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Treating high salt and high organic matter wastewater (HHW) generated during rapid socio-economic development is a significant challenge. This study aims to optimize a closed-cycle low-temperature evaporation (CCLE) system using mathematical modelling to be adapted to industrial applications. By using mathematical modelling and computational fluid dynamics (CFD), this study investigated the operating mechanism of the system under different operating conditions. Parametric analysis shows that increasing the compressor evaporation temperature and decreasing the condensation temperature is conducive to improving the performance of the heat pump unit, thereby increasing the wastewater treatment efficiency of the system and that a smaller heat transfer coil windward area is conducive to heat and mass transfer within the humidifier. The unique characteristics of the CCLE system are identified, and the wastewater treatment process under various operating conditions is explained. These findings may provide supporting information for the treatment of HHW by the CCLE system.

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Converting more CO2 absorbed by plant photosynthesis into biomass-activated carbon effectively reduces carbon emissions. In this study, we used a one-step preparation of biomass-activated carbon loaded with MgO nanoparticles to investigate the effect of Mg loading on the catalytic pyrolysis process. The influences of magnesium loading on biochar yield and fixed carbon production were assessed. The addition of 1% Mg weakened the carbonyl C=O, inhibited the dehydroxylation reaction, enhanced the C-H signal strength, and the formation of MgO inhibited the weaker- bound substituent breakage. Additionally, the addition of magnesium altered the morphological features and chemical composition of the biochar material. It also increased the activated carbon mesoporosity by 3.94%, biochar yield by 5.55%, and fixed carbon yield by 12.14%. The addition of 1% Mg increased the adsorption capacity of the activated carbon to potassium dichromate, acid magenta, methylene blue, and tetracycline effluents by 8.71 mg, 37.15 mg, 117.68 mg, and 3.53 mg, respectively. The results showed that MgCl2 played a significant role in promoting the thermal degradation of biomass and improving the solid yield and adsorption performance of activated carbon.

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Advances in technology have facilitated the development of lightning research and data processing. The electromagnetic pulse signals emitted by lightning (LEMP) can be collected by very low frequency (VLF)/low frequency (LF) instruments in real time. The storage and transmission of the obtained data is a crucial link, and a good compression method can improve the efficiency of this process. In this paper, a lightning convolutional stack autoencoder (LCSAE) model for compressing LEMP data was designed, which converts the data into low-dimensional feature vectors through the encoder part and reconstructs the waveform through the decoder part. Finally, we investigated the compression performance of the LCSAE model for LEMP waveform data under different compression ratios. The results show that the compression performance is positively correlated with the minimum feature of the neural network extraction model. When the compressed minimum feature is 64, the average coefficient of determination R2 of the reconstructed waveform and the original waveform can reach 96.7%. It can effectively solve the problem regarding the compression of LEMP signals collected by the lightning sensor and improve the efficiency of remote data transmission.

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A Cu/hydrazone catalyst has been applied in the coupling reactions of anilines for the synthesis of diarylamines and azobenzenes. The copper complex that is formed in situ plays a double duty by harnessing photon energy as a photocatalyst and then by catalysing organometallic elementary steps as a transition metal catalyst. By the selection of hydrazones and bases, the reaction selectivity of aniline can be tuned between homo-coupling and its cross-coupling with arylboronic acid, exhibiting the great potential of such hydrazones in organic synthesis.

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In this study, a new type of ecological floating bed (NT-EFB) employing ornamental plants (either Spathiphyllum floribundum, Hydrocotyle sibthorpioids, Chlorophytum comosum or Peperomia obtusifolia) was designed to purify confected eutrophic water for 39 days. The growth characteristics of the plants and the effect of water treatment were analyzed and compared. The results showed that: (1) all the four ornamental plants examined survived well in the eutrophic water and an increase of plant biomass was observed; (2) the degradation efficiency of TOC by adding plants was about 85.0%; (3) the removal rate of NH4+-N was about 97.0%; (4) all the four plants can be used as floating bed plants to treat eutrophic water and Hydrocotyle sibthorpioids had the best growth characteristics and treatment efficiency. The study provides an adequate reference for the treatment of eutrophication using ecological floating beds.

