Browsing by Subject "Sensor"
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Item Calix[4]arene-based ion or ion-pair receptors(2016-05) Yeon, Yerim; Sessler, Jonathan L.; Liu, Hung-wen; Keatinge-Clay, Adrian T; Dong, Guangbin; Kerwin, Sean MCalix[4]arene derivatives are one of the most important supramolecular scaffolds. They have been extensively exploited to build more elaborate systems. Calix[4]arene derivatives can stabilize host-guest complexes with various ions and neutral molecular guests through non-covalent interactions (e.g., hydrogen bonding, electrostatic interactions and cation-π interactions). This dissertation describes efforts to develop more efficient calix[4]arene-based ion and ion-pair receptors. Chapter 1 describes an overview of sensitive ion selective chromogenic and fluoregenic sensors based on calix[4]arene derivatives. Chapter 2 details a chromogenic calix[4]arene-calix[4]pyrrole sensor system formed by appending an indane substituent to the β-pyrrole position of the calix[4]pyrrole portion of the hybrid and its use in detecting cesium salts. The indane substituted calix[4]arene-calix[4]pyrrole system gives rise to a colorimetric response when only exposed to simple ion pairs containing the cesium cation. Chapter 3 describes amido-indole incorporated calix[4]arene anion receptors. An amido-indole moieties appended calix[4]arene provides multiple hydrogen bond donors for the interaction with anions. In Chapter 4, graphene field-effect transistors (GFETs) are introduced for cesium ion sensing based on electrostatic measurements. In this work, a crown-6-ether strapped calix[4]arene derivative that adopts a cesium ion selective conformation was prepared. Then, it was attached to various graphene field-effect transistors (GFETs) via π−π interactions. The co-complexation of Cs⁺ ion and calix[4]arene receptor on the GFETs alters the electronic behavior of the system in an ion and concentration dependent manner. This work serves to extend the fundamental chemistry of calix[4]arene-based cesium ion recognition to new research areas. Lastly, an experimental section and characterization data are provided in Chapter 5.Item Capacitive shear stress sensor with DC sensing capability for fluid flow measurements(2017-05-04) Snell, Colton Dee; Hall, Neal A.; Haberman, Michael RIn this work, the design, simulation, fabrication, and characterization of a shear stress sensor based on a differential capacitive sensing scheme are presented. The sensor is an adaptation of previous generations that utilized piezoelectric sensing techniques. The present generation of the device replaces the piezoelectric with a dielectric film, converting the sensing mechanism of the device from piezoelectric to capacitive. The motivation for this adaptation is to create a shear stress sensor capable of sensing static shear stresses, such as those generated by a constant flow across a surface. The sensors consist of an array of unit sensing cells, each of which contains three electrodes: two resting on the substrate, and a third resting on top of the dielectric, between the bottom electrodes. This configuration creates a resting capacitance between the top electrode and either bottom electrode that varies when the top surface of the device experiences shear stress and thus deflection of the top electrode. The departure from the resting capacitance is monitored by applying a sinusoidal signal to the bottom electrode, and observing the change in amplitude of the signal at the top electrode as the surface shears. The device is first modeled analytically and numerically to estimate the sensitivity for the device, which is used as the figure of merit in evaluation of these shear sensors. Sensitivity is defined in this context as the change in capacitance per Pascal [ΔC/Pa]. The fabrication and testing of the device are described, through which a measurement of the sensitivity of the sensors is obtained and found to be in agreement with the predicted sensitivity via simulation.Item Design and development of an X-ray sensor to measure the density and flow rate of drilling fluids in high pressure lines(2018-12) Singhal, Vivek, Ph. D.; Oort, Eric van; Chen, Dongmei; Bovik, Alan C; Barr, Ronald E; DiCarlo, DavidThere is a need for advanced technology that can accurately measure the density and mass flow rate of drilling fluids at the high pressure well inlet in real-time. Current reliance on antiquated metering technologies such as the pressurized mud balance and the pump stroke counter to make these measurements greatly impedes our ability to accurately predict the near well bore pressure profile and measure the delta flow rate, which is one of the primary indicators for trouble events such as kicks or lost circulation. In order to address this gap in technology an X-ray sensor was developed to make real-time measurements at greater than 99% percent accuracy and 1 Hz measurement frequency. The X-ray sensor can measure the density of drilling fluids in the 8 ppg to 20 ppg range and with flow rates of up to 1200 gpm. These measurements are made using 320 kV/1500W polychromatic X-ray source, which is well within the range of readily available industrial X-ray tubes. In the past such measurements would require X-ray voltages that