Noise Control Program for a Large Tractor Tug

1998 ◽  
Vol 35 (01) ◽  
pp. 55-64
Author(s):  
Raymond W. Fischer ◽  
Warren Snider ◽  
William L. Hurley
Keyword(s):  
Diesel Exhaust ◽  
Vibration Isolation ◽  
Noise Control ◽  
Prior Experience ◽  
Control Program ◽  
Noise Levels ◽  
Control Effort ◽  
High Noise ◽  
And Performance ◽  
Design Construction

To effectively reduce noise on small, high powered vessels such as tugboats, it is necessary to conduct a concerted noise control effort. For optimal improvement, the program must be carried through all phases of the design, construction and testing. This paper describes a program instituted by the owner and design agent early in the procurement process to control habitability noise on a large tractor tug. The owners, dedicated to maximizing crew comfort and performance while recognizing the benefits of on-deck communications, have found from prior experience that without appropriate treatments the tug would have unacceptably high noise levels. Noise goals were established and treatments were selected, both in terms of acoustic and non-acoustic impacts. Detail designs were developed for floating room treatments, genset and diesel exhaust vibration isolation, and absorptive materials. Later tests revealed that the noise goals had been met. This paper describes the program from initiation through acoustic trials, provides insights into some problem areas and makes recommendations for future designs.

A comparison of monolingual and bilingual toddlers’ word recognition in noise

2021 ◽  
pp. 136700692110286
Author(s):  
Giovanna Morini ◽  
Rochelle S. Newman
Keyword(s):  
Background Noise ◽  
Word Identification ◽  
Bilingual Children ◽  
Noise Levels ◽  
High Noise ◽  
Speech In Noise ◽  
Mixed Analysis ◽  
Correct Object ◽  
Language Exposure ◽  
And Performance

Aims and objectives: The purpose of this study was to examine whether differences in language exposure (i.e., being raised in a bilingual versus a monolingual environment) influence young children’s ability to comprehend words when speech is heard in the presence of background noise. Methodology: Forty-four children (22 monolinguals and 22 bilinguals) between the ages of 29 and 31 months completed a preferential looking task where they saw picture-pairs of familiar objects (e.g., balloon and apple) on a screen and simultaneously heard sentences instructing them to locate one of the objects (e.g., look at the apple!). Speech was heard in quiet and in the presence of competing white noise. Data and analyses: Children’s eye-movements were coded off-line to identify the proportion of time they fixated on the correct object on the screen and performance across groups was compared using a 2 × 3 mixed analysis of variance. Findings: Bilingual toddlers performed worse than monolinguals during the task. This group difference in performance was particularly clear when the listening condition contained background noise. Originality: There are clear differences in how infants and adults process speech in noise. To date, developmental work on this topic has mainly been carried out with monolingual infants. This study is one of the first to examine how background noise might influence word identification in young bilingual children who are just starting to acquire their languages. Significance: High noise levels are often reported in daycares and classrooms where bilingual children are present. Therefore, this work has important implications for learning and education practices with young bilinguals.

The physical environment

2018 ◽  
Author(s):  
Philip James
Keyword(s):  
Physical Environment ◽  
Urban Climate ◽  
Urban Environments ◽  
Artificial Light ◽  
Noise Levels ◽  
Light At Night ◽  
High Noise ◽  
P Elements ◽  
Micro Organisms ◽  
Diversity Of Life

Elements of the physical aspects of urban environments determine which micro-organisms, plants, and animals live in urban environments. In this chapter, climate, air, water, soil, noise, and light are discussed. Urban environments are affected by the climate of the region in which they are located, and in turn and create their own, distinctive urban climate. Air, water, and soil are all affected by urbanization. Pollution of these elements is common. High noise levels and artificial light at night (ALAN—a new phenomenon) are both strongly associated with urban environments. Details of both are discussed. The discussion in this chapter provides a foundation for further exploration of the diversity of life in urban environments and for later exploration of how organisms adapt to urban living, which will be discussed in Parts II and III.

