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In the context of the commitment to peak carbon emissions by 2030, specific sectors in China should take responsibility to change their energy consumption patterns. In China and across the globe, the construction sector is a major source of carbon dioxide emissions, as well as an indicator of economic growth and structural transformation. In this study, we examine panel data for 30 provinces or regions from 2008 to 2019 to dissect which macro-factors contribute to growth in carbon emissions, and which will lead to carbon emission reductions. Derived by the entropy method, the Green Finance Index is a comprehensive environmental regulation index related to reduction in emissions in each province. It presents an N shape for construction emissions, and provinces are currently striving to cross the first inflection point, which will help to curb emissions. Judging from the combined effects of this and other structural factors, the Green Finance Index can promote the decarbonization of production by playing the role of guiding and screening capital allocation. Population expansion, income levels, and financial development initially stimulate demand for construction, but their effects eventually level off. This paper can serve as a reference for developing countries that are experiencing industrialization and urbanization processes and handling gas discharge pressure at the same time.

The potential of periodate (PI) in sludge anaerobic digestion is not tapped, although it has recently attracted great research interest in organic contaminants removal and pathogens inactivation in wastewater treatment. This is the first work to demonstrate significant improvement in methane generation from waste activated sludge (WAS) with PI pretreatment and to provide underlying mechanisms. Biochemical methane potential tests indicated that methane yield enhanced from 100.2 to 146.3 L per kg VS (VS, volatile solids) with PI dosages from 0 to 100 mg per g TS (TS, total solids). Electron spin resonance showed PI could be activated without extra activator addition, which might be attributed to the native transition metals (e.g., Fe

The surface wettability of micron particles affects many engineering applications, such as forth flotation and dust removing. The settling velocities of glass beads with diameters in the range 15–100 μm and varying surface wettability were obtained using a high-speed dynamic system. The results showed that the surface wettability of the particle surface has a significant effect on the terminal settling velocity (VT) when the particle dimensionless diameter (d∗ = (∆g/v2)1/3d) is less than two. As the contact angles increase, the VT increases and the drag coefficient (CD) decreases. The classical Stokes model does not reflect this change; consequently, a modified Stokes model that considers surface wettability is proposed. Experimental results indicate that the average relative error of the proposed model is 3.10% for the modified settling velocity formula, and 3.06% for modified drag coefficient formula. Both modified formulas were validated using the experimental data of spherical aluminum oxide (Al2O3) particles.

Nowadays, conductive iron-containing materials (i.e., Fe3O4 and zerovalent iron) have attracted greatly attention in improving medium-chain carboxylic acids (MCCA) from waste activated sludge (WAS). However, the feasibility and mechanism of semi-conductive iron oxide, i.e., ferric oxide (Fe2O3), in stimulating MCCA synthesis from WAS via ethanol-driven chain elongation (CE) has been unclear. Therefore, this work is aimed to fill up the knowledge gap. Results showed that the MCCA yield in the Fe2O3-supplemented fermenter attained at 9162 mg COD/L (i.e., 6268 mg COD/L caproate and 2895 mg COD/L caprylate), which was 2.4 times that of the control system. Kinetic analysis proved that Fe2O3 enhanced both the potential and rate of MCCA synthesis. Mechanism analysis indicated that Fe2O3 facilitated the individual steps for MCCA production, i.e., hydrolysis, acidification and CE. Further investigation disclosed that the dissimilatory iron reduction (DIR) induced by Fe2O3 corrosion and released ferrous ions improved enzymes activities of hydrolysis and acidification, while the promotion of CE was mainly ascribed to increased electron transfer efficiency by crystalline Fe2O3. Further, Fe2O3 promotes electron transfer through several mechanisms, including stimulating extracellular polymeric substance (EPS) excretion, increasing EPS electroactivity, and enhancing electron transport system activity. Microbial analysis revealed that Fe2O3 induced microflora structure shifting towards substrates transformation, iron reduction and MCCA generation, and up-regulated the key enzymes in CE pathways. This work provides an efficient strategy for MCCA generation and WAS management.

