Harnessing poly(ionic liquid)s for sensing applications

The interest in poly(ionic liquid)s for sensing applications is derived from their strong interactions to a variety of analytes. By combining the desirable mechanical properties of polymers with the physical and chemical properties of ILs, new materials can be created. The tunable nature of both ionic liquids and polymers allows for incredible diversity, which is exemplified in their broad applicability. In this article we examine the new field of poly(ionic liquid) sensors by providing a detailed look at the current state-of-the-art sensing devices for solvents, gases, biomolecules, pH, and anions

Thermal Transient Measurements of an Ultra-Low-Power MOX Sensor

This paper describes a system for the simultaneous dynamic control and thermal characterization of the heating of an Ultra Low Power (ULP) micromachined sensor. A Pulse Width Modulated (PWM) powering system has been realized using a microcontroller to characterize the thermal behavior of a device. Objectives of the research were to analyze the relation between the time period and duty cycle of the PWM signal and the operating temperature of such ULP micromachined systems, to observe the thermal time constants of the device during the heating phase and to measure the total thermal conductance. Constant target heater resistance experiments highlighted that an approximately constant heater temperature at regime can only be obtained if the time period of the heating signal is smaller than 50 s. Constant power experiments show quantitatively a thermal time constant that decreases during heating in a range from 2.3 ms to 2 ms as a function of an increasing temperature rise between the ambient and the operating temperature. Moreover, we calculated the total thermal conductance. Finally, repeatability of experimental results was assessed by guaranteeing the standard deviation of the controlled temperature which was within C in worst case conditions

Fabrication of Wet-Responsive Bioinspired Adhesives and Their Applications

Department of Mechanical EngineeringInspired by the fascinating adhesion properties of various creatures in nature, various bioinspired adhesives have been developed. Since the bioinspired adhesives exhibit excellent adhesion strength and reversible adhesion, they have strong potential for a wide variety of applications including wearable devices, nanoscale manufacturing techniques, and soft robotics. However, the bioinspired adhesives made of conventional elastomeric materials have limited adhesion strengths to rough surfaces and limited controllability on adhesion strengths, which limits their practical applications. As the challenges mainly result from the fixed physical property (e.g. elastic modulus of material) of the elastomer-based adhesives, utilization of stimuli-responsive materials that enable active modulation of their mechanical properties on demand is expected to be an effective solution overcoming the limitations. Wet-responsive hydrogels are tunable in their shape, volume, and mechanical properties based on hydration/dehydration in an active and reversible manner. Therefore, it is expected that bioinspired adhesives made of the wet-responsive hydrogels could overcome the aforementioned challenges. In this dissertation, we propose wet-responsive bioinspired adhesives made of hydroxypropyl cellulose (HPC) hydrogel and polyethylene dimethacrylate (PEGDMA) hydrogel that exhibit superior surface adaptability and high adhesion-on/off switchability, respectively. For superior adaptability, a bioinspired adhesive comprised of wet-responsive HPC is proposed as it enables adaptation to a rough surface due to its controllable swelling behavior. By hydration/dehydration, the elastic modulus of the HPC hydrogel can be modulated on demand. In the presence of a small amount of water, the individual bioinspired HPC microstructures in the adhesive can be easily deformed along the rough surface with the decreased elastic modulus of the HPC. As dehydrated, the elastic modulus of HPC microstructures is recovered with maintaining the deformed morphology. Through these processes, the surface roughness-adapted HPC adhesive exhibits strong adhesion strength. Furthermore, the adaptable HPC adhesive is reusable as the deformed microstructures can recover their original shapes based on a shape-memory capability of HPC. In order to develop the bioinspired adhesive that exhibits actively controllable and switchable adhesion on demand, PEGDMA hydrogel with swelling behavior is utilized as it has shape-reconfigurable property. The prepared PEGDMA adhesive shows high adhesion strengths against substrates with the aid of bioinspired nano??? or microstructure array in the dry state (adhesion-on state). When the adhesive is exposed to water, a hydration???induced shape transformation of the array and macroscopic film bending occur, switching the adhesion off with an extremely high adhesion switching ratio. Also, the switchable adhesion behavior of the adhesive is maintained over repeating cycles of hydration and dehydration, indicating their ability to be used repetitively. As the rough surface adaptation and adhesion on/off properties of the developed adhesives only require water droplets, they have a wide range of applications in diverse fields. Specifically, the adhesives have a strong potential for use in a biomedical field as the HPC and PEGDMA hydrogels are biocompatible. Accordingly, we demonstrate several unique biomedical practical applications of the developed adhesives. Firstly, with the adaptable HPC adhesive, an attachable photonic skin is developed as a wearable skin-like sensor. The photonic skin consisting of an HPC mechanochromic sensor and the adaptable adhesive can firmly laminate to diverse substrates including human skins, detecting mechanical signals from various target objects. Secondly, the adhesion-switchable PEGDMA adhesive is utilized for a nanotransfer printing (nTP). We demonstrate that diverse metallic and semiconducting nanomembranes can be transferred from donor substrates to either rigid or flexible surfaces including biological tissues with the PEGDMA adhesive in a reproducible and robust fashion. In total, this dissertation presents the fabrication of wet-responsive bioinspired adhesives and their applications. The overall contents consist of three main themes, that are as follow: (1) fabrication of bioinspired adhesives with optimized geometries, (2) rough surface-adaptable adhesive made of wet-responsive HPC hydrogel and (3) adhesion-switchable adhesive made of wet-responsive PEGDMA hydrogel.clos