could only be achieved with linear accelerators thereby making the cost and size of equipment non-conducive to the drilling environment. However, recent advances in pipe manufacturing, particularly using a class of low density and high pressure materials known as carbon fiber reinforced polymers (CRPs) and, are now making it viable to re-visit relatively low cost X-rays systems for density and mass flowrate measurements. Windows constructed from CRPs allow us to bypass the high density carbon steel standpipe and make measurements at voltages that do not require a linear accelerator. In this paper we discuss the design and implementation of a CRP based X-ray sensor that is used to measure drilling mud density and mass flowrate at the high pressure well inlet.Item Design of a MEMS-based tunable graphene resonator with precision strain and force metrology(2016-05) Sun, Guoao; Cullinan, Michael; Akinwande, DejiMade of only on sheet of carbon atoms, graphene is the thinnest yet strongest material ever exist. Since its discovery in 2004, graphene have attracted tremendous research effort worldwide. Guaranteed by the superior electrical and excellent mechanical properties, graphene is the ideal building block for Nanoelectromechanical System (NEMS). However, one of the major challenges in producing highly accurate graphene-based nanoelectromechanical (NEMS) resonators is the poor fabrication repeatability of graphene-based NEMS devices due to small variations in the residual stress and initial tension of the graphene film. This has meant that graphene-based nanoelectromechanical resonators tend to have large variations in natural frequency and quality factor from device to device. However, by actively controlling the tension on the graphene resonator it is possible both to increase repeatability between devices and to increase the force/mass sensitivity of the nanoelectromechanical resonators produced. Such tension control makes it possible to produce electrometrical filters that can be precisely tuned over a frequency range of up to several orders-of-magnitude. In order to controllably strain the graphene resonator, a microelectromechanical system (MEMS) is designed and used to apply tension to the graphene. The MEMS device consists of a graphene resonator, electro-thermal actuator and two differential capacitive sensors. Using this setup, it is not only possible to tune the natural frequency of the graphene resonator, but also possible to perform high precision force and strain metrology on graphene beam. In addition to designing devices that can compensate for manufacturing errors in nanomanufactured devices, this thesis will present several methods that can greatly expand the scope and rate at which nanomaterials-based devices can be fabricated.Item Development of a reusable colorimetric calcium sensor based on a calix[4]arene-functionalized glass surface(2013-05) Yeon, Yerim; Sessler, Jonathan L.A dual functional chromogenic calix[4]arene, which contains both hydroxy azophenols and triazoles for colorimetric sensing and cationic recognition, respectively, has been synthesized. This system was further functionalized with dimethallylsilane to permit grafting to a glass surface. This grafting may be used to produce a surface modified glass slides that act as reusable ion-selective colorimetric sensors. UV/Vis spectral studies revealed that this compound is capable of binding the calcium cation in aqueous media and producing an easily detectable color change. The same is true for the modified surface setup. For the free receptor in acetonitrile solution, the absorption maximum undergoes a red shift from 390 nm to 496 nm upon exposure to calcium cations. In the case of the modified surface, exposure to acetonitrile solution of calcium perchlorate leads to a change in color from orange to red. Washing with acetone serves to remove the metal cations from the calix[4]arene-functionalized glass and restore the original orange color. The system is then ready for reuse. Specifically, following treatment with acetone, the glass may be submerged in a metal solution once again. In the case of exposure to calcium salts, this re-exposure results in a color change analogous to what was seen for a pristine system. In accord with design expectations, this process may be repeated several times. On the basis of this reproducibility, we think this system meets the reusability requirements necessary for the development of a practical sensor device.Item Development of the "NoSlip": a simple yet sophisticated paper analytical device for detection of proteins(2016-05) Cunningham, Josephine Carol; Crooks, Richard M. (Richard McConnell); Ellington, Andy; Richards, Ian; Anslyn, Eric; Hoffman, DavidThe two most successful commercial sensors in self-diagnostics are the pregnancy test and the blood glucose meter. Our opinion is that too much time has gone by without successful commercialization of more consumer operated sensors, despite there being a significant market opportunity. For that reason, we put together a team in 2012 with the objective to develop a sophisticated sensor that could use telemedicine to revolutionize individual’s involvement in their health monitoring. We chose paper as the sensor substrate because of it’s