scholarly journals Comparison of Cabin Noise of Airport Express Rail Systems

Acoustics ◽  
2021 ◽  
Vol 4 (1) ◽  
pp. 1-13
Author(s):  
Heow Pueh Lee ◽  
Sanjay Kumar ◽  
Saurabh Garg ◽  
Kian Meng Lim
Keyword(s):  
Low Frequency ◽  
The Other ◽  
Maximum Speed ◽  
Frequency Noise ◽  
Charles De Gaulle ◽  
Cabin Noise ◽  
Rail Systems ◽  
Railway System ◽  
The Difference ◽  
De Gaulle

In this paper, the cabin noise of four airport express rail systems, namely the Taiwan Taoyuan International Airport MRT, the Hong Kong Airport Express, RER B service from Paris Gare du Nord to Paris Charles de Gaulle Airport, and the Shanghai Maglev, have been measured. These four airport express rail systems have different specifications and maximum speeds, ranging from 100 to 300 km/h. The results show a significant low-frequency noise content below 100 Hz, which would not be captured if the measurements were conducted in dB(A). The difference between Leq in terms of dB(C) and dB(A) ranges from 11.3 to 17.0 dB. The maximum speed of the Taoyuan Airport MRT was found to be the lowest at 100 km/h and with the lowest Leq in terms of 66.4 dB(A) and 81.4 dB(C). The Shanghai Maglev has a maximum speed of 300 km/h but a relatively low Leq of 69.7 dB(A), although its top speed is almost three times the maximum of the other airport rail systems. It also has the lowest Lmax of 73.1 dB(A) among the four rail systems. Moreover, the Paris RER B railway system, with its top speed of 120 km/h, was measured to have the highest Leq and Lmax values of 72.8 dB(A) and 83.8 dB(A), respectively.

Reply to the Commentaries

2012 ◽  
Vol 14 (1) ◽  
pp. 93-95
Author(s):  
Christian Nuenlist ◽  
Anna Locher ◽  
Garret Martin
Keyword(s):  
Foreign Policy ◽  
Cold War ◽  
The Other ◽  
Charles De Gaulle ◽  
International Perspectives ◽  
Political Interests ◽  
Foreign Policies ◽  
French Foreign Policy ◽  
The Cold War ◽  
De Gaulle

Four distinguished analysts of French foreign policy under Charles de Gaulle provide in-depth assessments of the new book edited by Christian Nuenlist, Anna Locher, and Garret Martin, Globalizing de Gaulle: International Perspectives on French Foreign Policies, 1958–1969, published by Lexington Books. The commentators praise the book's wide scope and many of its essays and broad themes, but they raise questions about Garret Martin's contention (shared by a few, though not all, of the other contributors to the volume) that de Gaulle had a coherent if ultimately unsuccessful strategy to overcome the Cold War and move toward the unification of Germany and Europe. In article-length commentaries, both Andrew Moravcsik and Marc Trachtenberg take issue with Martin's view, arguing that de Gaulle's foreign policy involved more bluff and bluster than any genuine attempt to bring about the reunification of Germany or to end the Cold War. Moravcsik also provides a spirited defense of the “revisionist” conception of de Gaulle's policy toward Europe, which sees the general as having been guided mostly by his domestic economic and political interests—a conception that Trachtenberg has also come to accept. The forum ends with a reply by Nuenlist, Locher, and Martin to the four commentaries.

Charles de Gaulle and Europe: The New Revisionism

2012 ◽  
Vol 14 (1) ◽  
pp. 53-77 ◽  
Author(s):  
Andrew Moravcsik
Keyword(s):  
Foreign Policy ◽  
Cold War ◽  
The Other ◽  
Charles De Gaulle ◽  
International Perspectives ◽  
Political Interests ◽  
Foreign Policies ◽  
French Foreign Policy ◽  
The Cold War ◽  
De Gaulle

