| 1. |
- Aarrestad, Thea, et al.
(författare)
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Benchmark data and model independent event classification for the large hadron collider
- 2022
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Ingår i: SciPost Physics. - 2542-4653. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- We describe the outcome of a data challenge conducted as part of the Dark Machines (https://www.darkmachines.org) initiative and the Les Houches 2019 workshop on Physics at TeV colliders. The challenged aims to detect signals of new physics at the Large Hadron Collider (LHC) using unsupervised machine learning algorithms. First, we propose how an anomaly score could be implemented to define model-independent signal regions in LHC searches. We define and describe a large benchmark dataset, consisting of > 1 billion simulated LHC events corresponding to 10 fb−1 of proton-proton collisions at a center-of-mass energy of 13 TeV. We then review a wide range of anomaly detection and density estimation algorithms, developed in the context of the data challenge, and we measure their performance in a set of realistic analysis environments. We draw a number of useful conclusions that will aid the development of unsupervised new physics searches during the third run of the LHC, and provide our benchmark dataset for future studies at https://www.phenoMLdata.org. Code to reproduce the analysis is provided at https://github.com/bostdiek/DarkMachines-UnsupervisedChallenge.
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| 2. |
- Dai, Junxi, et al.
(författare)
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Promoted Sb removal with hydrogen production in microbial electrolysis cell by ZIF-67-derived modified sulfate-reducing bacteria bio-cathode
- 2023
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Ingår i: Science of the Total Environment. - : ELSEVIER. - 0048-9697 .- 1879-1026. ; 856
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Tidskriftsartikel (refereegranskat)abstract
- Bio-cathode Microbial electrolysis cell (MEC) has been widely discovered for heavy metals removal and hydrogen production. However, low electron transfer efficiency and heavy metal toxicity limit MEC treatment efficiency. In this study, ZIF-67 was introduced to modify Sulfate-reducing bacteria (SRB) bio-cathode to enhance the bioreduction of sulfate and Antimony (Sb) with hydrogen production in the MEC. ZIF-67 modified bio-cathode was developed from a bio-anode microbial fuel cell (MFC) by operating with an applied voltage of 0.8 V to reverse the polarity. Cyclic voltammetry, linear sweep voltammetry and electrochemical impedance were done to confirm the performance of the ZIF67 modified SRB bio-cathode. The synergy reduction of sulfate and Sb was accomplished by sulfide metal precipitation reaction from SRB itself. Maximum sulfate reduction rate approached 93.37 % and Sb removal efficiency could reach 92 %, which relies on the amount of sulfide concentration generated by sulfate reduction reaction, with 0.923 +/- 0.04 m(3) H-2/m(3) of hydrogen before adding Sb and 0.857 m(3) H-2/m(3) of hydrogen after adding Sb. The hydrogen was mainly produced in this system and the result of gas chromatography (GC) indicated that 73.27 % of hydrogen was produced. Meanwhile the precipitates were analyzed by X-ray diffraction and X-ray photoelectron spectroscopy to confirm Sb2S3 was generated from Sb (V).
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| 3. |
- Dai, Yi, et al.
(författare)
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Zn-doped CaFeO3 perovskite-derived high performed catalyst on oxygen reduction reaction in microbial fuel cells
- 2021
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Ingår i: Journal of Power Sources. - : ELSEVIER. - 0378-7753 .- 1873-2755. ; 489
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Tidskriftsartikel (refereegranskat)abstract
- Stable perovskite oxide is considered as a potential cathode for microbial fuel cells (MFCs). Herein, Zn is used as an effective element to modify the micro-structure and oxygen vacancy of perovskite to be a novel cathode catalyst. Physical characterizations show that due to partial volatilization at high temperature of Zn, perovskite forms hierarchically porous structures. Moreover, Zn is precipitated in electrochemical reaction to generate Zn vacancy in situ; thus, the active center of Fe has a superior interaction with oxygen-containing species, promoting the production of oxygen vacancy and forms a mixed valence state of Fe2+/Fe3+. The Zn-doped perovskite material CaFe0.7Zn0.3O3 exhibits remarkable oxygen reduction reaction (ORR) performances with outstanding onset potential (0.194 V vs. Ag/AgCl) and half-wave potential (-0.219 V vs. Ag/AgCl) under alkaline condition, which is better than Pt/C catalyst. Besides, CaFe0.7Zn0.3O3 shows an excellent four-electron pathway of ORR mechanism with remarkable corrosion resistance and stability, which enables a more reliable cathode electrocatalyst. The maximum power density of CaFe0.7Zn0.3O3 (892.10 +/- 90.79 mW m(-3)) testing on microbial fuel cell is comparable to the maximum power density (1012.86 +/- 84.03 mW m(-3)) of Pt/C. The findings of this work provide the feasibility of exploring inexpensive and high-performance cathode catalyst.
