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This paper aims to improve the bearing capacity of hydrostatic thrust bearing under working conditions of high speed and heavy load; a new wedge-shaped structure opened on an edge of oil seal is put forward, the loss and insufficiency for hydrostatic bearing capacity are made up by using dynamic pressure, and then, hydrostatic hydrodynamic lubrication is realized.

Oil film three-dimensional models of unidirectional and bi-directional hydrostatic hydrodynamic oil pad are established by using UG. The oil film pressure fields of two kinds of oil pad are simulated by using ANSYS ICEM CFD and ANSYS CFX; the pressure fields distribution characteristics are obtained, and the effects of workbench rotary speed and bearing weight on pressure field are analyzed. Also, the experimental verification is made.

The results demonstrate that with an increase in workbench rotary speed, the oil film pressure of two kinds of hybrid oil pad increases gradually, and the maximum pressure of the bi-directional one accounts for 95 per cent of the unidirectional one when the load is constant. With an increase in load, the oil film pressure of two kinds of hybrid oil pad increases gradually, the difference between them is 9.4 per cent under the condition of load of 25 t when the rotary speed is constant.

The paper can provide theoretical basis for a structure design of hybrid thrust bearing under different rotary speed and load conditions, and compensate the shortage of static pressure-bearing capacity by using dynamic pressure, improve the stability of vertical CNC machining equipment.

The purpose of this paper is to describe a simulation and experimental research concerning the effect of recess depth on the lubrication performance of a hydrostatic thrust bearing by constant rate flow.

The computational fluid dynamics and finite volume method have been used to compute the lubrication characteristics of an annular recess hydrostatic thrust bearing with different recess depths. The performances are oil recess pressure, oil recess temperature and oil film velocity. The recess depth has been optimized. A test rig is established for testing the pressure field of the structure of hydrostatic thrust bearing after recess depth optimization, and experimental results show that experimental data are basically identical with the simulation results, which demonstrates the validity of the proposed numerical simulation method.

The results demonstrate that the oil film temperature decreases and the oil film pressure first increases and then decreases with an increase in the recess depth, but oil film velocity is constant. To sum up comprehensive lubrication performance, the recess depth of 3.5 mm is its optimal value for the annular recess hydrostatic thrust bearing.

The computed results indicate that to get an improved performance from a constant flow hydrostatic thrust bearing, a proper selection of the recess depth is essential.

This study investigates the impact of AI finance on financing constraints of non-SOE firms in an emerging market.

Using a sample of non-SOE listed companies in China from 2011 to 2018, this research employs the cash–cash flow sensitivity model to examine the effect of AI finance on financing constraints of non-SOE firms.

We find that the development of AI finance can alleviate the financing constraints of non-SOE firms. Further, we document that such effect is more pronounced for smaller firms, more innovative firms and firms in developing areas.

This study suggests that emerging market countries can ease the financing constraints of non-SOE firms by promoting AI finance development.

This study, to the best of our knowledge, is the first one to explore the relationship between AI finance development and financing constraints of non-SOE firms in emerging markets.

The purpose of this paper is to solve the problem that the relationship between loading forces, which were applied at different positions on a plane, and output values of load-sharing dynamometer is non-linear.

First, the analytical model of ISPM (isodynamic surface proportional mapping method) method, which is used to calibrate dynamometer, was established. Then, a series of axial force calibration tests were performed on a load-sharing dynamometer at different loading positions. Finally, according to output values, calibration forces at different loading positions were calculated by ISPM method, and corresponding distribution histogram of calibration force error was generated.

The largest error between calculated force and standard force is 2.92 per cent, and the probability of calculated force error within 1 per cent is 91.03 per cent, which verify that the ISPM method is reliable for non-linear calibration of dynamometers.

The proposed ISPM method can achieve non-linear calibration between measured force and output signal of load-sharing dynamometer at different positions. In addition, ISPM method can also solve some complex non-linear problems, such as prediction of plane cutting force under the influence of multiple parameters, the force measurement of multi-degree-of-freedom platform and so on.

The major component of agriculture production includes the type of seed, soil, climatic conditions, irrigation pattern, fertilizer, weed control, and technology used. Soil is one of the prime elements in modern times for agriculture. Soil is also one of the primary and important factors for crop production. The available soil nutrient status and external applications of fertilizers decide the growth of crop productivity (Annoymous, 2017). The upcoming research question that needs to be addressed is What is the application of soil data on soil health management for sustaining agriculture? Driven by the need, the aim of the present study is (a) to explore the soil parameters of a district, (b) compare the values with the standards, and (c) pave a way for mapping the crops with suitability of soil health. This study will not only be beneficial for the district to take appropriate steps to improve the soil health but also would help in understanding the causal relationship among soil health parameters, cropping pattern, and crop productivity.

This study aims to get the essential data of the solubility and diffusion coefficient of gas in jet fuel for appropriately designing a kind of on-board inert gas generation system.

A test apparatus based on pressure–decay method was constructed to measure solubility and diffusion coefficient of gas in liquid. The test apparatus and method were verified via measurement of solubility and diffusion of CO₂ in the pure water.

