Mechanical and Aerospace Engineering News

The Department of Mechanical Engineering – Engineering Mechanics Graduate Seminar; Thursday, Dec. 12, 2013, 4:00 – 5:00 p.m. Room 112, ME-EM Bldg.,

Mr. D. H. Shin, Mechanical Engineering, Chung-Ang University

Title: Wettability Changes and Fringe Patterns of Contact Lines due to the
Local Aggregation Effect on Nanofluids Droplets during Evaporation

Recently, nanofluids (NF) are of substantial interest because of their potential in exhibiting improved thermal performance. The potential of nanofluids as the next generation of cooling fluids for automobiles and electronic devices has recently led to increased research. Mr. Shin’s research is currently focusing on characterization of nanofluid droplet evaporation by using an image visualization technique of the confocal microscope system.

This presentation will introduce a recent work regarding the nanofluid droplet
evaporation: Evaporation characteristics of nanofluid droplets with various volume fractions of 50 nm alumina (Al2O3) particles are experimentally examined. The effect of particle concentrations on droplet evaporation rates is examined and the corresponding wettability changes and the total evaporation time are also examined. Next, the contact lines of nanofluids droplets during evaporation are visualized using a slit-confocal microscopy, which allows a high-speed reflected mode. As the volume fraction of nanofluids increases, the total evaporation time and the initial contact angles decreases, while the droplet perimeters increase. In order to figure out the cause of results, the triple line of the droplet is visualized to study the wetting dynamics at the initial state using a digital image analysis technique. Conclusively, nanofluids droplets have a shorter total evaporation time than DI-water droplets do. It is observed that the nanofluid droplets are the more hydrophilic on the same kind of surfaces. Those results show the feasibility of using fringe patterns of contact lines can provide instability of a contact-line region in the thin film and further explain heat and mass transfer in this region.

Mr. Dong Hwan (DH) Shin is a visiting research scholar of Mechanical Engineering-Engineering Mechanics at Michigan Technological University. He received his B.S. and M.S. in Mechanical Engineering in Chung-Ang University (CAU) in 2008 and 2010, respectively. He continues his PhD candidate in CAU, Seoul, Korea. He has already been to MTU as a visiting scholar twice in 2010 and 2012. His research interests are nanofluid and its application, evaporation of micro-droplet and its application, flame spray and its application, and computational fluid dynamics. He has published 13 journal papers and 22 proceedings.

The Department of Mechanical Engineering – Engineering Mechanics
Graduate Seminar; Thursday, Dec. 5, 2013 4:00 – 5:00 p.m. Room 112, ME-EM Bldg.
Dr. Lyon (Brad) King, The Ron and Elaine Starr Professor of Space Systems Engineering, Michigan Technological University

Titie: Advanced Space Propulsion Research at MTU

Ion thrusters, plasma rockets, and arcjets sound like the stuff of science fiction, but in reality there are more than 200 spacecraft currently in orbit that utilize these technologies. Collectively these devices are known as ‘Electric Propulsion’ (EP) since they use electrical energy to eject ionized propellant and create thrust. EP devices are used on satellites as large as 5,000 kg and also on nanosatellites as small as 1 kg. The Ion
Space Propulsion Laboratory at MTU is actively developing thrusters that cover this entire range. This seminar will present an overview of the physics and performance limitations of EP devices in general. The talk will then describe a number of active research projects at MTU including metal-propellant Hall-effect thrusters, electrospray thrusters, and exotic devices that use ferrofluids as propellant.

Dr. Lyon (Brad) King is presently the Ron and Elaine Starr Professor of Space Systems Engineering at Michigan Technological University. Dr.King earned his Ph.D. in Aerospace Engineering from the University of Michigan in 1998. Prior to joining Michigan Tech Dr. King was a Postdoctoral Research Associate at the National Institute of Standards and Technology Ion Storage Group in Boulder, CO. Dr. King is an experimentalist with expertise in plasma physics, spacecraft design, and electric space propulsion systems. King shared the AIAA Outstanding Paper in Electric Space Propulsion in 1999 with co-author, Dr. Alec Gallimore, for studies of particle transport in Hall Thrusters. King is presently an Associate Editor of the AIAA Journal of Propulsion and Power. King was a past Fellow of the NASA Institute for Advanced Concepts (NIAC), a member of the NASA Nuclear Space Propulsion Technology Assessment Group, and a member of the Joint Army-Navy-NASA-Air Force Space Propulsion technical From 2009 to 2011 King was the Chair of the AIAA Electric Propulsion Technical Committee. King is a recipient of the National Science Foundation Faculty Early Career Award (CAREER) and the SAE International Ralph R. Teetor Engineering Educator Award. In 2004, King received the Presidential Early Career Award for Scientists and Engineers in a White House ceremony for DoD-sponsored research related to advanced space propulsion systems.

The Department of Mechanical Engineering – Engineering Mechanics Graduate Seminar; Thursday, Nov. 21, 2013 4:00 – 5:00 p.m. Room 112, ME-EM Bldg. Evandro Ficanha, Michigan Technological University

Title: Ankle impedance and ankle angles during step turn and straight walk: implications for the design of a steerable ankle-foot prosthetic robot

During locomotion, turning is a common and recurring event which is largely neglected in the current state-of-the-art ankle-foot prostheses, forcing amputees to use different steering mechanisms for turning, compared to non-amputees. A better understanding of the complexities surrounding lower limb prostheses will lead to increased health and well-being of amputees. The aim of this research is to develop a steerable ankle-foot prosthesis that mimics the human ankle mechanical properties. I will present the results of a series of experiments that were conducted to estimate the mechanical impedance of the human ankle when muscles were fully relaxed and co – contracting antagonistically. Also, the results of experiments on ankle rotations during different gait scenarios will be discussed to provide evidence that a multi -axis prosthesis may be needed to improve the mobility in amputees . The results of the aforementioned experiments were used for developing the control strategy of the ankle -foot prosthesis. A prototype ankle-foot prosthesis capable of controlling both dorsi/plantarflexion and inversion/eversion using a cable driven mechanism was developed and assessed as part of a feasibility study. The design is capable of reproducing the angles required for straight walk and step turn; generates 712N of lifting force in plantarflexion, and shows passive stiffness comparable to a non-load bearing human ankle impedance. To evaluate the performance of the ankle-foot prosthesis, a circular treadmill was developed to mimic human gait during steering. Preliminary results show that the device can appropriately simulate human gait with loading and unloading the ankle joint during the gait in circular paths.

In 2011 Evandro Ficanha completed his undergraduate degree as a mechanical engineer with a minor in Math at Michigan Tech. During his undergrad studies he worked at the Math Learning Center and did undergraduate research with different professors at the Mechanical Engineering Department. In his senior design project he helped to develop a hybrid electric bicycle to be used as an educational platform for teaching the technology concept in hybrid vehicles. Evandro received the “Outstanding Student Awards” for his senior design work. His current graduate research is focused on the development of powered ankle foot prosthetic robots capable of mimicking the mechanical properties of the human ankle. Also, he is a teaching assistant for Robotics and Mechatronics lab since 2012, where he has been continuously involved in reinvigorating the laboratory experiments and syllabus. In 2012, He received the “Outstanding Graduate Student Teaching Award” for his teachings efforts in the Robotics and Mechatronics lab.