Search results

The safety assessment of engineering structures under repeated variable dynamic loads such as seismic and wind loads can be considered as a dynamic shakedown problem. This paper aims to extend the stress compensation method (SCM) to perform lower bound dynamic shakedown analysis of engineering structures and a double-closed-loop iterative algorithm is proposed to solve the shakedown load.

The construction of the dynamic load vertexes is carried out to represent the loading domain of a structure under both dynamic and quasi-static load. The SCM is extended to perform lower bound dynamic shakedown analysis of engineering structures, which constructs the self-equilibrium stress field by a series of direct iteration computations. The self-equilibrium stress field is not only related to the amplitude of the repeated variable load but also related to its frequency. A novel double-closed-loop iterative algorithm is presented to calculate the dynamic shakedown load multiplier. The inner-loop iteration is to construct the self-equilibrated residual stress field based on the certain shakedown load multiplier. The outer-loop iteration is to update the dynamic shakedown load multiplier. With different combinations of dynamic load vertexes, a dynamic shakedown load domain could be obtained.

Three-dimensional examples are presented to verify the applicability and accuracy of the SCM in dynamic shakedown analysis. The example of cantilever beam under harmonic dynamic load with different frequency shows the validity of the dynamic load vertex construction method. The shakedown domain of the elbow structure varies with the frequency under the dynamic approach. When the frequency is around the resonance frequency of the structure, the area of shakedown domain would be significantly reduced.

In this study, the dynamical response of structure is treated as perfect elastoplastic. The current analysis does not account for effects such as large deformation, stochastic external load and nonlinear vibration conditions which will inevitably be encountered and affect the load capacity.

This study provides a direct method for the dynamical shakedown analysis of engineering structures under repeated variable dynamic load.

High-rise tower structures supported by side frame structure and viscous damper in chemical industry can produce plasticity under dynamic loads, such as wind and earthquake, which will heavily influence the long-term safety operation. This paper aims to systematically study the optimization design of these structures by free vibration and dynamic shakedown analysis.

The transfer matrix method and Euler–Bernoulli beam vibration are used to study the free vibration characteristic of the simplified high-rise tower structure. Then the extended stress compensation method is used to construct the self-equilibrated stress by using the dynamic load vertexes and the lower bound dynamic shakedown analysis for the structure with viscous damper. Using the proposed method, comprehensive parametric studies and optimization are performed to examine the shakedown load of high-rise tower with various supported conditions.

The numerical results show that the supported frame stiffness, attached damper or spring parameters influence the free vibration and shakedown characters of high-rise tower very much. The dynamic shakedown load is lowered down quickly with external load frequency increasing to the fundamental natural frequency of the structure under spring supported condition, while changed little with the damping connection. The optimized location and parameter of support are obtained under dynamical excitations.

In this study, the high-rise tower structure is simplified as a cantilever beam supported by a short cantilever beam and a damper under repeated dynamic load, and linear elasticity for solid is assumed for free vibration analysis. The current analysis does not account for effects such as large deformation, stochastic external load and nonlinear vibration conditions which will inevitably be encountered and affect the load capacity.

This study provides a comprehensive method for the dynamical optimization of high-rise tower structure by combining free vibration and shakedown analysis.

Given the rapid development of ethnic‐themed restaurants, this study aims to investigate how authentic atmospherics affects consumer emotions and behavioral intentions in Chinese restaurants in the USA.

A total of 348 usable responses from full table service restaurants in the USA were obtained via self‐administered questionnaires. A proposed model was tested following Anderson and Gerbing's two‐step approach: a measurement model and a subsequent structural model.

Using a structural equation modeling technique, this study found that authentic atmospherics significantly influences consumers' positive and negative emotions, and both types of emotions acted as full mediators between authentic atmospherics and behavioral intentions. Subsequent regression analyses revealed that menu presentation, furnishings, and music were significant predictors of positive emotions whereas menu presentation and music significantly influenced negative emotions.

The data were collected from only full table service restaurants. Therefore, generalizing the results for other segments of the restaurant industry may not be possible.

The findings have important implications for selecting and refining crucial elements of authentic atmospherics in order to enhance customers' favorable emotions, avoid unfavorable emotions, and ultimately heighten positive behavioral consequences.

Different from previous studies on the general aspect of atmospherics, this study exclusively investigates the effect of authentic atmospherics on customer post‐dining behavioral intentions in Chinese restaurants, one of the most popular ethnic restaurant segments in the US foodservice market. This study could also provide directions for improving the perceived authenticity of restaurant atmospherics.

