Reducing contaminating noise effects when calculating low-boom loudness levels.

During NASA X-59 quiet supersonic aircraft community response tests, low-boom recordings will contain contaminating noise from instrumentation and ambient acoustical sources. This noise can inflate sonic boom perception metrics by several decibels. This paper discusses the development and comparison of robust lowpass filtering techniques for removing contaminating noise effects from low-boom recordings.

Influences of low-frequency energy and testing environment on annoyance responses to supersonic aircraft noise when heard indoors.

The research reported is part of a larger effort to develop models to predict community response to transient sounds, including sonic booms. Such models can be used along with aircraft sound predictions to guide the design of supersonic aircraft to produce generally acceptable sounds. A test was conducted to examine the influence of low frequencies on people's responses to recorded and simulated booms and other environmental transients, heard indoors over earphones.

Retrospective analysis of the effect of acid-suppressant therapy on clinicopathologic parameters of cats with chronic kidney disease.

Objectives The aim was to retrospectively evaluate the effects of acid-suppressant therapy in a population of cats with chronic kidney disease (CKD). The study objectives were to evaluate the effects of acid-suppressant therapy on clinicopathologic variables and progression of CKD over time. Methods The databases of two institutions were searched over an 11 year time span for cats fitting inclusion criteria for CKD.

Effects of indoor rattle sounds on annoyance caused by sonic booms.

To expand national air transportation capabilities, NASA's Commercial Supersonic Technology Project is working to make supersonic flight practical for commercial passengers. As an aid in designing and certifying quiet supersonic aircraft, a noise metric is sought that will correspond to indoor annoyance caused by sonic booms, including the effects of indoor rattle sounds. This study examines how well several common aircraft noise metrics predict indoor annoyance based on the indoor and outdoor sound fields.