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| 4. |
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| 5. |
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| 6. |
- Sui, Zhongyi, et al.
(författare)
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An improved approach for assessing marine traffic complexity based on Voronoi diagram and complex network
- 2022
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Ingår i: Ocean Engineering. - : Elsevier BV. - 0029-8018 .- 1873-5258. ; 266, s. 112884-
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Tidskriftsartikel (refereegranskat)abstract
- The shipping industry is constantly expanding, and maritime traffic is increasing in numerous navigable waters. For maritime traffic safety, improving Situation Awareness (SA) is critical. However, the majority of relevant research placed a greater emphasis on the risk of a collision between two ships, but failed to capture the complexity of the global traffic situation. In this paper, a framework for evaluating marine traffic complexity is developed. With the combination of the Voronoi diagram and complex network, an improved Marine Traffic Complex Network (MTSCN) is coming into being. The geometric features of Voronoi diagram are used to divide the water area into multiple cells, setting safe distances is avoided by treating ships as neighbors and other ships. The impact of neighbors on the situation awareness and the impact of other ships on the collision risk of own ship are considered. This method can more truly demonstrate the traffic complexity in the water area. Simulations are introduced to investigate the validity of the proposed method with two ships crossing situation, three ships crossing situation and four ships crossing situation. The proposed method is further demonstrated using actual AIS data in the Yangtze River, and the correlation between complexity and other indicators has been analyzed. The result shows that the improved MTSCN may give an intuitive and accessible measure to capture the essence of maritime traffic, which will be helpful in understanding, monitoring, and controlling maritime traffic safety in the future. Additionally, the complexity based on MTSCN could enhance the SA of VTSOs by supporting decision-making.
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| 7. |
- Wei, Zhongbao, et al.
(författare)
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Noise-Immune Model Identification and State-of-Charge Estimation for Lithium-Ion Battery Using Bilinear Parameterization
- 2021
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Ingår i: IEEE Transactions on Industrial Electronics. - 0278-0046 .- 1557-9948. ; 68:1, s. 312-323
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Tidskriftsartikel (refereegranskat)abstract
- Accurate estimation of state of charge (SOC) is critical to the safe and efficient utilization of a battery system. Model-based SOC observers have been widely used due to their high accuracy and robustness, but they rely on a well-parameterized battery model. This article scrutinizes the effect of measurement noises on model parameter identification and SOC estimation. A novel parameterization method combining instrumental variable (IV) estimation and bilinear principle is proposed to compensate for the noise-induced biases of model identification. Specifically, the IV estimator is used to reformulate an overdetermined system so as to allow coestimating the model parameters and noise variances. The coestimation problem is then decoupled into two linear subproblems which are solved efficiently by a two-stage least squares algorithm in a recursive manner. The parameterization method is further combined with a Luenberger observer to estimate the SOC in real time. Simulations and experiments are performed to validate the proposed method. Results reveal that the proposed method is superior to existing method in terms of the immunity to noise corruption.
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| 8. |
- Yang, Weizhao, et al.
