Selective Wave Filtering in Time-Modulated Elastic Metamaterials

2018 ◽  
Author(s):  
Yiwei Xia ◽  
Giuseppe Trainiti ◽  
Alper Erturk ◽  
Massimo Ruzzene
Keyword(s):  
Single Port ◽  
Negative Capacitance ◽  
Time Modulation ◽  
Piezoelectric Patch ◽  
Flat Bands ◽  
Elastic Metamaterials ◽  
In Series ◽  
Port System ◽  
Opening And Closing ◽  
Time Periodic

We implement periodic stiffness time-modulation in a beam with piezoelectric patches and switchable shunted negative capacitance. The shunted negative capacitance circuits, connected in series with each piezoelectric patch through a switch, soften the structure. By alternatively opening and closing the switch, the beam’s stiffness effectively oscillates periodically between two values. We present a simplified theoretical model of time-periodic beams and describe the occurrence of flat bands in the dispersion diagrams. We show that a narrowband reflection from a time-modulated domain can be obtained for a broadband incident wave, hence qualifying the modulated domain as a single-port system with tunable response. We validate our theoretical findings by comparing time-domain simulations with experimental measurements of transient wavefields through scanning Doppler laser vibrometry.

scholarly journals Maneuverability of the Scope and Instruments within Three Different Single-Incision Laparoscopic Ports: An Experimental Pilot Study

Animals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1242
Author(s):  
Georg Haider ◽  
Ursula Schulz ◽  
Nikola Katic ◽  
Christian Peham ◽  
Gilles Dupré
Keyword(s):  
Motion Analysis ◽  
Single Incision ◽  
Single Port ◽  
Three Dimensional ◽  
Analysis Software ◽  
Port Access ◽  
Port System ◽  
Sils Port ◽  
Glove Port ◽  
Analysis System

Single-port access systems (SPASs) are currently used in human and veterinary surgeries. However, they pose technical challenges, such as instrument crowding, intra- and extracorporeal instrument collision, and reduced maneuverability. Studies comparing the maneuverability of the scopes and instruments in different SPASs are lacking. This study aimed to compare the maneuverability of three different SPASs: the Covidien SILS-port, Storz Endocone, and glove port. A clear acrylic box with artificial skin placed at the bottom was used to mimic the abdominal wall and cavity. The three SPASs were placed from below, and a 10-mm endoscope and 5-mm instrument were introduced. A motion analysis system consisting of 18 cameras and motion analysis software were used to track the movement of the endoscope and instrument, to determine the volume of the cone-shaped, three-dimensional figures over which movement was possible, with higher values indicating greater maneuverability. The Mann–Whitney U test was used for the analysis. The maneuverability of the endoscope alone was significantly higher in the glove port system than in the other two SPASs. When inserting an additional instrument, the maneuverability significantly decreased in the SILS-port and Endocone, but not in the glove port. The highest maneuverability overall was found in the glove port.

Band Gap Control in an Active Elastic Metamaterial With Negative Capacitance Piezoelectric Shunting

2014 ◽  
Vol 136 (6) ◽  
Author(s):  
Y. Y. Chen ◽  
G. L. Huang ◽  
C. T. Sun
Keyword(s):  
Band Gap ◽  
Elastic Waves ◽  
Low Frequency ◽  
Lattice System ◽  
Band Gaps ◽  
Negative Capacitance ◽  
Bending Waves ◽  
Stiffness Constant ◽  
Elastic Metamaterials ◽  
Gap Control

Elastic metamaterials have been extensively investigated due to their significant effects on controlling propagation of elastic waves. One of the most interesting properties is the generation of band gaps, in which subwavelength elastic waves cannot propagate through. In the study, a new class of active elastic metamaterials with negative capacitance piezoelectric shunting is presented. We first investigated dispersion curves and band gap control of an active mass-in-mass lattice system. The unit cell of the mass-in-mass lattice system consists of the inner masses connected by active linear springs to represent negative capacitance piezoelectric shunting. It was demonstrated that the band gaps can be actively controlled and tuned by varying effective stiffness constant of the linear spring through appropriately selecting the value of negative capacitance. The promising application was then demonstrated in the active elastic metamaterial plate integrated with the negative capacitance shunted piezoelectric patches for band gap control of both the longitudinal and bending waves. It can be found that the location and the extent of the induced band gap of the elastic metamaterial can be effectively tuned by using shunted piezoelectric patch with different values of negative capacitance, especially for extremely low-frequency cases.