Orbit transfer rocket engine integrated control and health monitoring system technology readiness assessment

The objectives of this task were to: (1) estimate the technology readiness of an integrated control and health monitoring (ICHM) system for the Aerojet 7500 lbF Orbit Transfer Vehicle engine preliminary design assuming space based operations; and (2) estimate the remaining cost to advance this technology to a NASA defined 'readiness level 6' by 1996 wherein the technology has been demonstrated with a system validation model in a simulated environment. The work was accomplished through the conduct of four subtasks. In subtask 1 the minimally required functions for the control and monitoring system was specified. The elements required to perform these functions were specified in Subtask 2. In Subtask 3, the technology readiness level of each element was assessed. Finally, in Subtask 4, the development cost and schedule requirements were estimated for bringing each element to 'readiness level 6'

Center Director's Discretionary Fund 2005 Annual Report

The FY 2005 CDDF projects were selected from the following spaceport and range technology and science areas: fluid system technologies; spaceport structures and materials; command, control, and monitoring technologies; and biological sciences (including support for environmental stewardship). The FY 2005 CDDF research projects involved development of the following: a) Capacitance-based moisture sensors to optimize plant growth in reduced gravity; b) Commodity-free calibration methods; c) Application of atmospheric plasma glow discharge to alter the surface properties of polymers for improved electrostatic dissipation characteristics; d) A wipe-on, wipe-off chemical process to remove lead oxides found in paint; e) A robust metabolite profiling platform for better understanding the "law" of biological regulation; f) An explanation of the excavation processes that occur when a jet of gas impinges on a bed of sand; g) "Smart coatings" to detect and control corrosion at an early stage to prevent further corrosion h) A model that can produce a reliable diagnosis of the quality of a software product; i) The formulation of advanced materials to meet system safety needs to minimize electrostatic charges, flammability, and radiation exposure; j) A lab-based instrument that uses the electro-optic Pockels effect to make static electric fields visible; k) A passive volatile organic compound (VOC) cartridge to filter, identify, and quantify VOCs flowing into or emanating from plant flight experiments

Team One Carbon Catcher Design Report

Overview The burning of fossil fuels largely contributes to the increase of CO2 in the atmosphere. The US Department of Transportation alone contributed almost 6 million metric tons of carbon dioxide emissions in 2018 (EIA). Due to this, this report proposes recycling captured CO2 into a base for cleaner burning fuel in order to reduce emissions from the transportation industry and many others, which has the potential to impact many areas. Extraction of atmospheric CO2 is possible through a membrane filtration system based on traditional nitrogen generation. The passive filtration system autonomously separates the CO2 from other air components, thereby reducing energy consumption. The system's working sensors and actuators utilize similar energy saving strategies, such as distributing cloud-computing services over multiple servers and mainframes to reduce computing power. The movement of air is directed by a scalable fan device, which is presented as a modular design to allow customization of fan parts to specific size and installation requirements. As an integrated device, Team 1’s Carbon Catcher operates with a high efficiency in order to maximize the commercial opportunity of converting captured CO2 into cleaner fuel while also reducing CO2 emissions and the greenhouse effect. Goal The goal of Team 1’s Carbon Catcher project proposal is to design a cost-effective, scalable, and modular atmospheric carbon dioxide removal system that is capable of being utilized in a range of urban environments and may fit a variety of different customer requirements or requests

