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This research aims to combine the throttling structure with the elastic element to enhance the load performance of aerostatic radial bearing.

In this research, a fluid–solid coupling model of the elastic throttling structure is established while considering the interaction between the elastic element and the flow field. The effects of elastic element structural parameters on the stiffness and load capacity of aerostatic radial bearing are then researched. Finally, the effect of elastic element modulus on air film load performance and elastic element deformation is analyzed.

The results indicate that the aerostatic radial bearing with elastic element can significantly improve the load capacity and stiffness when compared to the common aerostatic bearing. By choosing the proper combination of parameters, the load performance can be improved by at least 16%.

The throttling structure of aerostatic bearing is optimized in this work, which significantly enhances the load performance of the aerostatic bearing.

The purpose of this paper is to provide a solution for Reynolds equation with both throttling term and reverse throttling term and provides a reference for changing damping of hydrostatic bearing.

The reverse throttling term is introduced into the Reynolds equation, and the adaptive damping factor is used in the Newton iteration method to improve convergence of numerical calculations. The static and dynamic performances of this bearing are numerically investigated by the finite-element method.

The results indicate that the reflux orifices lead to a decrease in load capacity at a high eccentricity ratio. Additionally, the mass inflow rate is increased; however, the additional inflow increase can be controlled by enhanced backpressure of the reflux orifice. Nevertheless, the bearing with the reflux orifice shows superiority in resisting high-frequency disturbances and enhances direct damping by 20% under a high backpressure.

This work presents an adaptive Newton damping iterative method for solving Reynolds equation with both throttling term and reverse throttling term. This work also provides a new idea for bearing structure design in improving damping.

The purpose of this study is to determine the cavitation flow characteristics of the high-pressure differential control valve. The relationship between cavitation, flow coefficient and spool angle is obtained. By analyzing the relationship between different spool angles and energy loss, the energy loss at different spool angles is predicted.

A series of numerical simulations were performed to study the cavitation problem of a high-pressure differential control valve using the RNG k–e turbulence model and the Zwart cavitation model. The flow states and energy distribution at different spool angles were analyzed under specific working conditions.

The cavitation was the weakest when the spool angle was 120° or the outlet pressure was 8 MPa. The pressure and speed fluctuations of the valve in the throttle section were greater than those at other locations. By calculating the entropy production rate, the reason and location of valve energy loss are analyzed. The energy loss near the throttling section accounts for about 92.7% of the total energy loss. According to the calculated energy loss relationship between different regions of the spool angle, the relationship between any spool angle and energy loss in the [80,120] interval is proposed.

This study analyzes the cavitation flow characteristics of the high-pressure differential control valve and provides the law of energy loss in the valve through the analysis method of entropy. The relationship between spool angle and energy loss under cavitation is finally proposed. The research results are expected to provide a theoretical basis for the optimal design of valves.

Video distribution over the internet leads to heated net‐neutrality related debates between network operators and over‐the‐top application providers. The purpose of this paper is to analyze this debate from a new perspective that takes into account all of the assets that companies try to exploit in the so‐called battle for eyeballs in video distribution.

The systematic value chain analysis is used to determine the points along the value chain where net neutrality interacts with video distribution. The inputs to the analysis are the existing and proposed policy measures for net neutrality in Europe and in the USA, and a number of net neutrality incidents that have led to discussions earlier.

The paper finds that the current and proposed policy measures aimed at net neutrality each contribute to a certain extent to their intended effects. However, the analysis also shows that they are likely to lead to new debates in other parts of the value chain, as players try to compensate the loss of influence or revenue streams by rearranging the ways in which they exploit their assets.

Further and new debates are expected in the areas of peering and interconnection, distribution of resources between over‐the‐top and managed services and the role of devices with tightly linked search engines, recommendation systems and app stores.

The new perspectives offered by our value‐chain based analysis are valuable for policy makers who aim to promote net neutrality and simultaneously stimulate competition and innovation throughout the value chain.

This paper aims to establish an accurate mathematical model of a piezoelectric membrane restrictor that can be applied to control the shaft’s centerline orbit.

The methodology uses three coupled equations to establish a mathematical model of the piezoelectric membrane restrictor – Reynolds equation, the membrane deformation equation and the flow rate equation. A data identification method is used to propose the flow rate formulas for the piezoelectric membrane restrictor.

It has been found that the structural parameters, the membrane center deformation and the inlet and outlet pressures of the piezoelectric membrane restrictor have an effect on the static performance of the restrictor. The identified flow rate result of the piezoelectric membrane restrictor is consistent with the models.

The paper provides an accurate mathematical model of the piezoelectric membrane restrictor which can also be applied to other membrane restrictors.

A method for optimizing net positive suction head required of axial‐flow pumps has been proposed by the present author, which is based on the two‐dimensional potential flow model and without considering the tip gap effect. The objective of the paper is to confirm if the method is just and feasible for the case of viscous fluid flow in impellers with tip gap.