scholarly journals Single-Port Access Laparoscopy-Assisted Vaginal Hysterectomy: Our Initial Experiences with 100 Cases

2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
Young-Sam Choi ◽  
Kwang-Sik Shin ◽  
Jin Choi ◽  
Ji-No Park ◽  
Yun-Sang Oh ◽  
...  
Keyword(s):  
Vaginal Hysterectomy ◽  
Single Port ◽  
Bladder Injury ◽  
Safe Procedure ◽  
Single Port Access ◽  
Laparoscopically Assisted Vaginal Hysterectomy ◽  
Single Port Surgery ◽  
Port Access ◽  
Pelvic Hematoma ◽  
Port System

Objectives.To present our initial experiences with laparoscopically assisted vaginal hysterectomy performed using homemade transumbilical single-port system.Materials and Methods.We reviewed the medical records of one hundred patients who underwent single-port access laparoscopically assisted vaginal hysterectomy (SPA-LAVH). SPA-LAVH was performed with homemade single port system and conventional rigid laparoscopic instruments.Results.All procedures were successfully completed through the single-port system and vagina without need for extraumbilical puncture or conversion to laparotomy. The median patient age was 48.2 ± 6.5 years. Thirty-three patients had history of past abdominopelvic surgery. The median total operative time, largest dimension of the uterus, and weight of the uterus were 73.1 ± 24.6 min, 10.5 ± 2.1 cm, and 300.8 ± 192.5 gram, respectively. The median decline in the hemoglobin from before surgery to postoperative day 1 was 1.8 ± 0.9 g/dL. Bladder injury in occurred one patient who was repaired through intraoperative laparoscopic suture. The postoperative course was uneventful in most patients except for three who had a transient paralytic ileus, five who had pelvic hematoma, but they were recovered following conservative managements. No port-related complications were noted, and the cosmetic results were excellent.Conclusions.SPA-LAVH is technically safe procedure, and the homemade single-port system offers reliable access for single-port surgery.

Evidence of multimodal vibration damping using a single piezoelectric patch with a negative capacitance shunt

2017 ◽  
Vol 141 (5) ◽  
pp. 3643-3643
Author(s):  
Vicente Romero-García ◽  
Charlie Bricault ◽  
Charles Pézerat ◽  
Manuel Collet ◽  
Adrien Pyskir ◽  
...  
Keyword(s):  
Vibration Damping ◽  
Negative Capacitance ◽  
Piezoelectric Patch

scholarly journals Learning curve of surgical novices using the single-port platform SymphonX: minimizing OR trauma to only one 15-mm incision

2020 ◽  
Author(s):  
Rabi R. Datta ◽  
Sebastian Schönhage ◽  
Thomas Dratsch ◽  
Justus Toader ◽  
Dolores T. Müller ◽  
...  
Keyword(s):  
Medical Students ◽  
Learning Curve ◽  
Single Port ◽  
Learning Curves ◽  
Laparoscopic Skill ◽  
Single Port Surgery ◽  
Significant Difference ◽  
Port System ◽  
Laparoscopic Experience ◽  
Needle Thread

Abstract Background Minimally invasive single-port surgery is always associated with large incisions up to 2–3 cm, complicated handling due to the lack of triangulation, and instrument crossing. The aim of this prospective study was to report how medical students without any laparoscopic experience perform several laparoscopic tasks (rope pass, paper cut, peg transfer, recapping, and needle threading) with the new SymphonX single-port platform and to examine the learning curves in comparison to the laparoscopic multi-port technique. Methods A set of 5 laparoscopic skill tests (Rope Pass, Paper cut, Peg Transfer, Recapping, Needle Thread) were performed with 3 repetitions. Medical students performed all tests with both standard laparoscopic instruments and the new platform. Time and errors were recorded. Results A total of 114 medical students (61 females) with a median age of 23 years completed the study. All subjects were able to perform the skill tests with both standard laparoscopic multi-port and the single-port laparoscopic system and were able to significantly improve their performance over the three trials for all five tasks—rope pass (p < 0.001), paper cut (p < 0.001), peg transfer (p < 0.001), needle threading (p < 0.001), and recapping (p < 0.001). In 3 out of 5 tasks, medical students performed the tasks faster using the standard multi-port system—rope pass (p < 0.001), paper cut (p < 0.001), and peg transfer (p < 0.001). In the task recapping, medical students performed the task faster using the new single-port system (p = 0.003). In the task needle threading, there was no significant difference between the standard multi-port system and the new single-port system (p > 0.05). Conclusion This is the first study analyzing learning curves of the commercially available SymphonX platform for abdominal laparoscopic surgery when used by novices. The learning curve and the error rate are promising.

