Efficient simultaneous removal of diesel particulate matter and hydrocarbons from diesel exhaust gas at low temperatures over Cu–CeO_(2)/Al_(2)O_(3) coupling with dielectric barrier discharge plasma

Diesel particulate matter(DPM)and hydrocarbons(HCs)emitted from diesel engines have a negative affect on air quality and human health.Catalysts for oxidative removal of DPM and HCs are currently used universally but their low removal efficiency at low temperatures is a problem.In this study,Cu-doped CeO_(2) loaded on Al_(2)O_(3) coupled with plasma was used to enhance low-temperature oxidation of DPM and HCs.Removals of DPM and HCs at 200℃ using the catalyst were as high as 90%with plasma but below 30%without plasma.Operando plasma diffuse reflectance infrared Fourier transform spectroscopy coupled with mass spectrometry was conducted to reveal the functional mechanism of the oxygen species in the DPM oxidation process.It was found that Cu-CeO_(2) can promote the formation of adsorbed oxygen(M^(+)-O_(2)^(-))and terminal oxygen(M=O),which can react with DPM to form carbonates that are easily converted to gaseous CO_(2).Our results provide a practical plasma catalysis technology to obtain simultaneous removals of DPM and HCs at low temperatures.M+O-2Diesel particulate matter(DPM)and hydrocarbons(HCs)emitted from diesel engines have a negative affect on air quality and human health.Catalysts for oxidative removal of DPM and HCs are currently used universally but their low removal efficiency at low temperatures is a problem.In this study,Cu-doped CeO_(2) loaded on Al_(2)O_(3) coupled with plasma was used to enhance low-temperature oxidation of DPM and HCs.Removals of DPM and HCs at 200°C using the catalyst were as high as 90%with plasma but below 30%without plasma.Operando plasma diffuse reflectance infrared Fourier transform spectroscopy coupled with mass spectrometry was conducted to reveal the functional mechanism of the oxygen species in the DPM oxidation process.It was found that Cu–CeO_(2) can promote the formation of adsorbed oxygen(–)and terminal oxygen(M=O),which can react with DPM to form carbonates that are easily converted to gaseous CO_(2).Our results provide a practical plasma catalysis technology to obtain simultaneous removals of DPM and HCs at low temperatures.

FPSblo:A Blockchain Network Transmission Model Utilizing Farthest Point Sampling

Peer-to-peer(P2P)overlay networks provide message transmission capabilities for blockchain systems.Improving data transmission efficiency in P2P networks can greatly enhance the performance of blockchain systems.However,traditional blockchain P2P networks face a common challenge where there is often a mismatch between the upper-layer traffic requirements and the underlying physical network topology.This mismatch results in redundant data transmission and inefficient routing,severely constraining the scalability of blockchain systems.To address these pressing issues,we propose FPSblo,an efficient transmission method for blockchain networks.Our inspiration for FPSblo stems from the Farthest Point Sampling(FPS)algorithm,a well-established technique widely utilized in point cloud image processing.In this work,we analogize blockchain nodes to points in a point cloud image and select a representative set of nodes to prioritize message forwarding so that messages reach the network edge quickly and are evenly distributed.Moreover,we compare our model with the Kadcast transmission model,which is a classic improvement model for blockchain P2P transmission networks,the experimental findings show that the FPSblo model reduces 34.8%of transmission redundancy and reduces the overload rate by 37.6%.By conducting experimental analysis,the FPS-BT model enhances the transmission capabilities of the P2P network in blockchain.

3D Model Construction and Ecological Environment Investigation on a Regional Scale Using UAV Remote Sensing

The acquisition of digital regional-scale information and ecological environmental data has high requirements for structural texture,spatial res-olution,and multiple parameter categories,which is challenging to achieve using satellite remote sensing.Considering the convenient,facilitative,and flexible characteristics of UAV(unmanned air vehicle)remote sensing tech-nology,this study selects a campus as a typical research area and uses the Pegasus D2000 equipped with a D-MSPC2000 multi-spectral camera and a CAM3000 aerial camera to acquire oblique images and multi-spectral data.Using professional software,including Context Capture,ENVI,and ArcGIS,a 3D(three-dimensional)campus model,a digital orthophoto map,and multi-spectral remote sensing map drawing are realized,and the geometric accuracy of typical feature selection is evaluated.Based on a quantitative remote sensing model,the campus ecological environment assessment is performed from the perspectives of vegetation and water body.The results presented in this study could be of great significance to the scientific management and sustainable development of regional natural resources.

