UC San Diego Space and Rocket Science Makes Strong Showing at Barrio Logan Event

Space science and rockets built by UC San Diego students were front and center at the Barrio Logan Science and Art Expo on April 16, 2022. 

The event is an inclusive, annual art, science and culture fair for families from southern San Diego, organized in partnership by the Barrio Logan Association, the San Diego Festival for Science and Engineering, UC San Diego and other community partners. 

This year, two student organizations joined Professor Boris Kramer from the Department of Mechanical and Aerospace Engineering to crew a booth themed "Space Research at UCSD."

"We got a lot of attention," said Boris Kramer, a professor in the department, who was also in attendance. "It is incredibly rewarding to take part in these outreach events." 

Kramer's research group, whose work is supported by the National Science Foundation, showed recent research in space weather forecasting. They also investigate how holes in the sun's corona and solar storms can cause disruptions to satellites and GPS as well as cause Earth-based power outages. 

SEDS@UC San Diego showed off Vulcan I, the world's first rocket powered by a 3D printed engine to be designed and launched by undergraduate students in 2016. The organization has also developed a testing set up for static firing, various rocket engines, a lander testbed and more. 

The Rocket Propulsion Laboratory showcased their Phoenix rocket, designed to reach up to 50,000 ft in altitude, as well as their Marginal Stability rocket, which is designed to reach the Von Karman line typically considered the edge of space, at 52 miles above the surface of the Earth. 

 

Sylvia Herbert receives young investigator award from the Office of Naval Research

Sylvia Herbert is one of 32 researchers in the United States to receive an award from the 2022 Young Investigator Program at the Office of Naval Research. 

The highly competitive, early career award recognizes prior academic achievement and potential for significant scientific breakthrough. 

Herbert is an assistant professor in the UC San Diego Department of Mechanical and Aerospace Engineering. She leads the Safe and Autonomous Systems Lab at the Jacobs School and is part of the UC San Diego Contextual Robotics Institute. The research project she was awarded for focuses on constructing and adapting control barrier functions for guaranteed safe control of autonomous systems.

Mechanical engineer recognized by Society for Industrial and Applied Mathematics

Jorge Cortes, a professor in the Department of Mechanical and Aerospace Engineering has been inducted as a 2020 Fellow by the Society for Industrial and Applied Mechanics.
Cortes is being recognized for contributions to the control and optimization of network systems.

The fellows were nominated for their exemplary research as well as outstanding service to the community. Through their contributions, SIAM Fellows help advance the fields of applied mathematics and computational science.

Cortés' research interests are on distributed coordination algorithms, autonomous robotic networks, adversarial networked systems, mathematical control theory, geometric mechanics and geometric integration. The recent emergence of low-cost, highly-autonomous vehicles with control, communication, sensing, and computing capabilities has paved the way for the deployment of robotic sensor networks in a wide range of applications. Controlled motion coordination of these networks will have far-reaching implications in the monitoring of natural phenomena and the enhancement of human capabilities in hazardous and unknown environments. Motivated by these scenarios, Professor Cortes' research program is developing systematic methodologies to control autonomous, reliable, and adaptive mobile networks capable of operating in unknown and dynamic environments.

Ruth J. Williams, from the UC San Diego Department of Mathematics, is also being recognized for contributions to the study of stochastic processes and their applications.

Full SIAM release here: https://sinews.siam.org/Details-Page/siam-announces-class-of-2020-fellows

A new model for electrochemical kinetics in nanoscale systems

Understanding the speed at which electrochemical reactions occur can provide scientific insight for various processes ranging from biochemical reactions to charge storage in capacitors and batteries. However, to date, many of the theoretical and experimental analyses of electrochemical reaction speed- such as those in the widely used Butler-Volmer formulations are based on classical thermodynamics and adapt 19th century-based Arrhenius theory. In these cases, the charge transfer rate is assumed to constantly increase with applied voltage. While complementary theories consider the influence of the configurational rearrangements in the electrolyte and energy level occupancy, none have related the kinetics to the specific arrangement of the electrons in the material constituting the electrode. The latter aspect is very important for nanoscale materials where the bulk is but a small part of the whole.

Recently, a team of engineers at UC San Diego led by professor of mechanical engineering Prab Bandaru and involving Ph.D. students Hidenori Yamada and Rajaram Narayanan, probed in detail, both theoretically and experimentally, the specific characteristics of a nanostructured material with respect to its effect on charge transfer. They demonstrated that in a one-dimensional nanotube, the electrons are confined to a line, while in two-dimensional graphene, the electrons are confined to a plane. Based on these findings, the researchers expect that the restriction on electron motion hinders charge transfer and electrochemical kinetics. On the other hand, the reduced electron scattering could enhance the kinetics. The team resolved these issues by taking advantage of the specific arrangement of the electrons in the nanostructure. They applied their theories to explain the experimental variation of the electrochemical rate constant of single layer graphene.

