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Alcohol has a potential health risk to human health, so it is important to realise the rapid detection of alcohols. Based on this, the nano Na2Mg(CO3)2 was prepared by a simple hydrothermal method to establish a cataluminescence (CTL) gas sensor for alcohols. The Na2Mg(CO3)2with highly purified quality was characterised by scanning electron microscope, energy dispersive spectroscopy and the powder X-ray diffraction. The results show that the nano Na2Mg(CO3)2 is a peony-like substance with a large surface area, which will be beneficial to produce ultra-weak chemiluminescence reaction between the detector and the material. The peony-like Na2Mg(CO3)2 has good CTL response to alcohols (methanol, ethanol, n-propanol and n-butanol), showing high selectivity. The response time of Na2Mg(CO3)2 for four alcohols is between 1 and 2 s, which indicate that the material has the advantage of rapid response. The limit of detection of four alcohols defined as 3 N/S is about 7.91, 4.75, 6.69 and 8.10 mg/l, respectively. The optimum reaction conditions of the gas sensor based on nano Na2Mg(CO3)2 are mild and this nanomaterial can be used for alcohol detection.

Sludge-recycling enhanced flocculation (SEF) is an effective method for enhancing flocculation. In the conventional SEF process, the settled sludge is recirculated into the flocculation process without any further treatment. However, studies have shown that the efficacy of the SEF process could be improved by pre-treating the sludge. In this work, the acid activation of sludge was performed using a range of pH values (1.0-6.0) and charge states, with and without long-chain bridging. The resulting residual turbidities, floc fractal dimensions and floc morphologies were then analyzed, to examine the effects of sludge activation on the efficacy of SEF. In the absence of long-chain bridging, it was found that flocculation was enhanced by pH values between 2.0 and 5.0 in the electrostatic patch (EP) and near charge neutrality (NCN) states. In the EP state, the optimal pH for SEF enhancement was pH = 2.0; in the NCN state, the optimal pH was pH = 3.0. In terms of floc morphology, pH values between 2.0 and 5.0 resulted in larger average floc sizes and lower floc fractal dimensions than conventional SEF. However, in the presence of long-chain bridging, sludge activation did not enhance flocculation; residual turbidity increased with decreases in pH, in both the EP and NCN states. Based on these results, it may be surmised that the acid activation of sludge is suitable for cases without long-chain bridging.

Microplastic pollution has been considered as a global environmental issue that potentially threatens human health. However, research about microplastic pollution in urban rivers is still insufficient. This study analyzed the abundance and distribution of microplastics in surface water of the Nanfei River in Hefei, China. Microplastic concentrations ranged from 0.8 to 27 items/L along the studied river. The small size (50–333 μm) (47.58–84.89%) and white (55.65–88.89%) were predominant among all samples, except that collected from the source reach. Pellet was a typical and abundant microplastic type and accounted for 60.30%. PE and PP were the major polymers, occupying 55.24% and 22.86%, respectively. The results showed that traditional environmental management practices including salvaging surface garbage regularly and setting wooden suspended crossbars at tributary confluences could significantly mitigate the pollution degree of microplastics. The polymer risk index was calculated to describe the potential risk of microplastics, and the pollution level was still at high risk under various management practices. This study provides a valuable finding for future research on microplastics in urban city rivers, which may improve the knowledge that how to control and prevent microplastic pollution.

The content of volatile organic compounds (VOCs) in the atmosphere will endanger the health and safety of human beings which makes it very important to develop a simple and rapid method for the determination of gas pollutants. Based on this, a new type of gas sensor was proposed for the detection of trichloroethylene in air. PEG200/ZnO nanocomposite were prepared by hydrothermal method. The materials were characterized by scanning electron microscope, X-ray energy spectrum and fourier infrared spectrum. The high selectivity of the materials was verified by using the cataluminescence (CTL) intensity of 9 kinds of VOCs on the surface of the materials as a reference. The results show that trichloroethylene can produce CTL response on the surface of PEG200/ZnO nanocomposite. Temperature, air flow rate and detector concentration all have certain effects on the CTL intensity. By comparing the CTL intensity under different reaction conditions, it is found that the suitable temperature and air flow rate are 120 °C, 180 mL/min and there is a good linear relationship between the relative CTL intensity and the concentration of the detected substance (y = 28.588 x - 285.56, R=0.9593). The gas sensor has the advantage of rapid response, and trichloroethylene can produce the maximum CTL on the surface of the material within 3 ~ 5 s.