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This study evaluated the effects of temporary external voltage on the performance of two-chambered microbial fuel cells (MFC) that use nitrate wastewater as a substrate. Results indicate that the external voltage affected the performance of the MFC during their operation, and this effect remained even after the voltage was removed. The degradation efficiency of the chemical oxygen demand increased in the MFC under external voltages of 0.5, 0.8, and 1.1 V, and the optimal applied voltage was 1.1 V. Compared with the control group without external voltages, the MFC under a voltage of 1.1 V achieved higher current densities and efficiency of nitrate removal during their operation. The MFC with an applied voltage of 1.1 V also achieved the highest maximum power density of 2,035.08 mW/m3. The applied voltages of 0.5 and 0.8 V exerted a positive effect on the performance of the MFC. High-throughput sequencing was used to explore the anode and cathode biofilms. Results showed that the influence was highly associated with microbial community in bio-anode. The predominant functional family changed from Methanotrichaceae during start-up to Flavobacteriaceae in a steady phase.

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Lightning waveform plays an important role in lightning observation, location, and lightning disaster investigation. Based on a large amount of lightning waveform data provided by existing real-time very low frequency/low frequency (VLF/LF) lightning waveform acquisition equipment, an automatic and accurate lightning waveform classification method becomes extremely important. With the widespread application of deep learning in image and speech recognition, it becomes possible to use deep learning to classify lightning waveforms. In this study, 50,000 lightning waveform samples were collected. The data was divided into the following categories: positive cloud ground flash, negative cloud ground flash, cloud ground flash with ionosphere reflection signal, positive narrow bipolar event, negative narrow bipolar event, positive pre-breakdown process, negative pre-breakdown process, continuous multi-pulse cloud flash, bipolar pulse, skywave. A multi-layer one-dimensional convolutional neural network (1D-CNN) was designed to automatically extract VLF/LF lightning waveform features and distinguish lightning waveforms. The model achieved an overall accuracy of 99.11% in the lightning dataset and overall accuracy of 97.55% in a thunderstorm process. Considering its excellent performance, this model could be used in lightning sensors to assist in lightning monitoring and positioning.

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This study systematically assessed the inactivation mechanism on Staphylococcus aureus biofilms by a N2 atmospheric-pressure plasma jet and the effect on the biofilm regeneration capacity from the bacteria which survived, and their progenies. The total bacterial populations were 7.18 ± 0.34 log10 CFU ml-1 in biofilms and these were effectively inactivated (>5.5-log10 CFU ml-1) within 30 min of exposure. Meanwhile, >80% of the S. aureus biofilm cells lost their metabolic capacity. In comparison, ∼20% of the plasma-treated bacteria entered a viable but non-culturable state. Moreover, the percentage of membrane-intact bacteria declined to ∼30%. Scanning electron microscope images demonstrated cell shrinkage and deformation post-treatment. The total amount of intracellular reactive oxygen species was observed to have significantly increased in membrane-intact bacterial cells with increasing plasma dose. Notably, the N2 plasma treatment could effectively inhibit the biofilm regeneration ability of the bacteria which survived, leading to a long-term phenotypic response and dose-dependent inactivation effect on S. aureus biofilms, in addition to the direct rapid bactericidal effect.

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One of the NHC-iridium coordination assemblies containing 1,5-cyclooctadiene (COD) and iodide ion has been demonstrated as robust, efficient, recyclable solid molecular catalyst for N-formylation of diverse primary and secondary amines with CO2 and H2 under mild reaction conditions. Remarkably, in the case of N,N-dimethylformamide production, even at 0.1 mol % catalyst loading under solvent-free conditions, the solid catalyst can be readily recovered by simply filtration and reused more than 10 runs without noticeable loss of activity.

