•Complete phosphate removal achieved at influent Mg/Ca molar ratio of 3.8.•Mg/Ca molar ratios influence phosphate removal.•Mg/Ca molar ratios have significant impact on the EPS of biomass.•A higher ...Mg/Ca molar ratio could induce deterioration of anaerobic-anoxic EBPR.
In this study, the effect of three Mg/Ca molar ratios (5.0, 3.8 and 1.7) on denitrifying phosphate removal performance, biomass morphology, and Extracellular Polymeric Substances (EPS) were examined. Results showed that when the influent Mg/Ca molar ratio was 3.8, the anaerobic-anoxic EBPR performed complete phosphate removal. The microbial bacterial population was a mixed culture comprised of 81±3% DPAO and 13±2% denitrifying glycogen accumulating organisms (DGAO). A higher influent Mg/Ca molar ratio (5.0) had a distinct impact on phosphate removal, biomass morphology, and EPS. This probably induced the deterioration of the anaerobic-anoxic Enhanced Biological Phosphorus Removal (EBPR). The results of this study may inform the proper operation of an anaerobic-anoxic EBPR, and contribute to its application in the real world.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
The anaerobic acetate (HAc) uptake stoichiometry of phosphorus-accumulating organisms (PAO) in enhanced biological phosphorus removal (EBPR) systems has been an extensive subject of study due to the ...highly variable reported stoichiometric values (e.g. anaerobic P-release/HAc-uptake ratios ranging from 0.01 up to 0.93 P-mol/C-mol). Often, such differences have been explained by the different applied operating conditions (e.g. pH) or occurrence of glycogen-accumulating organisms (GAO). The present study investigated the ability of biomass highly enriched with specific PAO clades (‘Candidatus Accumulibacter phosphatis’ Clade I and II, hereafter PAO I and PAO II) to adopt a GAO metabolism. Based on long-term experiments, when Poly-P is not stoichiometrically limiting for the anaerobic VFA uptake, PAO I performed the typical PAO metabolism (with a P/HAc ratio of 0.64 P-mol/C-mol); whereas PAO II performed a mixed PAO-GAO metabolism (showing a P/HAc ratio of 0.22 P-mol/C-mol). In short-term batch tests, both PAO I and II gradually shifted their metabolism to a GAO metabolism when the Poly-P content decreased, but the HAc-uptake rate of PAO I was 4 times lower than that of PAO II, indicating that PAO II has a strong competitive advantage over PAO I when Poly-P is stoichiometrically limiting the VFA uptake. Thus, metabolic flexibility of PAO clades as well as their intrinsic differences are additional factors leading to the controversial anaerobic stoichiometry and kinetic rates observed in previous studies. From a practical perspective, the dominant type of PAO prevailing in full-scale EBPR systems may affect the P-release processes for biological or combined biological and chemical P-removal and recovery and consequently the process performance.
•The anaerobic stoichiometry of PAO I and II is intrinsically different.•Both PAO I and II exhibit a GAO metabolism for HAc-uptake under Poly-P depletion.•At high Poly-P content PAO I has faster HAc-uptake rates than PAO II.•PAO II has faster HAc-uptake rates than PAO I at low Poly-P content.•Prevalence of specific PAO clades may influence process performance.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Abstract
This paper presents an experimental investigation and a stress–strain model for ultra-high performance concrete (UHPC)-filled fiber reinforced polymer (FRP) tubes under cyclic axial ...compression. Test results from 12 cyclically loaded and 18 monotonically loaded cylindrical specimens with different tube thicknesses, curing regimes, and steel fibers are presented. The influence of the tested variables on the envelope curve, plastic strain, and stress deterioration was clarified to establish a theoretical stress–strain model. Through a comprehensive assessment of well-known cyclic stress–strain model developed for FRP-confined conventional concrete, a new model for FRP-confined UHPC under cyclic axial compression is proposed based on a more rational consideration of the key characteristics of FRP-confined UHPC. Both the monotonic envelope response and the cyclic response showed good agreement between the analytic predictions based on the proposed model and the test results, confirming the capability of the proposed model to predict the cyclic axial behavior of FRP-confined UHPC.
