Predicting and Controlling Noise Aboard Aircraft Carriers during Flight Operations – Recent Successes

2013 ◽  
Author(s):  
Raymond Fischer ◽  
Kurt Yankaskas ◽  
Jeffrey Komrower ◽  
Leonid Boroditsky
Keyword(s):  
Hearing Loss ◽  
Three Dimensional ◽  
Noise Prediction ◽  
Acoustic Model ◽  
Noise Levels ◽  
Flight Operations ◽  
Damping Material ◽  
The Us ◽  
Us Navy ◽  
Marine Vessels

Shipboard noise prediction software has progressed significantly over the last decade. Studies sponsored by the US Navy have led to the development of software capable of producing a highly accurate, three-dimensional acoustic model of the majority of marine vessels. However, noise on aircraft carriers had not been addressed to date because of the assumption that little could be done to effectively reduce the hazardous noise levels in compartments. A description of recent successful verification of the prediction software and the effective application of a novel sprayon damping material is provided. The goal is to reduce crew hearing loss, annoyance and impact on performance.

scholarly journals Sound Level Measurements in Berthing Areas of an Aircraft Carrier

2019 ◽  
Vol 63 (8) ◽  
pp. 918-929
Author(s):  
Nicholas Cody Schaal ◽  
Maria Majar ◽  
Andrew Hunter
Keyword(s):  
Sound Level ◽  
Noise Levels ◽  
Aircraft Carrier ◽  
Flight Operations ◽  
Close Proximity ◽  
Hearing Recovery ◽  
Us Navy ◽  
Noise Measurements ◽  
Time Periods ◽  
Hazardous Noise

Abstract Background Personnel assigned to aircraft carriers work and live in environments where hazardous noise areas and hearing recovery spaces such as sleeping areas are in close proximity to one another. Hazardous noise exposure occurring during on-duty time periods and elevated noise levels during off-duty periods in sleeping areas may be prohibiting adequate hearing recovery, thus potentially leading to hearing loss and may lead to adverse effects on sleep, leading to crew-member fatigue. This investigation characterizes Equivalent sound level (Leq) and standardized octave band center frequency noise levels according to berthing (sleeping) area location during flight operation and nonflight operation time periods on a US Navy aircraft carrier. In addition, the investigation compares noise measurements in sleeping areas to noise levels associated with auditory rest and poor sleep quality and quantity. Methods Noise levels were measured in berthing areas aboard a US Navy Nimitz-class aircraft carrier during a routine at-sea period. Sixty noise measurements were taken in eight sleeping locations. Leq in decibels ‘A’ weighted (dBA) and noise levels from 16 to 16 000 Hz in (dB) were measured during flight operations [Leq (flt ops)] and nonflight operations [Leq (nonflt ops)]. Leq was also measured according to sleep area shipboard locations of forward (FWD) Leq (FWD), middle (MID) Leq (MID), and rear (AFT) Leq (AFT). These data were compared to the 70 dBA American Conference of Governmental Industrial Hygienists (ACGIH) threshold limit value (TLV) for effective quiet areas. In addition, these data were compared to noise levels associated with hearing loss and sleep parameters. Statistical analysis was conducted with R version 3.5.2 using an alpha level of 0.05. Results Leq (flt ops) in sleeping areas was a statistically significant (P < 0.05) 6.4 dBA higher than the Leq (nonflt ops). Leq (FWD) and Leq (MID) in sleeping areas was a statistically significant (P < 0.05) 15.2 and 15.0 dBA higher, respectively, than the Leq (AFT) noise levels. Mean noise levels at standardized center (1/1) octave bands were highest between 500 and 4000 Hz, ranging from 65.2 to 69.8 dB. A total of 72% of all area Leq measurements exceeded the 70 dBA ACGIH TLV classified as effective quiet to allow for temporary threshold shift recovery. All noise measurements exceeded the World Health Organization’s noise threshold where adverse effects on sleep begin. Discussion/Conclusions Results suggest that sleeping area location in close proximity to relatively high noise sources and activities occurring on an aircraft carrier (i.e. flight operations) increase noise levels in sleeping areas. These findings raise serious concerns since high noise exposures both on duty and during off-duty/sleeping periods may inhibit auditory recovery from hazardous noise exposures. In addition, results suggest noise levels in sleeping areas are high enough to evoke negative sleep effects.

Immersive terrain: the US Navy, Sealab and Cold War undersea geopolitics

Area ◽  
2016 ◽  
Vol 48 (3) ◽  
pp. 332-338 ◽  
Author(s):  
Rachael Squire
Keyword(s):  
Cold War ◽  
The Us ◽  
Us Navy

Use of Polysiloxane Coatings for Topside Applications on US Navy Ships

2014 ◽  
Author(s):  
J. Peter Ault ◽  
Pete Lockwood ◽  
Robert Cloutier ◽  
David Kinee
Keyword(s):  
High Performance ◽  
Cost Effective ◽  
Effective Implementation ◽  
High Durability ◽  
Marine Industry ◽  
The Us ◽  
Us Navy ◽  
Oxidation Resistant ◽  
Marine Applications ◽  
Type V

Polysiloxane coatings are the most recent high performance coatings developed to take advantage of the heat and oxidation resistant properties of silicone-based materials. Commercially available polysiloxane coatings predominately consist of organic-inorganic siloxane materials (though some pure siloxane materials are available). Recently, the US Navy has approved polysiloxane coatings as “High Durability” in their specification for exterior weather resistant coatings (MIL-PRF-24635 Type V and VI). Navy approval comes after over 20 years of industry development of polysiloxane coatings for high performance industrial and marine applications, yet issues remain with their cost-effective implementation in the Navy fleet. This paper will review experiences of the offshore and marine industry with polysiloxane coatings and provide an update on the Navy adoption of the technology.