inherently low-cost and ease of fabrication, and electrochemistry as the detection method because the necessary equipment can be miniaturized into an inexpensive handheld reader while achieving sensitive and quantitative detection. The scientific journey that we have traveled thus far while working towards our stated objective is reported here. We’ve developed three different paper-based electrochemical sensors, where each new sensor is an improved version of the former. The first is a paper-based electrochemical sensor that uses conformational switching of DNA probes or aptamers for detection of thrombin and DNA at 16 nM and 30 nM, respectively. The second paper analytical device uses a magnetic microbead supported metalloimmunoassay for electrochemical detection of a model analyte and a biological warfare agent (ricin) at 767 fM and 34 pM, respectively. The concluding device is very similar to the second but with an alternative detection strategy involving galvanic exchange that makes the device a true point-of-need sensor while still maintaining the low-cost, ease of mass production, and dynamic range that is relevant for most biological markers. We’ve come a long way but the journey continues.Item Development of wireless DNA microarray sensors(2010-08) Chow, Kwok-Fan; Crooks, Richard M. (Richard McConnell); Bard, Allen J.; Bielawski, Christopher; Manthiram, Arumugam; Stevenson, KeithThe development of wireless DNA microelectrochemical microarray sensors is described. The operational principles of these sensors are based on bipolar electrochemistry. Bipolar electrodes are used to fabricate the wireless microarrays in this work. The systems are configured so that DNA sensing is carried out at the cathodic end of a bipolar electrode (BPE) and the result of the sensing experiment is reported at the anodic end of the BPE. There are two types of reporting platforms developed in this study. The first type relies on the emission of electrogenerated chemiluminescence (ECL). The system is configured so that ECL is emitted at the anodic end of the BPE when the target DNA is hybridized to the capture probe DNA immobilized on the cathodic end of the BPE. However, when there is no hybridization reaction occurs, there is no ECL emission on the electrode surface. The second type of reporting platform developed is based on silver electrodissolution at the anodic end of a BPE. When a reduction reaction occurs at the cathodic end of a BPE, it triggers oxidation and dissolution of silver deposited at the anodic end of the BPE. The loss of silver can easily be detected by the naked eye. This detection principle is used for DNA detection: when the target DNA is hybridized to capture probe DNA on the BPE, the BPE becomes shorter. However, if target DNA does not hybridize to the electrode surface, the length of the BPE remains the same. The BPE microarrays described in this work eliminate the need for complicated microfabrication procedures and instrumentation. For example, as many as 1000 BPEs can be simultaneously controlled using just two driving electrodes and a simple power supply. To fully utilize BPE microarrays for specific sensing tasks, a method based on robotic spotting was developed to modify the cathodic end of each BPE in the array. Because each BPE in a microarray is individually addressable, this development allows each BPE to perform a particular sensing operation.Item Enzymatic inhibition-based biosensing on nitrogen-doped carbon nanotube electrodes(2015-05) Rust, Ian Matthias; Stevenson, Keith J.; Webb, Lauren JWhile previous work has demonstrated the effectiveness of nitrogen-doped carbon nanotubes (N-CNTs) as biogenic electrode materials in first- and second-generation biosensors, this thesis primarily explores enzymatic inhibition-based biosensing schemes on N-CNT electrodes. This type of scheme enables the detection of enzymatic inhibitors, as opposed to enzymatic substrates, making these inhibition-based biosensors much more suitable for the monitoring of environmental pollutants. Presented in this thesis is a biosensor which couples N-CNTs with glucose oxidase (GOx) through spontaneous physical adsorption for the highly sensitive detection of aqueous silver ions. Included is a thorough discussion of the parameters that affect response time as well the biosensor’s aptitude for repeated use. A later chapter presents initial work towards the inhibition-based detection of sucralose, a relatively new environmental pollutant. A bi-enzymatic approach is explored, in which both GOx and invertase are immobilized on an N-CNT modified electrode. Finally, shifting focus from inhibition-schemes, the last remaining chapter investigates the coupling of CNTs and N-CNTs with methylene green (MG), a redox mediator used in second-generation biosensors based on NADH oxidation. Common coupling techniques are examined for their effectiveness in decreasing the overpotential required for NADH oxidation.Item Exploration of the iron chelator deferasirox : a multifaceted platform for the development of antineoplastic agents and water-soluble sensors(2022-10-06) Steinbrueck, Axel; Sessler, Jonathan L.; Anslyn, Eric V.; Liu, Hung-Wen; Fast, Walter L.; Page, Zachariah A.Chelators have gained considerable interest due to the wide range