Effects of an Isobutylene-Maleic Anhydride Copolymer on the Rheological Behavior and Early Hydration of Natural Hydraulic Lime.

Natural hydraulic lime (NHL) is a cementitious material widely used in the restoration of stone cultural relics and maintenance of historic buildings, the practical use of which is mainly hindered by its poor fluidity. Due to the multilayer (double-layer) adsorption that isobutylene-maleic anhydride (IBMA) has on the surface of NHL, the effects that IBMA copolymer have on the fluidity and hydration of NHL were thus investigated. Moreover, the yield stress and plastic viscosity of NHL pastes were found to be reduced significantly by the incorporation of IBMA. Combined with the effects of electrostatic repulsion and steric hindrance, the flocculated structures in NHL pastes were gradually dismantled, releasing the trapped water and leading to a significant enhancement in the fluidity of NHL. IBMA was found to postpone the early hydration of NHL. In particular, it showed that adding specific content of IBMA can significantly improve the early strength of NHL.

A New Index Developed for Fast Diagnosis of Meteorological Roles in Ground-Level Ozone Variations.

China experienced worsening ground-level ozone (O3) pollution from 2013 to 2019. In this study, meteorological parameters, including surface temperature (T 2 ), solar radiation (SW), and wind speed (WS), were classified into two aspects, (1) Photochemical Reaction Condition (PRC = T 2 × SW) and (2) Physical Dispersion Capacity (PDC = WS). In this way, a Meteorology Synthetic Index (MSI = PRC/PDC) was developed for the quantification of meteorology-induced ground-level O3 pollution. The positive linear relationship between the 90th percentile of MDA8 (maximum daily 8-h average) O3 concentration and MSI determined that the contribution of meteorological changes to ground-level O-3 varied on a latitudinal gradient, decreasing from ∼40% in southern China to 10%-20% in northern China. Favorable photochemical reaction conditions were more important for ground-level O3 pollution. This study proposes a universally applicable index for fast diagnosis of meteorological roles in ground-level O3 variability, which enables the assessment of the observed effects of precursor emissions reductions that can be used for designing future control policies. ELECTRONIC SUPPLEMENTARY MATERIAL: Supplementary material is available in the online version of this article at 10.1007/s00376-021-1257-x.

Kraft lignin grafted with isopentenol polyoxyethylene ether and the dispersion performance.

In order to develop a biomass-based superplasticizer, kraft lignin (KL) was grafted with isopentenol polyoxyethylene ether (TPEG) to prepare a novel macromonomer (KL-TPEG). It was shown that the retention ratio of the aliphatic CC bond increased from 81.07% to 90.20% with the increase of m(TPEG)/m(KL). When the grafting ratio was increased, the average number of TPEG grafted on one KL molecule was approximately 1.4, 3.1, 4.6, 6.2 and 7.6. The star-like structure was also confirmed by FT-IR, 1H NMR and GPC. KL-TPEG had favorable surface activity and dispersion stability on the cement particles. It was illustrated that the shear stress and shear viscosity of the cement slurries with KL-TPEG were significantly less than that of blank slurry. The dispersion-retention ability of KL-TPEG on the slurry was also gradually enhanced with the increase of the grafting ratio of TPEG. It was seldom reported on the biomass-based TPEG. Through modified with KL, the rheology behavior and the dispersion-retention ability of TPEG was greatly improved, and the cost of TPEG was also reduced, thus this study not only promoted the development of biomass-based macromonomer, but also helped for the high value utilization of lignin.

Fatores abióticos que afetam a distribuição do gênero Astyanax Baird & Girard, 1854 em riachos de cabeceiras de Chapada dos Guimarães, bacia do rio Cuiabá, Mato Grosso / Abiotic factor affect the distribution of the genus Astyanax baird & Girard, 1854 in chapada dos guimarães headstreams, Cuiabá river basin, Mato Grosso

Os principais fatores que influenciam a distribuição de uma espécie estão relacionados principalmente com a capacidade de dispersão, o comportamento, a presença de outras espécies e aos fatores físico­ químicos. Foram avaliados fatores ecológicos que afetam a distribuição do gênero Astyanax em riachos de cabeceira de Chapada dos Guimarães, bacia do Rio Cuiabá, Mato Grosso, Brasil. Foram amostrados 27 riachos de cabeceira de Chapada dos Guimarães, e os peixes foram coletados através do método de pesca elétrica, e os dados ambientais foram analisados pela Análise de Componentes Principais (PCA). Foram capturados 250 indivíduos pertencentes ao gênero Astyanax, sendo 95 A. asuncionensis, 62 A. abramis, 36 A. lineatus e 57 indivíduos identificados como A. scabripinnis (Jenyns, 1842) sensu Eigenmann, 1927. Em relação as características ambientais, as variações obtidas permitiram a formação de dois eixos da PCA explanaram 53,114 % da variância das sete variáveis analisadas. O Eixo 1, Componente Principal 1, explicou 31,147 % e o Eixo 2, Componente Principal 2, explicou 21,967 % da variação dos dados ambientais.A formação do eixo 1 foi influenciada positivamente pela profundidade e negativamente pela condutividade e pH. A formação do eixo 2 foi influenciada positivamente pela turbidez e negativamente pelo Oxigênio dissolvido. A ordenação das espécies ao longo dos eixos formados corroborou para a compreensão da distribuição dos espécimes.

The main factors that influence the species distribution are related mainly with the dispersion capacity, behavior, presence of other species and to the factors physicist-chemistries. Had been evaluated ecological factors that affect the distribution of the genus Astyanax in Chapada dos Guimarães headstreams, Cuiabá River basin, Mato Grosso, Brazil. Samples in 27 streams had been made in Chapada dos Guimarães, and the fish had been collected through the method of electric fish, and the ambient data had been analyzed with one technique of called ordinance of Principal Components Analysis (PCA). 250 individuals had been collect, being 95 A. asuncionensis, 62 A. abramis, 36 A. lineatus and 57 individuals had been captured identified like A. scabripinnis (Jenyns, 1842) sensu Eigenmann, 1927. In relation the ambient characteristics, the variables gotten allowed two axes of the PCA, who explain 53,114 % of the variance of the seven variables analyzed. Axle 1, Main Component 1, explained 31,147 % and Axle 2, Main Component 2, explained 21,967 % of the variation of the ambient data. The formation of axle 1 was influenced positively by the depth and negative by the conductivity and pH. The formation of axle 2 was influenced positively by the Turbidity and negative to the Dissolved Oxygen. The ordinance of the species throughout for the axes corroborated for the understanding of the distribution of specimens