The type 120 emergency valve is an essential braking component of railway freight trains, but corresponding diaphragms consisting of natural rubber (NR) and chloroprene rubber (CR) exhibit insufficient aging resistance and low-temperature resistance, respectively. In order to develop type 120 emergency valve rubber diaphragms with long-life and high-performance, low-temperatureresistant CR and NR were processed.

The physical properties of the low-temperature-resistant CR and NR were tested by low-temperature stretching, dynamic mechanical analysis, differential scanning calorimetry and thermogravimetric analysis. Single-valve and single-vehicle tests of type 120 emergency valves were carried out for emergency diaphragms consisting of NR and CR.

The low-temperature-resistant CR and NR exhibited excellent physical properties. The elasticity and low-temperature resistance of NR were superior to those of CR, whereas the mechanical properties of the two rubbers were similar in the temperature range of 0 °C–150 °C. The NR and CR emergency diaphragms met the requirements of the single-valve test. In the low-temperature single-vehicle test, only the low-temperature sensitivity test of the NR emergency diaphragm met the requirements.

The innovation of this study is that it provides valuable data and experience for future development of type 120 valve rubber diaphragms.

The purpose of this paper is to study the optimum culture condition of flax-retting enzyme, and applying the enzyme liquors to retting. In addition to research the structure of flax stem in enzyme retting using scanning electron microscopy (SEM).

The influence of cultural parameters such as moisture level, temperature, incubation time and inoculum size were evaluated with respect to polygalacturonase and xylanase yield. The structure of flax stem was revealed by SEM.

The flax was retted by dilute enzyme liquors (polygalacturonase/25 U/ml, xylanase/1 U/ml), and 24-h retting period was obtained. The SEM studies revealed the removal of a large amount of non-cellulosic gummy material of flax stem in enzyme retting.

First, flax-retting enzyme containing higher-yield polygalacturonase, lower-yield xylanase and no cellulose was yielded by SSF. Second, the composition of enzyme could meet flax retting and no damage cellulosic fibre. Finally, only low-cost wheat bran, citrus peel powder and mineral salt were employed in substrate, which could reduce the overall cost of enzyme production and flax retting.

Building the relationship between retting termination and pectin content remained in the fiber is crucial for ensuring the identity quality of retted flax. In order to measure the pectin content, pectin must be removed thoroughly from the fiber. The purpose of this paper is to find the most suitable method to extract pectin from flax phloem fiber.

Methods of extracting pectin from fruits were employed to ensure the complete removal of pectin from flax for the first time, including extraction with ethylene diamine tetraacetic acid, hydrochloric acid and ion exchange resin. Traditional ammonium oxalate-KOH method was adopted as control. Each procedure was optimized according to the yield of pectin. A characteristic chromogenic technique for determining the exact pectin amount was used, which ensured the precise measurement of pectin extracted.

Results showed that comparing with the traditional ammonium oxalate-KOH method, methods of hydrochloric acid and ion exchange resin extract >95 percent (w/w) pectin and the extract conditions are much milder.

Bulk of literatures have covered the problem of how to define the quality of retted flax. But the flax industry in China still uses sensory method to check the retting termination. Connect the fiber quality with pectin content is a brand new idea. Also, the exaction method employed from fruit pectin extract is applied in flax pectin for the first time. These methods are essential for building the relationship between the pectin content and retting termination and also significant for discovering the suitable enzyme for enzyme retting.

The purpose of this paper is to provide a cross-cultural comparison of Chinese and American hospitality customers who report critical incidents and the resulting influences that these incidents and recovery efforts had on behavior. Recognizing that hospitality-based organizations are increasingly operating internationally, the study provides insights for managing customer relationships.

The study utilizes the critical incident technique in conjunction with a structured self-administered questionnaire. The sampling approach resulted in 1,146 usable responses.

The results demonstrate statistically significant cultural differences between American and Chinese consumers in terms of reported critical incident types, recovery approaches, and post-incident private voice, public voice, and repurchase intention.

This research uses cultural value scores for China and the USA as a way to explain and discuss the findings. Hofstede's model was not tested and the provided explanations should be viewed with caution.

The results of this research can provide practitioners with guidelines in regards to service recovery tactics, as well as insights into how customers respond to critical incidents across different cultures.

