DNA origami is the fabrication of biochemical structures using DNA as the building material. Using base pair design principles, DNA can be synthesized to self-assemble into dynamic objects such as a piston. The resulting creations have potential applications in nanotechnology including drug delivery, enzyme immobilization, photolithography, environmental restoration, and biocompatible devices. The goal of this project was to design a nanoscale mechanical spring and determine the parameters for spring constant and size. First, a spring comprised of multiple columns of double-stranded DNA was designed and fabricated. Size measurements were taken and morphology was verified using a transmission electron microscope. To measure the force constant of this structure, the 5’ end of the first column was functionalized with a thiol group which was then bonded to a gold cantilever tip on an atomic force microscope (AFM). This construct was brought very close to a magnesium substrate and allowed to bond. Force measurements for the spring were taken via AFM by slowly retracting the cantilever from the substrate. The spring force constant was calculated from this data using Hooke’s law in order to predict the amount of work that the DNA nanospring can perform when included in a complex nanostructure. The nanostructures created in this project can be used in conjunction with other DNA origami designs in order to create increasingly complex machines on the nanoscale.

Enzymatic pathways comprising multi-step biochemical reactions in biological cells constitute a key part of life. Biomimetic reconstruction of these metabolic pathways holds tremendous promise for developing sustainably powered devices. In biological cells, enzymatic components are kept in strict compartments or in serial networks. To mimic this complex hierarchical assembly of enzymes found in nature, a common approach is immobilizing these enzymes on the surface of porous substrates i.e., anodic aluminum oxide (AAO) membrane. However, one common limitation has been immobilization of multiple enzymes with a single type surface chemistry. As a result, these approaches have failed to provide enough capability to control spatial localizations of enzymes on AAO surfaces. Solid-binding peptides (SBPs) offer a novel solution to circumvent these problems with their exquisite recognition and long range solid-coverage properties. The ease of genetic conjugation of these short peptides with large proteins makes them an ideal candidate in utilization as molecular linkers in designing new multi-enzymatic devices. In this study, the utilization of a gold binding peptide (AuBP) as a molecular linker in combination with histidine-tag to immobilize Lactate Dehydrogenase (LDH) and Formate Dehydrogenase (FDH) enzymes on AAO based flow bioreactor was demonstrated. The efficacy of the described approach was tested by monitoring the sequential lactate and formate break down by LDH and FDH enzymes spectrophotometrically. The overall sequential catalytic conversion with greater than 90% yield was observed. Furthermore, the surface selectivity of the SBP conjugated enzymes were tested by visualizing their localization on Ni-NTA patterned gold surface using fluorescence microscopy. Cumulatively, this study highlights the utility of solid binding peptides as a molecular linker for addressable immobilization of multiple enzymes in the AAO based devices.

This research details the design, construction, modeling, launch and post-flight analysis of a high-powered rocket through the Earth and Space Sciences’ Rockets and Instrumentation course at the University of Washington. The primary goal was to build and test a multistage cluster rocket, scheduled to launch March 2016 in Black Rock, NV. To exploit the exponentially decreasing drag at high altitudes the rocket was initially designed as a two-stage, with eight external motors and two internal motors providing 43 kN-s of total thrust with a max velocity of 750 m/s. Risk assessment shows three-stage ignition as a safer option, providing a ground launch of 10 kN-s of thrust. Once the main engine burns for 2 seconds, the external cluster motors will ignite, providing 19 kN-s of impulse before separating from the main stage at around 20,000 feet. The sustainer motor then ignites at a final impulse of 14 kN-s and will reach an apogee of approximately 47,000 feet. The recovery package was designed with two separate systems of dual deployment for drogue and main parachutes, as well as a GPS and an altimeter, using two different flight computers, one in each stage. Previously untested commercial telemetry instrumentation was chosen and simulated with electromagnetic software before launching. If the rocket performs as designed, it will be the highest rocket built and flown by a University of Washington student group.

Flash memory, the predominant long-term storage device, is rapidly approaching its scaling limit, and among next-generation memory devices, phase change memory is a promising alternative. Phase change materials such as germanium telluride store information through electrical differences between crystalline ordered and amorphous disordered states. Since the speed and power consumption of a phase change device is directly related to the melting point of the material, we seek to find methods to reduce the melting point of germanium telluride. In particular, it has been hypothesized that small doping concentrations of bismuth could greatly reduce the melting point of germanium telluride. To investigate the effects of these dopants on germanium telluride's melting point and electrical properties, we utilize ab-initio modelling techniques to simulate these phase change devices on the nanoscale level. These simulations are performed using the modelling software Siesta where we can examine the impact of small changes in parameters such as doping concentration, temperature, and device geometry. Already, we have found that bismuth doping at high concentrations causes the germanium telluride to display metallic properties. We are still hoping to explore lower doping concentrations and the effects of bismuth on melting point. 