This work proposed a novel strategy via heat-assisted potassium ferrate (PF) pretreatment to enhance methane production from waste activated sludge (WAS) during anaerobic digestion. In this research, five dosages of PF (i.e., 0, 0.05, 0.1, 0.3 and 0.5 g/g VSS) at two temperatures (i.e., 25 °C and 55 °C) were explored. Biochemical methane potential experiments illustrated that heat-assisted PF pretreatment improved cumulative methane production with the maximum yield up to 163.93 mL CH

The influence of ultrasound (US) and potassium permanganate (KMnO

Herein, a pipette-tip-enabled digital nucleic acid analyzer for high-performance COVID-19 testing is demonstrated. This is achieved by digital loop-mediated isothermal amplification (digital LAMP or dLAMP) using common laboratory equipment and materials. It is shown that simply fixing a glass capillary inside conventional pipette tips enables the generation of monodisperse, water-in-oil microdroplets with benchtop centrifugation. It is shown that using LAMP, the ORF1a/b gene, a standard test region for COVID-19 screening, can be amplified without a thermal cycler. The amplification allows counting of fluorescent microdroplets so that Poisson analysis can be performed to allow quantification with a limit of detection that is 1 order of magnitude better than those of nondigital techniques and comparable to those of commercial dLAMP platforms. It is envisioned that this work will inspire studies on ultrasensitive digital nucleic acid analyzers demanding both sensitivity and accessibility, which is pivotal to their large-scale applications.

Short-chain carboxylic acids (SCCAs) production from sewage sludge via anaerobic fermentation is usually restricted by low substrates availability and rapid products consumption. Therefore, the ultrasound (US)-sodium percarbonate (SPC) technique was proposed to effectively break the bottlenecks. Results showed the total SCCAs yield, acetate yield and particulate organics reduction respectively attained 392.8 mg COD/g VSS, 204.6 mg COD/g VSS and 47.4 % under the optimal condition. Mechanistic explorations disclosed that US + SPC largely reduced biodegradation resistances of particulate organics and improved sludge biodegradability. The destruction of spatial structure was the inherent mechanisms for initial solubilization and further degradation of solid-phase sludge. Besides, US + SCP up-regulated hydrolytic and SCCAs-forming enzymes, but downregulated the key enzyme for methanation. Meanwhile, US + SPC altered the microbial structure and stimulated functional microorganism enrichment, well correlated with substrate biotransformation and products output. Overall, this strategy could effectively enhance SCCAs production from WAS and reduce the environmental risk for subsequent sludge disposal.

As a powerful oxidizing agent, potassium permanganate (KMnO

Recently, phosphorus recovery as vivianite from sludge digestion system has attracted increasing attention because of its high recovery efficiency and economic value. However, the potential impact of vivianite on anaerobic digestion of waste activated sludge remains largely unknown. This study therefore aims to provide such support. Experimental results revealed that the maximal methane yield decreased from 103.55 to 76.55 mL/g volatile solids, with the vivianite level increasing from 0 to 500 mg P/L. Mechanism explorations showed that vivianite caused more substrates remaining in tightly-bound extracellular polymeric substances, and thus suppressed sludge solubilization. In addition, it was observed that hydrolysis, acidiogenesis, acetogenesis and methanogenesis bio-processes were all inhibited by vivianite. Microbial analysis revealed that vivianite significantly decreased the relative abundances of hydrolytic microbes, acidogens and methanogens. Further investigation showed that vivianite benefited sludge agglomeration and can enhance the mass transfer resistance of anaerobic digestion, further supporting the inhibitions on anaerobic digestion.

