities were classified into three types: work-unit, transitional, and commercial communities in the context of housing policy reform in China. Field survey data were used to characterize household waste generation patterns considering community stratification. Our results revealed a disparity in waste generation profiles among different households. The three community types differed with respect to family income, living area, religious affiliation, and homeowner occupation. Income, family structure, and lifestyle caused significant differences in waste generation among work-unit, transitional, and commercial communities, respectively. Urban waste generation patterns are expected to evolve due to accelerating urbanization and associated community transition. A multi-scale integrated analysis of societal and ecosystem metabolism approach was applied to waste metabolism linking it to particular socioeconomic conditions that influence material flows and their evolution. Waste metabolism, both pace and density, was highest for family structure driven patterns, followed by lifestyle and income driven. The results will guide community-specific management policies in rapidly urbanizing areas

Evidence of Noncollinear Spin Texture in Magnetic Moir\'e Superlattices

Moir\'e magnetism, parallel with moir\'e electronics that has led to novel correlated and topological electronic states, emerges as a new venue to design and control exotic magnetic phases in twisted magnetic two-dimensional(2D) crystals. Here, we report direct evidence of noncollinear spin texture in 2D twisted double bilayer (tDB) magnet chromium triiodide (CrI$_3$). Using magneto-optical spectroscopy in tDB CrI$_3$, we revealed the presence of a net magnetization, unexpected from the composing antiferromagnetic bilayers with compensated magnetizations, and the emergence of noncollinear spins, originated from the moir\'e exchange coupling-induced spin frustrations. Exploring the twist angle dependence, we demonstrated that both features are present in tDB CrI$_3$ with twist angles from 0.5$^o$ to 5$^o$, but are most prominent in the 1.1$^o$ tDB CrI$_3$. Focusing on the temperature dependence of the 1.1$^o$ tDB CrI$_3$, we resolved the dramatic suppression in the net magnetization onset temperature and the significant softening of noncollinear spins, as a result of the moir\'e induced frustration. Our results demonstrate the power of moir\'e superlattices in introducing novel magnetic phenomena that are absent in natural 2D magnets

Layer-by-Layer Assembly and Photocatalytic Activity of Titania Nanosheets on Coal Fly Ash Microspheres

In order to address the problem with titania distribution and recovery, series of Ti0.91O2/CFA photocatalysts (Ti0.91O2/CFA-n, n=2,4,6, and 8) were fabricated by assembling Ti0.91O2 nanosheets on coal fly ash (CFA) microspheres via the layer-by-layer assembly (LBLA) process and characterized by scanning electron microscopy (SEM), X-ray diffraction analysis (XRD), N2-sorption, and ultraviolet-visible absorption (UV-vis) techniques. The SEM images and UV-vis spectra illustrated that Ti0.91O2 nanosheets were immobilized successfully on the CFA by the LBLA approach and changed the characteristics of CFA noticeably. The photocatalytic activity of Ti0.91O2/CFA was evaluated by the photodegradation of methylene blue (MB) under UV irradiation. The results demonstrated that Ti0.91O2/CFA-6 showed the best photocatalytic activity among the series of Ti0.91O2/CFA irradiated for 60 min, with a decoloration rate above 43%. After photocatalysis, the Ti0.91O2/CFA could be easily separated and recycled from aqueous solution and Ti0.91O2 nanosheets were still anchored on the CFA