A sizable obstacle to the success of wearable devices in supporting good health, independent living, and workplace safety is compliance: is the user wearing the device and wearing it as it was designed? According to the United States Department of Labor, thousands of people are blinded each year from work-related eye injuries; this costs the industry more than $300 million in lost production time, medical expenses, and worker compensation (“Safety and Health Topics | Eye and Face Protection,” n.d.). This loss easily could be prevented by the usage of protective eyewear; thus is it imperative to know whether workers are complying with safety standards. Occupational Safety and Health Administration (OSHA) requires that all protective equipment, including personal protective equipment for eyes, face, head and extremities be provided (“General requirements. - 1910.132,” n.d.). Therefore, any manual laborer worker is required comply with safety standards, including wearing protective eyewear. This research investigated inexpensive sensors to monitor compliance with regard to safety goggles and workplace safety. To ensure high fidelity and accurate data, it is paramount to understand user behavior in the wearing and use of these devices. Specifically, detailed knowledge regarding the subject’s usage of protective eyewear, including the orientation and location on the head directly to inform the quality of compliance to safety standards. However, the addition of compliance monitoring functionality is limited by size, power consumption, cost, and form factor constraints inherent to the wearable device of interest. These limitations restrict the types of sensors that can be used to achieve compliance monitoring. After literature review and feasibility study of compliance monitoring techniques and existing biomedical wearables, including assessing electrostatic field sensing, magnetic sensing, and various approaches to eye tracking, we have decided to pursue magnetic sensors as the most viable option for compliance sensing. We are optimistic that magnetic sensing may offer a low cost and low energy solution for the detection of direction and orientation of protective eyewear. Therefore, with magnetic sensing we will determine if the protective eyewear is being worn on the bridge of the nose, on top of the head, or completely off of the body to determine compliance with safety standards. A preliminary design has been modeled and simulated to be evaluated for feasibility.

The security level of the interactions between human users and cyber systems is becoming more and more important in many areas. The traditional way of identifying a user is to utilize alphanumerical passwords, which are easy to realize but hard to memorize and vulnerable to various kinds of attack. To enhance security performance for user authentication, we take the advantage of the haptic interaction of new touchscreen devices that have recently been introduced. Previous studies show that how a person interacts with a haptic interface is unique and can be used for identification and authentication purposes. We applied this technique using the Microsoft Surface Pro 3, which has a pen, the N-trig digitizer. Having its API (ways for developers to talk to another site or services) made it easier to transfer data to the haptic password system. By developing an app on a writable windows tablet, we successfully captured ink data and pointer properties such as pressure, twist and orientation. We built a haptic password system and invited subjects to take specific tests. After data analysis, we found that this system is secure with good performance and forgery attack resistance. This system provides a complex but intuitive way of creating signature passwords. This haptic interaction technique can be applied to those pressure sensitive devices, such as tablets and signature touch screens. This could provide a much safer way of authorizing credit card transactions and lead to reduced transaction fraud.
 

In collaboration with Booz Allen Hamilton, our E E 497/498 Entrepreneurial Design Capstone project addresses the challenge of taking precisely georeferenced photographs of the underwater domain. These photographs will be mapped onto existing bathymetric datasets (from sources like NASA and NOAA) to provide visual textures of static and dynamic underwater points of interest. Our team’s role is the design and implementation of the imaging system hardware, which will complement visualization software under development at Booz Allen Hamilton’s Seattle office. Our design extends the OpenROV 2.8 platform, a small open-source, tethered, remotely-operated vehicle (ROV), with emphasis on developing a successful prototype using commercial off-the-shelf (COTS) parts at minimal cost. In total, our team has implemented (1) the extension of OpenROV into an underwater imaging platform, carrying a payload enabling hemispherical imaging below the ROV; (2) the design of a tethered surface buoy system, with access to Differential GPS data to act as a reference for geolocating the ROV; (3) the design of an ROV-mounted acoustic transmitter and buoy-mounted acoustic receiver array to determine underwater distance between the ROV and each array element; (4) the design of an efficient trilateration algorithm using nonlinear and linear least-squares optimization to accurately position the ROV relative to the buoy based on (3). Our research has significant implications for improving access to the underwater domain, including low-cost maritime sensing and deployment applications and military training and simulation applications.

