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A group of students and professors from Rollins College, in collaboration with Brigham Young University's acoustics group, measured far-field noise from the Space Launch System’s Artemis I mission liftoff. This presentation outlines the data collection process and measurements at locations 10 to 40 miles from Launch Complex 39B at Kennedy Space Center (KSC) in Cape Canaveral, Florida. Preliminary analysis of these measurements from outside the perimeter of KSC, including overall sound pressure levels, waveform characteristics, and frequency spectra, will be discussed.

The noise sources within a turbulent rocket plume are not well understood, let alone the radiation from multiple rocket nozzles. Even less is known about the noise sources during launch vehicle liftoff. This paper seeks to simultaneously address these noise source analysis challenges using data collected during the NROL-82 Delta IV Heavy (DIVH) launch from Vandenberg Space Force Base. The three-core DIVH’s liftoff noise was measured by a ground-based four-microphone array at a distance of 330 m. Hart et al. [Proc. Mtgs. Acoust. 45, 040003 (2022)] previously used this array with a cross-correlation technique to identify the overall noise source radiation locus as it switched from the flame trench exit to about 55 m downstream of the nozzle exit plane. Here, vector intensity is used to localize the frequency-dependent noise source axial distribution using a variant of the phase and amplitude gradient estimator method for acoustic intensity [Thomas et al., J. Acoust. Soc. Am. 137, 3366–3376 (2015)]. The results help clarify a complex noise source generation process that is both time and frequency-dependent and involves both free and impinging jet noise phenomena.

This presentation documents initial findings from far-field noise measurements at NASA’s Kennedy Space Center during liftoff of the Space Launch System’s Artemis I mission, which occurred on November 16, 2022. The vehicle— the most powerful ever successfully launched into orbit—consists of four liquid-fueled RS-25 engines and two five-segment, solid-fuel rocket boosters (SRBs). Because this was the first launch, the noise radiation characteristics of this vehicle were previously unknown. Overall sound pressure levels, waveform characteristics, and spectra are described at distances ranging from 1.5 to 8.4 km. The levels due to the SRBs’ ignition overpressure are particularly intense in the direction of the flame trench exit. The post-liftoff maximum one-third octave spectrum has a peak at 20 Hz, and maximum overall levels are greater than described in a pre-launch environmental assessment. These and other findings presently submitted to JASA Express Letters further understanding of super heavy-lift rocket acoustics.

NASA’s Space Launch System (SLS) launched the Artemis I mission at 1:47 am local time on November 16, 2022. The timing of the night launch offered a multitude of interesting weather effects over the propagation paths to measurement locations ranging from 1.5 km to 60 km. This presentation discusses spectra at different distances from Launch Complex 39B, both inside and outside the Kennedy Space Center perimeter. Preliminary analysis of the SLS sound pressure levels and spectra suggests many propagation phenomena are at play. In addition to geometric spreading, atmospheric absorption, and nonlinear propagation, complex weather profiles and ground effects are discussed. Initial results of a single-frequency Greens-function parabolic equation model, with estimated weather profiles along the propagation paths, will be offered with approximate source and receiver height to compare levels at several locations.

Historically, lasers have been used for a variety of purposes such as spectroscopy or optics. Lasers have even been used as a surveillance device; however, minimal research has been done in this area. In this experiment, a laser microphone was designed and tested with several different colored lasers to determine the frequency response of the received signal due to wavelength differences from the emitted light. The laser microphone included two telescoping lenses and an interferometer setup with a flimsy mirror as one of the arms. This mirror created a vibrating diffraction pattern when sound waves were played in close proximity. The interferometer was set up in an anechoic chamber, and a transimpedance photodiode was used to collect data of a moving diffraction pattern. With this setup, different sounds were recorded with varying levels of clarity, and the spectral response of the laser microphone was analyzed. With further research, a choice of laser color could be chosen to optimize the signal’s response.

