34 research outputs found

    Theoretical Study on Relaxed Surrounding Rock Pressure on Shallow Bias Neighborhood Tunnels under Seismic Load

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    To study the distribution of relaxed surrounding rock pressure on the shallow bias neighborhood tunnels under the combined action of horizontal and vertical earthquake force, finite element software was used for failure mode analysis. Moreover, with the pseudo-static method, the calculation formula for the relaxed pressure on the shallow bias neighborhood tunnels was derived and used to analyze the variation of the rupture angle of these tunnels under the action of the seismic force. The study shows that: shallow bias neighborhood tunnels basically follow a ā€œWā€ failure pattern under the combined action of horizontal and vertical seismic force, and the failure scope of the surrounding rock is controlled by four rupture angles. Rupture angles Ī²2 and Ī²3 between the deep and shallow tunnels of the shallow bias neighborhood tunnels are not affected by the surface slope. For tunnels with the same grade of the surrounding rock, the greater the seismic intensity, the smaller the value of Ī²2, and the greater the value of Ī²3. While at the same seismic intensity, the higher the grade of the surrounding rock, the smaller the Ī²2 and Ī²3. Ruptures angles Ī²1 and Ī²4 are influenced by the surface slope, seismic intensity and surrounding rock grades. A steeper surface slope leads to a smaller Ī²1 and a greater Ī²4; Ī²1 increase and Ī²4 decrease with increasing seismic intensity; while, Ī²1 and Ī²4 both show a decreasing trend with an increasing rock grade

    Practical Guidance for Ultrasonic Evaluation of Hemophilic Arthropathy

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    Hemophilic arthropathy is the most common complication of hemophilia and is also the main factor of disability in hemophilia patients. Using high-resolution musculoskeletal ultrasound examination technology, the joints of hemophilia patients can be rapidly evaluated and injury grade can be established, which can provide the basis and guidance for clinical evaluation, treatment and prognosis. Standardized ultrasound operation and scoring are very important for objective evaluation of joint condition. This paper introduces the ultrasonic examination and scoring method of hemophilic arthropathy which is suitable for the clinical needs of China in detail in order to improve the consistency of ultrasonic evaluation of hemophilia centers

    Research on ventilation cooling devices with low-energy consumption characteristics

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    Due to the problem of air conditioning shortage in summer, homeless people and poor residents are threatened by high temperature, a low-energy ventilation cooling device (LEVCD) is designed to prevent heatstroke and improve the living environment. The abandoned plastic bottles, as a core ventilation cooling accessory, were used to construct the LEVCD. The flow and ventilation cooling characteristics of the LEVCD were investigated. The representative image was fabricated to discuss ventilation cooling performance by examining temperature, pressure, and velocity nephograms. The fluid dynamics characteristics, such as the jet action and throttling effect, were analyzed. The temperature drop efficiency index is presented to examine the ventilation cooling characteristics of the LEVCD. The results show that the abandoned plastic bottles were recycled, which can effectively reduce environmental pollution. The ventilation cooling function is mainly induced by jet action. The ventilation cooling effect increases with the increase in inlet airflow velocity. The temperature drop efficiency increase with the increase in ambient temperature

    An analysis on comprehensive influences of thermoelectric power generation based on waste heat recovery

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    The thermoelectric characteristics of the thermoelectric power generation based on waste heat recovery, including the influence factors of cooling water flow rate, the overlapping value between load resistance and internal resistance and pressing block weight, were experimentally discussed. In addition to the experimental analyses of simple series-parallel configuration, the thermoelectric characteristics of complex series-parallel configurations were numerically simulated. The fast locating method was proposed to achieve the optimal thermoelectric characteristic. The results showed that the cooling water flow rate makes slight impact on total pressing block weight. All the thermoelectric characteristics increase with increasing pressing block weight. The overlapping value between internal resistance and load resistance is an core index, which determines the optimum thermoelectric efficiency. The changing law of thermoelectric characteristics of numerical simulations are identical with testing data, but the smoothness of simulation curves are better. Three complex series-parallel configurations perform identical total output power characteristic, which increases with increasing thermoelectric modules. However, the output power of a single thermoelectric module exhibits unique characteristic. The inflection points and peak value points in DSIP, ISDP and ISIP configurations are used to examine the output power characteristics of thermoelectric power generation and a single thermoelectric module

    Metabolic Profiles Reveal Changes in Wild and Cultivated Soybean Seedling Leaves under Salt Stress

