Gazex avalanche control system noise and vibration assessment

2021 ◽  
Vol 263 (6) ◽  
pp. 407-417
Author(s):  
Paul Bollard
Keyword(s):  
Control System ◽  
Monitoring Program ◽  
Primary Objective ◽  
Survey Period ◽  
Noise And Vibration ◽  
Residential Community ◽  
Vibration Data ◽  
Potential Damage ◽  
Human Hearing ◽  
Avalanche Control

Bollard Acoustical Consultants, Inc. was retained by the Placer County Planning Dept. to quantify noise and vibration levels resulting from the Gazex avalanche control system usage during the winter of 2018-2019. The primary objective of the monitoring program was to obtain a statistically representative sample of noise and vibration data during Gazex usage for comparison against criteria for potential damage to structures and human hearing. During the survey period, 75 discrete discharges of Gazex cannons occurred. Each discharge was monitored at five fixed monitoring sites in the Alpine Meadows residential community. At the completion of the survey, 1,079 of the possible 1,125 possible data points of interest had successfully been captured. The results of the surveys indicated that, although noise and vibration levels generated by the Gazex system were elevated to the point of being considered highly annoying to local residents, criteria for damage to hearing and structures were not exceeded during the survey period.

Commercialization of Active Isolation for Jet Aircraft

1997 ◽  
Author(s):  
Steve C. Southward ◽  
Douglas E. Ivers ◽  
Geoff C. Nicholson
Keyword(s):  
Control System ◽  
Vibration Control ◽  
Acoustic Noise ◽  
Development Program ◽  
Flight Test ◽  
Test Time ◽  
Vibration Source ◽  
Noise And Vibration ◽  
Transmission Path ◽  
Active Isolation

Abstract Active Noise and Vibration Control (ANVC) technology is a proven solution for noise and vibration problems in aircraft. The challenges in commercializing this solution range from the development issues of choosing the best actuation, sensor, and control technology to obtaining sufficient flight test time and satisfying FAA requirements. This paper examines significant case histories in the progression of the Lord active vibration control program from conception to market. Throughout the development program, several important discoveries were made regarding the performance, reliability, and economics of Active Isolation Systems (AIS) in jet aircraft. First, practical speaker-based solutions cannot achieve global acoustic noise cancellation for engine tones above about 200 Hz. A comparatively small array of structural actuators placed in the dominant transmission path, such as in or near the engine mounts, are capable of global cancellation in the cabin up to at least 500 Hz. Second, the performance is generally better when cabin microphones are used as error sensor inputs because the AIS control system can compensate for flanking paths better than if accelerometers are used as error sensors. Third, when the actuators are placed in the dominant transmission path and close to the vibration source, the control system will simultaneously achieve global acoustic noise reduction in the cabin and vibration reduction in the aircraft structure without affecting the engine casing vibration levels.

Evaluation of weigh-in-motion in Manitoba

1999 ◽  
Vol 26 (5) ◽  
pp. 655-666 ◽  
Author(s):  
Xun Zhi ◽  
Ahmed Shalaby ◽  
Dan Middleton ◽  
Alan Clayton
Keyword(s):  
Primary Objective ◽  
Vehicle Classification ◽  
Design Management ◽  
Western Canada ◽  
Data Sets ◽  
Survey Period ◽  
Weigh In Motion ◽  
Large Numbers ◽  
Traffic Volumes ◽  
American Society

The primary objective of a weigh-in-motion (WIM) system is to provide highway designers and agencies with information on the loads and traffic volumes using a particular highway, thereby facilitating improved pavement design, management, and weight enforcement. In this paper, the historic performance of WIM systems in Manitoba is evaluated. The results indicate that large numbers of unreasonable data are produced from the WIM systems, calibration procedures are not standardized, and there is drift in calibration. The performance of the Brokenhead WIM system was evaluated through a detailed survey conducted at the Brokenhead WIM site and the Westhawk Permanent Truck Weigh Station in August 1997. The Brokenhead site is on the Trans-Canada highway east of Winnipeg. It is the only WIM system in the country that measures truck characteristics and movements between eastern and western Canada. The survey produced a large database permitting the comparison of truck dimension measurements, truck weights, and vehicle classification between those produced by the WIM system and those observed manually. The results indicate that WIM axle-spacing data sets were outside the tolerance for 95% conformity specified by the American Society for Testing and Materials (ASTM). The system classified 5 to 9 axle combination trucks more accurately than some 2- and 3-axle vehicles. The WIM system underestimated about 90% of truck weights in the survey period. The degree of underestimation exceeded 50% of the corresponding static weights. This finding highlights the importance of quality control and corrections on WIM data prior to their use in research or engineering practice.Key words: weigh-in-motion, vehicle classification, calibration, axle spacing, axle load.

scholarly journals Extended High-Frequency Thresholds in College Students: Effects of Music Player Use and Other Recreational Noise

2013 ◽  
Vol 24 (08) ◽  
pp. 725-739 ◽  
Author(s):  
Colleen G. Le Prell ◽  
Christopher Spankovich ◽  
Edward Lobariñas ◽  
Scott K. Griffiths
Keyword(s):  
College Students ◽  
High Frequency ◽  
Noise Exposure ◽  
Population Level ◽  
Primary Objective ◽  
Repeated Testing ◽  
Listening Levels ◽  
Threshold Testing ◽  
Human Hearing ◽  
Music Player

