Risk Analysis Based on AHP and Fuzzy Comprehensive Evaluation for Maglev Train Bogie

The maglev bogie is the key subsystem for maglev train security. To ensure life and property security, it is essential to evaluate its risk level before its operation. In this paper, a combinational method of analytic hierarchy process and fuzzy comprehensive evaluation is proposed to assess hazards in a complex maglev bogie system associated with multiple subsystems' failures. The very comprehensive identification of risk sources has been done by analyzing the structure of maglev bogie. Furthermore, based on the fuzzy theory, linguistic evaluation set is classified according to risk tolerance. The score of each risk factor is obtained by weighted sum of the result of fuzzy comprehensive evaluation. Our results show that the degree of maglev bogie's risk is within the range of acceptability. The merits of this work facilitate finding the weak links and determining the maintenance of maglev bogie system

Risk Analysis Based on AHP and Fuzzy Comprehensive Evaluation for Maglev Train Bogie

The maglev bogie is the key subsystem for maglev train security. To ensure life and property security, it is essential to evaluate its risk level before its operation. In this paper, a combinational method of analytic hierarchy process and fuzzy comprehensive evaluation is proposed to assess hazards in a complex maglev bogie system associated with multiple subsystems’ failures. The very comprehensive identification of risk sources has been done by analyzing the structure of maglev bogie. Furthermore, based on the fuzzy theory, linguistic evaluation set is classified according to risk tolerance. The score of each risk factor is obtained by weighted sum of the result of fuzzy comprehensive evaluation. Our results show that the degree of maglev bogie’s risk is within the range of acceptability. The merits of this work facilitate finding the weak links and determining the maintenance of maglev bogie system

Rayleigh and S wave tomography constraints on subduction termination and lithospheric foundering in central California

The crust and upper mantle structure of central California have been modified by subduction termination, growth of the San Andreas plate boundary fault system, and small-scale upper mantle convection since the early Miocene. Here we investigate the contributions of these processes to the creation of the Isabella Anomaly, which is a high seismic velocity volume in the upper mantle. There are two types of hypotheses for its origin. One is that it is the foundered mafic lower crust and mantle lithosphere of the southern Sierra Nevada batholith. The alternative suggests that it is a fossil slab connected to the Monterey microplate. A dense broadband seismic transect was deployed from the coast to the western Sierra Nevada to fill in the least sampled areas above the Isabella Anomaly, and regional-scale Rayleigh and S wave tomography are used to evaluate the two hypotheses. New shear velocity (Vs) tomography images a high-velocity anomaly beneath coastal California that is sub-horizontal at depths of ∼40–80 km. East of the San Andreas Fault a continuous extension of the high-velocity anomaly dips east and is located beneath the Sierra Nevada at ∼150–200 km depth. The western position of the Isabella Anomaly in the uppermost mantle is inconsistent with earlier interpretations that the Isabella Anomaly is connected to actively foundering foothills lower crust. Based on the new Vs images, we interpret that the Isabella Anomaly is not the dense destabilized root of the Sierra Nevada, but rather a remnant of Miocene subduction termination that is translating north beneath the central San Andreas Fault. Our results support the occurrence of localized lithospheric foundering beneath the high elevation eastern Sierra Nevada, where we find a lower crustal low Vs layer consistent with a small amount of partial melt. The high elevations relative to crust thickness and lower crustal low Vs zone are consistent with geological inferences that lithospheric foundering drove uplift and a ∼3–4 Ma pulse of basaltic magmatism

Rayleigh and S wave tomography constraints on subduction termination and lithospheric foundering in central California