of potential applications for this class of molecules, including as therapeutics and chemosensors. Over recent decades, a number of metal chelators have successfully demonstrated cytotoxicity and targeted activity against cancer in vitro, in vivo and in preliminary clinical trials. Considering these promises, during my dissertation I have explored the strategic derivatization of the clinical iron chelator deferasirox with focus on the preparation of chelators that show enhanced activity against cancer cells. In addition, I have investigated the optimization of deferasirox as chemosensor for Fe³⁺ in water samples. In chapter 1, an overview on the recent progress in the use of transition metal chelators, pro-chelators, and ionophores as potential cancer chemotherapeutics is provided. This chapter focuses on the reported agents that are able to coordinate iron, copper, and zinc. Chapter 2 describes the design, synthesis, and biological evaluation of strategically functionalized derivatives of the FDA approved iron chelator deferasirox. Preparative efforts focused on derivatives containing organelle-targeting moieties and their in vitro activity against A549 lung cancer cells is discussed. In contrast to the parent chelator deferasirox, several of the new derivatives could be traced inside cells through fluorescent cell imaging. One of the derivatives exerted improved antiproliferative activity relative to deferasirox and was revealed to preferentially localises within the lysosome. Chapter 3 discusses the evaluation of deferasirox as colorimetric chemosensor for the detection and quantification of Fe³⁺ in aqueous samples. The optimization of deferasirox and the water-soluble, non-toxic derivative ExSO₃H are discussed. In addition, ExSO₃H was identified as potential chelator for uranyl (UO₂²⁺) in water and the interaction between these two species was investigated. Chapter 4 discusses the observation that a fluorescent turn-on response was produced when a water-soluble deferasirox derivative was allowed to interact with human serum albumin (HSA). This fluorescence was quenched in the presence of Fe³⁺, thus permitting the monitoring of the presence of this biologically important metal cation with a protein-bound chelator.Item Heterogeneous integration of graphene and Si CMOS for gas sensing applications(2014-12) Mortazavi Zanjani, Seyedeh Maryam; Akinwande, Deji; Banerjee, Sanjay K.; Aziz, Adnan; Sun, Nan; Li, WeiDetecting presence of gas molecules is of prominent importance for controlling chemical processes, safety systems, and industrial and medical applications. Despite enormous progress in this field over past few decades on developing and improving various types of gas sensors, sensors with higher sensitivity, selectivity, lower sensing limit, and lower cost that can perform at room temperature are highly sought-after. Discovery of graphene and its succeeding progress in nanotechnology has paved the way to design ultra-sensitive gas sensors that can detect individual gas molecules while operating at room temperature. Graphene is a promising candidate for gas sensing applications due to its unique transport properties, exceptionally high surface-to-volume ratio, and low electrical noise. In this dissertation, a graphene gas sensor fully integrated with silicon CMOS platform is presented, and its performance for detecting NO₂ and NH₃ gas molecules is investigated. This integration helps benefit the high gas sensitivity of graphene at room temperature as well as the compact size, robustness, low cost, and advantages of standard industrial scale production of CMOS technology. Recent progress in large scale growth of CVD graphene paves the path toward commercialization of graphene-based CMOS sensors to provide highly sensitive low-cost sensors for industrial applications. To best of our knowledge, this work is the first integration of mono-layer graphene and silicon CMOS. Also, this is the first implementation of graphene integrated gas sensor. Heterogeneous integration of monolayer graphene and silicon CMOS can introduce a platform to exploit the unique electronic properties of monolayer graphene for gas sensing applications and also take a step further toward commercialization of ultrasensitive monolithic graphene-based gas sensors. Furthermore, we were able to enhance sensitivity of CVD graphene to NH₃ by almost an order of magnitude. We experimentally showed that sensitivity of graphene to NH₃ can be enhanced by 7 folds compared to as-fabricated graphene by introducing NO₂ molecules as dopants. We observed this enhancement for graphene sensors microfabricated on SiO₂/Si substrate, as well as our integrated graphene-CMOS sensors. This finding not only increases current understanding on adsorption mechanisms of molecules to graphene, but also takes another step toward commercialization of graphene sensors.Item Interdigitated capacitor sensor for complex dielectric constant sensing(2010-05) Zhang, Sheng, 1986-; Neikirk, Dean P., 1957-; Dodabalapur, AnanthThe objective of this thesis is to develop a complex dielectric properties sensor using interdigitated capacitor (IDC) structure. IDCs are easy to fabricate and because of its planar structure, it can be easily integrated with other sensing components and