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There is an increasing popularity for the continuum robot in minimally invasive surgery owing to its compliance and dexterity. However, the dexterity takes the challenges in loading and precise control because of the absence of the shape tracking for the continuum robot. The purpose of this paper is to propose a new type of continuum manipulator with variable stiffness that can track the bending shape timely.

The low-melting-point alloy (LMPA) is used to implement the stiffness variation and shape detection for the continuum manipulator. A conceptual design for a single module is presented, and the principle of stiffness control based on the established static model is formulated. Afterward, a shape detection method is introduced in which the shape of the continuum manipulator can be detected by measuring the resistance of every LMPA. Finally, the effect of the proposed variable stiffness method is verified by simulation; the variable stiffness and shape detection methods are evaluated by experiments.

The results from the simulations and experiments indicate that the designed continuum manipulator has the ability of stiffness variation over 42.3% and the shape detection method has high precision.

Compared with conventional structures, the novel manipulator has a simpler structure and integrates the stiffness variation and shape detection capabilities with the LMPA. The proposed method is promising, and it can be conveniently extended to other continuum manipulators.

The purpose of this study is to find the multi-factor influence law of stress, strain rate and sulfate-reducing bacteria (SRB) on X70 pipeline steel in a simulated solution of sea mud and the order of influence of the three factors on X70 steel to develop a scientific basis for pipeline corrosion protection.

This paper studied the effects of stress, strain rate and SRB on the X70 pipeline steel corrosion behavior in simulated sea mud solution through orthogonal testing, electrochemical experiments and morphological observations.

The results of this study showed that stress proved to be the most relevant element for corrosion behavior, followed by SRB and strain rate. At high stresses (301 MPa and 576 MPa), stress dominated the corrosion behavior of X70 pipeline steel. However, at low stress (82 MPa), SRB played the most important role.

Subsea pipelines are in a very complex environmental regime that includes stress, strain rates and SRB, which often cause pipeline pitting and perforation. However, most scholars have only looked into the influence of single factors on metal corrosion. So, the single-factor experimental results of previous studies could hardly be applied to actual working conditions. There is an urgent need to understand the multi-factor influence law of stress, strain and SRB acting together on the pipeline corrosion behavior, especially to determine the dominant factor.

Expenditures on beauty, fitness and body shaping by females have increased significantly in recent years. Most previous studies examined this from the psychological perspective of self-acceptance and self-liking. However, this phenomenon may also have social implications. This study aims to provide a profound understanding of the social environment for female professionals as well as actionable insights for the government and social institutions.

A research model was developed based on impression management and social identity theories incorporating impression management motives, impression construction consumption and social identity. A survey study of 419 Chinese female professionals was conducted to test the research model.

This study surveyed 419 Chinese female professionals and found that impression management motives significantly drove female professionals to spend on their faces and bodies for impression construction, which in turn contributed to the enhancement of their social identities in three dimensions: relational identity, public identity and collective identity.

In a male-dominated society, it has become a norm that females should be cautious about their facial appearance and body shape. Females are often forced to consume to attain physical attractiveness and to construct a favorable social image. This study shows that consumption for impression construction has become a frequently used strategy for impression management and identifies key areas of societal concern.

This study aims to investigate how hoteliers leverage mobile technologies to shape services that allow customers to create their own unique and personalized experiences.

Guided by service-dominant logic and sociomateriality, this study analyzes hoteliers’ reasoning behind the design of mobile-based services through qualitative research. Data were collected from interviews with hotel managers representing best-practice companies in the industry.

The findings provide a rich description of mobile-based value co-creation in the hotel context. They delineate hoteliers’ understanding of mobile technologies as a means to co-create value, their strategic considerations and the forms in which value is expected to be co-created.

This study unearths the new roles of hoteliers, unique forms of value co-creation and their underlying structures in the specific context of mobile-based value co-creation. Practical implications based on industry best practices are provided for hospitality companies seeking to innovate by co-creating value with customers using mobile technologies.

This research paper contributes to the hospitality literature on IT-enabled service innovation and value co-creation by comprehensively explaining the underlying structure and design of co-created experiences facilitated by mobile-based services.

The supercritical design of tail rotor drive shaft has attracted more attention in helicopter design due to its high power–weight ratio and low maintenance cost. However, there exists excessive vibration when the shaft passes through the critical frequency. Dry friction damper is the equipment applied to the drive shaft to suppress the excessive vibration. In order to figure out the damping mechanism of the dry friction damper and improve the damping efficiency, the dynamic model of the shaft/damper system is established based on the Jeffcott rotor model.

The typical frequency response of the system is studied through bifurcation diagrams, amplitude-frequency characteristic curves and waterfall frequency response spectrum. The typical transient responses under frequency sweeps are also obtained.

The results show that the response of the system changes from periodic no-rub motion to quasi-periodic rub-impact motion, and then to synchronous full annular rub-impact, and finally, back to periodic no-rub motion. The slip of the rub-impact ring improves the stability of the system. Besides, the effects of the system parameters including critical dry friction force, rub-impact friction coefficient, initial clearance on the stability and the vibration damping capacity are studied. It is observed that the stability changes significantly varying the three parameters respectively. The vibration damping capacity is mainly affected by the critical dry friction force and the initial clearance.

Presented results provide guidance for the design of the dry friction damper.

With a mass of electronic multi-topic documents available, there is an increasing need for evaluating emerging analysis tools to help users and digital libraries analyze these documents better. The purpose of this paper is to evaluate the effectiveness, efficiency and user satisfaction of THC-DAT, a within-document analysis tool, in reading a multi-topic document.

