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Many electronic devices with touch-sensitive surfaces aim to provide vibrotactile feedback, along with visual or auditory feedback, to facilitate the interaction between the user and the interface. In parallel to these efforts, recent studies developed various vibration rendering techniques, enabling more complex vibration patterns to be generated on the touch surface. However, few have addressed sound radiation induced by vibrotactile rendering on a touch surface, which could significantly impact the haptic interaction's overall perception. This study presents a method to shape the acoustic radiation due to rendering high-fidelity vibrotactile feedback on a touch surface. The proposed method utilizes measured frequency response functions and a vibroacoustic representation of the touch surface to define the relationship between actuator driving signals, vibration responses on the touch surface, and radiated sound power. Proper actuator driving signals are derived from the optimization problem formulated using the relationship. The proposed method was demonstrated through vibration rendering experiments on a touch surface comprising an acrylic plate and voice coil actuators. The results showed that the proposed method could shape the acoustic radiation while rendering target vibration patterns at desired positions on the touch surface. This study's proposed method could allow haptic engineers to design vibrotactile feedback and sound radiation simultaneously for a more compelling haptic experience.

Existing elastic analysis methods cannot be adhered to in order to assess the structural integrity of a reactor vessel and internals for a beyond design basis earthquake. Elasto-plastic analysis methods are required, and the factors that affect the elasto-plastic behavior of reactor materials should be taken into account. In this study, a material behavior model was developed that considers the irradiation embrittlement effect, which affects the elasto-plastic behavior of the reactor material. This was used to perform the elasto-plastic time history analyses of the reactor vessel and its internals for beyond design basis earthquake. For this investigation, appropriate beyond design basis earthquakes and reliable finite element models were used. Based on the analysis results, consideration was given to the load reduction effect and the margin change. These were transferred to the internals due to the plastic deformation of the reactor vessel.

Vibration is a mechanical phenomenon and exists throughout society. The vibrations in daily life would cause emotional discomfort as well as physical fatigue. Vibration even can give a life threat depending on its magnitude. Vibration is one of the significantly important factors to consider for the safety of the overall society, and therefore study of vibration reduction is indispensable. This paper presents a novel tunable electromagnetic vibration absorber based on an elastic metamaterial. The electromagnetic vibration absorber is a lattice structure dynamic model comprising elastic metamaterial unit cells having negative refractive index property and interconnected by springs. To verify the tunability of the elastic-metamaterial-based vibration absorber, the electromagnetic stiffness change in a finite element (FE) model of the electromagnet was analyzed through a parametric study of the air gap size, internal composition of the electromagnet, and amount of current. The conditions under which the electromagnet generates the highest electromagnetic stiffness were also explored. Each different value of electromagnetic stiffness obtained from the parametric studies was used for FE analysis of the dynamic model to investigate the influence on bandgap variations. The results reveal that the variation of electromagnetic stiffness has an effect on the location and bandwidth of bandgap. Moreover, vibration reduction was achieved due to the structural aspects of the dynamic model and the negative refractive index property of the elastic metamaterial. It is demonstrated that the elastic metamaterial vibration absorber is tunable in real time with the change of electromagnetic stiffness and has vibration reduction effect in various frequency ranges.

In this paper, we present a pendulum-type elastic metamaterial that can be used to absorb the shock of a tether system. A tether system comprises a long and thin cable, so the resonant part of the elastic metamaterial should be attached to outside the cable. The unit cell of the elastic metamaterial consists of three strings and one ring, and strings are attached to the tether cable and reduces the shock transmitted to the satellite. We used modal analysis to find mode shapes of the unit cell of the elastic metamaterial that do not deform when in contact with the tether cable. A harmonic analysis on the properties of the strings confirmed the presence of bandgaps for the pendulum-type metamaterial because of the lateral resonance of the strings. The effect of the unit cell design parameters on the bandgaps were also investigated.

CW STED nanoscopy using illumination of continuous wave is considerably easy and less expensive to construct compared with the pulsed STED nanoscopy. In this study, to improve the resolution of CW STED nanoscopy, we analyzed the imaging characteristics of CW STED nanoscopy by amplitude modulation of incident light flux of the excitation beam illumination considering the polarization state and geometry of the pupil mask for amplitude modulation. We analyzed the imaging characteristics of STED nanoscopy by applying the characteristic, which shows an extremely confined electric field in transverse direction when the light waves with high spatial frequencies and with the same polarization direction are diffracted and interfered in the focal region. By applying linearly polarized illumination and the mixed-shaped aperture composed of the bow tie-shaped blocking area and the circular blocking aperture area, we analyzed that imaging resolution can be enhanced above 20% higher than the resolution of the conventional CW STED nanoscopy.

