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The breakdown of laminar flow in the clearance space of a journal is considered, and the point of transition is considered in relation to experiments carried out with ‘bearings’ of large clearance. Experiments involving flow visualization with very large clearance ratios of 0.05 to 0.3 show that the laminar regime gives way to cellular or ring vertices at the critical Reynolds number predicted by G. I. Taylor for concentric cylinders even in the presence of an axial flow and at a rather higher Reynolds number in the case of eccentric cylinders. The effect of the transition on the axial flow between the cylinders is small. The critical speed for transition as deduced by Taylor, is little affected by moderate axial flows and is increased by eccentricity. The effect of critical condition on the axial‐flow characteristics of the bearing system appears to be negligible, again for moderate axial flows. Assuming that the results can be extrapolated to clearances applicable to bearing operation, the main conclusion of this paper is that the breakdown of laminar flow, which is a practical possibility in very high‐speed bearings, is delayed by eccentric operation.

The purpose of this paper is to develop the Permanent Magnet Synchronous Motors drive which has possibility to work in sensorless mode at low speed based on back EMFs estimation.

Estimation uses modified Luenberger observer and the preprocessing of the EMFs before calculating the speed, using derivative and the Kalman filter (KF) to obtain smooth waveform of the estimated speed. This modification is needed because of the nonlinear change of the estimated back EMFs amplitude as a function of speed, in low-speed range.

How to use back EMF observer to estimate a speed in the low-speed range was found in the course of the work. Simple and effective algorithm uses KF and can work even with a relatively big deformation of the estimated back EMF.

Such sensorless drive may be used in low-cost constant or variable speed drive in domestic use or industrial application. Such drive may work properly where there is no initial load torque and the sign of the speed does not change.

Presented results challenge the view that at low-speed range (not the standstill), the back EMF-based method of position estimation is very difficult or impossible. However, the problem lays in proper speed estimation, not the position estimation.

The purpose of this paper is to analyze the relationship between market competition and distribution strategy for logistics service providers (LSPs), including freight price, service level (delivery speed), and service coverage.

The authors consider two risk-neutral LSPs in which one is an existing company and the other is a new entrant. The existing LSP has a sound distribution network and provides service in both local and remote areas. The new entrant LSP should determine the freight price and service coverage to compete for business. The authors use a Stackelberg game to model the competition between two LSPs with assumptions of consumers’ utility and demand distribution. Numerical examples are used to validate the findings.

The findings show that the distribution strategy for LSPs depends on the ratio of the cost difference and shipping speed difference and demand structure. The LSP with higher shipping speeds only need to meet demands in local areas and may stay out of the market in some cases. To compete for business in the whole areas is more profitable for the LSP with lower shipping speeds when either unit service cost or the potential demand in remote areas is low enough. Otherwise, the LSP with lower speeds should stay out the market of remote areas.

This study is a preliminary research on the relationship between market competition and distribution strategy for LSPs and contributes to service operations management literature and strategic management for LSPs.

To make a derivation of the load‐carrying capacity of elastohydrodynamic lubrication for special operating conditions, i.e. extremely heavy loads or extremely low rolling speeds based on the Newtonian fluid model by taking the Grubin‐type EHL inlet zone analysis, justify the load‐carrying capacity of elastohydrodynamic lubrication film in these operating conditions, and propose future trends of the research in EHL and mixed EHL based on the obtained results in the present paper.

A Grubin‐type EHL inlet zone analysis is carried out for the isothermal EHL of line contacts in special operating conditions, i.e. extremely heavy loads or extremely low rolling speeds based on the Newtonian fluid model. Comparison is made between the central EHL film thickness in line contacts, respectively, predicted by conventional EHL theories and accurately predicted from the present analysis for these operating conditions. An interpretation is made for the EHL film thickness in these operating conditions by taking the approach of the transportation and flow of the fluid through elastohydrodynamic contact when the EHL film is, respectively, thick and molecularly thin in the Hertzian zone. Conclusions are drawn on the load‐carrying capacity of EHL, EHL contact regimes and mixed EHL regimes in these operating conditions.

The present EHL inlet zone analysis shows that the EHL film thickness in the Hertzian zone is on the nanometer scale and the lubricant is non‐continuum across the film thickness in the Hertzian zone at relatively heavy loads in line contact EHL when the dimensionless rolling speed is lower than the dimensionless characteristic rolling speed U_ch=0.0372W^1.50/G. In this case, the central EHL film thickness in line contact EHL predicted by the conventional EHL theory may be several orders of magnitudes higher than that accurately predicted. This difference may be greater for heavier loads.The present results for line contact EHL based on the Newtonian fluid model show that in line contact EHL, for relatively heavy loads and the dimensionless rolling speed lower than the dimensionless characteristic rolling speed U_ch=0.0372W^1.50/G, the EHL analysis needs to further incorporate the lubricant non‐continuum effect across the film thickness in part of the lubricated area to investigate the EHL film thickness and the EHL film pressure in the contact in this very low film thickness condition; only the results based on such an analysis are believable for the EHL stage where the lubricant film thickness in the Hertzian zone approaches to zero and then vanishes; the results for EHL based on the Newtonian fluid model is unable to conclude that the EHL film thickness in the Hertzian zone is zero and dry contact occurs between the contact surfaces in EHL in any operating condition for ignoring the lubricant non‐continuum regime governing the EHL stage preceding the occurrence of the zero lubricant film thickness in EHL.

A very useful source of information for academic scientists, engineers and tribologists who are engaged in the study and application of the theory of elastohydrodynamic lubrication.

A derivation is first carried out for the isothermal EHL of line contacts in extremely heavy loads or extremely low rolling speeds by taking the Grubin‐type EHL inlet zone analysis by the present paper. Results and conclusions on the load‐carrying capacity of EHL in these operating conditions are first strict and thus convincing. These results are also original in clarifying the future trends of the researches in EHL and mixed EHL.

Purpose – This chapter aims to advise the public as well as municipal, state and national agencies about how pedestrian safety can be improved through changes in our built environment. Higher safety can lead to more walking and thereby a more sustainable society.

Methodology – The chapter is based on a review of literature, including a review of published papers and field studies by the author himself.

Findings – To reach ‘acceptable’ safety levels, all arterials and collector roads – at least segments with more than 50 pedestrians a day – should have sidewalks. The sidewalks should be separated from the roadway by a curb if speeds are low and by a barrier or wide separation strip in high-speed areas; that is, where speeds are higher than 50 km/h. Local roads also need sidewalks unless traffic volumes and speeds are very low. The major safety issue for pedestrians is, however, where they cross streets. Elderly pedestrians and pedestrians in a great hurry or under the influence of intoxicants in particular need streets to be narrow and have low speeds for them to be able to cross safely. Marking crosswalks or even signalising them will have only marginal safety effects at best. Posting them for low speed is also not enough unless we have photo speed-enforcement ensuring that everyone drives slowly. Rather, using narrow cross-sections or speed cushions at the approaches ensuring that 90-percentile speeds are no more than 30 km/h at crossing points is key to safety. In between crossing points a speed of 50 km/h is acceptable with pedestrians on adjacent sidewalks.

Social implications – We as a society need to encourage walking as a mode of transportation since walking promotes better health and a cleaner environment; that is, a more sustainable society. However, it has to be safe to walk or people will prefer to drive to their destinations. Also, distances between destination points have to be kept reasonably short and the environment, where people walk needs to be interesting and aesthetically somewhat pleasing to encourage walking.