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1 – 10 of over 4000Huizhe Li, Hongxia Ge and Rongjun Cheng
The goal of this study is to explore the effect of two-sided lateral gap with uncertain velocity on the stability of traffic flow on a curved road.
Abstract
Purpose
The goal of this study is to explore the effect of two-sided lateral gap with uncertain velocity on the stability of traffic flow on a curved road.
Design/methodology/approach
In this paper, an extended car-following model considering the effect of two-sided lateral gap with uncertain velocity on a curved road is proposed. The effects of different lateral positions and radius of different sizes can be considered as control signals. The stability condition of the new model is obtained by the control theory. The numerical simulations are carried out to analyze how the control signal and lateral positions and radius of curved road affect traffic flow stability. The results show that driving between two lanes and inaccurate speed estimates both have a negative effect on traffic flow stability, and the stability also decreases with the increase in the radius of curved road.
Findings
(1) Simulation of influencing factors of vehicle lateral position indicates that if the driver drives between two lanes, it would have a negative impact on traffic flow. (2) When the speed is fixed, the traffic flow becomes more and more unstable with the increase in the radius of the curve. (3) The stability of traffic flow will be affected when the driver estimates the speed of the vehicle ahead. Therefore, whether it is manual driving or future intelligent vehicle driving, it is necessary to accurately judge the speed of the front vehicle.
Originality/value
There is little research on two-sided lateral gap with uncertain velocity for the stability of traffic flow on a curved road. The enhanced model constructed in this study can better reflect the real traffic, which can also give some theoretical reference for the development of connected and autonomous vehicles (CAVs).
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To present some new designs of magnetic fluid exclusion seals for rolling bearings and possibility to use them in modern industrial sealing applications.
Abstract
Purpose
To present some new designs of magnetic fluid exclusion seals for rolling bearings and possibility to use them in modern industrial sealing applications.
Design/methodology/approach
In the paper is given principle of magnetic fluid sealing technology and are presented new designs of magnetic fluid exclusion seals for rolling bearings, such as compact magnetic fluid seals, two‐stages seals being combination of magnetic fluid seal and labyrinth seal or radial lip seal, magnetic fluid seals with “floating” magnetic system. This paper also shows examples of their application in various rotating process equipment.
Findings
Provides information about new designs of bearing seals and gives the main advantages of these seals over other types, such as total tightness, low viscous drag, maintenance‐free service and high reliability.
Originality/value
This paper offers some new designs of high‐performance magnetic fluid exclusion seals for rolling bearings and points their practical applications.
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Rabeb Rebhi, Amina Ibala and Ahmed Masmoudi
This paper aims at the improvement of the generating capability of a hybrid excited brushless claw pole alternator (HEBCPA).
Abstract
Purpose
This paper aims at the improvement of the generating capability of a hybrid excited brushless claw pole alternator (HEBCPA).
Design/methodology/approach
Following the identification of the HEBCPA influent sizing parameters, the investigation of their impact on the back‐EMF production capability is carried out considering a 3D‐finite element analysis (FEA).
Findings
The HEBCPA Back‐EMF production capability is highly affected by the variation of the influent sizing parameters. A selected combination of these parameters has led to an optimized generating capability.
Research limitations/implications
An experimental validation of the generating performance computed by 3D‐FEA shall be treated in the future.
Practical implications
The optimized HEBCPA is of great interest for the automotive applications as well as for wind energy generating systems.
Originality/value
The optimized HEBCPA is a new concept that has been proposed by the authors in a recent work.
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J.L. CHENOT, P. MONTMITONNET, P. BUESSLER and F. FAU
A technique for computing free surfaces by a steady state approach has been included in the hot rolling code ROLL3. It has been described in a previous paper, along with…
Abstract
A technique for computing free surfaces by a steady state approach has been included in the hot rolling code ROLL3. It has been described in a previous paper, along with applications to some simple rolling passes. In the present text, new developments are included to deal with more complex geometries, in particular when several potentially free surfaces exist. The problem of contact with flanks of grooves is given special care. Application to dog bone formation and flattening is presented. Then a case with two free surfaces is computed and compared to experiments. An application is then performed to beam roughing passes.
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This paper seeks to present some new designs of sliding bearings lubricated with magnetic fluids (ferrofluids) and the possibility of using them in modern bearing technology, in…
Abstract
Purpose
This paper seeks to present some new designs of sliding bearings lubricated with magnetic fluids (ferrofluids) and the possibility of using them in modern bearing technology, in new computer and audiovisual equipment among others.
Design/methodology/approach
The paper presents new designs of journal, thrust and journal‐thrust sliding bearings lubricated and sealed with magnetic fluids such as: magnetic fluid bearing bushing made of magnetizable material, pivot bearings with porous sleeve impregnated with ferrofluid, self‐aligning bearings, hydrodynamic ferrofluid bearings with spiral and herringbone grooves structure are presented. Moreover, examples are shown of applications in modern bearing technology.
Findings
The paper provides information about new designs of magnetic fluid sliding bearings assemblies and gives the main advantages of these bearings over conventional ball bearings, such as extremely low non‐repetitive run‐out (high‐accuracy of rotation), good damping and quietness of operation, maintenance free service and high reliability.
Originality/value
This paper offers some new designs of compact, low friction and self‐contained magnetic fluid sliding bearings and points up their practical applications.
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Ruilong Du, Yinglong Chen and Hua Zhou
The purpose of this paper is to propose a simulation model for studying the lubricating gap between the ring gear and the case in internal gear pumps.
Abstract
Purpose
The purpose of this paper is to propose a simulation model for studying the lubricating gap between the ring gear and the case in internal gear pumps.
