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Value co-creation is a new initiative for enterprises to form a competitive advantage, and user engagement is the basis for achieving value co-creation; nevertheless, few studies have discussed the influence mechanisms of user engagement on value co-creation behavior. In this study, the authors aim to reveal the influence mechanisms of online fitness user engagement on value co-creation behavior by considering emotional resonance and immersive experience as mediating variables.

The authors proposed and empirically tested a research model based on a survey involving 461 Chinese respondents through partial least squares structural equation modeling (PLS-SEM).

The results of this study confirm that consumer engagement, contributing engagement and social engagement are important drives of value co-creation behavior among online fitness users. Furthermore, emotional resonance and immersive experience have been revealed as important mediating mechanisms to explain why user engagement drives value co-creation behavior.

The results of this study suggest that practitioners need to focus on the social engagement and consumer engagement of users in online fitness communities and to provide the appropriate environment and conditions for online fitness user to achieve mutual value co-creation.

This study makes two main contributions. It examines user engagement in an online fitness community context and helps to understand its applicability in other contexts. It explains the influence mechanisms of online fitness user engagement on value co-creation behavior and enriches the studies related to the drivers of value co-creation behavior.

The purpose of this paper is to present a frequency domain technique for the recognition and location of winding movements and mechanical deformations in power transformers. Both, axial and radial coil movements, as well as changes in clamp pressure will be studied.

The developed algorithm is based on using a distributed s‐domain parameter equivalent network, which is cascaded with other sections to constitute a generalized model. The frequency domain transfer admittance is used as the main criterion to recognize, identify and locate the winding movement and deformation.

In order to reduce the number of failures due to winding movements and deformations, it is suggested to measure and store the transfer admittance over frequency range 0‐10 MHz region at normal operation as saved data for comparison with the corresponding data during failure. With the proposed technique, the type and the location of eventual displacement, as well as the number discs involved can be identified.

Although the simulation was based on real experimental data adopted from the literature, the algorithm should be tested for real transformers. Several checks have been conducted in order to validate the mathematical model.

A relatively simple mathematical model has been presented. It can be used for any transformer, to check the integrity of the winding in order to meet certain degree of equipment safety and reliability.

The purpose of this paper is to present a simulation method applied for investigation of helicopter ground resonance phenomenon.

The considered physical model of helicopter standing on ground with rotating rotor consists of fuselage and main transmission gear treated as stiff bodies connected by elastic elements. The fuselage is supported on landing gear modeled by spring-damper units. The main rotor blades are treated as set of elastic axes with lumped masses distributed along blade radius. Due to Galerkin method, parameters of blades motion are assumed as a combination of bending and torsion eigen modes. A Runge–Kutta method is applied to solve equations of motions of rotor blades and helicopter fuselage.

The presented simulation method may be applied in preliminary stage of helicopter design to avoid ground resonance by proper selection of landing gear units and blade damper characteristics.

Ground resonance may occur in form of violently increasing mutual oscillations of helicopter fuselage and lead-lag motion of rotor blades. According to changes of stiffness and damping characteristics, simulations show stable behavior or arising oscillations of helicopter. The effects of different blade balance or defect of blade damper are predicted.

The simulation method may help to determine the envelope of safe operation of helicopter in phase of take-off or landing. The effects of additional disturbances as results of blades pitch control as swashplate deflection are introduced.

To study optical resonances in metallic nanoparticles.

The metallic nanoparticle is modeled as a dielectric body dispersive in frequency with assigned dielectric constant. The electric field is expressed as function of the charge distribution through an integral formulation. By imposing the boundary conditions on the nanoparticle surface, the equations for the induced charge in the nanoparticle is obtained. The numerical solution of such equations allows to treat arbitrary geometries and to estimate the effects of deviations from ideality on the resonance values.

Plasmon resonances in metallic nanoparticles can be safely studied with an electro‐quasistatic approximation. The resonance frequencies depend greatly on the details of the geometry of the nanoparticles.

The free‐space wavelength is supposed to be much greater than the largest characteristic dimension of the nanoparticles. Consequently, a electro‐quasistatic model is used to evaluate the distribution of the charges induced in the metallic nanoparticle.

Two methods are presented for the evaluation of the resonance frequencies starting from the numerical solution for a given geometry.

Wire bonding is an important method of interconnection in microelectronics. Ultrasonic energy is known to soften metallic materials and hence when used in the wire bond process it is effective to decrease the flow stress similar to thermal energy. The paper aims to address this issue.

Detailed resonance studies show that some designs have closeby resonance compared to the bonding frequency which causes enhanced vibration resulting in such over squashed bonds. Hence, precautions in the design stage are necessary to understand the closeby resonance frequencies and corresponding mode shapes of the leadframe that are in‐plane in nature along the transducer axis that can be excited by the capillary's motion. This can be determined a priori using numerical methods such as finite element method. In this paper, one such case study has been dealt in detail to explain the overall methodology.

To minimize the effects of resonance, damping should be increased by bonding polyimide tapes to enhance damping and stiffness which results in better ball bonds with optimum bell shape.

The paper explains the methodology of wire bonding in microelectronics.

