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Exposure Levels of UV Radiation in Nondestructive Inspection Processes

AMS K Non Destructive Methods and Processes Committee
  • Aerospace Standard
  • AIR4964
  • Current
Published 2019-08-05 by SAE International in United States
Long wave ultraviolet or UV-A radiation (between 320 to 400 nm) is used for fluorescent inspections in magnetic particle and liquid penetrant examinations. The UV-A radiation is obtained from either fluorescent or high intensity discharge lamps that are stationary or portable. The commercially available UV-A lamps possess a large variation in intensity output that can cause a legitimate concern for possible health hazard. This draft reviews the nature of UV-A radiation emitted by these lights, blacklight equipment, acceptable UV dosage limits adopted by the American Conference of Governmental Industrial Hygienists (ACGIH) and the European Standards Committee for Nondestructive Testing, and recommendation of proper practices when working with UV-A radiation.
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Tuning Material Color and Thermal Properties Separately

  • Magazine Article
  • TBMG-34898
Published 2019-08-01 by Tech Briefs Media Group in United States

The color of a material can often tell how it handles heat. With clothing, for example, the darker the pigment, the warmer you're likely to feel on a hot day. Likewise, the more transparent a glass window, the more heat it can let through. A material's responses to visible and infrared radiation are often naturally linked.

 
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Nominal High-Altitude Electromagnetic Pulse (HEMP) Waveforms

Aerospace & Defense Technology: August 2019

  • Magazine Article
  • 19AERP08_08
Published 2019-08-01 by SAE International in United States

Calculating the characteristics of high-altitude electromagnetic pulses created by the detonation of a nuclear device.

Even before the Trinity nuclear test in July of 1945, physicists predicted a transient electromagnetic signal would be caused by high-energy photons released from the detonation interacting with the air around the detonation. Predictions of these signals were difficult to make due to the complexity of the physics unleashed by the detonation.

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Requirements for Plastic Encapsulated Discrete Semiconductors in Military and Avionics Applications

CE-12 Solid State Devices
  • Aerospace Standard
  • AS6294/4
  • Current
Published 2019-07-09 by SAE International in United States
This standard documents and establishes common industry practices, and screening and qualification testing, of plastic encapsulated discrete semiconductors (PEDs) for use in military and avionics application environments.
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Supergel System Cleans Radioactively Contaminated Structures

  • Magazine Article
  • TBMG-34732
Published 2019-07-01 by Tech Briefs Media Group in United States

A system was developed that can remove radioactive cesium contamination from porous structures such as brick and concrete that are hard to clean, as well as contamination from metal surfaces. The Supergel system focuses on rapid response, capturing as much of the contamination as possible, as quickly as possible, and filling a technology gap immediately.

 

Numerical Prediction and Verification of Noise Radiation Characteristics of Diesel Engine Block

Deere & Company-Sanghoon Suh
John Deere Technology Center India-Devendra Mandke, Deepak Ghaisas, Sachin Pawar
Published 2019-06-05 by SAE International in United States
To assess the contribution of structure-borne noise from an engine, it is critical to characterize the dynamic and vibro-acoustic properties of the engine components and assembly. In this paper, a component level study of a three-cylinder diesel engine block is presented. Virtual analysis was done to predict the natural frequencies and mode shapes of an engine block in the first step. Then, these results were used to decide the optimum test locations and an experimental modal test was conducted on the engine block. The initial virtual model results for the natural frequencies and mode shapes were correlated with the results from test. Then, the virtual model was updated with the damping derived from experimental modal test to match the vibration frequency response functions. Further, the virtual model was used for prediction of vibro-acoustic transfer functions. The vibro-acoustic transfer functions were also obtained from test. The results of transfer function were correlated with the test. In future, we plan to use this approach for prediction of the vibration and vibro-acoustic transfer functions for sub-assembly and eventually…
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Power Electronic Noise-Simulation Measurement Comparison

AVL LIST GmbH-Markus Resch, Thomas Resch, Stephan Brandl
AVL Software and Functions Gmbh-Peter Olbrich, Hartwig Reindl
Published 2019-06-05 by SAE International in United States
A growing development of hybrid or fully electrical drives increases the demand for an accurate prediction of noise and vibration characteristics of electric and electronic components. This paper describes the numerical and experimental investigation of noise emissions from power electronics, as one of the new important noise sources in electric vehicles.The noise emitted from the printed circuit board (PCB) equipped with multi-layer ceramic capacitors (MLCC) is measured and used for the calibration and validation of numerical model. Material properties are tuned using results from experimental modal analysis, with special attention to the orthotropic characteristic of the PCB glass-reinforced epoxy laminate sheet (FR-4). Electroacoustic excitation is pre-calculated using an extension of schematic-based EMC simulation and applied to the structural model. Structural vibrations are calculated with a commercial FEM solver with the modal frequency response analysis. Sound radiation is simulated using the wave-based approach (WBT). Simulation and experimental results are compared in a frequency range up to 10 kHz.The developed simulation methodology can successfully identify the main noise sources from the equipped PCB. Critical peak noise responses…
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Determining Vibro-Acoustic Characteristics and Structural Damping of an Elastic Monolithic Panel

Shiloh Industries, Inc.-Antonio Figueroa
Wayne State University-Sean Wu, Lingguang Chen
Published 2019-06-05 by SAE International in United States
Evaluations of the dynamic and acoustic responses of panels, partitions, and walls are of concern across many industries, from building home appliances, planning meeting rooms, to designing airplanes and passenger cars. Over the past few decades, search efforts for developing new methodologies and technologies to enable NVH engineers to acquire and correlate dynamically the relationship between input excitations and vibro-acoustic responses of arbitrary-shaped panels has grown exponentially. The application of a particular methodology or technology to the evaluation of a specific structure depends intimately on the goals and objectives of the NVH engineers and industries. In this work, we present the comparisons between the traditional modal analyses for structural vibrations together with sound intensity measurements of sound radiation and a laser-assisted Helmholtz equation least squares (HELS) method [1, 2, 3, 4] to characterize the dynamic and acoustic responses of an arbitrarily shaped structure subject to non-contact acoustic excitations. Input data for the latter include the normal surface velocities measured at a finite number of points on the surface of the structure that are accessible to…
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Electrical Characterization of Crystalline UO2, THO2 and U0.71TH0.29O2

  • Magazine Article
  • TBMG-34527
Published 2019-06-01 by Tech Briefs Media Group in United States

Tracking and identifying radiation sources in the age of nuclear proliferation and well- resourced non-state actors is a national priority. Current neutron detection methods favor large detector volumes and long data collection times. Additionally, portable neutron detection methods have persistent problems with low signal-to-noise (small pulse height) and require large applied voltages.

 

Electrical Characterization of Crystalline UO2, THO2 and U0.71TH0.29O2

Aerospace & Defense Technology: June 2019

  • Magazine Article
  • 19AERP06_08
Published 2019-06-01 by SAE International in United States

Evaluating the suitability of advanced alloys for use in uranium-based neutron detectors.

Tracking and identifying radiation sources in the age of nuclear proliferation and well-resourced non-state actors is a national priority. Current neutron detection methods favor large detector volumes and long data collection times. Additionally, portable neutron detection methods have persistent problems with low signal-to-noise (small pulse height) and require large applied voltages.

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