Four distinguished analysts of French foreign policy under Charles de Gaulle provide in-depth assessments of the new book edited by Christian Nuenlist, Anna Locher, and Garret Martin, Globalizing de Gaulle: International Perspectives on French Foreign Policies, 1958–1969, published by Lexington Books. The commentators praise the book's wide scope and many of its essays and broad themes, but they raise questions about Garret Martin's contention (shared by a few, though not all, of the other contributors to the volume) that de Gaulle had a coherent if ultimately unsuccessful strategy to overcome the Cold War and move toward the unification of Germany and Europe. In article-length commentaries, both Andrew Moravcsik and Marc Trachtenberg take issue with Martin's view, arguing that de Gaulle's foreign policy involved more bluff and bluster than any genuine attempt to bring about the reunification of Germany or to end the Cold War. Moravcsik also provides a spirited defense of the “revisionist” conception of de Gaulle's policy toward Europe, which sees the general as having been guided mostly by his domestic economic and political interests—a conception that Trachtenberg has also come to accept. The forum ends with a reply by Nuenlist, Locher, and Martin to the four commentaries.

The Effect of Fluctuations on the Perception of Low Frequency Sound

2007 ◽  
Vol 26 (2) ◽  
pp. 81-89 ◽  
Author(s):  
A T Moorhouse ◽  
D C Waddington ◽  
M D Adams
Keyword(s):  
Laboratory Tests ◽  
Sound Pressure ◽  
Hearing Threshold ◽  
Low Frequency ◽  
Fast Response ◽  
Pressure Level ◽  
Rate Of Change ◽  
Frequency Noise ◽  
The Difference ◽  
Method Of Adjustment

Results of laboratory tests are presented in which 18 subjects, including some low frequency noise sufferers, were presented with low frequency sounds with varying degrees of fluctuation. Thresholds of acceptability were obtained for each sound and each subject, using the method of adjustment. These thresholds were then normalised to individual low frequency hearing threshold. It was found that sufferers tend to set thresholds of acceptability closer to their hearing threshold than other subject groups. Also, acceptability thresholds were set on average 5dB lower for fluctuating sounds. It is proposed that a sound should be considered fluctuating when the difference between L10 and L90 exceeds 5dB, and when the rate of change of the ‘Fast’ response sound pressure level exceeds 10dB/s

The de Gaulle Problem

2012 ◽  
Vol 14 (1) ◽  
pp. 81-92 ◽  
Author(s):  
Marc Trachtenberg
Keyword(s):  
Foreign Policy ◽  
Cold War ◽  
The Other ◽  
Charles De Gaulle ◽  
International Perspectives ◽  
Political Interests ◽  
Foreign Policies ◽  
French Foreign Policy ◽  
The Cold War ◽  
De Gaulle

Four distinguished analysts of French foreign policy under Charles de Gaulle provide in-depth assessments of the new book edited by Christian Nuenlist, Anna Locher, and Garret Martin, Globalizing de Gaulle: International Perspectives on French Foreign Policies, 1958–1969, published by Lexington Books. The commentators praise the book's wide scope and many of its essays and broad themes, but they raise questions about Garret Martin's contention (shared by a few, though not all, of the other contributors to the volume) that de Gaulle had a coherent if ultimately unsuccessful strategy to overcome the Cold War and move toward the unification of Germany and Europe. In article-length commentaries, both Andrew Moravcsik and Marc Trachtenberg take issue with Martin's view, arguing that de Gaulle's foreign policy involved more bluff and bluster than any genuine attempt to bring about the reunification of Germany or to end the Cold War. Moravcsik also provides a spirited defense of the “revisionist” conception of de Gaulle's policy toward Europe, which sees the general as having been guided mostly by his domestic economic and political interests—a conception that Trachtenberg has also come to accept. The forum ends with a reply by Nuenlist, Locher, and Martin to the four commentaries.