Design/methodology/approach
The pressure distribution of the wedge-shaped oil film between the ring gear and the case is obtained based on the theory of film lubrication using the Reynolds equation implemented with MATLAB. After that, the balance of the ring gear is achieved by the radial micro motion of the ring gear. The power loss due to the leakage and the shear stress is then calculated for optimized design of the radial clearance.
Findings
The hydrodynamic effect and the squeezing effect of the wedge-shaped oil film play a role in the hydrodynamic balance of the ring gear, and they become more intense when the operating speed gets lower and the pressure gets higher. The optimal radial clearance should stay between 20 and 25 µm for the minimum power loss.
Originality/value
The present research provides the first simulation model that treats the oil film between the ring gear and the case as wedge-shaped oil film and explains why the ring gear stays balanced. Furthermore, the simulation model can be regarded as a tool for optimized design of the radial clearance.
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Shuang Yu, Jun Miao, Hua Wang and Zhiyuan Qian
The purpose of this paper is to find the root cause of the current issue for a scan drive mechanism which is used to drive and to control the Microwave Radiometer Imager (MWRI…
Abstract
Purpose
The purpose of this paper is to find the root cause of the current issue for a scan drive mechanism which is used to drive and to control the Microwave Radiometer Imager (MWRI) equipment of the FY‐3 meteorological satellite in China.
Design/methodology/approach
In order to find the root cause of the irregularly unstable motor current, some possible reasons for this anomaly, including satellite dynamic, telemetry, electronics and mechanism system, are investigated. The root cause is focused on the mechanism that is increasing friction caused by limitation rollers striking the rotating part from time to time, which has been verified by simulation and test.
Findings
Findings gained from the simulations and tests results were: for a rotational space mechanism with high velocity accuracy requirement, if the moment of inertial (MOI) of the load is quite large, the balance is the key factor to the equipment performance. Moreover, thermal gradient and temperature difference are also important factors, especially to the space mechanism with large dimensions. Even a very small thermal deformation can lead to quite a number of unexpected results.
Practical implications
The better performance of the next optimized MWRI equipment in orbit showed that the performed measures are very effective and useful. The experience gained in settling this issue can be used for the design of a space scanning mechanism with high rotating speed and high accuracy.
Originality/value
The paper is an original work for the authors. The issue has not been found in the related literatures. It is based on research work on an engineering problem of unstable current issue, which is significant to the MWRI payload of the FY‐3 satellite.
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T.S. Dhahi, U. Hashim, M.E. Ali and Nazwa Taib
Nanogap electrodes have important applications in power saving devices, electrochemical sensors and dielectric detections of biomolecules. The purpose of this paper is to report…
Abstract
Purpose
Nanogap electrodes have important applications in power saving devices, electrochemical sensors and dielectric detections of biomolecules. The purpose of this paper is to report on the fabrication and characterization of polysilicon nanogap patterning using novelties technique.
Design/methodology/approach
Polysilicon material is used to fabricate the nanogap structure and gold is used for the electrode and two chrome masks are used to complete this work; the first mask for the nanogap pattern and a second mask for the electrode. The method is based on the control of the coefficients (temperature and time) with an improved pattern size resolution thermal oxidation.
Findings
Physical characterization by scanning electron microscopy (SEM) demonstrates such nanogap electrodes could be produced with high reproducibility and precision. Electrical characterization shows that nanogap enhanced the sensitivity of the device by increase the capacitance and the conductivity as well. They have also good efficiency of power consumption with high insulation properties.
Originality/value
With this technique, there are no principal limitations to fabricating nanostructures with different layouts down to several different nanometer dimensions. The paper documents the fabrication of nanogaps electrodes on a polysilicon, using low‐cost techniques such as vacuum deposition and conventional lithography. Polysilicon is a low‐cost materials and has desirable properties for semiconductor applications. A method of preparing a nanogap electrode according to the present innovation has an advantage of providing active surface that can easily be modified for immobilizations of biomolecules.
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Rabeb Rebhi, Amina Ibala and Ahmed Masmoudi
The purpose of this paper is to investigate the generating capability of a novel hybrid excited brushless claw pole alternator (HEBCPA) with improved cost-effectiveness gained…
Abstract
Purpose
The purpose of this paper is to investigate the generating capability of a novel hybrid excited brushless claw pole alternator (HEBCPA) with improved cost-effectiveness gained thanks to the substitution the rotor NdFeB-made permanent magnet (PM) with ferrite ones.
Design/methodology/approach
The investigation of the magnetic features of the novel HEBCPA has been carried out using a 3D finite element analysis (FEA).
Findings
It has been found that the machine generating capability is not affected by the substitution of the single rotor NdFeB-made PM by stator and rotor ferrite-made ones, which represents a crucial cost benefit.
Research limitations/implications
An experimental validation of the features computed by FEA shall be considered as an outlook of the present work.
Practical implications
The novel HEBCPA could be of great interest for automotive generating systems.
Originality/value
The proposed HEBCPA with ferrite-made PMs is a novel concept.
Details
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Describes the development of laser welded tailored blanks and the benefits they bring to car design. One of the principle advantages is weight reduction, which steel makers have…
Abstract
Describes the development of laser welded tailored blanks and the benefits they bring to car design. One of the principle advantages is weight reduction, which steel makers have seized on to counteract the “threat” from aluminium and have invested in a number of laser welding facilities. One of these lines, at Laser Welded Blanks (LWB) in the UK West Midlands and supplied by VIL, is described in detail. The system features the VIL‐developed and patented edge preparation station (EPS) that incorporates a precision shear. In this way, the mating edges of the pieces are prepared with the close fit‐up needed to produce high quality blanks and allow welding at high speed. The VIL system, which is limited to linear welds, is contrasted with the more complex non‐linear system developed by some manufacturers.
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