| Sound Attenuation and Speech Intelligibility of a Modified Active Noise Reduction (ANR) Headset for Use by P3-C Sensor Operators |
MAY 95 |
33 pages |
| Authors:
C. E. Williams; D. W. Maxwell; G. B. Thomas; NAVAL AEROSPACE MEDICAL RESEARCH LAB PENSACOLA FL
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 | Sound attenuation and speech intelligibility evaluations were conducted on a modified active noise reduction (ANR) headset being considered for use by sensor operators in Navy P3-C aircraft. Measurements were obtained on 10 male ensigns in the Naval Aviation Flight Training Program. A comparison of the sound attenuation values obtained with the ANR on (combined passive and active attenuation) to values obtained with the ANR off' (passive attenuation) revealed 10-15 (B ... |
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| Sound Attenuation Evaluation of the Navy's HGU-84/P Helicopter Helmet |
JAN 95 |
18 pages |
| Authors:
D. W. Maxwell; C. E. Williams; NAVAL AEROSPACE MEDICAL RESEARCH LAB PENSACOLA FL
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| First article sound attenuation tests were conducted on samples of the HGU-84/P helicopter helmet, candidate replacement for the SPH-3C series of helmets, supplied for evaluation by the Naval Air Warfare Center Aircralt Division, Warminster, Pennsylvania. The tests were conducted in accordance with American National Standard ANSI 512.6-1984, Method for the Measurement of Real- Ear Attenuation of Hearing Protectors. Objective measurements of attenuation, microphone-in-real-ear (MIRE), were also obtained for database and ... |
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| The Development of Auditory Performance Standards for Naval Aviators: Radiocommunications Questionnaire Results |
09 AUG 1991 |
12 pages |
| Authors:
G. B. Thomas; C. E. Williams; NAVAL AEROSPACE MEDICAL RESEARCH LAB PENSACOLA FL
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| The establishment of hearing standards for naval aviators requires some determination of acceptable or normative performance in the operational environment. Because speech perception via radio link is the principal auditory ability required of aviators, questions regarding several aspects of radiocommunications were asked of 62 experienced aviators stationed at NAS oceana. Respondents to the questionnaire provided information regarding the frequency and cause of missed communications, the types of aircraft and flight ... |
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| Noise Exposure of Naval Communication Station Radio Operators: A Field Study |
JUL 1990 |
12 pages |
| Authors:
R. M. Robertson; J. W. Greene; C. E. Williams; D. W. Maxwell; NAVAL AEROSPACE MEDICAL RESEARCH LAB PENSACOLA FL
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| In 1979, the Naval Security Group Headquarters requested the Acoustical Sciences Division, Naval Aerospace Medical Research Laboratory (NAMRL), to determine the extent to which radio headsets being used at naval communication stations posed a potential damage risk to hearing. The purpose of this technical memorandum is to document data obtained during a site visit at the naval communication satation located near Homestead Air Force Base, Florida. The data-gathering visit followed ... |
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| Hot Corrosion of Co-Cr-Al-Y by Molten Sulfate-Vanadate Deposits, |
MAR 1987 |
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| Authors:
R. L. Jones; C. E. Williams
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 | The mechanisms of hot corrosion by molten sulfate-vanadate deposits were investigated by studying the corrosion of a Co-Cr-Al-Y gas turbine blade coating alloy by Na(sub 3)VO(sub 4), NaVO(sub 3), V(sub 2)O(sub 5) and Na(sub 2)SO(sub 4), or combinations thereof, in air or in controlled sulfur trioxide-air environments at 700 C. Corrosion behavior was largely controlled by acid-base reactions between the metal oxides and the acidic-basic components (i.e. Na(sub 2)O, V(sub ... |
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| Performance of High Temperature Coatings on F100 Turbine Blades under Simulated Service Conditions, |
MAR 1987 |
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| Authors:
R. L. Jones; C. E. Williams
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| The performance of various pack, gas phase, noble metal aluminide and overlay coatings, applied on F100 first-stage turbine blades, was determined in a 300 h simulated service test in the National Aerospace Laboratory (NLR) high temperature burner rig using flight-by-flight test conditions. An estimate of relative coating life and ranking, based on these particular blade-coating systems, was established. The Ni-Co-Cr-Al-Y overlay coating showed superior performance. The coating life of the ... |