(författare)
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Transcriptome sequencing provides evidence of genetic assimilation in a toad-headed lizard at high altitude
- 2021
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Ingår i: Asian Herpetological Research. - 2095-0357. ; 12:3, s. 315-322
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Tidskriftsartikel (refereegranskat)abstract
- Understanding how organisms adapt to the environment is a compelling question in modern evolutionary biology. Genetic assimilation provides an alternative hypothesis to explain adaptation, in which phenotypic plasticity is first triggered by environmental factors, followed by selection on genotypes that reduce the plastic expression of phenotypes. To investigate the evidence of genetic assimilation in a high-altitude dweller, the toad-headed agama Phr ynocephalus vlangalii, we conducted a translocation experiment by moving individuals from high-to low-altitude environments. We then measured their gene expression profiles by transcriptome sequencing in heart, liver and muscle, and compared them to two low-altitude species P. axillaris and P. fors ythii. The results showed that the general expression profile of P. vlangalii was similar to its viviparous relative P. fors ythii, however, the differentially expressed genes in the liver of P. vlangalii showed a distinct pattern compared to both the low-altitude species. In particular, several key genes (FASN, ACAA2 and ECI2) within fatty acid metabolic pathway were no longer differentially expressed in P. valgnalii, suggesting the loss of plasticity for this pathway after translocation. This study provides evidence of genetic assimilation in fatty acid metabolism that may have facilitated the adaptation to high-altitude for P. vlangalii.
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| 9. |
- Yu, Bowei, et al.
(författare)
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Age-specific and sex-specific associations of visceral adipose tissue mass and fat-to-muscle mass ratio with risk of mortality
- 2023
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Ingår i: Journal of Cachexia, Sarcopenia and Muscle. - : John Wiley & Sons. - 2190-5991 .- 2190-6009. ; 14:1, s. 406-417
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundLimited studies have explored the association between visceral adipose tissue (VAT) mass and fat-to-muscle mass ratio (FMR) and mortality. We aimed to evaluate the sex-specific association of VAT and FMR with all-cause and cause-specific mortality by age. MethodsA total of 438 896 participants (49.8% men, mean age +/- standard deviation: 57 +/- 8 years for men; 56 +/- 8 years for women) were included from the UK Biobank cohort. The nature of VAT was predictive, as obtained by sex-stratified, non-linear prediction models. Fat and muscle mass were estimated using a bioelectrical impedance assessment device. FMR was calculated as the fat mass divided by the muscle mass in the whole body. VAT and FMRs were divided into quintiles in ascending order, and the 3rd quintile was used as the reference. Cox regression analyses were used to estimate the associations between VAT, FMR and mortality. ResultsDuring a median of 12.4 years of follow-up, we documented 29 903 deaths. After adjusting for various covariates, the individuals in the highest quintiles of VAT and FMR had the highest hazard ratios (HRs) of all-cause mortality [1.24 (95% confidence interval: 1.17-1.33) for VAT and 1.24 (1.17-1.31) for FMR in men; and 1.11 (1.03-1.21) for VAT in women], except that the 1st quintile of FMR in women had the greatest HR [1.18 (1.09-1.27)]. Significant interactions were observed in both sexes according to age category (P for interaction < 0.05). Among men <50 years, participants in the 1st and 5th quintiles of VAT and FMR had significantly higher risks of mortality [1.30 (1.02-1.66) and 1.67 (1.27-2.19) in VAT; 1.25 (0.99-1.56) and 1.41 (1.11-1.79) in FMR, respectively]; in women, this phenomenon was observed in the >= 60 age group [1.16 (1.06-1.27) and 1.19 (1.08-1.31) in VAT; 1.18 (1.08-1.29) and 1.11 (1.01-1.22) in FMR, respectively]. VAT showed a linear positive association with mortality in women <60 years and a J-shaped association from respiratory disease in both sexes >= 60 years. FMR showed a linear positive association with mortality from cancer in men <60 years and a J-shaped association with mortality from cause-specific mortality in both sexes >= 60 years, except for mortality from cardiovascular disease in men. ConclusionsMost associations of VAT and FMR with all-cause mortality were J-shaped and were significantly modified by age status (<50, 50-59 and >= 60 years). The clinical implication is that regarding body composition and VAT mass, different health strategies may be adopted for people of different sexes and ages.
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| 10. |
- Zhang, Dong, et al.
