Free flexural vibrations of a piezoelectric bimorph plate with periodic edge conditions

This work analyzes the vibrations of a fully-electroded annular piezoelectric bimorph plate with a free inner edge and an outer edge that is built-in with a periodicity. To this end, a variational formulation with the extensive use of Lagrange multipliers for a bimorph plate with polar orthorhombic symmetry is performed first. The mechanical displacement and the electric potential that must satisfy constraint conditions at the electrodes are expanded as the sums of powers in the thickness coordinate. The resulting piezoelectric bimorph plate equations are used along with the introduction of appropriate Lagrange multipliers to analyze the polar orthorhombic annular sectorial plates with free radial and inner circumferential edges, and an entirely built-in or free outer edge. The results are then combined to obtain the solutions for the mixed boundary value problem. The extended Hamilton’s principle with the method of Lagrange multipliers is employed, followed by a Frobenius-type series expansion for solution functions. The eigensolutions are calculated from the resulting transcendental equation and compared with those obtained from an FEA to ensure the validity of the procedure

Plasmon-enhanced Infrared Spectroscopy Based on Metasurface Absorber with Vertical Nanogap

In this study, we introduce a sensing platform based on a plasmonic metasurface absorber (MA) with a vertical nanogap for the ultra- sensitive detection of monolayer molecules. The vertical nanogap of the MA, where the extremely high near-field is uniformly dis- tributed and exposed to the external environment, is formed by an under-cut structure between a metallic cross nanoantenna and themirror layer. The accessible sensing area and the enhanced near-field of the MA further enhance the sensitivity of surface-enhancedinfrared absorption for the target molecule of 1-octadecanethiol. To provide strong coupling between the molecular vibrations and plas- monic resonance, the design parameters of the MA with a vertical nanogap are numerically designed

Nonlinear Modeling and Dynamic Simulation Using Bifurcation and Stability Analyses of Regenerative Chatter of Ball-End Milling Process

A dynamic model for a ball-end milling process that includes the consideration of cutting force nonlinearities and regenerative chatter effects is presented. The nonlinear cutting force is approximated using a Fourier series and then expanded into a Taylor series up to the third order. A series of nonlinear analyses was performed to investigate the nonlinear dynamic behavior of a ball-end milling system, and the differences between the nonlinear analysis approach and its linear counterpart were examined. A bifurcation analysis of points near the critical equilibrium points was performed using the method of multiple scales (MMS) and the method of harmonic balance (MHB) to analyse the local chatter behaviors of the system. The bifurcation analysis was conducted at two subcritical Hopf bifurcation points. It was also found that a ball-end milling system with nonlinear cutting forces near its critical equilibrium points is conditionally stable. The analysis and simulation results were compared with experimental data reported in the literature, and the physical significance of the results is discussed

Web Server-based Distributed Machine Socialization System

In recent years, there has been an increasing trend of offering services that are useful to users, such as Google's Nest, through machine socialization between parts and devices in specific spaces such as automobiles, homes, and factories. The existing inter - device collaboration system is a centralized system using router, and it controls collaboration between devices by building OpenWrt and web server on router. However, due to the limited hardware resources on the router, it generates network traffic congestion as the number of requests from the client increases or the number of clients connected to the server increases. In this paper, we propose a distributed machine collaboration system based on web server using inter - device collaboration algorithm. The study of Micro Controller Unit (MCU) has reduced the traffic incidence by solving the request sent to the router from each device by oneself

Body Information Analysis based Personal Exercise Management System

Recently, people's interest in health is deepening. So health-related systems are being developed. Existing exercise management systems provided users with exercise related information using PC or smart phone. However, there is a problem that the accuracy of the algorithm for analyzing the user's body information and providing information is low.In this paper, we analyze users' body mass index (BMI) and basal metabolic rate (BMR) and we propose a system that provides the user with necessary information through recommendation algorithm. It informs the user of exercise intensity and momentum, and graphs the exercise history of the user. It also allows the user to refer to the fitness history of other users in the same BMI group. This allows the user to receive more personalized services than the existing exercise management system, thereby enabling efficient exercise

Design and Application of a Collocated Capacitance Sensor for Magnetic Bearing Spindle

This paper presents a collocated capacitance sensor for magnetic bearings. The main feature of the sensor is that it is made of a specific compact printed circuit board (PCB). The signal processing unit has been also developed. The results of the experimental performance evaluation on the sensitivity, resolution and frequency response of the sensor are presented. Finally, an application example of the sensor to the active control of a magnetic bearing is described

Institutional Leadership and Perceived Performance: Evidence from the Korean Minister Survey

Few empirical studies have explored Selznicks ideas on institutional leaderships role in creating, nourishing, and maintaining public institutions. Reconsidering and expanding Selznicks perspective, this study explores how perceived ministerial performance is associated with institutional leadership styles. Using data from the 2007 Korean Minister Survey, this study develops five types of institutional leadership (visionary, persuasive, resilient, coalition network, and maintaining) derived from an exploratory factor analysis and tests their association with ministers performance. It suggests that visionary leadership and persuasive leadership are the primary determinants of Korean ministers performance, and their effects are greater for ministers without presidential support. Resilient leadership and coalition network leadership are also significantly associated with ministers performance, but maintaining leadership has little effect on it. Moderating effects on the relationship between leadership type and performance include presidential support and the presence of a performance crisis. Further research is needed to develop different measures for ministerial performance from different sources in order to avoid the common method bias.This work was supported by a grant from the National Research Foundation of Korea, funded by the Korean government (NRF-2010-330-B00031)

Dynamic Imaging of Hydrate Specific Area Evolution during Xenon Hydrate Formation

Gas hydrates are ice-like structures formed under high pressure and low temperature conditions. They are considered as a potential energy source due to their abundance and the increase in energy demand worldwide. A fundamental understanding of hydrate formation and dissociation kinetics is essential in order to improve gas productivity from natural hydrates reservoirs. This paper investigates the evolution of hydrate specific area during the process of hydrate formation using dynamic 3D synchrotron microcomputed tomography. Xenon hydrate was formed inside a high-pressure low-temperature cell, filled with silica sand partially saturated with water. The cell has a height of 70.2 mm and an inner diameter of 9.7 mm, and is capable of sustaining an internal pressure of 150 MPa. During hydrate formation and dissociation, full 3D images are acquired at a time resolution of 45 seconds and a spatial resolution of 5.38 ?m/voxel. The reconstructed images were enhanced and segmented, and direct volume and surface area measurements were obtained. Initially, the specific area of hydrate increased with increasing hydrate saturation up to a certain hydrate saturation threshold (9% hydrate saturation). After this threshold, hydrate specific area started to decrease with increasing hydrate saturation. This is an indication that the small crystals of hydrates tend to merge and form larger crystals during the process of hydrate formation.This publication was made possible by partial funding from NPRP grant # NPRP8- 594-2-244 from the Qatar national research fund (a member of Qatar Foundation) and the Institute for a Secure and Sustainable Environment (ISSE), University of Tennessee- Knoxville, USA. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of funding agencies. This paper used resources of the Advanced Photon Source (APS), a U.S. Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory (ANL) under Contract No. DE-AC02-06CH11357. The PSMT images presented in this paper were collected using the x-ray Operations and Research Beamline Station 13-BMD at Argonne Photon Source (APS), ANL. We thank Dr. Mark Rivers of APS for help in performing the SMT scans. We also acknowledge the support of GeoSoilEnviroCARS (Sector 13), which is supported by the National Science Foundation, Earth Sciences (EAR-1128799), and the DOE, Geosciences (DE-FG02-94ER14466)