The crust and upper mantle structure of central California have been modified by subduction termination, growth of the San Andreas plate boundary fault system, and small-scale upper mantle convection since the early Miocene. Here we investigate the contributions of these processes to the creation of the Isabella Anomaly, which is a high seismic velocity volume in the upper mantle. There are two types of hypotheses for its origin. One is that it is the foundered mafic lower crust and mantle lithosphere of the southern Sierra Nevada batholith. The alternative suggests that it is a fossil slab connected to the Monterey microplate. A dense broadband seismic transect was deployed from the coast to the western Sierra Nevada to fill in the least sampled areas above the Isabella Anomaly, and regional-scale Rayleigh and S wave tomography are used to evaluate the two hypotheses. New shear velocity (Vs) tomography images a high-velocity anomaly beneath coastal California that is sub-horizontal at depths of ∼40–80 km. East of the San Andreas Fault a continuous extension of the high-velocity anomaly dips east and is located beneath the Sierra Nevada at ∼150–200 km depth. The western position of the Isabella Anomaly in the uppermost mantle is inconsistent with earlier interpretations that the Isabella Anomaly is connected to actively foundering foothills lower crust. Based on the new Vs images, we interpret that the Isabella Anomaly is not the dense destabilized root of the Sierra Nevada, but rather a remnant of Miocene subduction termination that is translating north beneath the central San Andreas Fault. Our results support the occurrence of localized lithospheric foundering beneath the high elevation eastern Sierra Nevada, where we find a lower crustal low Vs layer consistent with a small amount of partial melt. The high elevations relative to crust thickness and lower crustal low Vs zone are consistent with geological inferences that lithospheric foundering drove uplift and a ∼3–4 Ma pulse of basaltic magmatism

Observations of the vertical distributions of summertime atmospheric pollutants and the corresponding ozone production in Shanghai, China

Ground-based multi-axis differential optical absorption spectroscopy (MAX-DOAS) and lidar measurements were performed in Shanghai, China, during May 2016 to investigate the vertical distribution of summertime atmospheric pollutants. In this study, vertical profiles of aerosol extinction coefficient, nitrogen dioxide (NO2) and formaldehyde (HCHO) concentrations were retrieved from MAX-DOAS measurements using the Heidelberg Profile (HEIPRO) algorithm, while vertical distribution of ozone (O-3) was obtained from an ozone lidar. Sensitivity study of the MAX-DOAS aerosol profile retrieval shows that the a priori aerosol profile shape has significant influences on the aerosol profile retrieval. Aerosol profiles retrieved from MAX-DOAS measurements with Gaussian a priori profile demonstrate the best agreements with simultaneous lidar measurements and vehicle-based tethered-balloon observations among all a priori aerosol profiles. Tropospheric NO2 vertical column densities (VCDs) measured with MAX-DOAS show a good agreement with OMI satellite observations with a Pearson correlation coefficient (R) of 0.95. In addition, measurements of the O-3 vertical distribution indicate that the ozone productions do not only occur at surface level but also at higher altitudes (about 1.1 km). Planetary boundary layer (PBL) height and horizontal and vertical wind field information were integrated to discuss the ozone formation at upper altitudes. The results reveal that enhanced ozone concentrations at ground level and upper altitudes are not directly related to horizontal and vertical transportation. Similar patterns of O3 and HCHO vertical distributions were observed during this campaign, which implies that the ozone productions near the surface and at higher altitudes are mainly influenced by the abundance of volatile organic compounds (VOCs) in the lower troposphere

Supercritical CO2 Fluid Extraction of Elaeagnus mollis Diels Seed Oil and Its Antioxidant Ability