signal processing electronics. The design, fabrication, modeling, and testing of IDC sensors are presented in this thesis. Design parameters and their influence on sensor's output signals are discussed. Previous IDC models are reviewed and the limitations are studied. A new equivalent circuit model based on the fringing electric field distribution and a novel iterative data extraction algorithm combining Finite-Element Method (FEM) and the equivalent circuit model is studied. Results suggest that the algorithm can accurately extract relatively low dielectric constant and conductivity of material under test (MUT) from measured impedance data.Item Microfluidics for bioanalytical research : transitioning into point-of-care diagnostics(2014-12) Scida, Karen; Crooks, Richard M. (Richard McConnell)In this dissertation, three different microfluidic devices with bioanalytical applications are presented. From chapter to chapter, the bioanalytical focus will gradually become the development of a point-of-care sensor platform able to yield a reliable and quantitative response in the presence of the desired target. The first device consists of photolithographically-patterned gold on glass bipolar electrodes and PDMS Y-shaped microchannels for the controlled enrichment, separation from a mixture, and delivery of two charged dyes into separate receiving microchannels. The principle for the permanent separation of these dyes is based on the concept of bipolar electrochemistry and depended on the balancing/unbalancing of convective and electromigrating forces caused by the application of a potential bias, as well as the activation/deactivation of the bipolar electrodes. Two different bipolar electrode configurations are described and fluorescence is used to optimize their efficiency, speed, and cleanliness of delivery. The second device is a DNA sensor fabricated on paper by wax printing and folding to form 3D channels. DNA is detected by strand-displacement induced fluorescence of a single-stranded DNA. A multiplexed version of this sensor is also shown where the experiment results in “OR” and “AND” Boolean logic gate operations. In addition, the nonspecific adsorption of the reagents to cellulose is studied, demonstrating that significant reduction of nonspecific adsorption and increased sensitivity can be achieved by pre-treating the substrate with bovine serum albumin and by preparing all analyte solutions with spectator DNA. The third device, also made of paper, has a novel design and uses a versatile electrochemical detection method for the indirect detection of analytes via the direct detection of AgNP labels. A proof-of-concept experiment is shown where streptavidin-coated magnetic microbeads and biotin-coated AgNPs are used to form a composite model analyte. The paper device, called oSlip, and electrochemical method used are easily coupled so the resulting sensor has a simple user-device interface. LODs of 767 fM are achieved while retaining high reproducibility and efficiency. The fourth device is the updated version of the oSlip. In this case, the objective is to show the current progress and limitations in the detection of real analytes using the oSlip device. A sandwich-type immunoassay approach is used to detect human chorionic gonadotrophin (pregnancy hormone) present in human urine. Various optimization steps are performed to obtain the ideal reagent concentrations and incubation time necessary to form the immunocomposite in one step, that is, by mixing all reagents at the same time in the oSlip. Additionally, improvements to the electrochemical detection step are demonstrated.Item Multi-analyte biosensing : the integration of sensing elements into a photolithographically constructed hydrogel based biosensor platform(2005-05) Schmid, Matthew John; Willson, C. G. (C. Grant), 1939-The genome sequencing programs have identified hundreds of thousands of genetic and proteomic targets for which there are presently no ascribed functions. The challenge for researchers now is to characterize them, as well as identify and characterize their natural variants. Historically, this has meant studying each individual target separately. However, due to the recent development of multi-analyte microarray devices, these characterizations can be performed in a combinatorial manner in which a single experiment provides information on thousands of targets at a time. In the past decade, microarray technology has settled in on two major designs. The first entails spotting individual receptor types onto a functionalized glass substrate. This is a simple and inexpensive process; however, due to the limited resolution of the mechanical devices used to do the spotting, the densities of these arrays are relatively low. Moreover, receptor preparation requires substantial time and effort. The second variety of microarray uses photolithographic techniques adapted from the semi-conductor industry to chemically synthesize the receptor elements in situ on the sensing surface. Because lithographic patterning is spatially very precise, these arrays achieve very high densities, with as many as one million features per square centimeter. Although these arrays obviate the necessity for laborious "off chip" probe preparation, they are expensive