Prototype Tile Research Articles

Innovative triboelectric nanogenerator (TENG) design utilizing a stress ball for energy harvesting, wellness, and safety applications

The present manuscript introduces a cost-effective and simple method for creating a Triboelectric nanogenerator (TENG) that utilizes a stress ball as a base and FEP, Aluminum as triboelectric pairs. The TENG design demonstrates an innovative approach that can be used for energy harvesting, stress relief, and human safety simultaneously. The unique aspect of this TENG design is using a Polyurethane foam-based ball (Stress-Ball) with excellent elasticity as a spacer, eliminating the need for additional spacers. The TENG prototype produced a power density of 625 mW m−2 and 1.75 W m−2 in squeezing and tapping mode, respectively. Furthermore, four TENG devices integrated in the prototype tiles enable electrical energy generation to power 720 LEDs with every casual footstep. The TENG converts biomechanical energy produced from hand-squeezing exercises into electrical energy that can power small, wearable, and portable electronic devices such as calculators, thermometers, and watches. Wearable LEDs powered by squeezing the ball while walking on dark roads provided safety applications. Overall, the presented TENG design showcases an efficient and affordable way of generating electrical energy while also promoting human wellness and safety.

Design, prototyping, and evaluation of a concept for a shape-changing smart material building surface tile

A design concept for shape-changing smart material tiles for applications in environmentally responsive building facades is presented. In particular, the application considered is a tile that would change the shape of the building surface to favorably affect the interaction with solar irradiance. A lab-scale prototype system for smart material tiles composed of 3D printed thermally responsive shape memory polymer (SMP) and utilizing localized thermal material activation and uniform pressure actuation is examined. Tests utilizing the prototype tile are used to create and validate a computational (finite element) representation of the adaptive surface tile system. Toward developing this computational representation, a strategy is presented to determine and validate the material parameters for the 3D printed SMP by matching the tile shape predicted by the numerical model to the tile shape measured experimentally. This numerical representation was then implemented into a computational approach to explore the design space for this adaptive tile to have an effect on the solar irradiance on a building surface. More specifically, a series of numerical examples are considered that determine the location and size of material activation that minimize the area of the tile exposed to solar irradiance. Results indicate that the adaptive tile can change the surface of a structure to considerably improve the structure’s interaction with solar irradiance. Additionally, the importance of the control strategy for a multi-tile system was displayed, particularly with respect to the capability to significantly reduce the energy cost and affect the solar irradiance to a higher degree by accounting for neighboring tile interaction.

Developing a silica aerogel radiator for the HELIX ring-imaging Cherenkov system

This paper reports the successful fabrication of silica aerogel Cherenkov radiators produced in the first batches from a 96-tile mass production performed using pin-drying technique in our laboratory. The aerogels are to be used in a ring-imaging Cherenkov detector in the spectrometer of a planned balloon-borne cosmic-ray observation program, HELIX (High Energy Light Isotope eXperiment). A total of 36 transparent, hydrophobic aerogel tiles with a high refractive index of 1.16 and dimensions of 10 cm $\times $ 10 cm $\times $ 1 cm will be chosen as the flight radiators. Thus far, 40 out of the 48 tiles fabricated were confirmed as having no tile cracking. In the first screening, 8 out of the first 16 tiles were accepted as flight-qualified candidates, based on basic optical measurement results. To fit the aerogel tiles into a radiator support structure, the trimming of previously manufactured prototype tiles using a water-jet cutting device was successful.

Novel fused-silica charge detection tile for particle detectors

Develop a novel charge-detecting tile for future large-scale liquid xenon TPC for searching for neutrinoless double-beta decay. Use advanced microelectronic technologies to fabricate small metal pads on a fused-silica wafer. The pads are chained into orthogonal strips, and the strips are isolated at the cross sections. The size of the pads defines the pitch between parallel strips and can be flexibly tuned according to any optimized dimension from future Monte Carlo studies. Such tile also has good potential to suppress the radioactivity and control electronics noise. Furthermore, its modular design allows to easily cover a large size. The design and performance have been demonstrated by a prototype tile, particularly by comprehensive tests in liquid xenon. A new design of charge detection tile and the fabrication technologies have been developed, which would be useful for future noble liquid detectors.

Integrated plasma facing component calorimetry for measurement of shot integrated deposited energy in the NSTX-U.

The upgrade to the National Spherical Torus eXperiment (NSTX-U) [J. Menard et al., Nucl. Fusion 52, 083015 (2012)] increases the injected neutral beam power up to 12 MW and the plasma current up to Ip = 2 MA for plasma durations up to 5 s. The graphite plasma facing components have been re-designed to handle greater heat and energy fluxes than were seen in NSTX using a castellated design. We present the experimental testing and validation of a castellated graphite target, similar to the prototype tile design, instrumented with thermocouples at various depths in the castellation. During testing, incident heat flux is provided by a programmed electron beam system and surface temperatures are measured via infrared thermography directly viewing the target surface. It was found that the thermocouple response scaled linearly with the measured surface temperature rise regardless of thermocouple depth in the castellation. A sensitivity of 14.3 °C/kJ of deposited energy was found when treating individual castellations as a semi-infinite solid.