New technique for detection of changes in QRS morphology of ECG signals

1983 ◽  
Vol 244 (4) ◽  
pp. H560-H566
Author(s):  
S. L. Blumlein ◽  
G. Harvey ◽  
V. K. Murthy ◽  
L. J. Haywood
Keyword(s):  
Low Frequency ◽  
New Technique ◽  
Frequency Noise ◽  
Third Order ◽  
Ecg Signals ◽  
Qrs Morphology ◽  
Ectopic Beats ◽  
The Difference ◽  
A New Technique ◽  
Electrocardiogram Ecg

With the use of the electrocardiogram (ECG) as a prototype signal, a new technique was devised for detecting signals embedded in noise. Averaged "normal" digitized ECG signals formed a template to which subsequent ECG QRS complexes were compared. The difference between the averaged template signals and subsequent normal beats was white noise, whereas the difference between the template and ectopic beats consisted of nonrandom signal variation. The template to new signal comparison for the zero-, first-, second-, and third-order differences utilized an approximate F test. Accurate detection of abnormal signals associated with high- and low-frequency noise is accomplished with this method, and the practical clinical utility of the method is under study.

scholarly journals Low-Frequency Noise Reduction by Earmuffs with Flax Fibre-Reinforced Polypropylene Ear Cups

2018 ◽  
Vol 2018 ◽  
pp. 1-10
Author(s):  
Linus Yinn Leng Ang ◽  
Le Quan Ngoc Tran ◽  
Steve Phillips ◽  
Yong Khiang Koh ◽  
Heow Pueh Lee
Keyword(s):  
Noise Reduction ◽  
Material Selection ◽  
Low Frequency ◽  
Acrylonitrile Butadiene Styrene ◽  
Flax Fibre ◽  
Frequency Noise ◽  
Low Frequency Noise ◽  
Construction Sites ◽  
Military Vehicles ◽  
Cabin Noise

Soldiers and supporting engineers are frequently exposed to high low-frequency (<500 Hz) cabin noise in military vehicles. Despite the use of commercial hearing protection devices, the risk of auditory damage is still imminent because the devices may not be optimally customised for such applications. This study considers flax fibre-reinforced polypropylene (Flax-PP) as an alternative to the material selection for the ear cups of commercial earmuffs, which are typically made of acrylonitrile butadiene styrene (ABS). Different weaving configurations (woven and nonwoven) and various noise environments (pink noise, cabin booming noise, and firing noise) were considered to investigate the feasibility of the proposed composite earmuffs for low-frequency noise reduction. The remaining assembly components of the earmuff were kept consistent with those of a commercial earmuff, which served as a benchmark for results comparison. In contrast to the commercial earmuff, the composite earmuffs were shown to be better in mitigating low-frequency noise by up to 16.6 dB, while compromising midfrequency acoustical performance. Consequently, the proposed composite earmuffs may be an alternative for low-frequency noise reduction in vehicle cabins, at airports, and at construction sites involving heavy machineries.

The Mechanisms of Passive Ear Defenders

2002 ◽  
Vol 33 (5) ◽  
pp. 13-21 ◽  
Author(s):  
M. R. Paurobally ◽  
J. Pan
Keyword(s):  
Sound Absorption ◽  
Theoretical Study ◽  
Active Noise Control ◽  
Low Frequency ◽  
The Other ◽  
Frequency Noise ◽  
Transmission Characteristics ◽  
Active Noise ◽  
Theoretical Predictions

In this paper a model of the sound transmission characteristics of a conventional circumaural passive ear protector is presented for low frequency noise. It includes the effects of porous sound absorption material within the device as well as sound leakage. A theoretical study based on the model shows that the presence of sound absorption material effectively acts to increase the volume compliance of the system, thus decreasing its resonance frequency. The role of leakage on the other hand is mainly to shift the resonance to a higher frequency depending on the equivalent leakage diameter. Experimental results are provided in support of the theoretical predictions. The model is useful in providing an understanding of the mechanisms of conventional passive ear defenders and can be employed to guide their design. The modelling can also be extended to study and aid in the development of communication and active noise control ear protectors.