(författare)
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Design and Gait Optimization of Quadruped Robot Based on Energy Conservation
- 2020
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Ingår i: 2020 3rd International Conference on Control and Robots, ICCR 2020. ; , s. 112-119
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Konferensbidrag (refereegranskat)abstract
- Stability and energy consumption are important performance indicators for quadruped robots. In this paper, a simple quadruped robot with high dynamic performance and a distributed control system based on CPG are designed. Moreover, the ADAMS-MATLAB joint simulation platform is established to study the influence of gait parameters on gait stability and energy consumption. The optimal step length is obtained through theoretical calculation, and a gait optimization strategy is proposed to improve the stability of the quadruped robot and reduce the energy consumption. Finally, a single-leg experiment platform was built to realize the robot's specific gait under optimized conditions and test the accuracy and robustness of the control system. The results of experiment and simulation show the feasibility of the design and gait optimization methods for the quadruped robot and achieve energy consumption and high dynamic performance.
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| 11. |
- Zhang, Wei, et al.
(författare)
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Geochemical evaluation of heavy metal migration in Pb-Zn tailings covered by different topsoils
- 2016
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Ingår i: Journal of Geochemical Exploration. - : Elsevier BV. - 0375-6742 .- 1879-1689. ; 165, s. 134-142
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Tidskriftsartikel (refereegranskat)abstract
- Heavy metal migration was evaluated in Pb-Zn tailings covered by different topsoil constructions. The four topsoil constructions each had different interlayers: one with direct topsoiling above the tailings (CT); the second had a limestone interlayer between the tailings and topsoil with two geotextile layers set above and below the interlayer (SLS); the third had a lime interlayer, also with two geotextile layers (SL); and the fourth had a clay interlayer with two geotextile layers (SC). The topsoils were evaluated in a 210-day laboratory column leaching experiments and in a 3-year field cover application at an abandoned Pb-Zn tailings pond (northeastern China). The contents of Pb, Zn and Cd in the soils, leachates, interlayers and leaves of Amorpha fruticosa L. were analysed by inductively coupled plasma optical emission spectroscopy (ICP-OES).Results showed that the pH values of the leachates from the columns increased with time, from 6.5 to the range of 7.5 to 8.03, and the maximum in pH in C1 (tailings), C2 (CT), C3 (SLS), C4 (SL) and C5 (SC) appeared after the 180th day, at 7.85, 7.89, 7.78, 8.03, and 7.89, respectively. The topsoil effectively reduced the concentrations of Pb, Zn and Cd in the leachate, and the addition of a limestone or lime interlayer enhanced the efficiency, especially for Zn and Cd. The Pb, Zn and Cd concentrations in the topsoil that directly cover the tailings were appreciably less than the initial concentrations, resulting from the eluviation. The presence of a limestone or lime interlayer reduced the mobility of Zn and Cd, and a clay interlayer was effective in preventing the migration of Pb and Zn but had less impact on Cd.During the 3-year field experiment, the pH values of the topsoil increased slightly with time, from 7.15 to the range of 7.67 to 8.20. At the end of the experiment, Pb, Zn and Cd concentrations in the topsoil at the SLS, SL and SC plots showed little change compared with the initial value in 2012. Acid-soluble Pb, Zn and Cd concentrations of the upper soil (0–0.1 m) at CT increased from 0.19, 1.95 and 0.11 mg kg− 1 in 2012 to 1.82, 32.87 and 0.56 mg kg− 1 in 2015, indicating that acid-soluble heavy metals migrated from tailings to topsoil. Acid-soluble Cd in topsoil and in the interlayer showed a small increase at plot SC, indicating that Cd may migrate through the clay layer to topsoil with pore water. The Pb contents in leaves at SLS and SL were 2.38 and 3.04 mg kg− 1, which were appreciably lower than at CT and SC, and the Zn and Cd contents in leaves at CT were 45.78 and 0.26 mg kg− 1, which were higher than at SLS, SL and SC. Topsoiling with an interlayer could be a reliable technique for preventing toxic elements from moving downward or upward during ecological restoration of tailings ponds.
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| 12. |
- Zhang, Wei, et al.
