Valves and other mechanical components and equipment: A compilation

The articles in this Compilation will be of interest to mechanical engineers, users and designers of machinery, and to those engineers and manufacturers specializing in fluid handling systems. Section 1 describes a number of valves and valve systems. Section 2 contains articles on machinery and mechanical devices that may have applications in a number of different areas

Challenges in the development of the orbiter atmosphere revitalization subsystem

The space shuttle orbiter atmospheric revitalization subsystem provides thermal and contaminant control as well as total- and oxygen partial-pressure control of the environment within the orbiter crew cabin. Challenges that occurred during the development of this subsystem for the space shuttle orbiter are described. The design of the rotating hardware elements of the system (pumps, fans, etc.) required significant development to meet the requirements of long service life, maintainability, and high cycle-fatigue life. As a result, a stringent development program, particularly in the areas of bearing life and heat dissipation, was required. Another area requiring significant development was cabin humidity control and condensate collection

Integrated Application of Active Controls (IAAC) technology to an advanced subsonic transport project. ACT/Control/Guidance System study. Volume 2: Appendices

The integrated application of active controls (IAAC) technology to an advanced subsonic transport is reported. Supplementary technical data on the following topics are included: (1) 1990's avionics technology assessment; (2) function criticality assessment; (3) flight deck system for total control and functional features list; (4) criticality and reliability assessment of units; (5) crew procedural function task analysis; and (6) recommendations for simulation mechanization

Index to 1985 NASA Tech Briefs, volume 10, 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 1985 Tech 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

Principles of Small-Scale Hydraulic Systems for Human Assistive Machines

University of Minnesota Ph.D. dissertation. March 2017. Major: Mechanical Engineering. Advisor: William Durfee. 1 computer file (PDF); xiii, 288 pages.The high power and force density of hydraulic actuators, along with the ability to distribute system weight through the separation of the power supply and actuators makes hydraulic technology ideal for use in human assistive machines. However, hydraulic systems often operate inefficiently due to throttling losses in the control valves and have increased viscous losses in small-scale applications as bore size is decreased. The objective of this research is to address the limitations of small-scale hydraulics using validated modeling techniques to optimize performance and minimize system weight. This research compares and contrasts the use of different hydraulic technology as well as develops detailed models of small-scale hydraulic components. These models are used to construct a software tool that optimizes the design of a hydraulic system using specified input requirements of actuation, conduit lengths, operating pressure, and runtime. A system-level energetics analysis provides estimates of efficiencies and weights, while a heat transfer analysis estimates the working fluid and component surface temperatures. In addition, the dynamic performance of different small-scale pump and valve controlled hydraulic systems are simulated to compare the cycle efficiencies, rise times, and flow rate capabilities as a function of duty cycles. The use of an accumulator, unloading valves, variable displacement pumps, and proportional pressure control are explored to improve the efficiency of the system during intermittent operation. In addition a small-scale, digital, high frequency switching valve is designed and simulated to reduce the throttling losses of a traditional proportional control valve. This body of knowledge is used to design, prototype, and performance test two hydraulic powered ankle-foot orthoses. The first orthosis is an untethered system that provides active gait assistance. Hydraulics allows the system to be separated into two parts as the actuator is secured to the ankle, and the portable electrohydraulic power supply is positioned on the lower back. The second orthosis emulates the dynamics of a passive ankle-foot orthosis providing torque assistance to bring the ankle to a neutral position. This device is specifically designed to reduce the time and resources in the clinical prescription of passive ankle-foot orthoses while providing more quantitative metrics

The 15th Aerospace Mechanisms Symposium

Technological areas covered include: aerospace propulsion; aerodynamic devices; crew safety; space vehicle control; spacecraft deployment, positioning, and pointing; deployable antennas/reflectors; and large space structures. Devices for payload deployment, payload retention, and crew extravehicular activities on the space shuttle orbiter are also described

Southwest Research Institute assistance to NASA in biomedical areas of the technology utilization program

The activities are reported of the NASA Biomedical Applications Team at Southwest Research Institute between 25 August, 1972 and 15 November, 1973. The program background and methodology are discussed along with the technology applications, and biomedical community impacts

A power system simulator for transient stability studies

Imperial Users onl

The development of a high-speed patterning system for a narrow-fabric weaving machine

The development of a high-speed patterning system for a narrow-fabric weaving machin