Characterization of an Ionization Readout Tile for nEXO

A new design for the anode of a time projection chamber, consisting of a charge-detecting “tile", is investigated for use in large scale liquid xenon detectors. The tile is produced by depositing 60 orthogonal metal charge-collecting strips, 3 mm wide, on a 10 cm × 10 cm fused-silica wafer. These charge tiles may be employed by large detectors, such as the proposed tonne-scale nEXO experiment to search for neutrinoless double-beta decay. Modular by design, an array of tiles can cover a sizable area. The width of each strip is small compared to the size of the tile, so a Frisch grid is not required. A grid-less, tiled anode design is beneficial for an experiment such as nEXO, where a wire tensioning support structure and Frisch grid might contribute radioactive backgrounds and would have to be designed to accommodate cycling to cryogenic temperatures. The segmented anode also reduces some degeneracies in signal reconstruction that arise in large-area crossed-wire time projection chambers. A prototype tile was tested in a cell containing liquid xenon. Very good agreement is achieved between the measured ionization spectrum of a 207Bi source and simulations that include the microphysics of recombination in xenon and a detailed modeling of the electrostatic field of the detector. An energy resolution σ/E=5.5% is observed at 570 keV, comparable to the best intrinsic ionization-only resolution reported in literature for liquid xenon at 936 V/cm.

First negative ion beam measurement by the Short-Time Retractable Instrumented Kalorimeter Experiment (STRIKE)

The Source for Production of Ion of Deuterium Extracted from Rf plasma (SPIDER) test facility is under construction in Padova to optimise the operation of the beam source of ITER neutral beam injectors. The SPIDER beam will be characterised by the instrumented calorimeter STRIKE, whose main components are one-directional carbon-fibre-carbon-composite tiles. A small-scale version of the entire system has been employed in the BAvarian Test MAchine for Negative ions (BATMAN) testbed by arranging two prototype tiles in the vertical direction. The paper presents a description of the mini-STRIKE system and of the data analysis procedures, as well as some results concerning the BATMAN beam under varying operating conditions.

High energy flux thermo-mechanical test of 1D-carbon-carbon fibre composite prototypes for the SPIDER diagnostic calorimeter

Operation of the thermonuclear fusion experiment ITER requires additional heating via injection of neutral beams from accelerated negative ions. In the SPIDER test facility, under construction in Padova, the production of negative ions will be studied and optimised. STRIKE (Short-Time Retractable Instrumented Kalorimeter Experiment) is a diagnostic used to characterise the SPIDER beam during short pulse operation (several seconds) to verify if the beam meets the ITER requirements about the maximum allowed beam non-uniformity (below ±10%). The major components of STRIKE are 16 1D-CFC (Carbon-Carbon Fibre Composite) tiles, observed at the rear side by a thermal camera. This contribution gives an overview of some tests under high energy particle flux, aimed at verifying the thermo-mechanical behaviour of several CFC prototype tiles. The tests were performed in the GLADIS facility at IPP (Max-Plank-Institut für Plasmaphysik), Garching. Dedicated linear and nonlinear simulations were carried out to interpret the experiments and a comparison of the experimental data with the simulation results is presented. The results of some morphological and structural studies on the material after exposure to the GLADIS beam are also given.

Concentrated Solar Power Harvesting Using Self-powered, Wireless, Thin-profile, Lightweight Solar Tiles

This paper presents a modular and scalable approach to concentrated solar power (CSP) harvesting by using low-profile, light-weight, sun-tracking, millimeter-to-centimeter-scale mirror arrays that can be wirelessly controlled to reflect the incident solar energy to a central receiver. Conventional, utility-scale CSP plants use large-area heliostats, parabolic troughs, or dish collectors that are not only heavy and bulky, but also require significant labor for installation and maintenance infrastructure. Furthermore, form-factors of current heliostats are not compatible with low-profile roof-mountable systems, as seen by the dominance of the conventional Photovoltaic systems for roof-top installations. Solar TILE (STILE) technology to be presented in this work enables concentrated solar power harvesting on a given surface with form factor and weight per unit area comparable to those of ceramic tiles used on walls/floors or that of Photovoltaic modules. Self-powered operation by integrated solar cells, elimination of wiring for power transfer, wireless control, and weather-proof enclosure of moving parts help STILE technology promise lower installation and maintenance costs than PV approaches, while enabling novel beam-redirection applications over large surfaces. As the STILEs are made of mostly plastic, which costs at least an order of magnitude less than solar grade silicon, associated material costs could potentially be much cheaper than silicon PV cells. After a description of the STILE technology and a discussion of mirror scaling, we present a prototype tile with dimensions 33 × 33 × 6.4 cm3 and detail its wireless operation.