A series of steady, three‐dimensional, noncavitating and cavitating, turbulent, incompressible flows of water through two axial‐flow pump impellers were calculated by using CFD code Fluent. The two impellers included a reference one with constant circulation at outlet and an optimized one with variable circulation designed with the author's method and code. In computations, the throttling and unthrottling approaches were used, respectively. Comparison of hydraulic performance, averaged flow variables at the impeller inlet and exit, flow in the tip gap, flow variables on blade surfaces and suction performance between the optimized and reference impellers was made.

It was confirmed that the optimized impeller has better hydraulic and suction performances. The method for optimizing with variable flow circulation profile along blade span at the outlet to impeller is proper and practical. Additionally, an unstable regime in the head curves of two impellers is presented. In the regime, a stall occurs on the pressure side of the blade and a hysteresis exists, which causes a hysteresis‐loop.

The effect of suction entry on flow is represented approximately by using a free‐vortex and uniform axial velocity. The diffusing component behind the impellers is not taken into account. The unsteadiness of flow is not considered, which would have a connection with stall pattern in an axial‐flow impeller.

The hydraulic and suction performances and flow variables of two axial‐flow pump impellers with tip clearance are obtained successfully with CFD. Stall and hysteresis as well as hysteresis‐loop in head curve are observed by using throttling and unthrottling approaches.

IT does not require a very large crystal ball to envisage the growth of aviation during the next fifteen years. Sea travel has become too slow; air travel has become reliable and more independent of weather conditions; world trade has forced travel into the remotest areas; industrial countries have become more affluent, and the urge for private world travel has accompanied affluence. It is not surprising, therefore, to hear the Chairman of the British Airport Authority, Peter Masefield, predict a fifteenfold growth in air traffic in the United Kingdom during the next twenty years and to find the F.A.A. confidently anticipating a doubling of passenger traffic in five years and a nine‐fold increase in small jets in the same period.

This paper aims to present an effective approach to integrated circuit (IC) throughput enhancement, called TΔT thermal control. It does not require any micro-architectural change of the IC. The only modification is the attachment of an additional temperature sensor at the heatsink boundary. TΔT control technique enables assessment of changes in the dimension of cooling conditions and quick reaction to the dynamic changes in the surrounding environment. As a result, the chip can operate flexibly while minimizing thermal violation.

Using additional knowledge about the surroundings, the on-chip temperature is regulated. The approach is first investigated theoretically. To validate the utilized thermal model, the measured temperature values of the designed and fabricated testing device are compared with the simulated one. The authors evaluated the impact of the additional sensor location on the reaction time (RT). Using the Spice model, further investigation helps to verify the hypothesis.

The control technique described in this paper showed that the temperature of the chip can be regulated using an additional knowledge of the surrounding environment. It has also been demonstrated that the attachment of an additional temperature sensor close to the cooled surface of the package enables TΔT thermal control technique to react faster (rapid powering up/down of the IC). Therefore, this lowers the risk of shutdown while keeping the temperature close to the thermal limit (the maximal temperature of the chip) for a significant period. The simulation results showed that a higher ambient temperature leads to diminution of the interval in which the on-chip temperature stays almost constant when TΔT technique is used (time shift).

In this study, a new thermal throttling technique that uses the full physical ability of the chip operating under thermal constraint has been evaluated.

The purpose of this study is to address the issue that the traditional V-shaped ball valve profile shape is limiting the flow control characteristics in a series structure and to optimize the design profile by proposing an open-hole profile.

This paper proposes a Gaussian process regression surrogate model based on the genetic algorithm optimization of swarm intelligence, combined with the Expected Improvement point addition criterion, to optimize and correct the design profile. The flow regulation performance of the optimized V-shaped regulating ball valve is verified through a combination of numerical simulation and experiment.

The results demonstrate that the optimized V-shaped regulating ball valve has higher flow regulation accuracy and a more stable flow regulation process. After optimization, the flow characteristic curve of the spool is closer to the ideal equal percentage characteristic. The simulation results of the flow field are consistent with the experimental results.

The proposed method significantly reduces the optimization time, has higher efficiency and solves the problem that traditional optimization methods struggle with, which is ensuring optimal flow regulation performance. Compared to the traditional trial-and-error optimization method, the proposed method is more effective. The feasibility of the method is supported by experimental results.

Globe valves have good throttling ability, which permits its use in regulating flows. This paper aims to understand in detail the globe valve with different cage configurations and its impact on the flow characteristics that was carried out.

The computational study was carried out using FLUENT, a finite volume-based numerical code. Grid sensitivity tests were done and the results were validated experimentally. The effect of cage configuration on flow characteristics and valve coefficient was studied and optimised.

Valve coefficient was found to be dependent on cage configuration and reaches its maximum for the valve with triangular shaped aperture. Methodology to improve flow performance of a globe valve with highest valve coefficient is established.

Studies related with caged-type globe valves having different configurations are useful for improving their flow performance. In the present investigation, globe valves with different cage configurations and throttle positions are modeled to find out the valve coefficient, pressure and velocity contours inside and outside the cage and is validated with experimental results.