Mechanical Engineering and Materials Science REU

Beginning in summer 2012, the Department of Mechanical Engineering and Materials Science at Duke University will provide a research experience for undergraduate students (REU) and host undergraduates from around the country in its research laboratories. The REU students will work with a faculty member and their research group to tackle an innovative research project (see list of projects below). 

Stipend

Students admitted to the program will receive a competitive, monthly research stipend which includes:

• 9 weeks housing on Duke's campus
• $4200 stipend
• Up to $400 towards travel costs 

When to Apply

Applications are closed for 2013. Please check back in 2014.

Eligibility

All applicants must be United States citizens or permanent residents. The program is designed for student who are juniors during the internship period, but exceptional sophomores will also be considered. Students do not have to be majoring in mechanical engineering and materials science.

Dates

Selected students should expect to hear of their acceptance to the program by April 1. Student participants will be on site from late May to late July.

Research Opportunities for 2013

The following nine projects are available for the coming summer. Interested students are encouraged to apply. Questions about any of the projects or the REU program in general should be directed to Kathy Parrish (kparrish@duke.edu). To be considered for any project, students must apply online through the link above.

Engineering and Characterization of Complex Supported Lipid Bilayer Membranes

This research is motivated by the observation that rare, broadly neutralizing antibodies (NAbs), 4E10 and 2F5, associate with HIV-1 lipids as part of a required as a first step in neutralization before binding to membrane-proximal antigens. Subsequently, induction of these types of NAbs may be limited by immunologic tolerance due to autoreactivity with host cell membranes. Despite the significance of this lipid reactivity there is little experimental evidence detailing NAb-membrane interactions. Simple and efficient screening assays are needed to further define and understand NAb neutralization and autoreactivity, specifically in the context of how exposed chemical groups from lipid membranes help drive antibody interactions. The research thus focuses on understanding how membrane properties, such as composition, lipid domain organization, and lipid diffusivity contribute to 2F5/4E10-membrane interactions and antigen localization at the membrane interface. To this end, we have developed supported lipid bilayers (SLBs) whose compositions model the HIV-1 lipid Env. These SLBs have planar surfaces that facilitate the use of quantitative surface-characterization techniques such as high-resolution scanning-probe imaging, detection of fluorescence recovery after photobleaching, and neutron reflection measurements. We have begun to use these techniques to i) visualize domains of lateral membrane organization; ii) determine lipid diffusivity within domains; iii) determine differences in adhesion force (surface energy) of domains; and iv) correlate these differences with details of NAb-membrane binding, NAb/antigen localization, and, conformational details of NAb/antigen interactions at the membrane interface.  The REU student would work with a graduate student in an interdisciplinary research environment, and help in preparing and imaging SLBs.

Faculty Contact: Professor Stefan Zauscher (email)

Biomacromolecular Block-Copolymers and Brushes

Practical design of biologically inspired materials has large potential for positively impacting society's well-being, as biomolecular materials can deliver medical therapeutics, are employed in sensors to detect biological and chemical threats, and biomolecular nanostructures are used as scaffolds and templates to imbue novel function for inorganic materials. While most man-made polymeric materials serve structural purposes, they do lack precise sequence specificity and do not approach the functional sophistication of biomolecular materials. Biomolecules, however, provide structural and informational properties, whose functions are encoded within distinct sequences of diverse monomer sets. At present, however, there still is a lack of fundamental understanding to control or influence the hierarchical self assembly of biomolecular building blocks, although this step is critically necessary to unlock the potential of biomolecular materials.

We have shown that the template-independent polymerase, terminal deoxynucleotidyl transferase (TdT) can catalyze the growth of ssDNA from a short oligonucleotide initiator attached to a surface or create high molecular weight (up to 8 kb) homopolymer and copolymer DNA in solution with exquisite control of chain lengths. Furthermore, we have shown that a broad range of unnatural nucleotides with unique chemical functionalities (biotin, amine, and aldehyde groups) can be directly incorporated into the ssDNA by TdT catalyzed synthesis. The use of TdT to create complex DNA based hybrid materials in situ from a range of substrates and from genetically engineered polypeptides, is a rich and untapped area of soft matter research that we will exploit in the framework of the newly established NSF Materials Research Science and Engineering Center (MRSEC) in Softmatter at Duke. For example, temperature-triggered microphase separation of diblock DNA-polypeptide copolymers could lead to micelles that consist of a hydrophobic core (polypeptide) and a hydrophilic shell (polynucleotide), and will depend on the relative size of the blocks and their relative difference in solvation properties.

The REU student will engage with graduate students in the characterization of these biomacromolecular materials.

