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Mitigation of Community Noise from a Vacuum Excavator Using Simulations

Charles Machine Works-Vernon Stellman, Craig Clevenger, Jeff Smith
Dassault Systemes Simulia Corp.-Rahul Sanal, Karthik Mahadevan Muthuraman, Robert Powell
Published 2019-06-05 by SAE International in United States
Off-highway equipment operates in residential communities and must meet their radiated noise targets to be compliant with noise regulations and to be competitive in the marketplace. Traditional find and fix noise testing of late-stage prototype designs may cause launch delays, with intense time pressures that often result in missed opportunities to create excellent products with good value. Accurate simulation of noise from these machines allows noise targets to be assessed at each stage of product development, giving engineers time to develop low noise products without adding excessive manufacturing cost. Simulation of an early prototype of a new vacuum excavator showed excessive levels of radiated noise in two different frequency ranges. Further investigation of the simulation results of these two spectrum ranges indicated different noise mechanisms producing the excessive noise levels. An acoustic resonance was excited in the exhaust flow downstream of a silencer by highly vortical flow through a ninety-degree elbow. Broadband flow noise was also being generated downstream of this silencer, in a higher frequency range. Solutions to the two separate noise issues were…
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Steel Bars, Forgings, and Mechanical Tubing, Corrosion Resistant, 14Cr - 2.1Mo - 0.30Cb (Nb) - 1.0V (1.05 - 1.15C), Premium Aircraft Quality for Bearing Applications, Double Vacuum Melted

AMS F Corrosion Heat Resistant Alloys Committee
  • Aerospace Material Specification
  • AMS5900C
  • Current
Published 2019-05-23 by SAE International in United States

This specification covers a premium-aircraft-quality, corrosion-resistant steel in the form of bars, wire, forgings, mechanical tubing, and forging stock.


Steel Castings, Vacuum Melted, Vacuum Cast, Investment, Corrosion-Resistant, 13Cr - 8.0Ni - 2.2Mo - 1.1Al, 195 ksi (1344 MPa) Tensile Strength (Condition H1000), Homogenized, Solution, and Precipitation Heat Treated

AMS F Corrosion Heat Resistant Alloys Committee
  • Aerospace Material Specification
  • AMS5412B
  • Current
Published 2019-05-10 by SAE International in United States

This specification covers a corrosion-resistant steel in the form of investment castings.


Brake Vacuum Booster Characterization

Carr Engineering, Inc.-James Walker, Robert Rucoba, Dan Barnes, Steven Kent
Published 2019-04-02 by SAE International in United States
Brake vacuum booster characteristics are of great importance to understanding overall brake system operation in light vehicles so equipped. In recent years, engineering reports relevant to traffic crash reconstruction have discussed, among related areas, the operation of brake booster systems at high applied brake pedal force levels and with various levels of vacuum available within the booster. A vehicle-testing framework is presented for characterizing and understanding the operation of a vacuum booster with pedal force ranging above the vacuum runout point, as well as booster operation relative to varying levels of available vacuum and patterns of depletion of stored vacuum. Concepts are illustrated with measurements of exemplar vehicles. The objective of this paper is to promote improved understanding of brake booster operation and to advance more precise articulation of related concepts within the crash reconstruction community.
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Vacuum Gauge Calibration

AMS B Finishes Processes and Fluids Committee
  • Aerospace Standard
  • ARP7446
  • Current
Published 2019-03-06 by SAE International in United States
This SAE Aerospace Recommended Practice (ARP) addresses the general procedure for the best practices for minimizing uncertainty when calibrating thermal conductivity and cold cathode vacuum gauges, which includes the vacuum sensor(s) and accompanying electronics necessary for a pressure measurement to be made. It also includes the best practices for an in-process verification where limitations make it impossible to follow the best practices for minimizing uncertainty. Verifying the accuracy and operation of vacuum gauges is critical to ensure the maintenance of processes while under vacuum.
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A New Route to High Sensitivity Pressure Sensors

  • Magazine Article
  • TBMG-33898
Published 2019-03-01 by Tech Briefs Media Group in United States

Since their development in the 1950s, optical fibers have been used for power transmission, communication, imaging, and sensing. They are often used in situations where other sensing techniques can fail. Because optical fibers are dielectrics and versatile, they can be used in a variety of environments from vacuum chambers to the ocean floor.


Real-Time Airborne Particle Analyzer

  • Magazine Article
  • TBMG-29686
Published 2018-07-01 by Tech Briefs Media Group in United States

Particle analysis is useful for determining chemical compositions in a wide range of disciplines, from ascertaining the source of a petroleum sample to duplicating a fragrance. The technique is appealing to a broad cross-section of analytical sciences, but its applications are limited because, for existing equipment, sample size is limited, and testing is carried out under a high vacuum.


Method Converts Cotton Fabric Waste into Aerogel

  • Magazine Article
  • TBMG-29020
Published 2018-06-01 by Tech Briefs Media Group in United States

Aerogels are among the lightest materials in the world, and are highly porous with strong absorption capacity and low thermal conductivity. These unique properties make aerogels highly suitable for applications in areas including oil spill cleaning, personal care products such as diapers, and for heat and sound insulation.


Development of Hydrogen Burners and Vacuum Insulated Furnaces for Zero CO2 Emissions

Takaaki Takahashi, Noriyuki Ueno, Daisuke Sakuma
Published 2018-04-03 by SAE International in United States
The prevention of global warming has been a primary concern of the automotive industry for some time. The Toyota Environmental Challenge 2050 describes six individual initiatives to help build a future in which people and vehicles can coexist in harmony. These initiatives aim to eliminate CO2 emissions in vehicle manufacturing by 2050, as well as reduce CO2 emissions while driving. Heating-related processes were identified as being responsible for around 50% of plant CO2 emissions, the most significant single factor. Consequently, as the first step toward achieving zero plant CO2 emissions, the following two technologies were developed with the aim of reducing CO2 emitted in heating processes: (1) a hydrogen burner that generates CO2-free heat and (2) vacuum-insulated furnace walls that enable energy-saving and smart use of heat. These two items were combined into a heat management system with the aim of reducing CO2 emissions by 80%. One issue of hydrogen burners is reducing the generation of NOx at high flame temperatures. Adopting a new structure with two-stage combustion lowered the flame temperature and reduced NOx…
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Real-Time Automatic Test of AEB with Brake System in the Loop

Beihang University-Weiwen Deng
FAW-VW-Xi Chen
Published 2018-04-03 by SAE International in United States
The limitation of drivers' attention and perception may bring collision dangers, Autonomous Emergency Braking (AEB) can help drivers to avoid the potential collisions through active braking. Since the positive effect of it, motor corporations have begun to equip their vehicles with the system, and regulatory agencies in various countries have introduced test standards.At this stage, the actuator of AEB usually adopts Electronic Stability Program (ESP), but it poor performance of continuous working period and active pressure built-up for all wheels limits its implements. Electromechanical brake booster can realize power assisted brake without relying on the vacuum source and a variety of specific power curves. Moreover it can achieve the active braking with a rapid response, which make it can fulfill requirements of automotive electric and intelligent development. In order to further improve the response speed and stability of AEB system, this paper adopts the scheme which combines the ESP with electromechanical brake booster. In addition, employing an improved Time-to-Collision (TTC) model to takes accelerations into consideration.Due to the complexity of actual traffic conditions, a large…
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