Index to 1984 NASA Tech Briefs, volume 9, numbers 1-4

Short announcements of new technology derived from the R&D activities of NASA are presented. These briefs emphasize information considered likely to be transferrable across industrial, regional, or disciplinary lines and are issued to encourage commercial application. This index for 1984 Tech B Briefs contains abstracts and four indexes: subject, personal author, originating center, and Tech Brief Number. The following areas are covered: electronic components and circuits, electronic systems, physical sciences, materials, life sciences, mechanics, machinery, fabrication technology, and mathematics and information sciences

High-speed acoustic holography with arbitrary scattering objects

Recent advances in high-speed acoustic holography have enabled levitation-based volumetric displays with tactile and audio sensations. However, current approaches do not compute sound scattering of objects’ surfaces; thus, any physical object inside can distort the sound field. Here, we present a fast computational technique that allows high-speed multipoint levitation even with arbitrary sound-scattering surfaces and demonstrate a volumetric display that works in the presence of any physical object. Our technique has a two-step scattering model and a simplified levitation solver, which together can achieve more than 10,000 updates per second to create volumetric images above and below static sound-scattering objects. The model estimates transducer contributions in real time by reformulating the boundary element method for acoustic holography, and the solver creates multiple levitation traps. We explain how our technique achieves its speed with minimum loss in the trap quality and illustrate how it brings digital and physical content together by demonstrating mixed-reality interactive applications

Gas-Grain Simulation Facility: Fundamental studies of particle formation and interactions. Volume 2: Abstracts, candidate experiments and feasibility study

An overview of the Gas-Grain Simulation Facility (GGSF) project and its current status is provided. The proceedings of the Gas-Grain Simulation Facility Experiments Workshop are recorded. The goal of the workshop was to define experiments for the GGSF--a small particle microgravity research facility. The workshop addressed the opportunity for performing, in Earth orbit, a wide variety of experiments that involve single small particles (grains) or clouds of particles. Twenty experiments from the fields of exobiology, planetary science, astrophysics, atmospheric science, biology, physics, and chemistry were described at the workshop and are outlined in Volume 2. Each experiment description included specific scientific objectives, an outline of the experimental procedure, and the anticipated GGSF performance requirements. Since these experiments represent the types of studies that will ultimately be proposed for the facility, they will be used to define the general science requirements of the GGSF. Also included in the second volume is a physics feasibility study and abstracts of example Gas-Grain Simulation Facility experiments and related experiments in progress

OpenMPD: A Low-Level Presentation Engine for Multimodal Particle-Based Displays

Phased arrays of transducers have been quickly evolving in terms of software and hardware with applications in haptics (acoustic vibrations), display (levitation), and audio. Most recently, Multimodal Particle-based Displays (MPDs) have even demonstrated volumetric content that can be seen, heard, and felt simultaneously, without additional instrumentation. However, current software tools only support individual modalities and they do not address the integration and exploitation of the multi-modal potential of MPDs. This is because there is no standardized presentation pipeline tackling the challenges related to presenting such kind of multi-modal content (e.g., multi-modal support, multi-rate synchronization at 10 KHz, visual rendering or synchronization and continuity). This article presents OpenMPD, a low-level presentation engine that deals with these challenges and allows structured exploitation of any type of MPD content (i.e., visual, tactile, audio). We characterize OpenMPD’s performance and illustrate how it can be integrated into higher-level development tools (i.e., Unity game engine). We then illustrate its ability to enable novel presentation capabilities, such as support of multiple MPD contents, dexterous manipulations of fast-moving particles, or novel swept-volume MPD content

SoundBender: dynamic acoustic control behind obstacles

Ultrasound manipulation is growing in popularity in the HCI community with applications in haptics, on-body interaction, and levitation-based displays. Most of these applications share two key limitations: a) the complexity of the sound fields that can be produced is limited by the physical size of the transducers; and b) no obstacles can be present between the transducers and the control point. We present SoundBender, a hybrid system that overcomes these limitations by combining the versatility of phased arrays of transducers (PATs) with the precision of acoustic metamaterials. In this paper, we explain our approach to design and implement such hybrid modulators (i.e. to create complex sound fields) and methods to manipulate the field dynamically (i.e. stretch, steer). We demonstrate our concept using self-bending beams enabling both levitation and tactile feedback around an obstacle and present example applications enabled by SoundBender

Accommodation requirements for microgravity science and applications research on space station

Scientific research conducted in the microgravity environment of space represents a unique opportunity to explore and exploit the benefits of materials processing in the virtual abscence of gravity induced forces. NASA has initiated the preliminary design of a permanently manned space station that will support technological advances in process science and stimulate the development of new and improved materials having applications across the commercial spectrum. A study is performed to define from the researchers' perspective, the requirements for laboratory equipment to accommodate microgravity experiments on the space station. The accommodation requirements focus on the microgravity science disciplines including combustion science, electronic materials, metals and alloys, fluids and transport phenomena, glasses and ceramics, and polymer science. User requirements have been identified in eleven research classes, each of which contain an envelope of functional requirements for related experiments having similar characteristics, objectives, and equipment needs. Based on these functional requirements seventeen items of experiment apparatus and twenty items of core supporting equipment have been defined which represent currently identified equipment requirements for a pressurized laboratory module at the initial operating capability of the NASA space station

The Acoustic Hologram and Particle Manipulation with Structured Acoustic Fields

This book shows how arbitrary acoustic wavefronts can be encoded in the thickness profile of a phase plate - the acoustic hologram. The workflow for design and implementation of these elements has been developed and is presented in this work along with examples in microparticle assembly, object propulsion and levitation in air. To complement these results, a fast thermographic measurement technique has been developed to scan and validate 3D ultrasound fields in a matter of seconds