Ideally, the solution to job-shop scheduling problem (JSP) should effectively reduce the cost of manpower and materials, thereby enhancing the core competitiveness of the manufacturer. Deep learning ...(DL) neural networks have certain advantages in handling complex dynamic JSPs with a massive amount of historical data. Therefore, this paper proposes a dynamic job-shop scheduling model based on DL. Firstly, a data prediction model was established for dynamic job-shop scheduling, with long short-term memory network (LSTM) as the basis; the Dropout technology and adaptive moment estimation (ADAM) were introduced to enhance the generalization ability and prediction effect of the model. Next, the dynamic JSP was described in details, and three objective functions, namely, maximum makespan, total device load, and key device load, were chosen for optimization. Finally, the multi-objective problem of dynamic JSP scheduling was solved by the improved multi-objective genetic algorithm (MOGA). The effectiveness of the algorithm was proved experimentally.
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IZUM, KILJ, NUK, ODKLJ, PILJ, PNG, SAZU, UL, UM, UPUK
AbstractPermeability of subsurface porous media is one of the primary factors that affect fluid transport in porous rock. However, accurate prediction of rock permeability is a challenging task due ...to its intricate pore network. Development of digital rocks provides an effective approach to reveal and characterize the pore network. In this paper, a combination of digital rock petrophysics and ensemble machine learning (ML) models is proposed to improve the permeability prediction of subsurface porous media. The permeability of the numerically generated porous samples as outputs was determined by the lattice Boltzmann method (LBM). The five most important parameters (porosity, tortuosity, fractal dimension, average pore diameter, and coordination number) were selected as inputs for the permeability prediction. To improve the accuracy, feature selection and ML methods comparisons were conducted. Three feature selection methods based on expert knowledge, correlation coefficient, and importance score were compared. Moreover, a comparison was performed on six ML methods (support vector machine, artificial neural network, decision tree, random forest, gradient-boosting machine, and Bayesian ridge regression) that were optimized by particle swarm optimization (PSO). The results indicated that (1) the feature selection based on the expert knowledge obtained a higher performance than the groups based on the correlation coefficient and importance score, implying the importance of expert knowledge on feature selection, and thus on ML performance; (2) artificial neural network with hyperparameter tuning achieved the best performance in predicting permeability; and (3) the optimized ML method outperformed the empirical equations in predicting permeability. In conclusion, this study provides a fast and reliable approach predicting permeability of subsurface porous media based on numerically generated porous images. Moreover, the proposed framework can be further extended to determine other petrophysical properties, for example, the relative permeability and thermal conductivity.
Abstract
In pursuit of lightweighting of automobiles and low emission of transportation, the efforts to develop high-strength, heat-resistant and fatigue-resistant Al alloys and/or composites have ...been ongoing. Here we report a novel Al matrix composite with ultrahigh strength reinforced by a three dimensional network of nano-AlN particles for the first time. The
in-situ
synthesized AlN particles are connected by twinning bonding chains and built up a three dimensional network strengthening Al matrix enormously like the skeleton to human body. The composite containing 16.4wt.% AlN particles shows excellent properties: the ultimate tensile strengths can be up to 518MPa at room temperature and 190MPa at 350 °C. This peculiar performance results from the novel spatial distribution of nano-scale AlN particles. Our findings in this work would help to develop a potential candidate for high-performance heat resistance light-metal based materials.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
We discover a faint shell-type radio and X-ray source, G353.6-0.7, associated with HESS J1731-347. G353.6-0.7 is likely an old supernova remnant (SNR), based on radio (0.8, 1.4, and 5 GHz), infrared ...(8 mu m from the GLIMPSE Legacy Project and 21 mu m from the Midcourse Space Experiment), and X-ray (0.1-2.4 keV from the ROSAT survey and 5-20 keV from the INTEGRAL survey) data. The SNR, centered at (l, b) = (353.55 degree , -0.65 degree ) with a radius of similar to 0.25 unsupported character, closely matches the outline of the recently discovered extended TeV source HESS J1731-347, which has no previously identified counterpart. A diffuse X-ray enhancement detected in the ROSAT all-sky survey is coincident with lower half-shell of the SNR. Therefore the SNR is the best radio counterpart of both the HESS source and the diffuse X-ray enhancement. G353.6-0.7 has an age of similar to 27,000 yr. Altogether, the new discovery provides the best case that an old SNR emits TeV gamma -rays.
