TagScientific Measurement(4)

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  • FAA SPL V2 HR Trim

    SEL Sound Exposure Level and Energy Metrics

    An educational diagram illustrating acoustic measurement concepts including Sound Exposure Level (SEL), Lmax, LEQ, and energy, plotted as sound level (dB) over time (seconds). The graphic shows how SEL compresses a noise event's total energy into a normalized 1-second value, with Lmax appearing approximately 10dB above the LEQ reference line.
  • 1975-01-01

    Selection of airport noise analysis method and exposure limits

    This 1975 working paper from the Maryland State Aviation Administration examines methods for measuring and analyzing airport noise exposure, focusing on the Day-Night Average Sound Level (Ldn) as the recommended metric for assessing community noise impact. It reviews how sound characteristics such as magnitude, frequency, and time distribution affect human response, and evaluates criteria for acceptable noise limits based on effects including hearing loss, speech interference, sleep disturbance, and annoyance. The document also compares international noise exposure standards and proposes guidelines for land-use compatibility around airports.
  • 1975-01-01

    Selection of airport noise analysis method and exposure limits

    This 1975 working paper from the Maryland State Aviation Administration examines methods for measuring and analyzing airport noise exposure, focusing on the Day-Night Average Sound Level (Ldn) as the recommended metric for assessing community noise impact. It reviews how sound characteristics such as magnitude, frequency, and time distribution affect human response, and evaluates criteria for acceptable noise limits based on effects including hearing loss, speech interference, sleep disturbance, and annoyance. The document also compares international noise exposure standards and proposes guidelines for land-use compatibility around airports.

  • Kelsh Projection Stereoplotter (1960)

    Kelsh Projection Stereoplotter (1960). This was an automatic digital data input system used in conjunction with the photogrammetric plotter. The stereoplotter required two aerial photographs that have considerable overlap (60%). The photos are put onto transparent media and projected with a light source. Each image will be projected with overlap on the other. The operator,