The light detection and ranging (LiDAR) technology is based on irradiating near-infrared light and measuring the time-of-flight of the scattered light in an object. This technology is becoming increasingly important, as the requirement of three-dimensional camera technology for future autonomous vehicles is on the rise. In this study, we propose an ultra-wide field-of-view (FOV) optical system for LiDAR that can sequentially scan a beam emitted from a high power laser through a small beam steering system using a liquid lens and a fisheye lens. The proposed optical system consists of a series of liquid lenses for beam steering, a commercial fisheye lens with a wide FOV, and a relay optics to effectively conjugate the intermediate image planes of the two lens systems. To verify theoretical feasibility, we have designed a practical optical system with an FOV of approximately 170°, which is much higher than the FOVs in any other non-rotating LiDAR systems.

Digital holography is the best tool for measuring object information data. Parallel phase-shift digital holography (PPSDH) is particularly suitable for measuring moving objects. This method generates images of objects, but the image quality is diminished because they contain abundant speckle noise. In this paper, we propose an interpolation-based algorithm to reduce the levels of speckle noise in images generated by PPSDH, thus enhancing their quality.

A color-laser printing system consisting of a tandem laser scanning unit uses four laser diodes and a single polygonal mirror (PM) to expose light onto four photo-conductive drums. In this study, we developed a method to reduce periodical image noise, which is mainly generated during scanning by shape errors in a PM, during color mixing of a color-laser scanning system. Through fundamental optical and image analyses, the horizontal dot shift induced by shape errors in the PM was expected to generate visible image noise with a period of 2.8 mm. In addition, the dominant cause of the horizontal dot shift was the peak-to-valley error and the pyramidal angle of each mirror. In order to reduce the periodical image noise (moire) in color mixing, a horizontal-synchronization detection-optics layout was proposed, and its effectiveness was verified through image-printing experiments.

Electrodynamic (EDS) type suspension is appropriate for a high-speed maglev train as control is not essential to levitate a train. However, the trains might oscillate large in the vertical direction since there is no control for the EDS type maglev train. Linear Synchronous Motor (LSM) is used to propel trains as it can generate large propulsion force with high efficiency. LSM generate periodic, not uniform, Electromagnetic (EM) force and it cause vertical and lateral vibration. Therefore, EM forces acting on a maglev vehicle should be investigated to determine the vibration characteristics of a high-speed maglev train. An excitation force on bogies is nonlinearly changed by air gap between ground coils and magnets on bogies. Therefore, relative position of guide and a bogie could be defined to contracting time variant excitation force. The study focuses on verifying vertical and lateral vibration due to LSM that makes repeating propulsion force to a maglev vehicle. We made a transient 3-D EM analysis model that could simulate levitation and guidance force of a maglev vehicle. The model was constructed based on straight rail of the conventional maglev system, L0 series in Japan. We compared the simulation results, levitation, and guidance forces on single ground coil, with another study results. Also, total EM forces on a bogie in simulation results was compared with real track experimental results of another study. We could evaluate ride comport and running stability using our transient EM force by coupling with rigid body simulation.

As multilayer ceramic capacitors (MLCCs) act like piezo-actuators, printed circuit board (PCB) such as solid-state drive (SSD) vibrates and radiates acoustic noise when input AC electric field’s frequency coincides with the resonance frequency of the PCB. To minimize PCB vibration, in this study, the effect of mounting condition of MLCC was analyzed. Finite element (FE) models of PCB and MLCC was constructed to simulate various mounting condition. Each FE model was verified with experiment in previous studies. First, the influence of solder height was analyzed. The vibration amplitude at the center point of PCB was increased as the solder height increased. Second, the influence of mounting direction and position of MLCC was analyzed. As the vibration level varies considerably with frequency, especially for resonant frequencies, three mode shapes were chosen as the reference mode shapes considering the wave propagation direction. Parametric study was performed by changing the mounting direction by 0 and 90 degree and mounting position within a 3 X 3 grid for each reference mode. Low vibration was observed when MLCCs were mounted at nodal point with orthogonal direction to wave propagation direction.

Excessive bulking force during ureteral access sheath (UAS) placement may induce injury. The sliding friction between surfaces can be reduced with the application of ultrasonic vibration. We investigated the efficacy and safety of an ultrasonic vibration transducing device for reducing the maximal ureteral access sheath insertion force (UASIF).A device was developed for transducing ultrasonic longitudinal-axis vibration onto the UAS at an adjustable amplitude and frequency while measuring the degree of UASIF. In the pilot study, six porcine models were used to investigate the optimal amplitude and frequency of vibration and to calculate sample size. Twelve porcine models were utilized in a randomized controlled trial. Resected ureters were pathologically evaluated for ureteral injury.The transduction of ultrasonic vibration at an amplitude of 0.04 g and a frequency of 18,000 Hz resulted in a maximal UASIF reduction of 36.4% (interquartile range 32.7-43.1). Maximal UASIF tended to decrease with increasing vibration frequency. No significant differences in UASIF reductions were observed according to amplitude. In the randomized controlled trial, the maximal UASIF reduction was 37.0% (interquartile range 21.4-44.2). Grade II injury was pathologically diagnosed in 8.3% (1/12) of the ureters in both groups.The transduction of ultrasonic longitudinal-axis vibration onto the UAS reduces maximal UASIF and does not harm the ureter. Reducing the velocity of sheath insertion may further reduce maximal UASIF.