Background: Human hearing is sensitive to sounds from as low as 20 Hz to as high as 20,000 Hz in normal ears. However, clinical tests of human hearing rarely include extended high-frequency (EHF) threshold assessments, at frequencies extending beyond 8000 Hz. EHF thresholds have been suggested for use monitoring the earliest effects of noise on the inner ear, although the clinical usefulness of EHF threshold testing is not well established for this purpose. Purpose: The primary objective of this study was to determine if EHF thresholds in healthy, young adult college students vary as a function of recreational noise exposure. Research Design: A retrospective analysis of a laboratory database was conducted; all participants with both EHF threshold testing and noise history data were included. The potential for “preclinical” EHF deficits was assessed based on the measured thresholds, with the noise surveys used to estimate recreational noise exposure. Study Sample: EHF thresholds measured during participation in other ongoing studies were available from 87 participants (34 male and 53 female); all participants had hearing within normal clinical limits (≤25 HL) at conventional frequencies (0.25–8 kHz). Results: EHF thresholds closely matched standard reference thresholds [ANSI S3.6 (1996) Annex C]. There were statistically reliable threshold differences in participants who used music players, with 3–6 dB worse thresholds at the highest test frequencies (10–16 kHz) in participants who reported long-term use of music player devices (>5 yr), or higher listening levels during music player use. Conclusions: It should be possible to detect small changes in high-frequency hearing for patients or participants who undergo repeated testing at periodic intervals. However, the increased population-level variability in thresholds at the highest frequencies will make it difficult to identify the presence of small but potentially important deficits in otherwise normal-hearing individuals who do not have previously established baseline data.

Runoff and infiltration characteristics of pavement structures—review of an extensive monitoring program

2007 ◽  
Vol 56 (10) ◽  
pp. 133-140 ◽  
Author(s):  
M. Illgen ◽  
K. Harting ◽  
T.G. Schmitt ◽  
A. Welker
Keyword(s):  
Boundary Conditions ◽  
Surface Runoff ◽  
Stormwater Runoff ◽  
Monitoring Program ◽  
Primary Objective ◽  
Urban Drainage ◽  
Surface Slope ◽  
Intensive Monitoring ◽  
Various Boundary Conditions ◽  
Pavement Structures

The stormwater runoff and infiltration performance of permeable pavements has been systematically evaluated within an intensive monitoring program. The primary objective of the investigation was to generate a broad database, which enables the development of an advanced simulation module for urban drainage modelling. Over 160 field and lab scale experiments have been completed and analyzed for surface runoff and infiltration characteristics. The test series include several pavement types under various boundary conditions such as diverse precipitation impacts, varying surface slope and layer construction as well as different stages of surface clogging and several base and subgrade layer characteristics. The results represent a reliable and comprehensive database that allows profound conclusions and substantial recommendations.

Anticipative monitoring to improve chemotherapy induced nausea.

2017 ◽  
Vol 35 (15_suppl) ◽  
pp. 10120-10120
Author(s):  
Reza Elaidi ◽  
Stephane Oudard ◽  
Hail Aboudagga ◽  
Constance Thibault ◽  
Lorraine Waechter ◽  
...  
Keyword(s):  
Monitoring Program ◽  
Primary Objective ◽  
P Values ◽  
Anti Cancer ◽  
Patient Waiting Time ◽  
Secondary Objective ◽  
Grade 3 ◽  
Improving Patient Care ◽  
Positive Results

10120 Background: The PROCHE [Programme for optimisation of the chemotherapy network] initiative is an innovative oncology-monitoring program designed to reduce patient waiting time and chemotherapy wastage, ultimately improving patient care. Methods: Primary objective was to evaluate the incidence of nausea reported by grade (NCI-CTC AE: from 0 to 4) from 2008 to 2016. Association was quantified using Mantel-Haenszel khi2 and exact p-values. Secondary objective compared the 2009-2016 patients with the control patients of 2008 period. Results: Between Oct 2008 and Oct 2016, 3012 patients participated in the program, representing 36 803 questionnaires completed over the whole period. Nausea was, clinically and statistically, significantly improved during the whole follow-up period with a decrease of grade 3-4 from 0.6% to 0.08% and a decrease of grade 1-2 from 29.3% to 8.2%. The already adapted nausea management in 2008 with 70% of questionnaires reported no nausea improved to 92% in 2016, with a 10% improvement the year after program initiation. As MASCC propose to change guidelines with an improvement above 10%, such an organization may impact new recommendations. Conclusions: Anticipating anti-cancer treatment adaptation and prevention, following guidelines and using adapted antiemetics, explain these positive results. The PROCHE initiative improves chemotherapy induced nausea. [Table: see text]

ANALYSIS OF THE FACTORS DECREASING THE EFFICIENCY OF OPERATION OF ACTIVE NOISE AND VIBRATION CONTROL SYSTEMS IN DUCTS AND THE WAYS OF IMPROVEMENT OF PROTECTION

Akustika ◽  
2021 ◽  
pp. 205-209
Author(s):  
Andrey Vasilyev
Keyword(s):  
Control System ◽  
Vibration Control ◽  
Control Systems ◽  
Active Noise Control ◽  
Medium Temperature ◽  
Noise And Vibration ◽  
Active Systems ◽  
System Protection ◽  
Active Noise ◽  
Operating Medium

The factors influencing on the active noise and vibration control system efficiency of operation and the ways of the system protection improvement are discussed. Analysis of factors decreasing the efficiency of operation of active noise and vibration control systems in ducts is showing that there are such factors as physical characteristics of operating medium (temperature, pressure, moisture, vibrations, dust), masking acoustic and vibrating interferences of other sources of noise and vibration etc., which may significantly reduce the efficiency, reliability and durability of active systems operation. The ways of improvement of protection of the elements of the active noise and vibration control system are discussed. Further improvement of active noise control and vibration system elements protection allows the system to operate with higher efficiency and reliability. Widely, achieving of good results in the solution of this problem helps us to extend the possibilities of active noise and vibration control systems practical application.

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