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Numerical Simulation of the Early Flame Development Produced by an Advanced Radio Frequency Ignition System in an Optical Access Engine

Università degli Studi di Perugia-Federico Ricci, Jacopo Zembi, Michele Battistoni, Carlo Grimaldi, Gabriele Discepoli, luca petrucci
  • Technical Paper
  • 2019-24-0231
To be published on 2019-10-07 by SAE International in United States
In order to reduce engine emissions and fuel consumption, extensive research efforts are being devoted to develop innovative ignition devices, able to extend the stable engine operating range towards increasing lean conditions. Among these, radio frequency corona ignition systems, which produce a strong electric field at a frequency of about 1 MHz, can create discharges characterized by simultaneous thermal and kinetic effects. These devices can considerably increase the early flame growth speed, initiating the combustion process in a wide region, as opposed to the local ignition generated by traditional sparks. To explore the corona ignition behavior, experimental campaigns were carried out to investigate different operating conditions, in a constant volume calorimeter designed to measure the thermal deposited energy. The present work compares the combustion development generated by a traditional spark and the corona igniter through computational fluid dynamics simulations. First, simulations are carried out to reproduce the experimental results in the calorimeter, comparing the measured and predicted pressure traces in an inert environment. The validated approach is then applied in a second step to the…
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Shape-Shifting Origami Could Help Antenna Systems Adapt On-the-Fly

Aerospace & Defense Technology: September 2019

  • Magazine Article
  • 19AERP09_05
Published 2019-09-01 by SAE International in United States

Conventional reconfigurable electrical and radio frequency (RF) structures commonly used in applications involving real-time reconfigurability in response to fast varying operational scenarios require specialized substrates or complex electrical circuits. Origami-based RF reconfigurable components and modules offer a solution with unique properties. First, they enable reconfigurability over continuous-state ranges (as opposed to discrete states). Second, they do not require specialized mechanical support for multilayer frequency-selective surface structures. Moreover, deployable origami-based RF structures can achieve large surface reconfigurability ratios from folded to unfolded states. Finally, these structures allow for independent control of multiple figures of merit: bandwidth, frequency of operation, and angle of incidence.

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Multi-Agent RF Propagation Simulator

Aerospace & Defense Technology: June 2019

  • Magazine Article
  • 19AERP06_07
Published 2019-06-01 by SAE International in United States

Adesirable interface between multiagents is through over-the-air RF connections that include not only the intended direct RF communications paths but also highly variable multiray propagation, range attenuation, external RF influences, and near-earth influence. These influences are all difficult to predict, control, and repeat in an outdoor environment. This outdoor testing, as has traditionally been done, is extremely expensive while simultaneously providing fewer data points than more controlled events and the testing events are generally not repeatable.

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Multi-Agent RF Propagation Simulator

  • Magazine Article
  • TBMG-34531
Published 2019-06-01 by Tech Briefs Media Group in United States

A desirable interface between multi-agents is through over-the-air RF connections that include not only the intended direct RF communications paths but also highly variable multi-ray propagation, range attenuation, external RF influences, and near-earth influence. These influences are all difficult to predict, control, and repeat in an outdoor environment. This outdoor testing, as has traditionally been done, is extremely expensive while simultaneously providing fewer data points than more controlled events and the testing events are generally not repeatable.

The ‘Relativity’ of High Q Capacitors

  • Magazine Article
  • TBMG-34557
Published 2019-06-01 by Tech Briefs Media Group in United States

For many high-power RF applications, the “Q factor” of embedded capacitors is one of the most important characteristics in the design of circuits. This includes products such as cellular/telecom equipment, MRI coils, plasma generators, lasers, and other medical, military, and industrial electronics.

High-Performance, Current-Steering Digital-to-Analog Converter

  • Magazine Article
  • TBMG-34395
Published 2019-05-01 by Tech Briefs Media Group in United States

A current-steering digital-to-analog converter (DAC) was developed that achieves improved switching times (up to 75% faster) in high-speed (gigahertz), high-resolution (8-14 bits) applications resulting in improvement of spurious free dynamic range (SFDR).

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Damage and Repair of Aerospace Composite Materials

Charles Lu
  • Progress In Technology (PT)
  • PT-200
Published 2019-04-30 by SAE International in United States
Damage and Repair of Aerospace Composite Materials reports the latest developments on the detection and repair of composite structures from the perspective of ten SAE technical papers, especially chosen for this book. This micro-collection of papers offers an overview of composite utilization on large-scale commercial aircraft as well as an outline of general damage inspection and repair of composite structures. On the damage detection side, really important techniques are explained, including: • Porosity inspection of large composite panels. • Damage detection of large composites using acoustic ultrasonic and radio frequency methods. • Discrimination of damaged and undamaged composite panels using acoustic emission sensors. • Automated defect inspection system integrated in the production line by utilizing laser sensors and cameras. The latest studies in damage repair of composite structures are also presented, including: • the design of a bonded repair technique for multilayer laminate composite panels. • the analysis on the performance of bolted repair vs. bonded repair. • the method for economically repairing the holes on composites. • the development of a novel cutting tool…
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Connector Accessories, Electrical General Specification for

AE-8C1 Connectors Committee
  • Aerospace Standard
  • AS85049E
  • Current
Published 2019-04-22 by SAE International in United States
This specification covers connector accessories for use with electrical connectors, see 6.8.
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JAUS / SDP Transport Specification

AS-4JAUS Joint Architecture for Unmanned Systems Committee
  • Aerospace Standard
  • AS5669A
  • Current
Published 2019-04-22 by SAE International in United States
This SAE Aerospace Standard (AS) specifies a data communications layer for the transport of messages defined by the Joint Architecture for Unmanned Systems (JAUS) or other Software Defined Protocols (SDP). This Transport Specification defines the formats and protocols used for communication between compliant entities for all supported link-layer protocols and media. Although JAUS is the SDP used as the example implemented throughout this document, AS5669 can be used for any SDP that meets the required capabilities. A Software Defined Protocol is defined as an application data interface for communicating between software elements. The SDP is agnostic of the underlying communications protocol and in fact communicates in much the same manner regardless if the communicating entities are collocated in the same memory space or separated by a satellite link.
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Evaluation of Low Mileage GPF Filtration and Regeneration as Influenced by Soot Morphology, Reactivity, and GPF Loading

FCA US LLC-Jordan Elizabeth Easter, Kiran Premchand
University of Michigan-Stanislav Bohac, John Hoard
Published 2019-04-02 by SAE International in United States
As European and Chinese tailpipe emission regulations for gasoline light-duty vehicles impose particulate number limits, automotive manufacturers have begun equipping some vehicles with a gasoline particulate filter (GPF). Increased understanding of how soot morphology, reactivity, and GPF loading affect GPF filtration and regeneration characteristics is necessary for advancing GPF performance. This study investigates the impacts of morphology, reactivity, and filter soot loading on GPF filtration and regeneration. Soot morphology and reactivity are varied through changes in fuel injection parameters, known to affect soot formation conditions. Changes in morphology and reactivity are confirmed through analysis using a transmission electron microscope (TEM) and a thermogravimetric analyzer (TGA) respectively.Evaluations regarding the impact of these varied soots on GPF performance is accomplished through monitoring of GPF filtration efficiency as a function of soot loading and monitoring of soot oxidation rates during GPF regeneration events. Size-dependent filtration efficiency across the GPF is determined with a Scanning Mobility Particle Sizer (SMPS). Soot oxidation during regeneration events is determined using a radio frequency (RF) sensor and periodic weighing of the GPF on…
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