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High power and speed are new demands for rotating machinery which needs the journal bearings with high dynamic characteristics. The critical speed of the rotor-bearing system is one of the most significant parameters to evaluate the dynamic characteristics. This paper aims to investigate the theoretical and experimental analysis of a rotor system supported by large diameter elliptical bearings.

To obtain the theoretical and experimental support for rotor-bearing system design, dynamic characteristics theoretical analysis based on the finite difference method is given and an experiment focuses on critical speed identification is carried out.

The theoretical calculation results indicate that the critical speed is near to 800 rpm and there is no large vibration amplitude round working speed (1,500 rpm). Using the test bench in the factory unit, vibration data including three experimental processes are obtained. According to the vibration data, the critical speed is identified which also indicates that it is stable when working at 1,500 rpm.

The design method for the rotor system supported by large diameter elliptical bearing can be obtained by the theoretical and experimental results shown in this paper.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-04-2020-0122/

We use a combination of continuum and car-following models to explore the potential impact of speed-controls on (i) decreasing travel times at times of congested flow; and (ii) increasing the safety of motorway flow approaching the site of an accident.

The study examines the existence of target level of working capital and the speed of adjustment toward the target for eight manufacturing sectors of Indian economy. In addition, this study examines the impact of financial constraints on the speed of adjustment.

This study is based on secondary financial data of 1936 Indian manufacturing companies from eight sectors for a period of 18 years (2000–2018). This study employs two-step GMM techniques to arrive at results.

Results of the study confirm that firms do have target working capital, but the speed of adjustment from the current level of working capital to the target working capital is slow, and the speed of adjustment varies across sub-sectors. Moreover, we found that firms that are likely to be less constrained adjust their working capital quickly compared to firms facing high financial constraints.

This study contributes to working capital management literature by examining the speed with which the firms move toward their target and also the impact of financial constraints on the speed of adjustment across eight manufacturing sectors of Indian economy. Further, the study examines the impact of financial constraints on the speed of adjustment.

The research first and uniquely explores the antecedent relationship among three highly studied environmental forces – competitive intensity (CI), market turbulence (MT) and technological turbulence (TT) – in a service context. Next, given the importance of services to the USA and global gross domestic product (GDP) and the unique characteristics of services versus product firms, the research examines the impact of environmental forces on innovation speed capability, a less studied but critical enabler of service innovation. Finally, this study aims to suggest the importance of the sequential relationship between two dynamic capabilities – innovation speed and operational flexibility – to realize advantage.

This study surveyed 264 US service firms in a business to business context and tested this research model using structural equation modeling.

The results yielded three major conclusions: in a service context when examining the relationship among the three environmental forces, CI appears to have the driving influence on MT and TT, MT, however, was the only environmental force that this study found to bare positive and significant direct influence on innovation speed. Looking at the zero-order effect of MT and TT on innovation speed this study found each to be positive and significant suggesting a negative suppression effect and innovation speed’s influence on performance relative to competitors is fully mediated by operational flexibility.

The paper contributes to context, as service firms represent the majority of the USA and global GDP. This study extends the literature on the highly studied environmental forces (MT, TT and CI) by examining how they influence each other in an antecedent role and in service context. This study extends service literature by going beyond the influence of environmental forces on innovation to examine the dynamic capability of innovation speed, suggested as uniquely important to service context and distinct from the more highly studied innovation construct. The study also extends prior research in the manufacturing (product) context that suggests the importance of sequential congruence between two critical dynamic capabilities – innovation speed and operational flexibility – necessary to deliver competitive advantage.

This paper seeks to analyze the family firm's capital structure decisions, focusing on the speed of adjustment (SOA) as well as on the effect of distance from the target capital structure on the SOA towards target short-term and long-term debt ratios in unlisted small and medium-sized family firms.

Methodologically, we use dynamic panel data estimators to estimate the effects of distance on the speeds of adjustment towards those targets. Data for the period 2006–2014 were collected for two research sub-samples: one sub-sample with 398 family firms; the other sub-sample contains 217 non-family firms.

The results show that the deviation from the target debt ratios impacts negatively on the speeds of adjustment towards target short-term and long-term debt ratios in unlisted family firms. These results suggest that family firms, deviating from target debt ratios, face deviation costs, i.e. insolvency costs, inferior to the adjustment costs, i.e. transaction costs. Therefore, family firms stay away from the target debt ratios for a long time than do non-family firms.

The research sample comprises a low number of family firms, therefore for future research we suggest increasing the size of the sample of family firms to get a deeper understanding of family firms' SOA towards capital structure. Additionally, we suggest the analysis of other potential determinants of the speed of adjustment towards target capital structure.

The results obtained suggest that the distance from the target short-term and long-term debt ratios can be avoided if these firms do not depend almost exclusively on internal finance to adjust towards target capital structure. Moreover, for policymakers, we suggest the creation/promotion of alternative external finance sources, allowing reduced transaction costs that contribute to a faster adjustment of small family firms towards target capital structure.

The most previous research focusing on capital structure decisions have focused on listed family firms. To fill this gap, this study examines the speed of adjustment towards target debt ratios in the context of unlisted family firms. Moreover, transaction costs are a function of debt maturity, therefore this study examines separately the speeds of adjustment towards target short-term and long-term debt ratios. This paper shows that the adjustment costs (i.e. transaction costs) could hold back family firms from rebalancing its capital structure.

The purpose of the paper is to investigate the causal relationships and speed of adjustment of stock prices to changes in macroeconomic information (MEI) in Ghana from 1996 to 2018 using monthly data. The paper seeks to conduct the investigation at individual MEI level rather than the composite MEI.