The solubility of CO₂ and O₂ in RP-3 jet fuel with the temperature from 253 to 313 K under three various pressures were measured and compared with theoretical value calculated by a relative density method provided in the standard of ASTM D2780-92, and the deviation is within 10 per cent. The diffusion coefficients of CO₂ and O₂ in RP-3 jet fuel are determined by monitoring the gas pressure in a hermetic cell versus time with the temperature from 253 to 333 K. The measured diffusivity-temperature relation can be well fitted through the Arrhenius equation for engineering applications. The obtained correlation can be used to predict the diffusion coefficient of CO₂ and O₂ in RP-3 jet fuel under a wide temperature range.

The semi-empirical correlation of solubility and diffusion coefficient in RP-3 jet fuel obtained from the experimental data could be used to support the design of an inert gas generation system.

There are no essential data of solubility and diffusion of CO₂ and O₂ in RP-3 jet fuel; therefore, it is fatal if the quantity and rate of mass transfer of CO₂ and O₂ in RP-3 jet fuel must be assessed, e.g. during the design of green on-board inert gas generation system.

The purpose of this paper is to construct a new algorithm of program procedure for medical grey relational method based on SAS software.

Based on the SAS environment, the authors construct a new algorithm of program procedure through the following methods: the construction data set, confirmation of the comparison sequence and reference sequence, the original data transformation, calculation of the grey relational coefficient of reference sequence and comparison sequence and calculating the correlation.

The results show that the novel algorithm of program procedure for medical grey relational method based on SAS software satisfies the properties properly. It also fully confirmed the biggest advantage of the grey relational analysis is that its requirements are not too high for the amount of data, and it does not need to follow the typical distribution.

The paper succeeds in constructing a novel algorithm of program procedures for medical grey relational method and providing a valuable tool for solving similar problems.

This paper aims to prepare a residual rust epoxy coating by adding different quantities of phytic acid (PA) on the surface of the rusty steel and investigate the corrosion protection of PA and its action mechanisms.

A residual rust epoxy coating by adding different quantities of PA was prepared on the surface of the rusty steel. The influence of PA on the corrosion resistance of epoxy-coated rusty steel was investigated by means of electrochemical impedance spectroscopy and adhesion testing.

Results indicated that PA can substantially improve the corrosion resistance of epoxy-coated rusty steel. This improvement is due to the reaction of PA with residual rust and generation of new compounds with protection properties and increased adhesive strength effects on the coating/metal interface. The coating showed better protection performance when 2 per cent PA was added.

Considering the structure of the active groups, PA has strong chelating capability with many metal ions and can form stable complex compounds on the surface of a metal substrate, thereby improving corrosion resistance. In recent years, PA has been reported to be useful in the conversion of coatings or as green corrosion inhibitor. To the best of the authors’ knowledge, few studies have reported the use of PA as a rust converter or residual rust coating. The present work aims to improve the corrosion resistance of residual rust epoxy coating by adding PA.

This paper aim to investigate the influence of PA on the corrosion behavior of carbon steel with blast cleaned or pre-rusted treatments, and interpret the inhibition mechanism of PA on the steel with different surface treatments.

The influence of PA on the corrosion behavior of blast cleaned or rusty steel was investigated by means of electrochemical impedance spectroscopy (EIS). The EIS data were analyzed using the @ZsimpWin commercial software. The morphology and component of steel after immersion were characterized by scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), Fourier transformation infrared (FTIR) and X-ray diffractometer (XRD).

EIS analysis results indicated that PA had good corrosion inhibition for blast cleaned or rusty steel. SEM, EDS, FTIR and XRD further indicated that PA had two main corrosion inhibition processes for the corrosion inhibition of blast cleaned or rusty steel: corrosion dissolution and formation of protective barrier layers.

Most published works focus the attention only toward the effect of corrosion inhibitor for the clean metal surfaces. However, the surface condition of metal sometimes is unsatisfactory in the practical application of corrosion inhibitor, such as existing residual rust. Some studies also have shown that several corrosion inhibitors could be applied on partially rusted substrates. These inhibitors mainly include tannins and phosphoric acid, but not PA. Therefore, the authors investigated the influence of PA on the corrosion behavior of carbon steel with blast cleaned or pre-rusted treatments in this paper.

The purpose of this paper is to investigate the pose control of rigid spacecraft subject to dead-zone input, unknown external disturbance and parametric uncertainty in space maneuvering mission.

First, a 6-Degree of Freedom (DOF) dynamic model of rigid spacecraft with dead-zone input, unknown external disturbances and parametric uncertainty is derived. Second, a super-twisting-like fixed-time disturbance observer (FTDO) with strong robustness is developed to estimate the lumped disturbances in fixed time. Based on the proposed observer, a non-singular fixed-time terminal sliding-mode (NFTSM) controller with superior performance is proposed.

Different from the existing sliding-mode controllers, the proposed control scheme can directly avoid the singularity in the controller design and speed up the convergence rate with improved control accuracy. Moreover, no prior knowledge of lumped disturbances’ upper bound and its first derivatives is required. The fixed-time stability of the entire closed-loop system is rigorously proved in the Lyapunov framework. Finally, the effectiveness and superiority of the proposed control scheme are proved by comparison with existing approaches.

The proposed NFTSM controller can merely be applied to a specific type of spacecrafts, as the relevant system states should be measurable.

A NFTSM controller based on a super-twisting-like FTDO can efficiently deal with dead-zone input, unknown external disturbance and parametric uncertainty for spacecraft pose control.

This investigation uses NFTSM control and super-twisting-like FTDO to achieve spacecraft pose control subject to dead-zone input, unknown external disturbance and parametric uncertainty.