Library classroom renovated as an active learning classroom

PurposeSeveral books and articles about learning space design have recently been published, giving much needed attention to new types of informal learning spaces such as the library commons. This paper aims to address this issue.Design/methodology/approachThis paper describes the redesign of a formal learning space: the general assignment classroom. In 2010, one of the University of Iowa's Main Library classrooms was converted to an “active learning” space. The library location was selected as home for this prototype TILE classroom – Transform, Interact, Learn, Engage. The university's goal is to create similar spaces in a variety of sizes and configurations across campus.FindingsThe classroom is technologically rich, but was designed first and foremost for its pedagogical potential in fostering engaged learning. Ease of use was a primary focus, allowing the technology to fade into the background. Early adopters participated in a faculty institute on active learning and were provided with institutional support for reworking their classes to make them more learning‐centric. The configuration of the room and the focus on active learning enabled support for larger class sizes, while retaining the intimacy and active participation of a small discussion group.Originality/valueThe TILE classroom is one strategy in the institution's overall goal of improving student learning, increasing undergraduate retention, and psychologically shrinking the size of the university.

A novel technique for the production of cool colored concrete tile and asphalt shingle roofing products

The widespread use of solar-reflective roofing materials can save energy, mitigate urban heat islands and slow global warming by cooling the roughly 20% of the urban surface that is roofed. In this study we created prototype solar-reflective nonwhite concrete tile and asphalt shingle roofing materials using a two-layer spray coating process intended to maximize both solar reflectance and factory-line throughput. Each layer is a thin, quick-drying, pigmented latex paint based on either acrylic or a poly(vinylidene fluoride)/acrylic blend. The first layer is a titanium dioxide rutile white basecoat that increases the solar reflectance of a gray-cement concrete tile from 0.18 to 0.79, and that of a shingle surfaced with bare granules from 0.06 to 0.62. The second layer is a “cool” color topcoat with weak near-infrared (NIR) absorption and/or strong NIR backscattering. Each layer dries within seconds, potentially allowing a factory line to pass first under the white spray, then under the color spray. We combined a white basecoat with monocolor topcoats in various shades of red, brown, green and blue to prepare 24 cool colored prototype tiles and 24 cool colored prototypes shingles. The solar reflectances of the tiles ranged from 0.26 (dark brown; CIELAB lightness value L *=29) to 0.57 (light green; L *=76); those of the shingles ranged from 0.18 (dark brown; L *=26) to 0.34 (light green; L *=68). Over half of the tiles had a solar reflectance of at least 0.40, and over half of the shingles had a solar reflectance of at least 0.25.

Development, installation, and initial operation of DIII-D graphite armor tiles

An upgrade of the DIII-D vacuum vessel protection system has been completed. The ceiling, floor, and inner wall have been armored to enable operation of CIT-relevant double-null diverted plasmas and to enable the use of the inner wall as a limiting surface. The all-graphite tiles replace the earlier partial coverage armor configuration which consisted of a combination of Inconel tiles and graphite brazed to Inconel tiles. A new all-graphite design concept was chosen for cost and reliability reasons. The ten minute duration between plasma discharge required the tiles to be cooled by conduction to the water-cooled vessel wall. Using two and three-dimensional analyses, the tile design was optimized to minimize thermal stresses with uniform thermal loading on the plasma-facing surface. Minimizing the stress around the tile hold-down feature and eliminating stress concentrators were emphasized in the design. The design of the tile fastener system resulted in sufficient hold-down forces for good thermal conductance to the vessel and for securing the tile against eddy current forces. The tiles are made of graphite, and a program to select a suitable grade of graphite was undertaken. Initially, graphites were compared based on published technical data. Graphite samples were then tested for thermal shock capacity in an electron beam test facility at the Sandia National Laboratory (SNLA) in Albuquerque, New Mexico, USA. The expected operational heat load to the tiles is 500 W/cm 2 for 10 s over the entire tile during limiter operation and 1000 W/cm 2 over a 2 cm wide band for 10 s for divertor operation. Comparative stress analysis was performed on the basis of 1000 W/cm 2 uniformly distributed on the front surface for 5 s with 10 min between pulses. Prototype tiles survived beam heating to the limit of the beam system which was 1000 W/cm 2 for 4 s or 1750 W/cm 2 for 1.75 s. The electron beam facility at the Sandia National Laboratory was used to deposite higher heat flux in a 2 cm wide band in order to model divertor heat flux conditions. These tests were successful with heat fluxes up to 2500 W/cm 2 for 5 s. Both the ion beam and the electron beam tests produced surface temperatures up to 3100 °C which resulted in minor surface erosion but no structural cracking. Installation of approximately 1600 armor tiles was accomplished in November/December 1987. Initial operation experience with the new armor system is summarized.