Parasites can compromise the health and fitness of individual fish, and it is important to generate baseline information that can then be used to document changes in the abundance and distribution of potentially pathogenic parasites. The ectoparasitic copepod Salmincola edwardsii was assessed with respect to prevalence (percentage of infected fish per site), infection intensity (number of parasites per infected fish), and attachment location on Brook Trout Salvelinus fontinalis in northwest New Brunswick, Canada. Ten sample sites were assessed, with six sites on two streams in the Quisibis River basin and four sites on three streams in the Restigouche River basin. Parasite species identity was supported by 100% sequence identity with S. edwardsii in a variable region within 28S rDNA. The prevalence of fish infected per site ranged from 19.0% to 79.6%, with an overall prevalence of 48.5 ± 19.1% (mean ± SD) per site. Mean infection intensity was 1.5 ± 0.9 copepods/fish (range = 1-7), with parasites almost exclusively surrounding the dorsal fin and/or adipose fin (97.6%). There was no influence of trout age-class on parasite prevalence. Some fish presented with fin erosion at the site of parasite attachment (12.5%), and 6.2% also presented with hyperplastic skin lesions where no parasites were observed, that could be misinterpreted as secondary bacterial or fungal infections. Skin and fin damage were significantly more common when fish were infected with three or more individual parasites. The pathogenic potential of this parasite makes its presence noteworthy as a risk to salmonids that are both recreationally and ecologically important.

To improve understanding of super heavy-lift rocket acoustics, this letter documents initial findings from noise measurements during liftoff of the Space Launch System's Artemis-I mission. Overall sound pressure levels, waveform characteristics, and spectra are described at distances ranging from 1.5 to 5.2 km. Significant results include: (a) the solid rocket boosters' ignition overpressure is particularly intense in the direction of the pad flame trench exit; (b) post-liftoff maximum overall levels range from 127 to 136 dB, greater than pre-launch predictions; and (c) the average maximum one-third-octave spectral peak occurred at 20 Hz, causing significant deviation between flat and A-weighted levels.

In September 2021, an Atlas V rocket without solid rocket boosters was launched from Vandenberg Space Force Base, California, carrying the NASA/USGS Landsat 9 satellite. In this launch configuration, the plumes from the RD-180 engine’s two nozzles are unobstructed, providing the opportunity to analyze the sound generated by a liquid-fuel rocket engine with an azimuthally asymmetric nozzle geometry. Acoustical data were collected at various locations surrounding the launch pad, ranging from a few hundred meters to several kilometers. This paper discusses an overview of the measurement logistics, the types of analyses that may be performed using these data, and an initial analysis of the azimuthal variability of the overall sound pressure level and spectra.

Our aim was to compare the tensile strength of the native scapholunate ligament (SLL) with that of an all-suture anchor construct in a cadaveric model. The scaphoid and lunate were isolated, preserving all segments of the SLL. Using a servohydraulic testing machine, we increased the load until peak load-to-failure of the native SLL was reached in nine specimens (mean ± standard deviation, 273 ± 132 N). Using the same specimens, two JuggerKnot 1.4-mm suture anchors (Zimmer Biomet) were placed into the lunate and tensioned through transosseous tunnels in the scaphoid. Sutures were tied over the radial nonarticular aspect of the scaphoid. Load-to-failure testing was repeated. The mean peak load-to-failure for the all-suture anchor constructs was 172 ± 59 N versus 231 ± 117 N for the native group (p = 0.157). This represents approximately 75% of the native ligament strength. (Journal of Surgical Orthopaedic Advances 29(3):169-172, 2020).

Mapping and quantifying the area and type of disturbance within forests is critical for sustainable forest management. Grizzly bear (Ursus arctos) have large home ranges and diverse habitat needs and as a result, information on the extent, type, and timing of disturbances is important. In this research we apply a remote-sensing-based disturbance mapping technique to the southeastern extent of a grizzly bear range. We apply a data fusion approach with MODIS 250 m and Landsat 30 m spatial resolution imagery to map disturbances biweekly from 2001–2011. A regression tree classifier was applied to classify the disturbance events based on spatial and temporal characteristics. Fire was attributed as a disturbance based on a national fire database. Results indicate that across the 130,727 km2 study area, 4,603 km2 of forest were disturbed over the past decade (2001–2011), impacting 0.35% of the study area annually. Overall, 68.7% of the disturbance events were attributed to forest harvest, followed by w...