The question of how to better represent harmonic and non-harmonic sounds with cochlear implants was addressed by reviewing journal articles on the subject and experimenting by simulation. By using electrodes to broadly stimulate the auditory nerves, cochlear implants can enable profoundly deaf individuals to understand a conversation in a quiet room. Because of this broad stimulation however, cochlear implant (CI) users have difficulty discerning pitch. The ability to discern pitch is not only nice for listening to music and necessary for understanding tonal languages like Chinese, but also has been shown to be important for aiding in the separation and understanding of speech in noisy environments. New processing strategies are being developed to represent pitch that rely on representing its fundamental frequency f_0 by amplitude modulating the carrier pulse trains sent to each electrode. This approach has improved users’ performance in timbre tests, melody recognition tests and Chinese tone recognition tasks but there is still much room for experiment and refinement. Since the harmonic components of pitched sound are evenly spaced in the frequency domain, two pitched sounds having fundamental frequencies related by a simple ratio will have overlapping harmonic components and be perceived as more consonant while notes with more complex relationships share fewer components and are perceived as more dissonant. Previous studies on normal hearing listeners as young as 9-months old have shown that it takes longer for subjects to notice and respond to a change in note sequences when the sequences switch from dissonant to consonant relationships than from consonant to dissonant ones. A better understanding of perceptual consonance and dissonance for CI users would aid in the development of better processing strategies and simulations. Experiments are proposed to investigate this perception by studying the reaction times of subjects to changes between electrode stimulation patterns.

Real-time quantification of chemical compounds in urban and non-urban environments has far-reaching prospective benefits for our society. Such a possibility could provide instantaneous detection of dangerous chemicals, identification of areas that require air quality restoration, estimation of agricultural effectivity, etc. However, currently, dynamic and efficient platforms to perform quantification do not exist and only a few static sensors are deployed in sparse locations, e.g., a typical city has only a handful of such sensors. While several mobile devices have been constructed, they are typically large, expensive and imprecise. These factors make them practically unrealizable for gathering environmental data in real-time from a wide variety of locations. In our project, we address this fascinating and challenging problem by building an inexpensive, mobile multi-sensor device, that communicates with a mobile phone. We designed the device to incorporate an array of inexpensive sensors, many of which have cross sensitivities to particles measured by other sensors. We had performed testing on a variety of sensors to identify most efficient and precise sensors. To improve performance of the device and obtain readings, we have implemented a neural network, based on olfactory system in moths. We have assembled a prototype of a multi-sensor device according to our design. Our preliminary results show that the network was capable of discriminating and tracking more precise values of contaminants, that could even include mixtures of compounds. We are currently working on implementing a server-side application that will integrate information from multiple devices and will produce a real-time “heat-map” of contaminants and pollution levels across a geographic area.

Only a small portion of the market sells printers that are compatible with Google cloud print. In the case where a customer purchases a printer that is not compatible with Google cloud print, the printer can only be used through a wireless, wired, or USB connection. With the aim of allowing users to print from anywhere and at anytime, our project intends to design a low-cost and user friendly device that is capable of converting a regular printer into a cloud printer. The project is being developed on a small portable Linux machine (raspberry pi) using a 16GB SD card and a small Wi-Fi adapter. The raspberry pi is initially configured as an access point, enabling the user to connect wirelessly to the device. Once connected, the user then navigates to a web page hosted on the device accessing a user friendly interface to set up the printer. After the initial setup has been completed, the raspberry pi will then turn into a Wi-Fi client which allows itself to receive instructions through the Internet. The device will then interface with the printer through a USB cable. The users then can log in to their Google cloud print account on any device from any place at any time to print on the registered printer. This device, once developed, would provide a low cost and user friendly alternative to the existing expensive cloud-ready printers and allow users to take advantage of Google cloud print.

The Large Hadron Collider (LHC) is one of the largest physics experiments in the world, and is best known for the discovery of the Higgs Boson. At the LHC, specialized sensors are used to detect high energy particles as they move away from beam collisions centered in detectors placed around the complex. These sensors are similar to what you would find in a standard camera; however the sensors are tuned to detect particles other than photons. The current sensors in the LHC are slowly degrading from radiation, and are built on an old outdated process. A new sensor is being designed which will not be compatible with the current sensor, requiring a new control system. The project is  focused on building a control system for a model of a candidate replacement sensor. Once the actual replacement sensor has been produced, the control system will be able to assist the testing and validation process of the physical sensor. The emulator control system I have designed offers a high speed method to test the emulated sensor, providing an interface between a host computer and the sensor. The control system is designed to be modular in order to allow researchers to use the design on a variety of different field programmable gate arrays (FPGAs) if more speed is required. The design of the control system has been completed and tested, and is currently being inegrated into the sensor mode, creating a full readout system. The creation of a fully emulated readout system is an essential step in improving the results gathered by the detectors in the LHC.