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By using the commercially available ruthenium pincer complex (Ru-MACHO-BH) as a catalyst, the challenging direct hydrogenation of lactams and analogues has been successfully accomplished to deliver corresponding value-added amino alcohols in good-to-excellent yields under mild reaction conditions. Remarkably, in addition to N-protected lactams, unprotected ones could also be readily reduced in the presence of a catalytic amount of weak base or even under neutral reaction conditions, which further highlights the broad substrate scope and the protocol efficiency.

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Fresh blue algal from Chao Lake was used in this study. The crude extracts of phycocyanin were obtained with freeze-thaw method. The purification of phycocyanin was performed by combining two-step salt precipitation and two-step column chromatography. The reagent grade phycocyanin was achieved. Phycocyanin and impurity solution were obtained respectively in various stages subjected to the UV-Vis absorption spectrum scanning. With the development of the four-step purification process, the absorption peak of phycocyanin solution was redshifted from 260 to 280 nm in the wavelength range from 250 to 300 nm, and the maximum absorption peak of phycocyanin was redshifted from 617 to 620 nm in the wavelength range from 500nm to 700 nm. In the wavelength range from 250 to 700 nm, it showed that the impurity solution mainly contained impurity proteins and part of the phycocyanin in the first salting out, and mainly contained nucleic acids and vitamins substance in the second salting out. The first outflow components mainly contained phycoerythrin separated by the first column chromatography. The last outflow components mainly contained allophycocyanin separated by the second column chromatography. After the four-step purification process, the final purity of phycocyanin (A620/A280) is greater than 4,which met the standard of reagent grade．Thus it can be seen that two-step salt precipitation had a main function which was to remove impurity proteins, nucleic acids and vitamins substance, and two-step column chromatography main function was to remove phycoerythrin and allophycocyanin which were similar to phycocyanin.

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Using TH 880-F type dust tester and low pressure impactor (LPI), the size-segregated atmospheric particulates were collected, the particle size distribution characteristics and the content of lead were analyzed in the unorganized emission area (1 and 2) from the Blast and ISA furnaces within a lead-zinc smelter in Yunnan province. The results showed that lead in PM2.5(fine particulate matter, particle size <2.5 µm) accounted for 66.6% and 43.1% of PM10(particulate matter, particle size <10 µm) and TSP(total suspended particle, particle size<100 µm) in unorganized emission area 1, and the corresponding proportions in the unorganized emission area 2 were 54.1% and 38.7%, all these showed that the lead pollution mainly existed in small size particles. There was a close correlation between the lead content in the unorganized emission particulate matter and the wind direction and wind speed in the surface meteorological data, followed by the wind energy density. In lead smelting area, the correlation of lead content in the unorganized emission particulate matter with the wind direction and wind speed was the highest, followed by the wind energy density w. In the slag field, the correlation between lead content in the unorganized emission particulate matter and the vertical distribution of the temperature (γ) of the boundary layer was the highest, followed by the component u and v, and then the wind energy density w.

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Dry anaerobic digestion of sewage sludge can recover biogas as energy; however, its low C/N ratio limits it as a single substrate in the anaerobic digestion. Rice straw is an abundant agricultural residue in China, which is rich in carbon and can be used as carbon source. In the present study, the performance of dry co-digestion of sewage sludge and rice straw was investigated under mesophilic (35 °C) and thermophilic (55 °C) conditions. The operational factors impacting dry co-digestion of sewage sludge and rice straw such as C/N ratio, moisture content, and initial pH were explored under mesophilic conditions. The results show that low C/N ratios resulted in a higher biogas production rate, but a lower specific biogas yield; low moisture content of 65 % resulted in the instability of the digestion system and a low specific biogas yield. Initial pH ranging 7.0-9.0 did not affect the performance of the anaerobic digestion. The C/N ratio of 26-29:1, moisture content of 70-80 %, and pH 7.0-9.0 resulted in good performance in the dry mesophilic co-digestion of sewage sludge and rice straw. As compared with mesophilic digestion, thermophilic co-digestion of sewage sludge and rice straw significantly enhanced the degradation efficiency of the substrates and the specific biogas yield (p < 0.05) at the conditions of C/N ratio 26:1, moisture content 80 %, and natural initial pH. Although high concentrations of ammonia-nitrogen (NH4-N, 1500 mg/kg wet weight) were formed during thermophilic digestion, there was no obvious inhibition occurred. The results indicated that rice straw can be used as carbon source for the dry co-digestion of sewage sludge under mesophilic and thermophilic conditions.

