Over-supply in Public Transportation: Case Study of Bus and Metro Lines in Harbin City, China

As the two most important modes in public transportation, the coordinated development of bus and metro networks significantly influences the efficiency of public transportation. However, two parallel bus and metro lines belonging to different operators may lead to supply competition and consequently yield over-supply. Taking two parallel bus and metro lines in Harbin city, China as a case study, this paper, drawing on game theory, establishes a utility model based on the two lines’ frequencies, and reveals and explains the fundamental reason for the over-supply problem using a Nash equilibrium. In an attempt to resolve this issue, the study proposes a new operation mode: integrating frequencies of the two modes to obtain larger total profits then reallocating the total profits to the two modes. The case study shows that this new operation mode can effectively solve the over-supply problem while satisfying both operators of the two modes, and hence having practical value

New Failure Mode and Effects Analysis based on D Numbers Downscaling Method

Failure mode and effects analysis (FMEA) is extensively applied to process potential faults in systems, designs, and products. Nevertheless, traditional FMEA, classical risk priority number (RPN), acquired by multiplying the ratings of occurrence, detection, and severity, risk assessment, is not effective to process the uncertainty in FMEA. Many methods have been proposed to solve the issue but deficiencies exist, such as huge computing quality and the mutual exclusivity of propositions. In fact, because of the subjectivity of experts, the boundary of two adjacent evaluation ratings is fuzzy so that the propositions are not mutually exclusive. To address the issues, in this paper, a new method to evaluate risk in FMEA based on D numbers and evidential downscaling method, named as D numbers downscaling method, is proposed. In the proposed method, D numbers based on the data are constructed to process uncertain information and aggregate the assessments of risk factors, for they permit propositions to be not exclusive mutually. Evidential downscaling method decreases the number of ratings from 10 to 3, and the frame of discernment from 2^{10} to 2^3 , which greatly reduce the computational complexity. Besides, a numerical example is illustrated to validate the high efficiency and feasibility of the proposed method

Optimal Extent of Transhiatal Gastrectomy and Lymphadenectomy for the Stomach-Predominant Adenocarcinoma of Esophagogastric Junction: Retrospective Single-Institution Study in China

Background: The optimal extent of gastrectomy and lymphadenectomy for esophagogastric junction (EGJ) cancer is controversial. Our study aimed to compare the long-term survival of transhiatal proximal gastrectomy with extended periproximal lymphadenectomy (THPG with EPL) and transhiatal total gastrectomy with complete perigastric lymphadenectomy (THTG with CPL) for patients with the stomach-predominant EGJ cancer.Methods: Between January 2004, and August 2015, 306 patients with Siewert II tumors were divided into the THTG group (n = 148) and the THPG group (n = 158). Their long-term survival was compared according to Nishi's classification. The Kaplan–Meier method and Cox proportional hazards models were used for survival analysis.Results: There were no significant differences between the two groups in the distribution of age, gender, tumor size or Nishi's type (P > 0.05). However, a significant difference was observed in terms of pathological tumor stage (P < 0.05). The 5-year overall survival rates were 62.0% in the THPG group and 59.5% in the THTG group. The hazard ratio for death was 0.455 (95% CI, 0.337 to 0.613; log-rank P < 0.001). Type GE/E = G showed a worse prognosis compared with Type G (P < 0.05). Subgroup analysis stratified by Nishi's classification, Stage IA-IIB and IIIA, and tumor size ≤ 30 mm indicated significant survival advantages for the THPG group (P < 0.05). However, this analysis failed to show a survival benefit in Stage IIIB (P > 0.05).Conclusions: Nishi's classification is an effective method to clarify the subdivision of Siewert II tumors with a diameter ≤ 40 mm above or below the EGJ. THPG with EPL is an optimal procedure for the patients with the stomach-predominant EGJ tumors ≤30 mm in diameter and in Stage IA-IIIA. For more advanced and larger EGJ tumors, further studies are required to confirm the necessity of THTG with CPL