Cadmium (Cd) is a common contaminant in aquatic environments. However, little is known about the mechanisms underlying Cd toxicity in the freshwater snail Cipangopaludina cathayensis (Heude, 1890). ...This study to investigate the toxic effects of Cd on the standard metabolism, antioxidant activities, immune function, and hepatopancreas transcriptome profiles of C. cathayensis. C. cathayensis was exposed to 0.25, 0.5, 1.0, or 1.5 mg/L Cd for 3 h, with results showing that Cd significantly inhibited oxygen consumption and ammonia excretion and disrupted the respiratory metabolism of C. cathayensis. In addition, the O:N ratio dropped below 7, indicating that C. cathayensis may rely exclusively on proteins as an energy source under Cd stress. To understand how Cd impacts the antioxidant activities, immune function, and transcriptional profiles, C. cathayensis were exposed to 0.5 (low exposure, L14) or 1.5 (high exposure, H14) mg/L Cd for 14 days. Our results indicate that Cd exposure leads to oxidative stress and immunosuppression, with the latter effect being larger for exposure to higher Cd concentrations. A total of 2172 differentially expressed genes (DEGs) were identified by transcriptome analysis of the hepatopancreas, of which 885 were upregulated and 1287 were downregulated. Gene ontology and KEGG analyses revealed that the DEGs in the H14 group are enriched for energy generation terms and the “oxidative phosphorylation” pathway, respectively. Therefore, up-regulation of energy metabolism may be an adaptive strategy under Cd stress. Moreover, several genes involved in antioxidant activity were downregulated, whereas genes related to reactive oxygen species generation were upregulated. In addition, many immunity-related genes were identified within the DEGs, indicating that Cd toxicity may affect immune defense. Further, DEGs in the H14 group were enriched for disease-associated pathways. Taken together, our results indicate that Cd exposure leads to metabolic disorders, oxidative stress, and immunosuppression and thus may potentially contribute to disease outbreaks.
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•Cadmium exposure inhibited respiration and disturbed the metabolism of C. cathayensis.•Cadmium induced oxidative stress in C. cathayensis hepatopancreas.•Immunosuppression occurred after exposure to cadmium stress, potentially leading to disease outbreaks.•Differentially expressed genes related to metabolism, immune responses, and antioxidant activity were also identified.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Type H vessel is a specific vessel subtype that is strongly positive for CD31 and endomucin (CD31hiEmcnhi). It has already been identified that it can tightly regulate the coupling of angiogenesis ...and osteogenesis in the long bone of mice and human beings. The long bone is formed through endochondral ossification, which is the same type of process happening in mandibular condyle. Although the ossification of long bone and mandibular condyle has the same developmental process, the existence of type H vessels in the mouse condyle remains unclear. To address this, we identified that abundant type H vessels existed in the subchondral bone of the mouse condylar head and endosteum of the mouse condylar neck. Meanwhile, immunofluorescence imaging of the condyles in different ages of male C57BL/6J mice demonstrated that type H vessels decreased while aging. Furthermore, we validated a positive correlation between type H vessels and Osterix+ osteoprogenitors in the condyle induced by mandibular advancement. Mechanistically, we confirmed that deferoxamine mesylate, which promoted the proliferation of type H endothelial cells by activating hypoxia-inducible factor 1α (HIF-1α) signaling pathways, largely prevented the osteopenia in the condyle induced by botulinum toxin type A. Collectively, these results demonstrate that in the mouse condyle, type H vessels in areas of high function positively correlate with bone formation. In addition, we show a novel influence of HIF-1α signaling on osteogenesis via an increase in type H vessels. In conclusion, promoting angiogenesis of type H vessels is a promising strategy for the therapeutic improvement of osteogenesis in mandibular condyle.
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CMK, NUK, OILJ, SAZU, UKNU, UL, UM, UPUK
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