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| Zinc Sulfate Reactions in Hot Corrosion, |
AUG 1986 |
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| Authors:
R. L. Jones; C. E. Williams
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| To further understanding of the potential effects of zinc containing contaminants or fuel additives in gas turbine hot corrosion, the corrosion of CoCrAlY (a gas turbine blade coating alloy) spray coated with 50 mole percent zinc sulfate-sodium sulfate was compared with that of CoCrAlY spray coated with sodium sulfate alone at 700 and 850 C in air containing controlled sulfur trioxide partial pressures. Thermobalance experiments showed that zinc sulfate delayed ... |
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| Mixed MgSO(sub 4)-Na(sub 2)SO(sub 4) Effects in the 973 K Hot Corrosion of CoCrAlY, |
JAN 1986 |
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| Authors:
R. L. Jones; C. E. Williams
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| The presence of magnesium sulfate in sodium sulfate affects the chemistry and corrosion behavior of the sulfate melt in relation to the low temperature (973 K) hot corrosion of CoCrAlY. Under equivalent conditions, less sulfation of Co(sub 3)O(sub 4) by sulfur trioxide was found with 50 m/o magnesium sulfate-sodium sulfate than with pure sodium sulfate, and there was less corrosion in sulfur trioxide environment thermobalance tests for CoCrAlY coupons coated ... |
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| Development of a Navy Hearing Conservation Management Information System (HECMIS) |
NOV 1984 |
45 pages |
| Authors:
R. M. Robertson; C. E. Williams; NAVAL AEROSPACE MEDICAL RESEARCH LAB PENSACOLA FL
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| Due to the lack of an efficient and economical way to obtain essential data from medical records, naval hearing conservation management personnel lack the capability for assessing the adequacy of their programs. A model Hearing Conservation Management Information System (HECMIS) developed for the Navy Environmental Health Center (NEHC), Norfolk should alleviate this problem. The HECMIS, currently undergoing further operational modeling at NEHC, now contains some 19,000 DD-2215 forms and 12.400 ... |
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| Attitude Determination of Triad and TIP-II and -III Gravity-Gradient-Stabilized Satellites. |
DEC 1977 |
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| Authors:
C. E. Williams; JOHNS HOPKINS UNIV LAUREL MD APPLIED PHYSICS LAB
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| The attitude of a satellite refers to the rotational orientation of the spacecraft relative to some reference triad of Cartesian axes (these being, for the type of spacecraft treated here, the orbit radius vector, the normal-to-the-orbit plane, and the vector cross product of the two). Mathematically, the attitude is usually represented by nine direction cosines and/or three Euler angles. The numerical determination of these parameters is the objective of attitude ... |
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| SAS-C Solar Array Deployment Dynamics. |
AUG 1975 |
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| Authors:
C. E. Williams; JOHNS HOPKINS UNIV LAUREL MD APPLIED PHYSICS LAB
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| SAS-C has four segmented solar arrays, each consisting of three contiguous, spring-connected solar panels. Array deployment involves unfolding from an inverted 'N' configuration to an extended planar configuration. The deployment dynamics of this type of mechanical system are such that the possibility of damage to any one of the four solar arrays, because of undesirable deployment dynamics, is quite significant. Minimizing this possibility has been the objective of an analytical ... |
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| THE SPEECH INTERFERENCE EFFECTS OF AIRCRAFT NOISE. |
SEP 1967 |
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| Authors:
C. E. Williams; K. N. Stevens; M. H. L. Hecker; K. S. Pearsons; BOLT BERANEK AND NEWMAN INC CAMBRIDGE MASS
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| For various aircraft flyovers, speech intelligibility scores and calculations of AI (Articulation Index) were obtained as functions of time. These data were then used to establish the relation between AI and intelligibility for time-varying noise. A similar relation was also obtained for steady-state simulated jet noise. A comparison of the two relations showed that for a given AI, the time-varying noise provided less masking than the steady-state noise. The difference ... |
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