Duckweed (Lemna minor) as a Model Plant System for the Study of Human Microbial Pathogenesis

BACKGROUND: Plant infection models provide certain advantages over animal models in the study of pathogenesis. However, current plant models face some limitations, e.g., plant and pathogen cannot co-culture in a contained environment. Development of such a plant model is needed to better illustrate host-pathogen interactions. METHODOLOGY/PRINCIPAL FINDINGS: We describe a novel model plant system for the study of human pathogenic bacterial infection on a large scale. This system was initiated by co-cultivation of axenic duckweed (Lemna minor) plants with pathogenic bacteria in 24-well polystyrene cell culture plate. Pathogenesis of bacteria to duckweed was demonstrated with Pseudomonas aeruginosa and Staphylococcus aureus as two model pathogens. P. aeruginosa PAO1 caused severe detriment to duckweed as judged from inhibition to frond multiplication and chlorophyll formation. Using a GFP-marked PAO1 strain, we demonstrated that bacteria colonized on both fronds and roots and formed biofilms. Virulence of PAO1 to duckweed was attenuated in its quorum sensing (QS) mutants and in recombinant strains overexpressing the QS quenching enzymes. RN4220, a virulent strain of S. aureus, caused severe toxicity to duckweed while an avirulent strain showed little effect. Using this system for antimicrobial chemical selection, green tea polyphenols exhibited inhibitory activity against S. aureus virulence. This system was further confirmed to be effective as a pathogenesis model using a number of pathogenic bacterial species. CONCLUSIONS/SIGNIFICANCE: Our results demonstrate that duckweed can be used as a fast, inexpensive and reproducible model plant system for the study of host-pathogen interactions, could serve as an alternative choice for the study of some virulence factors, and could also potentially be used in large-scale screening for the discovery of antimicrobial chemicals

Model Experimental Study of Damage Effects of Ship Structures under the Contact Jet Loads of Bubble in a Water Tank

The damage effects of ship structures under the contact jet loads of bubble are studied by using an electric spark bubble as well as high-speed photography. A series of model experiments of ship structures under contact explosion was carried out in a water tank. On the one hand, we monitored the displacement and period of the oscillation of a hull plate of a ship model with a large bending rigidity. On the other hand, we observed the overall motion of a box-beam model with a small bending rigidity. The results show that when the distance parameter is less than 0.6, the bubble jet will impact on the surface of the structure directly, which is defined as “contact bubble jet” herein. The contact bubble jet causes significant local loads on the ship and induces the “sagging moment” effect. This mainly results from the relatively negative bending moment caused by the bubble attached to the hull. With the increase of detonation distance, this negative bending moment decreases. As a result, the oscillation amplitude of the ship structure decreases sharply and the oscillation period reduces gradually

Metrological Standardizing for Future Microfluidic-based Point-of-Care Diagnostic Products

Point-of-Care diagnostic devices are considered to be one potential killer application of the maturing microfluidic technology. Metrological standardizing plays an important role in speeding up success of microfluidics from the lab bench to market. To build its own specific domain, microfluidics needs to be armed with defined vocabulary and integrated standard system. In this article, we discuss the relationship between microfluidic commercialization and standardization. Metrological issues of microfluidic technology are investigated and divided into three main categories: materials, process development and device characterization. Existing standards and associated organizations are listed while a future roadmap of microfluidic metrology is proposed

Effect of tempering on microstructure and mechanical properties of 3Mn-Si-Ni martensitic steel