scholarly journals Piezoelectric Shunt Stiffness in Rhombic Piezoelectric Stack Transducer with Hybrid Negative-Impedance Shunts: Theoretical Modeling and Stability Analysis

Sensors ◽  
2019 ◽  
Vol 19 (15) ◽  
pp. 3387
Author(s):  
He ◽  
Zheng ◽  
Zhao ◽  
Wu
Keyword(s):  
Coupled System ◽  
Analytical Framework ◽  
Negative Stiffness ◽  
Negative Capacitance ◽  
Control Engineering ◽  
Locus Method ◽  
In Series ◽  
The Stability ◽  
Stiffness And Damping ◽  
Piezoelectric Shunt

Negative-capacitance shunted piezoelectric polymer was investigated in depth due to its considerable damping effect. This paper discusses the novel controlled stiffness performance from a rhombic piezoelectric stack transducer with three hybrid negative-impedance shunts, namely, negative capacitance in series with resistance, negative capacitance in parallel with resistance, and negative inductance/negative capacitance (NINC) in series with resistance. An analytical framework for establishing the model of the coupled system is presented. Piezoelectric shunt stiffness (PSS) and piezoelectric shunt damping (PSD) are proposed to analyze the stiffness and damping performances of the hybrid shunts. Theoretical analysis proves that the PSS can produce both positive and negative stiffness by changing the negative capacitance and adjustable resistance. The Routh–Hurwitz criterion and the root locus method are utilized to judge the stability of the three hybrid shunts. The results point out that the negative capacitance should be selected carefully to sustain the stability and to achieve the negative stiffness effect of the transducer. Furthermore, negative capacitance in parallel with resistance has a considerably better stiffness bandwidth and damping performance than the other two shunts. This study demonstrates a novel electrically controlled stiffness method for vibration control engineering.

Demonstration of compact solid-state opening and closing switch utilizing GTOs in series

1991 ◽  
Vol 38 (4) ◽  
pp. 706-711 ◽  
Author(s):  
T.F. Podlesak ◽  
J.L. Carter ◽  
J.A. McMurray
Keyword(s):  
Solid State ◽  
In Series ◽  
Opening And Closing

scholarly journals Experimental Analysis of a Cantilever Beam With a Shunted Piezoelectric Periodic Array

2010 ◽  
Author(s):  
Benjamin S. Beck ◽  
Kenneth A. Cunefare ◽  
Massimo Ruzzene ◽  
Manuel Collet
Keyword(s):  
Cantilever Beam ◽  
Experimental Analysis ◽  
Periodic Array ◽  
Negative Capacitance ◽  
Velocity Amplitude ◽  
Periodic Arrays ◽  
Piezoelectric Patch ◽  
Propagating Waves ◽  
Piezoelectric Elements ◽  
Active Circuit

The use of both shunted piezoelectric elements and periodic arrays have been investigated independently as well as used in conjunction to modify the vibration of a system. Piezoelectric patches bonded to a cantilever beam which are shunted with an active circuit, specifically a negative capacitance shunt, can control broadband flexural vibrations of a structure. Also, periodic arrays integrated into a structure allow for modification of propagating waves through the mechanical “stop-bands”. The performance of a combined shunted periodic piezoelectric patch array will be analyzed here by investigating the velocity amplitude of the beam away from the array and in the array section, and the number of control elements in the array.

Sign in / Sign up

Export Citation Format

Share Document