Supercritical fluid carbon dioxide (SF-CO2) was used to extract oil from Elaeagnus mollis Diels (E. mollis Diels) seed and its antioxidant ability was also investigated. The effect of extraction pressure (20–35 MPa), extraction temperature (35–65 C), extraction time (90–180 min) and seed particle size (40–100 mesh) on the oil yield were studied. An orthogonal experiment was conducted to determine the best operating conditions for the maximum extraction oil yield. Based on the optimum conditions, the maximum yield reached 29.35% at 30 MPa, 50 C, 150 min, 80 mesh seed particle size and 40 g/min SF-CO2 flow rate. The E. mollis Diels seed (EDS) oil obtained under optimal SF-CO2 extraction conditions had higher unsaturated fatty acid content (91.89%), higher vitamin E content (96.24 ± 3.01 mg/100 g) and higher total phytosterols content (364.34 ± 4.86 mg/100 g) than that extracted by Soxhlet extraction (SE) and cold pressing (CP) methods. The antioxidant activity of the EDS oil was measured by DPPH and hydroxyl radical scavenging test. EDS oil extracted by different methods exhibited a dose-dependent antioxidant ability, with IC50 values of no significant differences. Based on the results of correlation between bioactive compounds, lupeol and -tocopherol was the most important antioxidant in EDS oil

Forms of Nutrients in Rivers Flowing into Lake Chaohu: A Comparison between Urban and Rural Rivers

Nutrient inputs from rivers play an important role in lake eutrophication. To compare the forms characteristics of phosphorus (P) and nitrogen (N) in rivers flowing through rural and urban areas, water samples were collected seasonally from five urban rivers and six rural rivers flowing to Lake Chaohu, China. Higher total phosphorus (TP), particulate phosphorus (PP), soluble reactive phosphorus (SRP), and dissolved nonreactive phosphorus (DNP) concentrations and SRP/TP percentages were observed in urban rivers than in rural rivers, and PP/TP and DNP/TP ratios were lower in urban rivers than in rural rivers. The concentrations of total nitrogen (TN) and all N forms other than dissolved organic nitrogen (DON) were significantly higher in urban rivers than in rural rivers. NH4+/TN levels were higher in urban rivers, whereas PN/TN and DON/TN ratios were significantly lower in urban rivers compared with rural rivers. NO3−/TN and NO2−/TN levels were similar between the two groups of rivers. TP, BD-P, and NaOH-P levels in urban river surface sediments were significantly higher than those in rural rivers. NaOH-P/TP ratios were significantly elevated in urban rivers, whereas HCl-P/TP and Res-P/TP ratios were significantly lower compared with rural rivers. Urban rivers have transferred large quantities of NH4+ and SRP into Lake Chaohu, resulting in higher TP and TN levels and NH4+/TN and SRP/TP ratios. Decreasing the input of NH4+ and SRP into urban rivers is a high priority for mitigating eutrophication and algal blooms in Lake Chaohu

The role of tubificid worms (

Sediment resuspension is an important internal lake process in regulating nutrient cycling and ecosystem structure. Tubificid worms are widely and abundantly distributed in freshwater ecosystems and are able to alter the sediment characteristics. This study was conducted to verify the hypothesis that the alteration of sediments by tubificids may substantially influence the sediment resuspension process. Specifically, we investigated the influence of Limnodrilus hoffmeisteri (Tubificidae) on sediment resuspension using an apparatus designed to simulate the sediment resuspension process in Lake Taihu (China). We examined L. hoffmeisteri according to its density (30 000 ind.m−2) in Lake Taihu and simulated the light (3.2 m.s−1), moderate (5.1 m.s−1) and strong (8.7 m.s−1) wind processes present in Lake Taihu. Tubificids loosened the sediment through their feeding and defecation activities and increased the sediment water content. The appearance of tubificids increased the suspended solids (SS) in a 1.6 m water column under all three wind processes. During the sedimentation process, SS decreased rapidly in both the control and tubificid treatments. The total SS in the water column was significantly increased by tubificids and it changed significantly with time. In addition, the small size particles of the SS in the tubificid treatment were higher than that in the control. So, the appearance of tubificid worms (L. hoffmeisteri) enhanced sediment resuspension and raised the proportion of small size particles in SS.- Tubificid worms (imnodrilus hoffmeisteri) loosen sediment and increase the sediment water content and surface roughness. - Tubificid worms increase suspended solids in the water column during light, moderate, and strong wind processes. - Tubificid worms raise the proportion of fine particles in suspended solids