A Duet for Sailors and Pansies: Queer Archival Work and Male Same-Sex Dancing in Follow the Fleet (1936) and Other Depression-Era Films

2021 ◽  
pp. 186-213
Author(s):  
David Lugowski
Keyword(s):  
Essential Role ◽  
Contextual Analysis ◽  
Same Sex ◽  
Hollywood Films ◽  
Production Code ◽  
The Us ◽  
Us Navy ◽  
Mass Entertainment ◽  
Archival Work ◽  
Depression Era

This chapter explores a queer all-male dance lesson for partnered sailors in the Fred Astaire–Ginger Rogers musical Follow the Fleet (1936), using archival research (scripts, Production Code Administration records) and comparative textual and contextual analysis. It raises the queerness of Rogers and Astaire before exploring two intersecting axes. The association of sailors with queer behavior and effeminate “pansies” occurs in military scandals, paintings, and Depression-era Hollywood films, including Sailor’s Luck and Son of a Sailor (both 1933). The queerness of male same-sex dancing arises in ballet and in film, including Suicide Fleet (1931). Various institutions criticized or attempted to censor such representations, but they also found acceptance. The US Navy, for example, wanted the comical dance lesson removed from Fleet; instead, it was only rewritten, suggesting the inability to remove queerness from culture and its essential role in mass entertainment.

Tumblehome Ships - From Greek Triremes to the Zumwalt

2021 ◽  
Author(s):  
Robert Forrest Roddy
Keyword(s):  
World War I ◽  
World War ◽  
Steam Power ◽  
Loss Of Life ◽  
Damage Stability ◽  
The Us ◽  
Us Navy ◽  
Major Loss

After almost a century the US Navy has reintroduced tumblehome into the design of naval combatants. This paper discusses some of the reasons tumblehome was originally designed into ships and why it served it owners well for many centuries. The transition from sail to steam power a little over a century ago led to a variety of problems with the combatant ships designed with tumblehome where the lack of damage stability caused a major loss of life as these ships sank so quickly. During World War I ships designed with tumblehome fell out of favor and some of the ships were actually modified to remove the tumblehome from the design. These changes in the design of tumblehome ships are discussed in this paper.

Optimization of the Hybrid Ship Transport Factor through Retrofitted Wave Cancelling Side-Hull Expansions and Bow Bulb

2015 ◽  
Author(s):  
Manivannan Kandasamy ◽  
Ping C. Wu ◽  
Scott Bartlett ◽  
Loc Nguyen ◽  
Frederick Stern
Keyword(s):  
High Performance ◽  
Negative Impact ◽  
Fiscal Year ◽  
Hull Form ◽  
Transport Factor ◽  
Resistance Reduction ◽  
The Us ◽  
Us Navy ◽  
Speed Range ◽  
Design Speed

The US Navy is currently considering the introduction of a Flight III variant beginning with DDG-123 in Fiscal Year 2016. The new design incorporates a new combat system and associated power and cooling upgrades. The overall system improvements increase the payload of the ship and the resulting increased displacement has a negative impact on the service life allowance for range, fuel consumption and sea-keeping characteristics. The present objective is to increase the hull displacement without resistance and sea-keeping penalty and with minimal modifications to the baseline DTMB-5415 design (open literature surrogate of the existing DDG-51 hull form) by using retrofitted blisters in the form of side hull expansions and a bow-bulb. The investigation makes use of high-performance CFD computing for analysis of wave cancellation mechanisms. A candidate modified 5415 design with both blisters and bow bulb shows a resistance reduction of ~11% w.r.t.the baseline 5415 in the design speed range of 15-19 knots, even though the displacement is increased by 8%, such that the transport factor is increased by 19%.

scholarly journals 3-D Printable Polymer Pelletizer Chopper for Fused Granular Fabrication-Based Additive Manufacturing

Inventions ◽  
2018 ◽  
Vol 3 (4) ◽  
pp. 78 ◽  
Author(s):  
Aubrey Woern ◽  
Joshua Pearce
Keyword(s):  
Additive Manufacturing ◽  
Open Source ◽  
Low Cost ◽  
Three Dimensional ◽  
High Tolerance ◽  
Entire Process ◽  
Composite Fabrication ◽  
The Us ◽  
Color Mixing ◽  
Returns On Investment

Although distributed additive manufacturing can provide high returns on investment, the current markup on commercial filament over base polymers limits deployment. These cost barriers can be surmounted by eliminating the entire process of fusing filament by three-dimensional (3-D) printing products directly from polymer granules. Fused granular fabrication (FGF) (or fused particle fabrication (FPF)) is being held back in part by the accessibility of low-cost pelletizers and choppers. An open-source 3-D printable invention disclosed here allows for precisely controlled pelletizing of both single thermopolymers as well as composites for 3-D printing. The system is designed, built, and tested for its ability to provide high-tolerance thermopolymer pellets with a number of sizes capable of being used in an FGF printer. In addition, the chopping pelletizer is tested for its ability to chop multi-materials simultaneously for color mixing and composite fabrication as well as precise fractional measuring back to filament. The US$185 open-source 3-D printable pelletizer chopper system was successfully fabricated and has a 0.5 kg/h throughput with one motor, and 1.0 kg/h throughput with two motors using only 0.24 kWh/kg during the chopping process. Pellets were successfully printed directly via FGF as well as indirectly after being converted into high-tolerance filament in a recyclebot.

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