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A sensitive and simple method for high-performance liquid chromatography (HPLC) determination of traces of chromium species in lake sediments after preconcentration by cloud point extraction (CPE) has been developed. Simultaneous preconcentration of Cr(III) and Cr(VI) in sediment samples was achieved by CPE with 1-(2-thiazolylazo)-2-naphthol (TAN) as the chelating agent and non-ionic surfactant octylphenoxypolyethoxyethanol (Triton X-114) as the extractant. Baseline separation of the TAN chelates of Cr(III) and Cr(VI) was realized on a RP-C(18) column by using a mixture of methanol-water (69:31, v/v) solution and 4.5 mmol L(-1) CTMAB buffered with 0.03 mol L(-1) NaAc-HAc solution (pH 5.5) as the mobile phase at a flow rate of 0.8 mL min(-1). The variables affecting the complexation and extraction steps were examined. The precision (R.S.D.) for seven replicate injections of a mixture of 100 microg L(-1) of Cr(III) and Cr(VI) was 1.2 and 0.9% for the retention time, 4.7 and 2.7% for the peak area, respectively. The concentration factor was 45 for Cr(III) and 40 for Cr(VI). The detection limit (LOD) of this method, calculated as three times the standard deviation of the blank signals was 7.5 microg L(-1) for Cr(III) and 3.5 microg L(-1) for Cr(VI), respectively. The proposed procedure was applied to the speciation of chromium in sediment samples with satisfactory results.

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The 355 nm photon-initiated microscopic reaction mechanisms of the mixed aqueous solution of nitrobenzene and nitrous acid in the presence or absence of O(2) were studied by the laser flash photolysis technique. The main transient absorption peaks in the recorded spectra were assigned and the growth/decay trends of several transient species were investigated. It was found that the OH radical formed from the photolysis of nitrous acid triggered most of the subsequent radical reactions. The rate constant of the reaction between OH radical and nitrobenzene was measured to be (3.4 +/- 0.1) x 10(9) l mol(-1) s(-1). The product from this reaction, namely C(6)H(5)NO(2)-OH adduct, was found to react with O(2) to yield C(6)H(5)NO(2)-OHO(2) adduct with a rate constant of (1.6 +/- 0.2) x 10(9) l mol(-1) s(-1). Final steady-state products were identified by GC/MS analysis and were in accordance with the transient spectroscopic results. The possible reaction pathways were proposed.

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With the Pressure-State-Response (PSR) model developed by the Organization for Economic Cooperation and Development (OECD) and United Nations Environment Program (UNEP), this paper assessed the ecological security of the regions along Huaihe River in Anhui Province. Based on it, a revised integrative assessment model of regional ecological security and corresponding indicator system were built, in light of the social, economic and environmental characteristics of the regions. The weight of 17 indicators was estimated by Analytic Hierarchy Process (AHP) and Delphi technique, and three mathematical functions for these indicators were established. The results showed that the integrative ecological security degree of the regions based on PSR model was 0.41, and that after adding social-economic components was 0.34. Compared with the criterion set in this paper, the two assessment results of the regions were at comparatively unsafe level. However, the difference between the two results was 20.6%. To confirm the main elements that affect regional ecological security, the assessment model and corresponding indicator system should be combined with regional characteristics, and assessed with multi-model.

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