Wildfire management agencies in Canada are at a tipping point. Presuppression and suppression costs are increasing but program budgets are not. Climate change impacts and increasing interface values-at-risk are challenging suppression effectiveness and resulting in more wildfire disasters. We conducted semi-structured interviews with these agencies to understand the strategies, policies, and preparedness procedures they currently use to manage wildfires. We summarize the results of this national agency assessment, and based on what we heard and our review of agency internal documents, discuss agency challenges and opportunities to be better prepared for a future with more wildfire. A double wildfire paradox exists requiring communities and critical values in wildfire-dependent ecosystems to be FireSmart, and wildfire management agencies to allow more wildfire on the landscape by implementing a risk-based appropriate response approach. We conclude with a proposed future path for wildfire management in Canada. To co-exist with wildfire, agencies in Canada must also strengthen and adjust their wildfire management capacity and capability. This necessitates stronger horizontal collaboration, enhanced resource sharing, investments to develop innovative decision support tools, and an increased focus on prevention and mitigation. Keywords: Emergency management, Disasters, Wildfire management, Presuppression, Suppression, Preparedness

Ultrathin iron-cobalt oxide nanosheets (CoFe-ONSs) synthesized via a facile one-step routine by using NaBH4 as the reductant were used for H2O2 activation and tetracycline (TC) elimination. The CoFe-ONSs realized 83.5% removal of TC under the neutral conditions after 50 min with 0.3 g/L catalyst, 20 mM H2O2 and 50 mg/L TC. The effects of catalyst dosage, H2O2 concentration, initial pH, temperature, initial TC concentration, anions and water sources on TC degradation were studied. Hydroxyl ( OH) radicals were the main active species in the entire reaction, which was demonstrated by quenching experiments, fluorescence detection and the electron paramagnetic resonance (EPR) technology. Additionally, the redox cycles of FeII/FeIII and CoII/CoIII were participated in OH generation. What’s more, the plausible degradation pathways were put forward followed with detected intermediates. The CoFe-ONSs displayed negligible iron ions leaching and held high TC elimination performance even after five trials. Therefore, the CoFe-ONSs may expand the heterogeneous Fenton-like catalysts family and display great potential in eliminating antibiotic contaminants from wastewater.

We examined the seasonal distribution of lightning- and human-caused wildfires ≥ 2ha in Canada for two time periods: 1959–2018 and 1981–2018. Furthermore, we investigated trends in seasonality, number of fires per year and number of days with fire starts per year for human- and lightning-caused fires. Nationally, lightning fires peaked from June to August, whereas human fires peaked during May. There was, however, notable variation in the seasonal distributions of human- and lightning-caused fires between ecozones. Likewise, trends in season start and end dates varied among ecozones and time series, with trends generally being stronger for human-caused fires. Trends in the number of fires from 1959 to 2018 suggested significant increases in the number of lightning-caused fires and days with lightning ignitions across almost all ecozones, while from 1981 to 2018 there was a significantly decreasing trend in the number of human-caused fires and days with human ignitions in almost all ecozones. The highest densities of human-caused fires occurred in the Montane Cordillera and Atlantic Maritime, while the highest density of lightning-caused fires occurred in the Boreal Shield West. The Montane Cordillera and Taiga Shield West showed significant increases in the number of lightning fires and days with lightning ignitions across both time series.

Strained silicon is becoming a new technology in silicon industry where the novel strain-induced features are utilized. In this paper we present a molecular dynamic prediction for the elastic stiffnesses C11, C12 and C44 in strained silicon as functions of the volumetric strain level. Our approach combines basic continuum mechanics with the classical molecular dynamic approach, supplemented with the Stillinger–Weber potential. Using our approach, the bulk modulus, effective elastic stiffnesses C11, C12 and C44 of the strained silicon, including also the effective Young's modulus and Poisson's ratio, are all calculated and presented in terms of figures and formulae. In general, our simulation indicates that the bulk moduli, C11 and C12, increase with increasing volumetric strain whilst C44 is almost independent of the volumetric strain. The difference between strained moduli and those at zero strain can be very large, and therefore use of standard free-strained moduli should be cautious.