Elastic modulus and stress relationships in stretched and shortened frog sartorii

1976 ◽  
Vol 230 (1) ◽  
pp. 205-210 ◽  
Author(s):  
W Halpern ◽  
RL Moss
Keyword(s):  
Elastic Modulus ◽  
Sarcomere Length ◽  
Rana Pipiens ◽  
Low Frequency ◽  
The Other ◽  
Dynamic Elastic Modulus ◽  
Structural Rearrangements ◽  
Active Stress ◽  
Longitudinal Dynamic ◽  
The Difference

The longitudinal dynamic elastic modulus (delta stress/delta strain) of 11 sartorius muscles (Rana pipiens; 3 degrees C) was measured at static strains, 0.57 less than L/Lo less than 1.53. Pseudorandom white-noise displacements less than +/-0.031% Lo (mean, peak to peak) were imposed on tetanically stimulated and resting muscles to obtain the isometric moduli. The active elastic modulus at each length was determined as the difference between the low-frequency (15-80 Hz) asymptotes of the tetanic and resting modulus functions. Resting moduli were found to increase with stretch at a declining rate, suggesting that some resting elasticity is attributable to active crossbridges. For isometric, tetanically stimulated muscles above L/Lo = 1.0, the ratio dynamic elastic modulus/active stress was nearly constant (65.4); the data predict zero modulus at a stretched length corresponding to zero active stress. Hence, the modulus per crossbridge exhibits sarcomere length invariance. On the other hand, active muscles below L/Lo = 0.77 manifest a significant (P less than or equal to 0.05) additional modulus beyond that found at the same active stress in the stretched muscle. Sarcomeric structural rearrangements are suggested as a possible source of this additional modulus.

A Criterion for Predicting the Annoyance Due to Lower Level Low Frequency Noise

1983 ◽  
Vol 2 (4) ◽  
pp. 160-168 ◽  
Author(s):  
N. Broner ◽  
H.G. Leventhall
Keyword(s):  
Sound Pressure Level ◽  
Sound Pressure ◽  
Low Frequency ◽  
Threshold Effect ◽  
Pressure Level ◽  
The Other ◽  
Frequency Noise ◽  
Low Frequency Noise ◽  
Estimation Task ◽  
Noise Annoyance

In a study of the annoyance due to low frequency noise, 75 subjects (consisting of 21 complainants and 54 controls) carried out a magnitude estimation task and rated the annoyance due to lower-level low frequency noise (55dB–75dB). After allowing for a threshold effect, it was found that the E-weighted sound pressure level was, in general, the best predictor of lower-level low frequency noise annoyance. However, it was not a significantly better predictor than any of the other nine noise measures considered. The widely available dB(A) noise measure was therefore suggested as a useful predictor of group annoyance due to lower-level low frequency noise.

scholarly journals Acoustic Metamaterials: A Potential for Cabin Noise Control in Automobiles and Armored Vehicles

2016 ◽  
Vol 08 (05) ◽  
pp. 1650072 ◽  
Author(s):  
Linus Yinn Leng Ang ◽  
Yong Khiang Koh ◽  
Heow Pueh Lee
Keyword(s):  
Noise Control ◽  
Fuel Efficiency ◽  
Low Frequency ◽  
Acoustic Mode ◽  
Frequency Noise ◽  
Acoustic Metamaterials ◽  
Structural Modifications ◽  
Cabin Noise ◽  
Automobile Design ◽  
Armored Vehicles

The aim of this paper is to provide an overview of the existing industrial practices used for cabin noise control in various industries such as automotive, marine, aerospace, and defense. However, emphasis is placed on automobiles and armored vehicles. Generally, automobile cabins usually constitute of thin structural panels, where the fundamental frequency typically falls below 200[Formula: see text]Hz. If a specific structural mode couples with a specific acoustic mode of the cabin, booming noise occurs. As such, discomfort may be felt by the occupants. Fundamentally, vibroacoustics problems may be minimized if the acoustic modes and the structural modes are decoupled, which is achieved usually by structural modifications or acoustical treatments. However, if excessively performed, the weight limitation of an automobile design will be exceeded; not to mention the adverse effect of increased weight on several factors such as fuel efficiency, mileage life of tires and acceleration of the vehicle. Moreover, current solutions have several drawbacks in low frequency noise control. In light of this, it is of great interest to explore the feasibility of acoustic metamaterials as an alternative with hope to improve cabin noise.

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