Faculty Contact: Professor Stefan Zauscher (email)

Harnessing Bacteria for the Fabrication of Inorganic Materials

In this project we seek to demonstrate that bacteria can be harnessed for the biosynthesis and deposition of semiconducting nanoparticles and thin films that have useful technological properties in areas as diverse as energy generation, microelectronics and biosensing. Specifically, we use engineered bacteria (You laboratory) to generate well controlled cadmium sulfide (CdS) particles and thin films. CdS thin films play an important role in photovoltaic technology and for optoelectronic devices. The currently used chemical bath deposition for the synthesis of CdS thin films remains, however, a continuing challenge. Here, biology may offer complementary, and possibly vastly better, options. The bacterial biosynthesis and precipitation of CdS nanocrystals intracellularly and extracellularly has been prototypically shown, and useful biochemical reduction pathways have been engineered. Here we harness engineered bacterial expression systems for the deposition of nanocrystalline CdS thin films and particles with core-shell morphology.

The REU student will work with a graduate student on nanoparticle synthesis and characterization using advanced surface analytical tools, such as AFM, XPS, SEM. 

Faculty Contact: Professor Stefan Zauscher (email)

Vectorial Folding Of Polypeptide Chains

The folding of proteins is one of the most important yet not completely understood topics in biology. The question “Can we predict how proteins will fold?” was listed in 2005 as one of the 125 most important unsolved problems in science by the Science magazine. Significant progress has been made toward understanding the protein folding through in vitro experiments and computer simulations, but much less is known about folding in vivo. During co-translational folding, the nascent polypeptide chain (NPC) is extruded sequentially in a vectorial manner from the ribosome exit tunnel and starts folding under severe conformational constraints. It is presently unknown how such 1D constraints affect the folding pathway. 

The long-term objective of this proposal is to advance understanding of protein folding by:  

• studying the vectorial folding of single proteins under 1D constraints by Atomic Force Microscopy(AFM)-based single-molecule force spectroscopy (AFM-SMFS) and computer simulations using steered molecular dynamics (SMD) calculations.
• directly examining the folding behavior of the nascent polypeptide chain emerging from the ribosome using AFM mechanical manipulations.

Atomic force microscopy is a novel form of (non-optical) microscopy that can be mastered easily by undergraduate students. Although some knowledge of biology as it relates to proteins and their “folding” problem would be desirable it is not a pre-requisite for participation.

Faculty Contact: Professor Piotr Marszalek (email)

Construction of an Atomic Force Microscope for Combined Mechanical and Optical Measurements in Nanobiotechnology

The objective of this proposal is to provide hands-on experience to undergraduate students in the design and construction of a robust high-precision and very inexpensive research-grade atomic force microscope that can be operated on top of an inverted optical microscope for combined force and fluorescence measurements 1. The instrument will be designed in a modular fashion in such a way that its future modifications, improvements and expansions will be easy to implement and these perpetual improvements will provide yet another avenue of continuous research experience for future undergraduate students. 

We note that a complete home-made AFM instrument (Fig. 1A) was already designed, constructed and successfully used in the Marszalek laboratory by several undergraduate students, and its design was published by Rabbi and Marszalek2. This AFM instrument will require a complete design overhaul to be able to work on top of an inverted microscope. To capture the fluorescence from the molecule being stretched by the AFM, the microscope objective (Fig. 1B) needs to be inserted into the AFM head and positioned right below the sample. It will occupy the space that in a traditional AFM is taken by a high precision piezoelectric stage that translates the sample in the z direction for the mechanical stretching of molecules. Therefore, in the new AFM, the Z-stage that moves the sample will need to be located outside of the AFM head (e.g. as in Fig. 1C, Z-sample stage). One of the main difficulties for the new AFM to operate successfully will be to keep the molecule stretched within the focal depth of the microscope objective. To achieve this goal, the whole AFM head will need to be also translated in the Z direction, relative to the sample. This can be achieved e.g. by attaching another high precision piezoelectric Z stage directly to the top of the AFM head and  mounting it on the body of the optical microscope (e.g. as in Fig. 1C, AFM head Z-stage). This modification will force the relocation of the laser from the top of the head to a horizontal location inside the head (Fig. 1C).

This project will involve undergraduate students who will work over the summer in Dr. Marszalek laboratory to design and construct such an instrument. This project will provide an extremely fulfilling experience for these undergraduate students in the planning and execution of their real-world engineering activities whose final product will be a sophisticated research-grade instrument. The students will directly get experience in designing and constructing an instrument which is composed of very precise mechanical, electrical, electronic and opto-electronic components, which need to be perfectly aligned and actuated/probed by digital to analog interfaces controlled by a computer. Thus, their practical experience will integrate many areas of engineering. Importantly, their product will be later used for real research activities done by their undergraduate peers. These activities will focus on simultaneous measurements of the elastic and optical properties of single molecules such as DNA and various proteins (force spectroscopy) that will be labeled with fluorescent probes. 

Faculty Contact: Professor Nico Hotz (email)

Hotspot Cooling by Jumping Condensate

The objective of this project is to develop a novel phase-change cooling technique for hotspot thermal management of microprocessors and power electronics. The hotspot cooling is enabled by the self-propelled jumping condensate on water-repellant superhydrophobic surfaces, on which condensate droplets spontaneously jump by themselves. (The detailed process can be watched on the Discovery Channel: http://watch.ctv.ca/clip231340).