The authors reviewed related literature first, then performed a user-centered, comparative evaluation of two within-document analysis tools, THC-DAT and BOOKMARK. THC-DAT extracts a topic hierarchy tree using hierarchical latent Dirichlet allocation (hLDA) method and takes the context information into account. BOOKMARK provides similar functionality to the Table of Contents bookmarks in Adobe Reader. Three novel kinds of tasks were devised for participants to finish on two tools, with objective results to assess reading effectiveness and efficiency. And post-system questionnaires were employed to obtain participants’ subjective judgments about the tools.

The results confirm that THC-DAT is significantly more effective than BOOKMARK, while not inferior in efficiency. There is some evidence that suggests THC-DAT can slow down the process of approaching cognitive overload and improve users’ willingness to undertake difficult task. Based on qualitative data from questionnaires, the results indicate that users were more satisfied when using THC-DAT than BOOKMARK.

Adopting THC-DAT in digital libraries or electrical document reading systems contributes to promoting users’ reading performance, willingness to undertake difficult task and general satisfaction. Moreover, THC-DAT is of great value to addressing cognitive overload problem in the information retrieval field.

This paper evaluates a novel within-document analysis tool in analyzing a multi-topic document, and proved that this tool is superior to the benchmark in effectiveness and user satisfaction, and not inferior in efficiency.

This study aims to use a sample of 2,120 individual hotel properties between 2011 and 2013 to evaluate the impact of loyalty programs on hotel operational and financial performance.

This study provides empirical support for the impact of loyalty program based on both cross-sectional and panel data analyses and uses the instrumental variable technique to avoid potential heteroscedasticity, autocorrelation and simultaneity issues.

Findings of this study show that loyalty program expenses have a significant and positive impact on all three operational performance indicators of RevPAR, ADR and Occupancy and the financial performance indicator of gross operating profit.

This study suggests that the benefits of loyalty programs should be understood against the backdrop of a reasonable set of controlled variables such as e-commerce, franchise, advertising, other marketing expenses, hotel size and hotel chain scales.

Given the conflicting viewpoints about the positive and negative impacts of loyalty programs, and that the literature is scant on empirical validation of the impact of loyalty programs on the overall operational and financial performance of hotel properties, this study is an early attempt to empirically test the impact of loyalty programs on a number of hotel operational and financial performance indicators by using an extensive list of individual hotel properties between 2011 and 2013.

This paper aims to search the optimum content of Ni on the microstructure, phase and electrochemical behavior of high-strength low alloy (HSLA) steel in the 3.5 wt.% NaCl solution.

The microstructure and corrosion resistance of Ni-containing HSLA steel in the simulated marine environment was studied by optical microscopy, scanning electron microscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and electrochemical techniques.

The sample containing 3.55 wt.% of nickel exhibited a finer grain size of 10 μm and a lower i_corr of 2.169 µA cm⁻². The XRD patterns showed that the Fe-Cr-Ni solid solution, FeC and Cr₃C₂ were observed in samples when Ni was added. Besides, the 3.55 wt.% of nickel addition enhanced the charge transfer resistance of the low alloy steel which suggested the sample possessed excellent inhibition of electrochemical reaction and corrosion resistance. The XPS spectrum suggested that nickel was beneficial to improve the corrosion resistance of steel by forming protective oxides, and the ratio of Fe²⁺/Fe³⁺ in protective oxides was increased.

Finding the comprehensive performance of HSLA steel which can be applied to unmanned surface vehicles in marine operations.

This study has a guiding significance for optimizing the composition of HSLA steel in a Cl- containing environment.

The purpose of this paper is to present a new technique for monitoring gas leakage in underground pipelines to prevent dangerous explosions.

A novel system for monitoring methane concentration in underground spaces was developed by integrating the multi-channeled air sampling method with an infrared gas sensor. A pipe installation methodology (without excavation) was established and verified accordingly.

The proposed approach was proven successful in reducing the quantity of sensors needed for real-time monitoring of underground pipeline leakage by about 80 per cent. Furthermore, this system lowers total operational cost by as much as 60 per cent.

The results presented here represent a possible solution to reducing the public safety risks associated with explosions and fires caused by pipeline leakage in underground spaces. Its total cost is low and its monitoring efficiency is high.

This paper aims to investigate the effects of different volume fractions of Al₂O₃-water nanofluid on flow and heat transfer under chaotic convection conditions in an L-shaped channel, comparing the difference of numerical simulation results between single-phase and Eulerian–Lagrangian models.

The correctness and accuracy of the two calculation models were verified by comparing with the experimental values in literature. An experimental model of the L-shaped channel was processed, and the laser Doppler velocimeter was used to measure the velocities of special positions in the channel. The simulated values were compared with the experimental results, and the correctness and accuracy of the simulation method were verified.

The calculated results using the two models are basically consistent. Under the condition of Reynolds number is 500, when the volume fractions of nanofluid range from 1% to 4%, the heat transfer coefficients simulated by single-phase model are 1.49%–25.80% higher than that of pure water, and simulated by Eulerian–Lagrangian model are 3.19%–27.48% higher than that of pure water. Meanwhile, the friction coefficients are barely affected. Besides, there are obvious secondary flow caused by lateral oscillations on the cross sections, and the appearance of secondary flow makes the temperature distributions uniform on the cross section and takes more heat away, thus the heat transfer performance is enhanced.

The originality of this work is to reveal the differences between single-phase and two-phase numerical simulations under different flow states. The combination of chaotic convection and nanofluid indicates the direction for further improving the heat transfer threshold.