to produce and are limited to two types of receptors (oligonucleotides and peptides). This dissertation presents the development work performed on a hydrogel-based biosensor platform which provides a high density and low cost alternative to the two aforementioned designs. The array features are fabricated lithographically from a liquid pre-polymer doped with biologically active sensing elements at sizes as small as 50[micrometer]. Each of the feature types is uniquely shaped, which enables the features to be mass-produced in batches, pooled together and then assembled into randomly ordered arrays using highly-parallelized self-assembly techniques. The three-dimensional hydrogel features accommodate a wide variety of sensing elements, such as enzymes, antibodies and cells, which cannot be deployed using the traditional designs. This dissertation presents methods developed to integrate cellular and oligonucleotide sensing elements into the hydrogel features which preserve their biological activity and optimize the sensor's performance.Item Near-infrared and mid-infrared integrated silicon devices for chemical and biological sensing(2014-12) Zou, Yi, active 21st century; Chen, Ray T.Silicon has been the material of choice of the photonics industry over the last decade due to its easy integration with silicon electronics as well as its optical transparency in the near-infrared telecom wavelengths. Besides these, it has very high refractive index, and also a broad optical transparency window over the entire mid-IR till about 8[Mu]m. Photonic crystal is well known that it can slow down the speed of light. It also can provide a universal platform for microcavity optical resonators with high quality factor Q and small modal volumes. The slow light effect, high Q and small modal volumes enhance light-matter interaction, together with high refractive index of silicon can be utilized to build a highly sensitive, high throughput sensor with small footprint. In this research, we have demonstrated highly compact and sensitive silicon based photonic crystal biosensor by engineering the photonic crystal microcavity in both cavity size and cavity-waveguide coupling condition. We have developed solutions to increase biosensor throughput by integrating multimode interference device and improving the coupling efficiency to a slow light photonic crystal waveguides. We have also performed detailed investigations on silicon based photonic devices at mid-infrared region to develop an ideal platform for highly sensitive optical absorption spectroscopy on chip. The studies have led to the demonstration of the first slot waveguide, the first photonic crystal waveguide, and the first holey photonic crystal waveguide and first slotted photonic crystal waveguide in silicon-on-sapphire at mid-infrared. The solutions and devices we developed in our research could be very useful for people to realize an integrated photonic circuit for biological and chemical sensing in the future.Item Novel reactivity of materials from porphyrins, and highly conjugated scaffolds(2018-04-12) Lammer, Aaron David; Sessler, Jonathan L.; Ansyln, Eric; Que, Emily; Sean Roberts; Liu, BenThe study of photo responsive compounds is of immense importance to many fields of chemistry and materials development. As the need for green chemistry grows, light is an ever more attractive reagent. Light functions as a nondestructive, noninvasive implement in sensing systems. Light emitting materials have found extensive use in electric materials as devices are developed that require greater energy efficacy and flexibility. This dissertation covers the authors work in the synthesis and characterization of highly conjugated organic systems, and resulting interaction with light. Chapter 1 gives a brief overview of all projects explored in this dissertation. This summary includes the previous work and remaining challenges of each topic. Chapter 2 describes the development and utilization of texaphyrins as photo-catalysts in the break down of natural products. Chapter 3 describes our work toward photo activated hydrogels for targeted drug release. Chapter 4 describes the development of novel BODIPY systems for metal and fullerene binding. Chapter 5 describes the development of electroluminescent materials. Chapter 6 details the synthesis and characterization of compounds discusses in this dissertation.Item Passive, wireless corrosion sensors for reinforced concrete structures(2007-08) Puryear, John M. H. (John Mark Howard); Wood, Sharon L.Corrosion of steel in reinforced concrete structures is a costly problem. Effective planning is required to raise the considerable capital expended annually on the repair and replacement of structures damaged by corrosion. Essential to this planning is knowledge that corrosion has initiated in a given structure. The passive, wireless corrosion sensor is a technology that could potentially provide this knowledge of initiation of corrosion, both economically and reliably. The sensor, which consists of two resistor-inductor-capacitor circuits, requires no onboard power supply or wires to send a signal. The signal of the sensor is obtained by magnetic coupling with a reader coil. As a threshold sensor, the sensor has a binary output with one signal