Improved Vancouver Raman Algorithm Based on Empirical Mode Decomposition for Denoising Biological Samples

2019 ◽  
Vol 73 (12) ◽  
pp. 1436-1450 ◽  
Author(s):  
Fabiola León-Bejarano ◽  
Martin O. Méndez ◽  
Miguel G. Ramírez-Elías ◽  
Alfonso Alba
Keyword(s):  
Empirical Mode Decomposition ◽  
Raman Spectra ◽  
Biological Samples ◽  
Biological Material ◽  
Noise Levels ◽  
Synthetic Material ◽  
High Noise ◽  
Mode Decomposition ◽  
Mean Filter ◽  
The Mean

A novel method based on the Vancouver Raman algorithm (VRA) and empirical mode decomposition (EMD) for denoising Raman spectra of biological samples is presented. The VRA is one of the most used methods for denoising Raman spectroscopy and is composed of two main steps: signal filtering and polynomial fitting. However, the signal filtering step consists in a simple mean filter that could eliminate spectrum peaks with small intensities or merge relatively close spectrum peaks into one single peak. Thus, the result is often sensitive to the order of the mean filter, so the user must choose it carefully to obtain the expected result; this introduces subjectivity in the process. To overcome these disadvantages, we propose a new algorithm, namely the modified-VRA (mVRA) with the following improvements: (1) to replace the mean filter step by EMD as an adaptive parameter-free signal processing method; and (2) to automate the selection of polynomial degree. The denoising capabilities of VRA, EMD, and mVRA were compared in Raman spectra of artificial data based on Teflon material, synthetic material obtained from vitamin E and paracetamol, and biological material of human nails and mouse brain. The correlation coefficient (ρ) was used to compare the performance of the methods. For the artificial Raman spectra, the denoised signal obtained by mVRA ([Formula: see text]) outperforms VRA ([Formula: see text]) for moderate to high noise levels whereas mVRA outperformed EMD ([Formula: see text]) for high noise levels. On the other hand, when it comes to modeling the underlying fluorescence signal of the samples (i.e., the baseline trend), the proposed method mVRA showed consistent results ([Formula: see text]. For Raman spectra of synthetic material, good performance of the three methods ([Formula: see text] for VRA, [Formula: see text] for EMD, and [Formula: see text] for mVRA) was obtained. Finally, in the biological material, mVRA and VRA showed similar results ([Formula: see text] for VRA, [Formula: see text] for EMD, and [Formula: see text] for mVRA); however, mVRA retains valuable information corresponding to relevant Raman peaks with small amplitude. Thus, the application of EMD as a filter in the VRA method provides a good alternative for denoising biological Raman spectra, since the information of the Raman peaks is conserved and parameter tuning is not required. Simultaneously, EMD allows the baseline correction to be automated.

Energy flow and performance evaluation of inerter-based vibration isolators mounted on finite and infinite flexible foundation structures

2022 ◽  
Vol 14 (1) ◽  
pp. 168781402110704
Author(s):  
Zhuang Dong ◽  
Jian Yang ◽  
Chendi Zhu ◽  
Dimitrios Chronopoulos ◽  
Tianyun Li
Keyword(s):  
Power Flow ◽  
Vibration Isolation ◽  
Vibration Suppression ◽  
Flow Behavior ◽  
Flexible Beam ◽  
Vibration Isolators ◽  
Force Transmissibility ◽  
And Performance ◽  
Flexible Foundation ◽  
Isolation Performance

This study investigates the vibration power flow behavior and performance of inerter-based vibration isolators mounted on finite and infinite flexible beam structures. Two configurations of vibration isolators with spring, damper, and inerter as well as different rigidities of finite and infinite foundation structures are considered. Both the time-averaged power flow transmission and the force transmissibility are studied and used as indices to evaluate the isolation performance. Comparisons are made between the two proposed configurations of inerter-based isolators and the conventional spring-damper isolators to show potential performance benefits of including inerter for effective vibration isolation. It is shown that by configuring the inerter, spring, and damper in parallel in the isolator, anti-peaks are introduced in the time-averaged transmitted power and force transmissibility at specific frequencies such that the vibration transmission to the foundation can be greatly suppressed. When the inerter is connected in series with a spring-damper unit and then in-parallel with a spring, considerable improvement in vibration isolation can be achieved near the original peak frequency while maintaining good high-frequency isolation performance. The study provides better understanding of the effects of adding inerters to vibration isolators mounted on a flexible foundation, and benefits enhanced designs of inerter-based vibration suppression systems.

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