A novel pretreatment technique (i.e., using Sodium percarbonate, SPC) to improve the short-chain fatty acids (SCFA) production waste activated sludge (WAS) was proposed in this study. Results indicated that the maximum SCFA production of 1605.7 mg COD/L and acetic acid of 52.9% were attained at 0.2 g SPC/g TSS, being 8.4 and 2.8 times of the control (191.3 mg COD/L and 19%), respectively. Meanwhile, the optimal time for SCFA accumulation was decreased from 6d (control) to 4d (0.2 g/g TSS). Mechanism explorations unraveled that SPC largely accelerated WAS solubilization and enhanced the bioavailability of organics released from WAS. It improved enzymatic activities related to hydrolysis and acidogenesis, while suppressed the Coenzyme F

Additional file 2: Figure S1. Gene map of the P. alkekengi var. franchetii chloroplast genome. Genes shown outside the outer circle are transcribed clockwise, and those inside are transcribed counterclockwise. Genes belonging to different functional groups are color coded. The darker gray in the inner circle indicates the GC content, and the lighter gray indicates the AT content. The inner circle also indicates that the chloroplast genome contains two copies of the inverted repeat (IRA and IRB), a large single-copy region (LSC) and a small single-copy region (SSC). The map was constructed using OrganellarGenomeDRAW. Figure S2. Gene map of the P. minima chloroplast genome. Genes shown outside the outer circle are transcribed clockwise, and those inside are transcribed counterclockwise. Genes belonging to different functional groups are color coded. The darker gray in the inner circle indicates the GC content, and the lighter gray indicates the AT content. The inner circle also indicates that the chloroplast genome contains two copies of the inverted repeat (IRA and IRB), a large single-copy region (LSC) and a small single-copy region (SSC). The map was constructed using OrganellarGenomeDRAW. Figure S3. Gene map of the P. pubescens chloroplast genome. Genes shown outside the outer circle are transcribed clockwise, and those inside are transcribed counterclockwise. Genes belonging to different functional groups are color coded. The darker gray in the inner circle indicates the GC content, and the lighter gray indicates the AT content. The inner circle also indicates that the chloroplast genome contains two copies of the inverted repeat (IRA and IRB), a large single-copy region (LSC) and a small single-copy region (SSC). The map was constructed using OrganellarGenomeDRAW. Figure S4. Amino acid frequencies in the chloroplast genomes of five Physalis species. Figure S5. Neighbor-joining (NJ) tree based on the complete chloroplast genome sequences of 36 species of Solanaceae. Numbers above branches indicate bootstrap support, and circled by the red dotted lines are the five Physalis species.

Additional file 1: Table S1. Information on the four Physalis species used in the study. Table S2. Quality control of the Illumina sequencing of chloroplast genome of Physalis species. Table S3. Relative synonymous codon usage (RSCU) in five Physalis chloroplast genomes. Table S4. Evolutionary divergence among Physalis species based on complete chloroplast genome sequences. Table S5. Universal primers for amplifying complete chloroplast genomes. Table S6. The 36 studied species belonging to 11 genera of Solanaceae, and the corresponding chloroplast whole genome GenBank accession number.

The motion of single bubbles rising in 2-octanol solutions was investigated experimentally. By using a high-speed video system to follow the rising bubble, the sequences of the recorded frames were digitized and analyzed using image analysis software. The periodical fluctuation of the bubble terminal velocity was observed, which is indicative of a nonconstant bubble drag coefficient. Then, the measured drag coefficient was compared with correlations available in the literature. The comparison shows that these correlations cannot give fully satisfactory results in predicting the fluctuated drag coefficient. Using the extensive experimental data, the authors proposed a new correlation to predict the drag coefficient calculated from the fluctuated motion with the added mass force and history force included. In virtue of nonlinear curve fitting, the drag coefficient of the single bubble is correlated as a function of the Re number, Eo number, We number, and Mo number based on the equivalent bubble diameter. T...