indicating that corrosion has not initiated and another signal indicating that corrosion has initiated. Multiple designs of the sensor have been tested in concrete and reinforced concrete structures, some full-scale, subjected to extreme environmental conditions over long durations. Certain designs have proved highly reliably at indicating the initiation of corrosion, verifying the concept of the passive, wireless corrosion sensor.Item Re/connect : an interdisciplinary exploration of wearable technology in devised theatre(2015-05) Weller, Kristen Ann; Glavan, James; Beckham, Andrea; Lowery, AllisonHow can theatrical costumes help develop a narrative about intimacy in a world that is increasingly detaching from physical contact? My thesis explores this question through interactive costumes and the use of Wearable technology. I created two micro-controlled costumes that employed a variety of proximity sensors and LEDs that light in reaction to the touch and closeness of another person. The costumes are a response to the statement made by MIT psychologist Sherry Turkle: "We're lonely, but afraid of intimacy." The garments were featured in both an interdisciplinary devised theatrical production I helped create, entitled RE/CONNECT, and an interactive educational exhibit, illustrating the importance of physical touch in an increasingly digital age. Only by integrating new and old technologies will theatre remain relevant and funded in a world that is losing interest in physical interaction. Beyond the benefits of study for the production team, the final thesis performance attracted audience members from a wide demographic range, including those outside of the theatrical community with positive results. By incorporating nontraditional technologies in performance, and allowing audience members to experience these technologies firsthand outside of a museum, I have challenged my colleagues in the theatre and sciences to further investigate applications of developing technologies, and put to art and technology in deeper conversation.Item Scheduling observers and agents over a shared medium with hard delivery deadlines(2019-09-25) Al Jurdi, Rebal; Andrews, Jeffrey G.; Heath, Robert W., Jr., 1973-; de Veciana, Gustavo; Vikalo, Haris; Viswanathan, HarishApplications that require ultra low latency and high reliability--such as intelligent transportation, telemedicine, and industrial automation--often involve a significant element of control and decision making. In particular, such systems involve three logical components: observers (e.g. sensors) measuring the state of an environment or dynamical system, a centralized executive (e.g. controller) deciding on the state, and agents (e.g. actuators) that implement the executive's decisions. The executive harvests the observers' measurements and decides on the short-term trajectory of the system by instructing its agents to take appropriate actions. All observation packets (typically uplink) and action packets (typically downlink) must be delivered by hard deadlines to ensure the proper functioning of the controlled system. This is very challenging in a wireless system due to inherent uncertainties in wireless channels due to phenomena such as fading and unpredictable interference, and for this reason applications with hard deadlines historically have typically used wired communication connections. This dissertation studies three main aspects involving communication systems with hard deadlines. First, we develop a probabilistic framework to study the outage of a controlled system. We model a communication method that uses periodic transmission frames, link adaptation, and controlled channel access. We obtain simple, closed-form expressions and upper and lower bounds on the probability of outage due to packet decoding errors and deadline violations. We perform detailed system-level simulations to identify design guidelines such as the optimal amount of training time, as well as benchmarking the proposed system design versus non-cooperative cellular, cooperative fixed-rate, and cooperative relaying systems. Second, we develop a novel framework that abstracts the context around different control and decision processes by using a common mathematical model to formulate and solve the observer selection problem (OSP). The executive solves this problem to select a feasible, schedulable sequence of observations that maximize its knowledge about the state of the system. To solve this constrained selection problem, we devise a branch-and-bound algorithm that efficiently prunes the search space. This work is fundamentally different from existing work on real-time communications in that communication reliability is not conveyed by packet loss or error rate, but rather by the extent of the executive's knowledge about the state of the system it controls. Third, we derive conditions that reduce the OSP constraint to 1) a sum (sum-of-weights) constraint and 2) an extremal (max-weight) constraint. We prove an optimal substructure of OSP which shows that if an observation sequence is optimal, then all of its subsequences are suboptimal. We propose a dynamic programming algorithm to optimally solve OSP with a sum constraint, and a reverse linear search to solve OSP with an extremal constraint