(författare)
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Vertical distribution and historical loss estimation of heavy metals in an abandoned tailings pond at HTM copper mine, northeastern China
- 2016
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Ingår i: Environmental Earth Sciences. - : Springer Science and Business Media LLC. - 1866-6280 .- 1866-6299. ; 75:22
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Tidskriftsartikel (refereegranskat)abstract
- In the tailings pond of the Hongtou Mountain (HTM) copper mine in northeastern China, four sampling points were set at intervals of 80 m along the discharge direction of the tailings slurry to investigate the vertical distribution characteristics of heavy metals in shallow layer (0–5 m) tailings. In addition, 18 sampling points were set by a grid method (50 m × 50 m) to estimate the historical loss amount of contaminants from the surface layer (0–1.2 m) of the HTM tailings pond. Tailings samples were taken at every 0.2 m, and the pH value, the total content and acid-soluble fraction of heavy metals and chemical compositions were determined following the standard methods. The results showed that the pH values of tailings ranged from 3.01 to 8.11, which increased with depths from 0 to 2.2 m, and varied between pH values of 7.0 and 7.5 in 2.2–5 m. Cu, Zn, Cd and S were the major contaminants in the tailings. The total Cu content was higher at the downstream sampling points near the dam. Zn and Cd were higher at the upstream sampling points near the discharge. Three distinct zones (oxidised zone, cemented layer and unoxidised zone) were found in the HTM tailings pond. The depth of the oxidised zone was 0.4 m, and the elements in the oxidised tailings were obviously lower due to the sulphides oxidation and acid mine drainage. Cu was enriched in the cemented layer, and the Cu content reached values between 1200 and 3000 mg/kg, which were 1.5–3 times higher than the average value. Zn, Cd, Ni and Fe were also slightly elevated in the cemented layer. Below the groundwater table, the acid-soluble fraction of Cu, Zn and Cd was relatively stable at a lower level and showed insignificant variations, as the cemented layer and groundwater could efficiently prevent the oxidation process. The amount of Cu, Zn and Cd leaving the tailings pond with drainage water was 8.08, 21.60 and 72.93%, respectively, of the amount released from oxidation. Most of the Cu released from oxidation was retained in the cemented layer. The total mass of S, Zn and Cd released from the tailings to surrounding ecosystems was estimated approximately 762.75 t, 6997.5 and 86.06 kg, respectively, in the last 20 years.
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| 13. |
- Zou, Huiyun, et al.
(författare)
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Persistent transmission of carbapenem-resistant, hypervirulent Klebsiella pneumoniae between a hospital and urban aquatic environments
- 2023
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Ingår i: Water Research. - : Elsevier BV. - 0043-1354 .- 1879-2448. ; 242
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Tidskriftsartikel (refereegranskat)abstract
- The increasing prevalence of infections caused by carbapenem-resistant hypervirulent Klebsiella pneumoniae strains (CR-hvKP) prompts the question of whether these strains also circulate outside of clinical settings. However, the environmental occurrence and dissemination of CR-hvKP are poorly studied. In the current study, we investigated the epidemiological characteristics, and dissemination dynamics of carbapenem-resistant K. pneumoniae (CRKP) isolated from a hospital, an urban wastewater treatment plant (WWTP), and adjacent rivers in Eastern China during one year of monitoring. A total of 101 CRKP were isolated, 54 were determined to be CR-hvKP harboring pLVPK-like virulence plasmids, which were isolated from the hospital (29 out of 51), WWTP (23 out of 46), and rivers (2 out of 4), respectively. The period with lowest detection rate of CR-hvKP in the WWTP, August, corresponded with the lowest detection rate at the hospital. Comparing the inlet and outlet of the WWTP, no significant reduction of the detection of CR-hvKP and relative abundance of carbapenem resistance genes was observed. The detection rate of CR-hvKP and the relative abundance of carbapenemase genes were significantly higher in the WWTP in colder months compared to warmer months. Clonal dissemination of CR-hvKP clones of ST11-KL64 between the hospital and the aquatic environment, as well as the horizontal spread of IncFII-IncR and IncC plasmids carrying carbapenemase genes, was observed. Furthermore, phylogenetic analysis showed that the ST11-KL64 CR-hvKP strain has spread nationally by interregional transmission. These results indicated transmission of CR-hvKP clones between hospital and urban aquatic environments, prompting the need for improved wastewater disinfection and epidemiological models to predict the public health hazard from prevalence data of CR-hvKP.
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