The motion of particle-laden bubbles is common in the gas–liquid-solid three-phase process like flotation. In this study, the motion of particle-laden bubbles in the stagnant deionized water was obtained by high-speed dynamic imaging. The experimental ranges of the mean bubble diameter and particle diameter were 2.76–3.95 mm and 58.2–196.35 μm, respectively. Results show that the terminal rising velocity decreases with the increase in the diameter of covering particles and the decrease in bubble diameter. For the coverage below 50%, the terminal rising velocity decreases sharply as coverage increases; while for 50% to nearly 100%, decreases slowly. The sharp decrease is mainly because particles immobilize the bubble surface and increases the drag, which is similar to the effect of contaminants in liquid on bubble motion. When the coverage exceeding 50%, the interface mobility of particle-laden bubbles is completely retarded. The slow decrease is attributed to the decreasing net buoyancy caused by decreasing density difference between water and the particle-laden bubble. Based on the impact of particle coverage on bubble behavior, the measured data were compared with predictions by the available models of the terminal rising velocity and drag coefficient for the bare bubble in the contaminated liquid. Comparison results show that the terminal rising velocity model given by Zheng et al. (2020) and the drag coefficient model given by Wang et al. (2019) can be extended to particle-laden bubbles with a mean error of 4.8% and 0.6%, respectively. The aspect ratio of particle-laden bubbles is negatively correlated to the terminal rising velocity like that of bare bubbles. A new aspect ratio prediction model for particle-laden bubbles related to the ratio between coverage and the Eo number was introduced to facilitate direct prediction of the terminal rising velocity. The comprehensive prediction models of particle-laden bubbles behaviors given in this study are helpful for the design and optimization of equipment that contains bubble-particle aggregates.

In this paper, we apply machine-learning techniques to construct detecting models of stock market manipulation. By combining manually collected China Securities Regulatory Commission punishment cases from 2014 to 2016 with financial information of listed companies, we construct a training set and a test set to compare the detecting ability of support vector machine (SVM) and logistic model. Considering imbalanced data, we further incorporate Borderline Synthetic Minority Oversampling Technique (Borderline SMOTE) to oversample minority class and then find that Borderline SMOTE–SVM performs better than SVM and benchmark model in detecting manipulation. To enhance detecting performance of the models, we innovatively introduce market sentiment indicators which are extracted from analyst rating reports, financial news, and Guba comments into our indicators set. The results indicate that the new indicators generate significant marginal increment to the model accuracy.

Flotation of fine minerals is becoming increasingly challenging. Mineral particles are believed to collide and attach efficiently to air bubbles in highly turbulent circular pipes. In this study, vortex generators (VGs) are adopted to strengthen the turbulence and improve the collection efficiency of fine minerals in pipe flow flotation. Computational fluid dynamics simulations, bubble size measurements, and flotation tests are conducted in a modified pipe unit with VGs and an initial pipe unit without VGs. The simulation results show that the VGs induce streamwise vortices and increase the turbulent dissipation rate in the pipe unit. Bubble size distribution measurements show that the VGs decrease the bubble size slightly at high velocities. Flotation tests prove that vigorous turbulence induced by VGs is beneficial to the recovery of fine particles. In particular, the flotation rate constant of −20 µm particles at a liquid velocity of 0.7 m/s increases by more than 40% in the presence of VG-s5. Nevertheless, the excessive turbulence induced by VG-s5 caused a 20% decrease in the flotation rate of +45–74 μm particles when the liquid velocity increases to 2.0 m/s. This indicates that a relationship exists between turbulence and the particle size recovered. For a specified particle size, turbulence can be adjusted by varying the vortex generator spacing and changing the flow velocity to achieve the optimum flotation performance.

The separation of fine particles has always been challenging in flotation. Strong turbulence is considered to be beneficial. In our previous study, vortex generator (VG), commonly used to improve heat transfer by enhancing turbulence, was proved to be effective for fine particle flotation. However, the turbulent effect of VG on different sized fine particles is still poorly understood, which hinders the industrial application. Flotation tests and flow field simulations were conducted on a pipe flow unit with VGs and without VGs under different Reynolds numbers (Re). Results showed that, VGs improved the flotation of particles with a diameter less than 37 μm and especially for particles less than 15 μm. Nevertheless, VGs were detrimental to the flotation of particles in the size range of 37–74 μm when Re exceeds 10,000. These results are attributed to the high turbulent energy dissipation (e) caused by counter-rotation vortex pairs induced by VGs. The increased e enhances the collision efficiency while reduces the stability efficiency for increased particle size, which indicates there is a correlation between particle size and turbulence at which the optimal recovery can be achieved. In the experimental range of this study, the optimal flotation rate was observed when the ratio of turbulent Kolmogorov eddy scale and particle diameter is 0.3.