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    <div><p>Clarification of the metabolic mechanisms underlying salt stress responses in plants will allow further optimization of crop breeding and cultivation to obtain high yields in saline-alkali land. Here, we characterized 68 differential metabolites of cultivated soybean (<i>Glycine max</i>) and wild soybean (<i>Glycine soja</i>) under neutral-salt and alkali-salt stresses using gas chromatography-mass spectrometry (GC-MS)-based metabolomics, to reveal the physiological and molecular differences in salt tolerance. According to comparisons of growth parameters under the two kinds of salt stresses, the level of inhibition in wild soybean was lower than in cultivated soybean, especially under alkali-salt stress. Moreover, wild soybean contained significantly higher amounts of phenylalanine, asparagine, citraconic acid, citramalic acid, citric acid and Ī±-ketoglutaric acid under neutral-salt stress, and higher amounts of palmitic acid, lignoceric acid, glucose, citric acid and Ī±-ketoglutaric acid under alkali-salt stress, than cultivated soybean. Further investigations demonstrated that the ability of wild soybean to salt tolerance was mainly based on the synthesis of organic and amino acids, and the more active tricarboxylic acid cycle under neutral-salt stress. In addition, the metabolite profiling analysis suggested that the energy generation from Ī²-oxidation, glycolysis and the citric acid cycle plays important roles under alkali-salt stress. Our results extend the understanding of mechanisms involved in wild soybean salt tolerance and provide an important reference for increasing yields and developing salt-tolerant soybean cultivars.</p></div

    Optimal Route Searching with Multiple Dynamical Constraintsā€”A Geometric Algebra Approach

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    The process of searching for a dynamic constrained optimal path has received increasing attention in traffic planning, evacuation, and personalized or collaborative traffic service. As most existing multiple constrained optimal path (MCOP) methods cannot search for a path given various types of constraints that dynamically change during the search, few approaches for dynamic multiple constrained optimal path (DMCOP) with type II dynamics are available for practical use. In this study, we develop a method to solve the DMCOP problem with type II dynamics based on the unification of various types of constraints under a geometric algebra (GA) framework. In our method, the network topology and three different types of constraints are represented by using algebraic base coding. With a parameterized optimization of the MCOP algorithm based on a greedy search strategy under the generation-refinement paradigm, this algorithm is found to accurately support the discovery of optimal paths as the constraints of numerical values, nodes, and route structure types are dynamically added to the network. The algorithm was tested with simulated cases of optimal tourism route searches in China&rsquo;s road networks with various combinations of constraints. The case study indicates that our algorithm can not only solve the DMCOP with different types of constraints but also use constraints to speed up the route filtering

    Modeling Random Exit Selection in Intercity Expressway Traffic with Quantum Walk

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    In intercity expressway traffic, the multiplicity of available routes leads to randomness in exit selection. Random exit selection by drivers is hard to observe, and thus it is a challenge to model intercity expressway traffic sufficiently. In this paper, we developed a Random Quantum Traffic Model (RQTM), which modeled the stochastic traffic fluctuation caused by random exit selection and the residual regularity fluctuation with the quantum walk and autoregressive moving average model (ARMA), respectively. The RQTM considered the random exit selection of a driver as a quantum stochastic process with a dynamic probability function. A quantum walk was applied to update the probability function, which simulated when and where a driver will leave the expressway. We validated our model with hourly traffic data from seven exits from the Nanjingā€“Changzhou expressway in eastern China. For the seven exits, the coefficients of determination of the RQTM ranged from 0.5 to 0.85. Compared with the classical random walk and the ARMA model, the coefficients of determination were increased by 21.28% to 104.98%, and the relative mean square error decreased by 11.61% to 32.92%. We conclude that the RQTM provides new potential for modeling traffic dynamics with consideration of unobservable random driver decision making

    Modeling Random Exit Selection in Intercity Expressway Traffic with Quantum Walk

    No full text
    In intercity expressway traffic, the multiplicity of available routes leads to randomness in exit selection. Random exit selection by drivers is hard to observe, and thus it is a challenge to model intercity expressway traffic sufficiently. In this paper, we developed a Random Quantum Traffic Model (RQTM), which modeled the stochastic traffic fluctuation caused by random exit selection and the residual regularity fluctuation with the quantum walk and autoregressive moving average model (ARMA), respectively. The RQTM considered the random exit selection of a driver as a quantum stochastic process with a dynamic probability function. A quantum walk was applied to update the probability function, which simulated when and where a driver will leave the expressway. We validated our model with hourly traffic data from seven exits from the Nanjing&ndash;Changzhou expressway in eastern China. For the seven exits, the coefficients of determination of the RQTM ranged from 0.5 to 0.85. Compared with the classical random walk and the ARMA model, the coefficients of determination were increased by 21.28% to 104.98%, and the relative mean square error decreased by 11.61% to 32.92%. We conclude that the RQTM provides new potential for modeling traffic dynamics with consideration of unobservable random driver decision making
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