Novel Smart N95 Filtering Facepiece Respirator with Real-time Adaptive Fit Functionality and Wireless Humidity Monitoring for Enhanced Wearable Comfort

The widespread emergence of the COVID-19 pandemic has transformed our lifestyle, and facial respirators have become an essential part of daily life. Nevertheless, the current respirators possess several limitations such as poor respirator fit because they are incapable of covering diverse human facial sizes and shapes, potentially diminishing the effect of wearing respirators. In addition, the current facial respirators do not inform the user of the air quality within the smart facepiece respirator in case of continuous long-term use. Here, we demonstrate the novel smart N-95 filtering facepiece respirator that incorporates the humidity sensor and pressure sensory feedback-enabled self-fit adjusting functionality for the effective performance of the facial respirator to prevent the transmission of airborne pathogens. The laser-induced graphene (LIG) constitutes the humidity sensor, and the pressure sensor array based on the dielectric elastomeric sponge monitors the respirator contact on the face of the user, providing the sensory information for a closed-loop feedback mechanism. As a result of the self-fit adjusting mode along with elastomeric lining, the fit factor is increased by 3.20 and 5 times at average and maximum respectively. We expect that the experimental proof-of-concept of this work will offer viable solutions to the current commercial respirators to address the limitations.Comment: 20 pages, 5 figures, 1 table, submitted for possible publicatio

Flowcuits: Crafting Tangible and Interactive Electrical Components with Liquid Metal Circuits

We present Flowcuits, a DIY fabrication method to prototype tangible, interactive and functional electrical components by manipulating liquid metal mechanisms. The generated prototypes afford both physical and visual interactions to demonstrate the inner working, underlying concepts and mechanics of fundamental electronic elements and circuits, which we propose as a method to support playful learning. The fabrication process follows simple imprinting and sealing of fluidic circuits with a 3D printed stamp on a commonly accessible and inexpensive moldable substrate such as 'blu tack'. Utilizing gallium-indium (Ga-In) liquid metal as the conductive element, we demonstrated our approach can create interactive and customizable electronic components such as switches, variable resistors, variable capacitors, logic gates and pressure sensors. In this paper, we present the design analogy of Flowcuits, DIY fabrication approach including a parametric 3D stamp design toolkit and results from a technical evaluation of the demonstrators. The stamps are printed with a low-cost 3D printer and all the materials are inexpensive and reusable, enabling Flowcuits to be easily used without any advance lab facilities

Program test objectives milestone 3

The following conclusions have been developed relative to propulsion system technology adequacy for efficient development and operation of recoverable and expendable launch vehicles (RLV and ELV) and the benefits which the integrated propulsion technology demonstrator will provide for enhancing technology: (1) Technology improvements relative to propulsion system design and operation can reduce program cost. Many features or improvement needs to enhance operability, reduce cost, and improve payload are identified. (2) The Integrated Propulsion Technology Demonstrator (IPTD) Program provides a means of resolving the majority of issues associated with improvement needs. (3) The IPTD will evaluate complex integration of vehicle and facility functions in fluid management and propulsion control systems, and provides an environment for validating improved mechanical and electrical components. (4) The IPTD provides a mechanism for investigating operational issues focusing on reducing manpower and time to perform various functions at the launch site. These efforts include model development, collection of data to validate subject models, and ultimate development of complex time line models. (5) The IPTD provides an engine test bed for tri/bi-propellant engine development firings which is representative of the actual vehicle environment. (6) The IPTD provides for only a limited multiengine configuration integration environment for RLV. Multiengine efforts may be simulated for a number of subsystems and a number of subsystems are relatively independent of the multiengine influences

NASA SBIR abstracts of 1991 phase 1 projects

The objectives of 301 projects placed under contract by the Small Business Innovation Research (SBIR) program of the National Aeronautics and Space Administration (NASA) are described. These projects were selected competitively from among proposals submitted to NASA in response to the 1991 SBIR Program Solicitation. The basic document consists of edited, non-proprietary abstracts of the winning proposals submitted by small businesses. The abstracts are presented under the 15 technical topics within which Phase 1 proposals were solicited. Each project was assigned a sequential identifying number from 001 to 301, in order of its appearance in the body of the report. Appendixes to provide additional information about the SBIR program and permit cross-reference of the 1991 Phase 1 projects by company name, location by state, principal investigator, NASA Field Center responsible for management of each project, and NASA contract number are included