The buzz, squeak, and rattle (BSR) problem is one of the most important issues affecting vehicle satisfaction related to unexpected noise and vibration and has been attracting increased attention because of the rise of electric and hybrid vehicles. However, until recently, the vehicle underbody BSR has not been studied as extensively as the upper-body or interior BSR owing to a number of complex issues, such as the lack of suitable methods for measuring or visualizing the underbody BSR. This study proposes a method for localizing the rattle noise source in the vehicle underbody using the accelerations measured during a vehicle driving test. The acceleration signals are denoised by considering the characteristics of rattle; then, a series of rattle-induced impulse signal units included in the denoised acceleration signals are identified via machine learning at the level of BSR experts. Finally, the accelerometer closer to the rattle noise source is quantitatively determined by analyzing the correlation indexes in the frequency domain based on the properties of the rattle-induced impulse signal units, which depend on their relative position from the rattle noise source. The proposed method is based only on the accelerations measured from the driving test and the rattle signal transmission characteristics, and does not require complex vehicle dynamics analysis; therefore, it can be widely used regardless of the vehicle type at low cost.

The relationship between slider and lubricant becomes increasingly important as the mechanical spacing between slider and disk is reduced to satisfy the demand for higher areal density. At a reduce...

Excessive bulking force during primary access of the ureteral access sheath may induce ureteral injury. We investigated the efficacy of preoperative α-blockade to reduce ureteral access sheath insertion force and determine the upper limit required to avoid ureteral injury.In this randomized controlled trial 135 patients from a single institution who had ureteropelvic junction or renal pelvis stones and were scheduled to undergo retrograde intrarenal surgery were prospectively enrolled from December 2015 to January 2017. Of the patients 41 and 42 were randomly assigned to the control and experimental groups, respectively. The experimental group received α-blockade preoperatively. The 21 patients who were pre-stented were assessed separately. We developed a homemade device to measure maximal ureteral access sheath insertion force.Our ureteral access sheath insertion force measurement device showed excellent reproducibility. Higher insertion velocity resulted in greater maximal sheath insertion force. Maximal insertion force in the α-blockade group was significantly lower than in the control group at the ureterovesical junction (p = 0.008) and the proximal ureter (p = 0.036). Maximal insertion force in the α-blockade group was comparable to that in pre-stented patients. Female patients and patients 70 years old or older showed a lower maximal ureteral access sheath insertion force than their counterparts. The rate of grade 2 or greater ureteral injury was lower in the α-blockade group than in controls (p = 0.038). No injury occurred in any case in which ureteral access sheath insertion force did not exceed 600 G.Preoperative α-blockade and slow sheath placement may reduce maximal ureteral access sheath insertion force. If the force exceeds 600 G, a smaller diameter sheath may be an alternative. Alternatively the procedure can be terminated and followed later by pre-stented retrograde intrarenal surgery.

In most cases of molding with glass or optical polymers, the birefringence caused by the internal mechanical stresses remaining in the molding material is inevitably avoided. The distribution of the residual stress can be annealed through slow cooling, but is disadvantageous in terms of shape accuracy and manufacturing time. In this study, an analytical model is suggested for calculating the diffracted field near the focal plane by considering two primary meaningful parameters: the difference in the orientation angle between the fast axis and the slow axis and the path difference between the two axes. To verify the reliability of the analytical model, the experimental spot profile from the image forming lens of the laser scanning unit with a specific degree of birefringence was compared with the analytical result. Also, based on the validated optical analysis model, the optical performance in the near-focus region was analyzed considering the variation of the orientation angle deviation and the phase delay difference between the two axes.

In most cases of molding with glass or optical polymers, it is expected that there will be birefringence caused by the internal mechanical stresses remaining in the molding material. The distribution of the residual stress can be annealed by slow cooling, but this approach is disadvantageous with respect to the shape accuracy and manufacturing time. In this study, we propose an analytical model to calculate the diffracted field near the focal plane by considering two primary parameters, the orientation angle of the fast axis and the path difference. In order to verify the reliability of the analytical model, we compared the measured beam spot of the F-theta lens of the laser scanning unit (LSU) with the analytical result. In addition, we analyzed the calculated result from the perspective of the polarization status in the exit pupil. The proposed analysis method can be applied to enhance the image quality for cases in which birefringence occurs in a lens material by suitably modeling the amplitude and phase of the incident light flux.