Linkages of volatile fatty acids and polyhexamethylene guanidine stress during sludge fermentation:Metagenomic insights of microbial metabolic traits and adaptation

The massive use of polyhexamethylene guanidine(PHMG),as a typical bactericidal agent,raised environmental concerns to the public.This work comprehensively revealed the hormesis effects of PHMG occurred in waste activated sludge(WAS)on the generation of volatile fatty acids(VFAs)during anaerobic fermentation.The low level of PHMG(100 mg/g TSS)significantly promoted the VFAs generation(1283 mg COD/L,compared with 337 mg COD/L in the control)via synchronously facilitating the solubilization,hydrolysis,and acidification steps but inhibiting methanogenesis.Metagenomic analysis showed that the functional anaerobe(i.e.,Bacteroides,Macellibacteroide and Parabacteroide)and corresponding genetic expressions responsible for extracellular hydrolysis(i.e.,clp P),membrane transport(i.e.,ffh and gsp F),intracellular substrates metabolism(i.e.,ald and paa F)and VFAs biosynthesis(i.e.,ACACA and FASN)were enhanced in the optimal presence of PHMG.Moreover,the anaerobic species could respond and adapt to low PHMG stimuli via quorum sensing(i.e.,cqs A,rpf C and rpf G),and thus maintain the high microbial metabolic activities.However,they were unable to tolerate the toxicity of excessive PHMG,resulting in the extremely low VFAs production.This work enlightened the effects of emerging pollutants on WAS fermentation at the genetic levels,and provided guidance on the WAS treatment and resource recovery.

Dissimilarity of different cephalosporins on volatile fatty acids production and antibiotic resistance genes fates during sludge fermentation and underlying mechanisms

The distinct influences of cephalosporins(CEPs, i.e., cefamandole nafate and cefpirome sulfate) affiliated to different generations on the volatile fatty acids(VFAs) production and antibiotic resistance genes(ARGs) fates during waste activated sludge(WAS) fermentation were unveiled. The presence of CEPs mainly exhibited negative effects on the total VFAs production(5%–15% reduction), especially the cefamandole nafate, which is quite different to previous understanding. Further investigation revealed that the CEPs contributed to the solubilization and hydrolysis but inhibited the acidification process by affecting the functional microbial populations(i.e., Tissierella) and general microbial metabolic activities(i.e., pyruvate metabolism and VFAs biosynthesis). In addition, CEPs(especially the cefpirome sulfate)caused the propagation of ARGs(i.e., bla TEM, tet X and mex F) during WAS fermentation. CEPs enhanced the cell membrane permeability to promote the antibiotics mechanism of efflux pump and the horizontal transfer of ARGs. Also, the CEPs altered the regulatory systems(i.e., two component system) and microbial populations associated with ARGs, resulting in the proliferation of specific ARGs. Overall, the dissimilarity of different CEPs impacts on the WAS fermentation for VFAs production and ARGs variations enlightened the diverse environmental behaviors of anthropogenic pollutants and evoked the caution of ecological risks.

Mechanisms of allicin exposure for the sludge fermentation enhancement:Focusing on the fermentation processes and microbial metabolic traits

As a frequently used product with antimicrobial activity,consumed allicin might be dis-charged and concentrated in waste-activated sludge(WAS).However,the influence of al-licin(as an exogenous pollutant)on WAS fermentation has not been clearly revealed.This study aimed to disclose the impacts of allicin on volatile fatty acid(VFA)generation dur-ing WAS fermentation.The results showed that the appropriate presence of allicin(10 mg/g TSS)significantly enhanced the VFA yield(1894 versus 575 mg COD/L in the control)with increased acetate proportion(24.3%).Further exploration found that allicin promoted WAS solubilization,hydrolysis and acidification simultaneously.Metagenomic analysis revealed that the key genes involved in extracellular hydrolysis metabolism(i.e.,CAZymes),mem-brane transport(i.e.,gtsA and ytfT),substrate metabolism(i.e.,yhdR and pfkC)and fatty acid synthesis(i.e.,accA and accD)were all highly expressed.Allicin also induced the bacteria to produce more signalling molecules and regulate cellular functions,thereby enhancing the microbial adaptive and regulatory capacity to the unfavourable environment.Moreover,the variations in fermentative microbes and their contributions to the upregulation of func-tional genes(i.e.,ytfR,gltL,INV,iolD and pflD)for VFA generation were disclosed.Overall,the simultaneous stimulation of functional microbial abundances and metabolic activities contributed to VFA production in allicin-conditioned reactors.

New insights into different surfactants’impacts on sludge fermentation:Focusing on the particular metabolic processes and microbial genetic traits

Surfactants were expected to exhibit positive effects on the waste activated sludge(WAS)disposal.However,the systematic comparison of different categories of surfactants on the WAS fermentation and the functional mechanisms,especially microbial metabolic traits,have not yet been precisely explored.This study revealed the positive effects of different surfactants on the volatile fatty acid(VFA)production,which followed the order of alkyl polysaccharides(APG)>sodium dodecylbenzene sulfonate(SDBS)>hexadecyl trimethyl ammonium bromide(HTAB).Mechanistic exploration found that the presence of different surfactants improved solubilization and hydrolysis steps,and then contributed to the subsequent acidification with different efficiencies.The functional microorganisms associated with VFA generation were enriched in surfactant-conditioned reactors.Metagenomic analysis further indicated that the key genes involved in the particular process of VFA generation were over-expressed.The simultaneous bioavailable substrate improvement,functional bacterial enrichment,and metabolic activity upregulation induced by different surfactants jointly contributed to VFA promotion during WAS fermentation.This study could provide a comprehensive realization of surfactants’impacts on theWAS fermentation process,and more importantly,it reminded the public to discern the distinct interplaying effects induced by different chemicals in regulating the WAS disposal and resource recovery.