This project is primarily experimental but will also involve the development of scaling laws.  The student will have the opportunity to fabricate the nano-structured superhydrophobic surface and integrate it into a phase-change cooling system for hotspot mitigation.

More information about the Microscale Physicochemical Hydrodynamics Laboratory (µPHYL) can be found online at http://www.duke.edu/web/uphyl/. Interested students are encouraged to visit our lab at 181 & 183 Hudson Hall.

Faculty Contact: Professor Chuan-Hua Chen (email)

Thermohydroelectric Generator

The objective of this project is to develop a new technique to generate electricity by harvesting waste heat. In a closed-loop phase change system, condensate drops can self-propel themselves upon coalescence on a superhydrophobic condenser. (The detailed process can be watched on the Discovery Channel: http://watch.ctv.ca/clip231340). Electricity can then be generated from the jumping drops via electrostatic induction. 

This project is primarily experimental but will also involve the development of scaling laws.  The student will have the opportunity to develop a thermohydroelectric generator from scratch. High-speed photography will be used to study the energy conversion processes.  

More information about the Microscale Physicochemical Hydrodynamics Laboratory (µPHYL) can be found online at http://www.duke.edu/web/uphyl/. Interested students are encouraged to visit our lab at 181 & 183 Hudson Hall.

Faculty Contact: Professor Chuan-Hua Chen (email)

Super Hydrogel for Biomedical Applications

We propose to create novel hydrogels that contain over 80% water yet have similar fracture toughness as rubbers used in car tires and can maintain the high toughness over 10,000 cycles of deformation.  While hydrogels are widely used in biomedicines, the scope of applications of hydrogels, however, is often severely limited by the mechanical behavior of hydrogels. For example, most hydrogels have fracture toughness on the order of 10 J/m2, much lower than the value required for artificial cartilage (i.e. ~1000 J/m2). 

In the current project, we propose to develop hydrogels consisting of two interpenetrating polymer networks, in which one network contains polymer segments so-called mechanophores that can be reversibly activated by mechanical forces. We hypothesize that the reversible mechanochemical activation of the mechanophores on one network dissipates large amounts of mechanical energies in the deformed hydrogel, while the other network maintains the shape of the hydrogel once unloaded. Since the polymer chains are intact during activation of mechanophores, the new hydrogel can possess both extremely high fracture toughness and anti-fatigue properties. Motivated students with background in chemical engineering, materials science, and biomedical engineering are welcome to apply for a REU position. 

Faculty Contact: Professor Xuanhe Zhao (email)

Soft Active Materials

The research in Duke Soft Active Materials Laboratory is motivated by new materials and phenomena emerging on the interface between engineering and biology. We are currently particularly interested in soft materials which are easily deformed by multiple thermodynamic forces (e.g. stress, electric field, magnetic field, and chemical potential) and their applications in various technologies such as energy storage, energy harvesting, biofouling, drug delivery, tissue engineering, robotics, microfluidics, and water treatment. Motivated students with background in solid mechanics, materials science, biomedical engineering, and applied mathematics are welcome to apply for a REU position.

Faculty Contact: Professor Xuanhe Zhao (email)

Nonlinear Aeroelasticity

A number of research projects are underway in our research group. Each of these is concerned with some aspect of DYNAMICS and usually involves the dynamic interaction of a fluid and an elastic structure. This field of study is often termed AEROELASTICITY,i.e. aerodynamics plus elasticity. Recent work has emphasized nonlinear aspects of the phenomena. Research in this field has often been motivated by aerospace applications such as the oscillations of aircraft wings, turbine blades in jet engines and the wind loading on missiles during their launch. However applications to biomedical engineering, e.g. blood flow through arteries or airflow through the mouth; civil engineering, e.g. wind loads on bridges and buildings; electrical engineering, e.g. wind induced oscillations of power lines and energy harvesting; and to many other aspects of engineering are also studied world wide and are of interest to our group at Duke. Current projects involve an opportunity for either theoretical or experimental work. Students are welcome to suggest project ideas of their own and are encouraged to discuss those with Professor Dowell. 

Current research projects underway include the following: 

• Dynamic response of structures under fluid or solar pressure loading leading to instabilities and limit cycle oscillations. Systems of interest include high performance aircraft; folding wing aircraft undergoing radical shape changes; long span, highly flexible wings typical of uninhabited air vehicles; hypersonic inflatable aerodynamic decelerators and solar sails for interplanetary travel.
• Control of such systems
• Investigation of nonlinear effects such as freeplay, structural stiffness and damping changes due to large deflections, and shock wave motion including viscous effects in an aerodynamic flow. 
• Energy harvesting from self excited and forced aeroelastic systems.

Collaborating faculty include Professors Donald Bliss, Linda Franzoni, Henri Gavin, Kenneth Hall, Laurens Howle, Josiah Knight, Brian Mann and Lawrence Virgin. Many of the projects make use of our acoustic test chamber, active control test facilities, nonlinear dynamics laboratory and/or wind tunnel laboratory. Research projects usually involve team effort with faculty, PhD students, MS students and undergraduates working together.

Faculty Contact: Professor Earl Dowell (email)