Quantitative approach was used in this paper. Monthly data span of 1996–2018 was used. The delay and half-life technique was used to determine the speed with which the information resulting from the changes in the macroeconomic are evident in the stock price. Thereafter, Toda–Yamamoto Granger no-causality approach was used to examine the causal relationship amongst variables.

The paper revealed that although the market adjustment to MEI has improved, the speed is till slow. The exchange rate exhibited the slowest speed in respect of the market reaction while the market reaction to money supply was the fastest. Toda–Yamamoto Granger no-causality estimation also revealed a bi-directional causality between MEI (gross domestic product, interest rate and money supply) and stock price and uni-directional relationship flowing from MEI (the exchange rate and foreign direct investment) to stock price. The paper also found no causality between inflation and stock price.

The findings although revealed improved level of market efficiency in comparison with the earlier data, the speed of adjustment is still undesirable. Rigorous approach should be adopted for the implementation of major reforms such as alternative market so as to increase the number of share listing and to increase the scope of investors' participation to enhancing trading volume and marketability and ultimately speed up information diffusion.

The practical implication of the low level of information processing rate of Ghana Stock Exchange (averagely more than a month) is that astute investors and market analysts could employ MEI to outperform the market prior to their infusion onto the stock market.

This study is one of the few studies in the Ghanaian literature that has extended the investigation of the speed of adjustment beyond composite or aggregate macroeconomic level estimation to estimation at individual variable level. This contribution is very relevant since each macroeconomic variable has unique characteristics and require specific policy framework, it is important to consider the speed of adjustment from the perspective of each of the individual variables.

Friction pairs of the hydro-viscous drive speed regulating start device should be designed based on the rated torque. To obtain design basis of the rated torque of the hydro-viscous drive speed regulating start device, studies on effect of torque ratio (a ratio of the load torque to the rated torque) on speed regulating start were carried out theoretically and experimentally.

Under different torque ratio, the modified Reynolds, the thermal energy and the viscosity-temperature equations were solved simultaneously by using finite element method to reveal variation laws of the oil film load capacity and torque transmission during the starting process. Then, speed regulating start experiments were carried out to study the following performance of the output speed.

The results show that oil film thickness decreases with the increase of the torque ratio; when oil film thickness is less than 0.05 mm, oil film temperature increases rapidly with the decrease of oil film thickness, which eventually deteriorates performance of the speed regulating start; when the torque ratio decreases to about 0.3, output speed shows a better following performance.

It indicates that, to acquire a better speed regulating start, the rated torque of the hydro-viscous drive speed regulating start device should not be less than three times of the load torque. Achievements of this work provide theoretical basis for optimal design of the friction pairs of the hydro-viscous drive speed regulating start device.

The purpose of this paper is to reveal the effect of working oil temperature, load and starting time on hydro‐viscous drive speed‐regulating start.

The authors developed an experimental equipment and carried out a number of experiments under different temperatures, load and starting time.

The results show that both the temperature rise of working oil and the increase of load can induce fluctuations in output speed, but the effect of the working oil temperature rise is more serious; also the longer the starting time is, the more perfectly the output speed can trace the given speed.

It indicates that the working oil temperature should be kept in a certain range by using a cooling device in practical application; and that under this experimental condition, kinematics viscosity of the working oil should be greater than 45 mm²/s under rated working temperature, and the relatively suitable starting time should range from 90 to 120 s.

The paper explains the effect of various factors on speed‐regulating start, and provides the basis for the design and the application of hydro‐viscous drives.

It is now well known among aircraft engineers that the compressibility of the air has an increasingly important effect on the aerodynamic forces as the flight speed rises and approaches the speed of sound. As a result of the development of the gas turbine and other improvements, aircraft speeds have risen very rapidly during the last few years, and compressibility effects are, therefore, of great importance in many new aircraft designs. Unfortunately, the designer is faced with very great difficulties in attempting to predict the behaviour of a new aircraft flying at high speeds. The main reason for this is simply that there is very little systematic knowledge of air flow at high speeds past wings and bodies. A further difficulty arises because many of the methods and ideas which have proved so useful in the design of low speed aircraft may have to be changed completely when high speeds are considered. To mention only one example, it is well known that at low speeds a separation of the boundary layer at the rear of an aerofoil causes an increase of drag, but is not so well known that a separation of the same kind at supersonic speeds causes a reduction of drag (for a given incidence). Because there may be differences as important as this between high and low speeds it is not enough that the designer should merely modify his present methods and ideas to allow for compressibility; he must regard the design problems of high speed flight as completely new ones, and acquire a new scientific background to deal with them. It is important that the designer of high speed aircraft should have a sound knowledge of the fundamental principles of air flow at high speeds. Unfortunately, much of the information which is available on this subject is scattered among a large number of books and reports, and is not easily accessible. Thus there is a great need for a book giving a concise introduction to the subject, to enable the aircraft designer to read and understand the current reports dealing with recent developments, and to provide the scientific background which is so necessary for good design.

THE sinking speed of an, aeroplane is defined as the vertical component of the forward velocity in gliding flight. It is easy to show that the sinking speed so defined is included in the general equation of the rate of climb with engine on, the rate of climb being the difference between the “rising speed,” corresponding with the horsepower available, and the sinking speed, which in turn corresponds with the horse‐power required. Thus the sinking speed always plays an important rôle in all conditions of flight and it is the author's opinion that, especially in performance calculations, the use of the quantities rising an,d sinking speed are preferable to the more commonly used power‐quantities.