Search

Your search keyword '"Markvicka, Eric J."' showing total 29 results
Start Over Author "Markvicka, Eric J."
29 results on '"Markvicka, Eric J."'

27. Designing liquid metal microstructures through directed material extrusion additive manufacturing

Author

Hur, Ohnyoung, Tutika, Ravi, Klemba, Neal, Markvicka, Eric J., and Bartlett, Michael D.

Abstract

Material extrusion (MEX) of soft, multifunctional composites consisting of liquid metal (LM) droplets can enable highly tailored properties for a range of applications from soft robotics to stretchable electronics. However, an understanding of how LM ink rheology and print process parameters can reconfigure LM droplet shape during MEX processing for in-situ control of properties and function is currently limited. Herein, the material (ink viscosity, and LM droplet size) and process (nozzle velocity, height from print bed, and extrusion rate) parameters are determined which control LM microstructure during MEX of these composites. The interplay and interdependence of these parameters is evaluated and nearly spherical LM droplets are transformed into highly elongated ellipsoidal shapes with an average aspect ratio of 12.4 by systematically tuning each individual parameter Material and process relationships are established for the LM ink which show that an ink viscosity threshold should be fulfilled to program the LM microstructure from spherical to an ellipsoidal shape during MEX. Additionally, the thin oxide layer on the LM droplets is found to play a unique and critical role in the reconfiguration and retention of droplet shape. Finally, two quantitative design maps based on material and process parameters are presented to guide MEX additive manufacturing strategies for tuning liquid droplet architecture in LM-polymer inks. The insights gained from this study enable informed design of materials and manufacturing to control microstructure of emerging multifunctional soft composites.

Published
2023
Full Text
View/download PDF

29. Design and Development of a Miniature In Vivo Surgical Robot with Distributed Motor Control for Laparoendoscopic Single-Site Surgery

Author

Markvicka, Eric J

Subjects
Analytical, Diagnostic and Therapeutic Techniques and Equipment, Biomedical Devices and Instrumentation, Biomedical Engineering and Bioengineering, Surgery, Surgical Procedures, Operative
Abstract

Paradigm shifts in invasiveness, recovery time, cosmesis, and cost have been seen within the field of general surgery through major advances in surgical technology. Some of the most advanced types of general surgery now include Minimally Invasive Surgery (MIS), LaparoEndoscopic Single-Site (LESS) surgery, and Natural Orifice Translumenal Endoscopic Surgery (NOTES). One of the newest and rapidly developing catalysts is robotic platforms. Such platforms have improved ergonomics and control, increased workspace and dexterity, and have surpassed the efficacy of many non-robotic platforms such as traditional laparoscopic surgical tools. This thesis presents the design and development of a four-degree-of-freedom (4- DOF) miniature in vivo surgical robot with distributed motor control for laparoendoscopic single-site surgery. The robotic platform consists of a two-armed robotic prototype, distributed motor control system, insufflated insertion device, and a remote surgeon interface. Advisor: Shane Farritor

Published
2014

Catalog

Books, media, physical & digital resources
See catalog results