(a) Atomic force microscopy image of a section of the single layer graphene (SLG) sample transferred onto a p-Si/SiO₂ substrate. The wrinkles on the sample surface corresponding to the line scan (white line) are displayed in the lower left inset. The Raman spectrum of the transferred SLG is indicated in the top right inset. (b) Schematic of the three-electrode droplet electrochemical cell (actual experimental arrangement shown in the top right inset). The SLG working electrode (WE), Pt wire counter electrode (CE) and a reference (REF) saturated calomel electrode are indicated.

The researchers detailed their findings in a recent issue of the Journal of Physical Chemistry Letters. 

The team discovered that the charge transfer rate may either increase, decrease or remain constant, and that such variation is sensitive to the orientation as well as the relevant dimensionality of the nanostructure. As charge transfer per unit time determines the electrical current that may be obtained from a given electrode, the UC San Diego study provides a firm rationale for the use of nanostructures in charge storage electrodes, with applications encompassing solid state battery-related systems, wearable sensors, etc., where electrical current modulations would impact energy and power delivery.

A plot of the charge transfer related electrochemical rate constant (k) normalized to the k_η=0V as a function of the applied voltage (η), considered with respect to the redox potential. The experimental data is a poor fit with the theoretical fits expected from conventional Butler-Volmer (B-V) kinetics as well as three-dimensional Marcus-Hush-Chidsey (MHC) kinetics, but could be fit well through a dimensionality dependent electrochemical model proposed by a team of engineers at UC San Diego.

Paper: Dimensionality-Dependent Electrochemical Kinetics at the Single-Layer Graphene–Electrolyte Interface, R. Narayanan, H. Yamada, B.C. Marin, A. Zaretski, and P.R. Bandaru, J. Phys. Chem. Lett., 2017, 8 (17), pp 4004–4008.

Eggshells -- nature's ceramic material

UC San Diego engineers investigate why eggshells are so strong

Think breaking an egg is easy? Try holding it sideways between your hands and pressing it, you'll find that it's almost impossible to break. That's what Eric Nicholas Hahn, a UC San Diego Ph.D. alumnus from the Department of Materials Science and Engineering, demonstrates in the video below:

Hahn was part of a team of researchers led by mechanical engineering professor Marc Meyers that investigated what makes eggshells so strong. Their findings were published last week in Journal of the Royal Society Interface.

The function of the eggshell is to protect the embryo from the environment, but it cannot be too strong otherwise the chick would not be able to break out and hatch. It is made of calcium carbonate, an important biomineral, which is different from hydroxyapatite, the mineral component of bone.

In the study, eggs of different sizes, from quail to ostrich, were tested on their strength using an electromechanical system that compressed the eggs between two pieces of rubber. When an egg is compressed in this way, tensile stresses develop radially in the shell. It is only when this radial tensile stress reaches a critical level, equal to the tensile strength of calcium carbonate, that the egg breaks.

Eric Nicholas Hahn, the first author of the study.

Chicken eggs were found to have a compressive strength of 100 lbs, whereas ostrich eggs gave values of more than 1000 lbs. Size and shell thickness were the most important factors in determining shell strength. The strength of eggshells decreases with increasing size and thus thickness, but the force required to break the egg increases because the stress (force/area) is less.

"This paper revealed, for the first time, the mechanism by which the eggs break when subjected to axial compression. It is not the compression by my hands that breaks the egg, but the tension generated radially,” Meyers said.

Meyers was interested in this topic since he was a child growing up in Brazil. He added, "We would like to check the universality of our equations by testing eggs of all kinds of birds. There are a variety of interesting birds that we did not test because their eggs are difficult to come by: penguins, eagles, dinosaur..."

Source: The Royal Society Publishing Blog

Full paper: "Nature's technical ceramic: the avian eggshell."

Pokebots Go!

It's no surprise that the theme of this quarter's Mechanical and Aerospace Engineering 3 (MAE3) robot competition was Pokemon Go - students were charged with building robots that could loft balls into a laser-cut Pokestop for points. Team W.H.O. beat out more than 40 other teams to get to the semi-finals with their unique design.

The team, consisting of second year physics major John-Paul Pascual, second year political science major Alex Velazquez, second year aerospace major Goutham Marimuthu and third year mechanical engineering major Kevin Tsao, used sheet metal to create a wall that traveled along a rail and prevented the other team's robot from accessing the balls.

When one team went around the wall, team W.H.O. simply moved their robot forward and dropped the sheet metal which opened like a pair of wings to prevent the other team's robot from depositing the balls at the Pokestop. Check out their website for more on the design!

Team W.H.O. lost in the semifinals to another team with that used a blocking mechanism - one that prevented their own from working.

"We had a lot of diversity in the robots this year," said MAE3 instructor Nate Delson. "I'm proud of all of our students and mentors."

Mentors and winning teams were provided with custom, 3D-printed trophies.

Also unique to the competition this year were the controllers, designed and fabricated by summer interns in the EnVision Arts and Engineering Maker Studio, with the help of the MAE Department.