This study adds to the existing literature by investigating empirically critical incident types, recovery tactics, and the consumer post-encounter behaviors of public voice (i.e. complaining), private voice (i.e. negative word-of-mouth, positive word-of-mouth), and repurchase intention in China and the USA.

The authors test the effect of expenditure decentralization and fiscal equalization on short- and long-run economic growth and estimate two-step generalized method of moment (GMM) simultaneous equations models, using panel data for China and India for the period 1985 to 2005. The authors estimate two simultaneous equations: a growth equation and equalization equation and find that expenditure decentralization has a negative and statistically significant effect at conventional levels on short-run economic growth for both China and India. However, the authors also find that this result is sensitive to the set of included explanatory variables. This leads the authors to conclude that expenditure decentralization has no effect on short-run economic growth for either country. The authors also find that expenditure decentralization has a positive and statistically significant effect on fiscal equalization for both countries but find no evidence that fiscal equalization affects short-run economic growth for either China or India. In contrast, the authors find that expenditure decentralization has a positive effect on long-run economic growth in the case of India, but not in the case of China. Finally, the authors report evidence that fiscal equalization has no effect on long-run economic growth in the case of China; however, the authors find that equalization has a positive and statistically significant at conventional levels effect on long-run economic growth in India.

The authors estimate two-step GMM simultaneous equations models, using panel data for China and India for the period 1985 to 2005. To examine the effect of fiscal decentralization (FD) policies on economic growth in China and India, the authors estimate two equations: a growth equation and an equalization equation. For the growth equation, the authors adopt a production-function-based model that is widely used in the empirical literature on growth; however, the authors do make some compromises with this specification due to the unavailability of certain data. For the equalization equation, the authors include variables that economic theory and empirical evidence suggest influence fiscal disparities among subnational governments which in turn influence the demand for horizontal fiscal equalization (HFE). To the extent possible, the authors employ the same econometric specification, variable constructions and sample periods for both China and India. The authors believe this strategy provides a more rigorous test of the FD hypothesis.

The authors find that expenditure decentralization has a negative and statistically significant effect at conventional levels on short-run economic growth for both China and India. However, the authors also find that this result is sensitive to the set of included explanatory variables. This leads to conclude that expenditure decentralization has no effect on short-run economic growth for either country. The authors also find that expenditure decentralization has a positive and statistically significant effect on fiscal equalization for both countries but find no evidence that fiscal equalization affects short-run economic growth for either China or India. In contrast, the authors find that expenditure decentralization has a positive effect on long-run economic growth in the case of India, but not in the case of China. Finally, the authors report evidence that fiscal equalization has no effect on long-run economic growth in the case of China; however, the authors find that equalization has a positive and statistically significant at conventional levels effect on long-run economic growth in India.

Due to the importance of FD policies, especially to many developing countries that are currently pursuing decentralization reforms, future research should examine the effect of FD on economic growth for other countries. Furthermore, although it would be difficult to do so, future research should examine whether FD promotes political stability on ethnically diverse countries.

To the best of the authors’ knowledge, no one has examined the effect of FD policies on India's growth experience. What is more is that this is also the first of its kind to have a comprehensive empirical investigation into these two major developing countries with very interesting similarities and differences in FD policies. It is thus of great importance to examine the effect of expenditure decentralization and HFE on economic growth in China and India.

The purpose of this paper is to build a seven‐degrees of freedom (DOF) parallel‐serial robot system which has the advantage of mechanical novelty and simplicity compared with the existing platforms, and to share the experience of converting a popular motion base to an industrial robot for use in full‐mission tank training processes of three armored arms.

By studying the concept of the robot system, a novel parallel‐serial robot with seven DOF driven by electrical servo motors is built. And the transmission modules and Hooke joints are explored and designed in detail. Then the inverse kinematics based on coupling compensation and time‐jerk synthetic optimization methods for trajectory planning of the simulator are presented and further discussed in order to satisfy the requirements of high stability and perfect performance. In advance, the feasibility and applicability of this triune parallel‐serial robot system are verified.

A prototyped test shows that the performance of the system is of a satisfaction with real‐time tracking any trajectories given by the visual system smoothly. Finally, the characteristics of the robot system are realized and verified by experiments and an industrial application.

The triune full‐mission tank training simulator developed in this paper has been used in the military industry and it has a great potential application.

This successful usage of the novel and simple parallel robot system in the military industry expands the range of its applications in real‐life task more operators training. And the proposal methods of inverse kinematics based on coupling compensation and trajectory planning enhanced the theoretical research of the parallel robot.