Current Issue : January - March Volume : 2019 Issue Number : 1 Articles : 5 Articles
The effects of a membrane restrictorâ??s design parameters on the performance of a hydrostatic\nopposed-pad bearing are presented in this article. Compared to the single-pad bearing, the opposed-pad\nbearing can perform much better in terms of static stiffness over a wider load range. It is also found\nthat, for small bearing eccentricity, the optimal design restriction ratio of 0.25 still results in high\nbearing stiffness even if the dimensionless stiffness of membrane is not the optimal value of 1.33.\nFurthermore, decreasing the ratio of the upper effective area to the lower effective area generally\nincreases the applicable working range of the bearing. Additionally, for high loading demands,\nthe chance for further improvement of bearing performance by employing different design parameter\nfor each pad is examined. Finally, a design procedure for designing the membrane restrictor for\nan opposed-pad bearing to achieve high static stiffness is given....
The aim of this study is to execute the fluid dynamics simulation of high\nspeed jet under distinct input velocities (i.e. , 114.1, 142.4, 165.6, 186.2 and\n286.9 m/s). In particular, this study focuses on the impact velocity and velocity\nof two-phase flow (gas-liquid). Firstly, the three-dimensional geometric\nmodel of high speed jet is established on the basis of the actual operational\nconditions. Next, the unstructured grids of high speed jet are generated by\nmeans of ANSYS Fluent. Finally, the fluid dynamics simulation of high speed\njet is implemented by using Fluent. The simulation results show that when\nthe input velocity of the liquid increases, the impact velocity declines sharply,\nwhile according to the Bonuli law of conservation of energy, the impact effect\non the device shows exponential growth with increasing input velocity. In addition,\nthe relationship between the impact velocity and the input velocity\nand the relationship between the impact effect on the device and the input\nvelocity are achieved, which could provide certain theoretical guidance for\npredicting the working pressure and velocity of high speed jet based on real\ninput velocity....
A landslide inventory serves as the basis for assessing landslide susceptibility, hazard,\nand risk. It is generally prepared from optical imagery acquired from space borne or airborne\nplatforms, in which shadows are inevitably found in mountainous areas. The influences of\nshadow inventory on a landslide susceptibility model (LSM), however, have not been investigated\nsystematically. This paper employs both the shadow and landslide inventories prepared from\neleven For mosat-2 annual images from the I-Lan area in Taiwan acquired from 2005 to 2016, using a\nsemiautomatic expert system. A standard LSM based on the geometric mean of multivariables was\nused to evaluate the possible errors incurred by neglecting the shadow inventory. The results show\nthat the LSM performance was significantly improved by 49.21% for the top 1% of the most highly\nsusceptible area and that the performance decreased gradually by 15.25% for the top 10% most highly\nsusceptible areas and 9.71% for the top 20% most highly susceptible areas. Excluding the shadow\ninventory from the calculation of landslide susceptibility index reveals the real contribution of each\nfactor. They are crucial in optimizing the coefficients of a non deterministic geometric mean LSM,\nas well as in deriving the threshold of a landslide hazard early warning system....
Road safety depends on several factors associated with the vehicle, to the infrastructure,\nas well as to the environment and experience of vehicle drivers. Concerning the vehicle factors\ninfluencing the safety level of an infrastructure, it has been shown that the dynamic interaction\nbetween the carried liquid cargo and the vehicle influences the operational safety limits of the vehicle.\nA combination of vehicle and infrastructure factors converge when a vehicle carrying liquid cargo\nat a partial fill level performs a braking maneuver along a curved road segment. Such a maneuver\ninvolves both longitudinal and lateral load transfers that potentially affect both the braking efficiency\nand the lateral stability of the vehicle. In this paper, a series of models are set together to simulate the\neffects of a sloshing cargo on the braking efficiency and load transfer rate of a partially filled road\ntanker. The model assumes the superposition of the roll and pitch independent responses, while the\nvehicle is equipped with Anti-lock braking System brakes (ABS) in the four wheels. Results suggest\nthat cargo sloshing can affect the performance of the vehicle on the order of 2% to 9%, as a function of\nthe performance measure considered. A dedicated ABS system could be considered to cope with\nsuch diminished performance....
As a frequently occurring natural disaster, drought will cause great damage to agricultural\nproduction and the sustainable development of a social economy, and it is vital to reasonably\nevaluate the comprehensive risk level of drought for constructing regional drought-resistant strategies.\nTherefore, to objectively expound the uncertainty of a drought risk system, the precondition cloud\nand maximum entropy principle coupling model (PCMEP) for drought risk assessment is proposed,\nwhich utilizes the principle of maximum entropy to estimate the probability distribution of cloud\ndrops, and the two-dimensional precondition cloud algorithm to determine the certainty degree of\ndrought risk. Moreover, the established PCMEP model is further applied in a drought risk assessment\nstudy in Kunming city covering 1956â??2011, and the results indicate that (1) the probability of drought\nevents for different levels exhibits a slight increasing trend among the 56 historical years; and (2) both\nthe integrated certainty degree and its component of drought risk are more evident, which will be\nmore beneficial to determine the drought risk level. In general, the proposed PCMEP model provides\na new reliable idea to evaluate the comprehensive risk level of drought from a more objective and\nsystematic perspective....
Loading....