The dependence of microstructures and mechanical properties on tempering temperature (from 180 to 650 °C) in a designed 3Mn-Si-Ni martensitic steel was systematically analyzed. Microstructure was characterized using scanning and transmission electron microscopy; mechanical properties were measured using uniaxial tensile test and Charpy V-notch impact test. After tempering at different temperatures, recovery, partial recrystallization, carbides precipitation and decomposition of residual austenite were observed. After tempering at 230 °C, an excellent combination of strength (1550 MPa) and toughness (91.5 J) was achieved, due to high dislocation density and ε-carbides precipitation. However, with an increase in tempering temperature from 320 to 550 °C, tempered martensite embrittlement was observed, where impact energy was ~ 10 J. It was ascribed to cementite formation instead of transition carbides and decomposition of residual austenite. With an increase in tempering temperature up to 650 °C, high fracture impact toughness of 75 J was obtained with deteriorated tensile strength of 850 MPa due to strong recovery and partial recrystallization

A Study of the EH36 Surface Sediment Layer under Joint Protection from Seawater Electrolysis Antifouling and Impressed Current Cathode Protection (ICCP) in a Marine Environment

A joint protection device for seawater electrolysis antifouling and ICCP was constructed, and comparative experiments were conducted to study the composition of the EH36 surface deposition layer under joint protection in a marine environment. Surface morphology analysis, energy-dispersive spectroscopy (EDS) imaging analysis, and X-ray diffraction (XRD) composition analysis were performed on the surface deposition layers of the experimental samples. The experimental results showed that under joint protection, a sedimentary layer was rapidly formed on the surface of EH36 to isolate the seawater medium, and this layer was mainly composed of Mg(OH)2 and a small amount of CaCO3. There was no corrosion on the surface of the EH36 substrate. When only ICCP was used, a relatively thin layer of calcium magnesium was deposited on the surface of EH36. Marine fouling organisms adhere to the surface of calcium and magnesium sedimentary layers and the EH36 substrate, and their attachment affects the formation of calcium and magnesium sedimentary layers. Moreover, marine fouling organisms cause corrosion on the surface of the EH36 substrate. The joint protection of seawater electrolysis antifouling and ICCP can simultaneously prevent electrochemical corrosion and marine biological fouling corrosion on the surface of EH36

Characteristics of Pore Structure and Fractal Dimension of Isometamorphic Anthracite

The geologic conditions of No. 3 coal seams are similar to Sihe and Zhaozhuang Collieries, however, the gas production is significantly different. To better understand the effect of pores, by means of experimental measurements and quantitative analysis, the pore properties of high-rank isometamorphic anthracite were thoroughly studied. Our study showed that the pore structures were predominantly adsorptive, accounting for more than 88% of the specific surface area. The coal pores showed typical three-stage fractal characteristics at boundary points of 1 nm and 9 nm (7 nm of coal samples from Zhaozhuang Colliery), and the fractal dimension with 1–9 nm (or 1–7 nm), as being significantly larger than those measured outside the given ranges. Pores in samples from Sihe Colliery were mainly open spherical or ellipsoidal pores in shape; conversely, those from Zhaozhuang Colliery were mainly Y-shaped, V-shaped, or ‘ink-bottle’ type

Unified modeling of the microstructure and densification of TC4 powder titanium alloy during hot deformation

An accurate material constitutive model is very important to apply numerical simulation technology to predict, establish and optimize the thermoplastic forming process parameters of powder titanium alloy. To achieve this goal, the microstructure evolution and densification of TC4 powder titanium alloy were investigated during compression at temperatures from 860 °C to 960 °C, strain rates from 0.05 s−1 to 20 s−1 and strains from 0.357 to 1.204. The results show that the microstructure undergoes dynamic recrystallization under different conditions. High temperature, large deformation degree and low strain rate are helpful to reduce porosity, pore size and pore colony. Plastic deformation and diffusion are two main mechanisms of densification. The microstructure evolution and densification model were established, combining the power constitutive law, a unified constitutive model was proposed to predict flow stress, microstructure and relative density of TC4 powder titanium alloy. The model constants were determined through a genetic algorithm. The predicted values of flow stress and relative density agreed well with the experimental values. The variations in relative density with temperature, strain rate and strain were analyzed based on the prediction results