This paper aims to study the sensitivity enhancement effect of the gold nanorod on fiber surface plasmon resonance (SPR) sensor. It proposes modeling the sensing effects of fiber SPR sensor decorated with metal nanoparticles. By using simulation and experiment, the sensitivity enhancement effect of the gold nanorod was studied and demonstrated.

The paper opted for an exploratory study using simulation approach of finite-difference time-domain. Specifically, the effect of ratios and aspect ratios of gold nanorod on sensing performance are investigated theoretically. Based on the mathematical models, the validation experiments by using the gold nanorod with the aspect ratios of 5.1 were done to verify the sensitivity enhancement effect of the gold nanorod.

In conclusion, it is evident that with the increases of the aspect ratios, the sensing sensitivity of the refractive index increases first, then gradually stabilizes or decreases. After parameter optimization, the ratios and aspect ratios of gold nanorod are chosen to be 8 nm and 12.5, respectively, which makes the optimal refractive index sensitivity of 4465.53 nm/RIU be realized. In addition, the validation experiments by using the gold nanorod with the aspect ratios of 5.1 verify the sensitivity enhancement effect of the gold nanorods.

This paper proposes and demonstrates a new method for the sensitivity enhancement of fiber SPR sensor. After parameter optimization, the maximum sensitivity of 4465.53 nm/RIU was achieved by using 8 nm gold nanorods with the aspect ratios of 12.5. To verify the sensitivity enhancement of the gold nanorods, the authors also did the validation experiments. The testing results indicated that after the decoration of the gold nanorods, the sensitivity of the sensing probe increases from 2190.57 nm/RIU to 2693.24 nm/RIU, which demonstrates the sensitivity enhancement effect of the gold nanorods.

The purpose of this paper is to develop new knowledge in experimental characterization of contaminants in engine lubricants, using surface plasmon resonance (SPR) sensing that can be applicable for on‐line condition monitoring of lubricant quality and engine component performance.

The effect of change in optical properties (e.g. transparency, absorption, and refractive index) of engine lubricants caused by the introduction of contaminants, such as gasoline, coolant, and water, on the surface plasmon resonance characteristics is analyzed experimentally. In SPR measurement, variations in both the refractive index and absorption cause changes in the SPR curve, which is the dependence of reflectivity vs incidence angle. The SPR characteristics (e.g. refractivity) of engine lubricant contaminated by gasoline, water and coolant at different concentration are measured as a function of resonance angle and analyzed with respect to different concentration (1%‐10%) of contaminants. Also, pattern recognition analysis between fresh and used engine lubricants is performed, to show applicability of Bayesian classification methodology for on‐line monitoring and predicting engine lubricant condition.

It was shown experimentally that attenuation of surface plasmons due to introduction of contaminants to the engine lubricant leads to a noticeable change in resonance angle and reflectivity minimum of the SPR curve due to an increase in the dielectric permittivity. In addition, the changes in the SPR characteristics were observed between fresh and used engine lubricant, causing resonance angle and reflectivity minimum of the SPR curve to shift.

The knowledge generated in this study lays the informational basis to further develop an on‐line system for engine lubricant condition monitoring using miniaturized SPR sensors fully suitable for on board applications.

SPR characterization is originally applied for analysis of optical properties of engine lubricants caused by the introduction of contaminants, such as gasoline, coolant, and water.

The purpose of this paper is to introduce a fast and simple method to calculate an estimation of parameters of interest of microstrip antennas, such as the resonance frequencies for example.

The Trefftz collocation method will be used to solve the governing differential equations of the problem. This method uses trial functions that satisfy, in a certain region the governing differential equations. Complete sets of solutions of such equations are required so that completeness and convergence can be guaranteed. The values of the wavenumbers for which the solution of the governing equation is unbounded, are those correspondent to the resonance frequencies of the antenna. After finding the wavenumbers, with the help of empirical correction formulas (because of the effect of the fringing field), the actual resonance frequencies are determined.

The Trefftz collocation method was found to be a very simple, fast and accurate method for the computation of the electric field under the patch of a microstrip antenna. Results obtained from this method showed excellent accuracy with less computational effort than other methods previously used.

Although the resonance wavenumbers may be accurate for any shape of antenna (because of the method convergence), the resonance frequencies might not be so accurate for irregular shapes since the parameters of the empirical formulas are approximated. Also the resonant cavity model is only valid for antennas made of thin substrates.

This formulation of the Trefftz method was for the first time applied to this problem, showing promising results.

The purpose of this paper is to extend the understanding of innovation in service ecosystems by focussing on the role of values resonance in relation to the integration of brands, service systems and experience rooms.

An empirical, explorative case study of an innovative service system is carried out using a narrative approach and presented in the form of a saga.

Insights gleaned from the empirical study are used for conceptual developments. Analysis of the empirical case study is presented as four lessons linked to values, brands, service systems and experience rooms.

The paper extends a conceptual framework of innovative resource integration in service ecosystems. The paper also contributes four propositions to inform theory: values resonance is a basis for service innovation, the innovative integration of brands based on values resonance can foster innovation, the integration of resources across service system boundaries grounded in values resonance can enable innovation and the integration of experience rooms into a coherent servicescape based on values resonance can support novel forms of resource integration and value co-creation efforts in service ecosystems.