Evaluation Of The Temperature Equivalent Of Measured Sound Levels

Description

DEDICATION

This project is dedicated to Almighty God for his protection, kindness, strength over my life throughout the period and also to my — for his financial support and moral care towards me. Also to my mentor — for her academic advice she often gives to me. May Almighty God shield them from the peril of this world and bless their entire endeavour Amen.

ACKNOWLEDGEMENT

The successful completion of this project work could not have been a reality without the encouragement of my — and other people. My immensely appreciation goes to my humble and able supervisor Mr. — for his kindness in supervising this project. My warmest gratitude goes to my parents for their moral, spiritual and financial support throughout my study in this institution.
My appreciation goes to some of my lecturers among whom are Mr. —, and Dr. —. I also recognize the support of some of the staff of — among whom are: The General Manager, Deputy General manager, the internal Auditor Mr. — and the —. Finally, my appreciation goes to my elder sister —, my lovely friends mercy —, —, — and many others who were quite helpful.

ABSTRACT

This study was carried out to evaluate the temperature equivalent of measured sound levels. In this study we consider road noise measurements using Statistical Pass-By method (SPB) in assessing this noise pollution problem. For passenger cars, a temperature coefficient of −0.103 dB/◦C was obtained while no statistically significant proof was found that temperature influences the sound-pressure levels for heavy vehicles at the speeds in this study (45–65 km/h). In this speed range for heavy vehicles, not only the tyre/road noise is a significant source of pass-by vehicle noise but also the power unit noise, on which the temperature influence is more complicated. Additionally, the analysis of various temperatures (air, road and estimated tyre temperature) revealed that the air temperature appears to be best suited for the temperature correction procedure. In third-octave bands, no effect was observed in the low-frequency range for passenger cars, contradicting previous research. Negative correction coefficients were found in the middle and high-frequency range, although trends presented in other studies were not observed.

TABLE OF CONTENTS

COVER PAGE

TITLE PAGE

APPROVAL PAGE

DEDICATION

ACKNOWLEDGEMENT

ABSTRACT

CHAPTER ONE

INTRODUCTION

1.1      Background of the project

• Problem statement
• Aim and objectives of the project
• Research question
• Research hypothesis
• Significance of the study
• Scope of the study

CHAPTER TWO

LITERATURE REVIEW

• Sound level meter
• Classification sound level meter
• The Effect of Noise
• review of related studies

CHAPTER THREE

3.1      Materials and Methods

CHAPTER FOUR

• Result and discussion

CHAPTER FIVE

• Conclusion

References

 

CHAPTER ONE

1.0                                                      INTRODUCTION

1.1                                       BACKGROUND OF THE STUDY

One form of pollution is the noise and it is effect on the life ” air, soil and water”. Its effects are directly on the human. This kind of pollution is due to the urban life and depends on industry which increase the population (Gerges, 2012).

So the noise pollution is harmful to human, therefor it’s important to reduce the exposure to noise in order to protect the human health.

The negative effects of this kind of pollution is very dangerous on the ear health and the psychological (Manwani et.al., 2010).

The noise pollution as an environmental problem importance of recognize the ill effects on human health in addition to the environment in each day.

Noise can come from many places: Industrial Sources, Transport Vehicles, Household, Agricultural Machines, and Equipment.

Industrial devices which generate noise “air turbulence and vortices”, especially at high velocities of air. Due to the moving or rotating solid object, so turbulence can be generated such as “the blade tip of a ventilator fan”, which is cause changing in pressure between the fluid and atmospheric pressure, such as introducing an obstacle into a high speed of fluid flow or by cleaning air jet (Fredel, 2010).

Noise produced from electrical equipment such as “motors and generators” is generally low frequency, imposed on a broadband cooling system noise. Electrical motors convert electrical energy to magnetic energy then to the mechanical energy with the useful torque output of the motor shaft. Part of the transformation energy is converted to heat energy, that is cause a rise in rotors, then casing temperature; therefore an electric motor should be supplied with a cooling system (Pfeiffer, 2017).

Inefficient maintenance air conditioner can generate loud noise. Industrial and commercial air conditioner can be noisy due to their location and size, near the residential buildings. These loud noise which exceeds the allowable noise levels are produced from the air conditioners and other types of devices.

Each day thousands vehicles move through streets. The noise coming from vehicles, including motorcycles, produce excessive sounds.

Noise features one of the major environmental risks to human health, with road traffic noise being the most common source of community noise in urban areas (Havard et al., 2011). The systematic reviews that endorsed the update of World Health Organization’s (WHO) Environmental Noise Guidelines in 2018 (WHO, 2018) point out moderate- to high-quality evidence of correlations between exposure to environmental noise and several health complications. Road traffic noise specifically is linked to the incidence of ischemic heart diseases (Kempen et al., 2018), cortical awakenings and self-reported sleep disturbance (Basner et al., 2018) and emotional and conduct disorders in children (Clark et al., 2018), among others. Besides human well-being, traffic noise also affects wildlife (Parris et al., 2019). The continuing urbanisation and growing population, especially in densely built-up areas, increase exposure to road traffic noise. Even though measures as a modal shift to railway, pedestrian and bike traffic have been supported, the EU Reference Scenario 2016 predicts for the time horizon of 2050 that road transport is expected to maintain its dominant role, especially for passenger transport (Capros et al., 2016).

In order to mitigate the impacts entailed by road-traffic-noise exposure, there must first be a solid base for assessing road traffic noise. Various standards and regulations are already in place for this purpose.

It is generally accepted that road traffic noise decreases with increasing temperature in the case of asphalt pavements, with A-weighted noise levels dropping by up to 1 dB each 10 ◦C increase in air temperature for dense asphalts (Bühlmann et al., 2011). Additionally, this effect is larger for passenger cars compared to trucks (Sandberg et al., 2013). Even though there are already standardised procedures for temperature correction, the extent to which temperature affects the measured noise levels is still unclear, especially for SPB. As road traffic noise results from multiple noise-generating mechanisms, the effect of single parameters, such as temperature, is complex to assess. The generation mechanisms are generally categorised under power-unit noise, aerodynamic noise, and tyre/road noise [Rasmussen et al., 2017]. Power-unit noise is the mechanical and combustion noise associated with vehicle propulsion; aerodynamic noise results from the turbulent airflow around the body (at higher speeds). Lastly, the tyre/road noise is generated by the interaction between the tyre and the road at the pavement surface. Tyre/road noise itself is a convoluted combination of various generation and amplification mechanisms that result in noise in different, and often overlapping, frequency ranges (Ling et al., 2021).

Temperature affects the different components of tyre/road noise to various extents. Still, this influence is mostly attributed to the softening of the tyre rubber with increasing temperatures, increasing the damping of vibrations that would otherwise result in noise (Ling et al., 2021). While the temperature increase decreases the stiffness of the pavement, its effect on noise reductions is only noticeable if the tyre and pavement stiffness are in the same order of magnitude (pavement stiffness/tyre stiffness < 10). For conventional hot asphalt mixtures and in the typical temperature range achieved in the field, high temperatures cannot reduce the pavement stiffness to values comparable to the stiffness of a rubber tyre. This effect only becomes prominent if alternative materials, such as crumb rubber substituting mineral aggregate, are used to increase the asphalt elasticity (Bendtsen et al., 2010). Road noise is assumed to be dominant at speeds above 45 km/h and the effect of temperature on power unit noise and aerodynamic noise is negligible. The influence of temperature on the noise propagation towards the environment within the scope of ISO also appears to be insignificant.

As temperature influences emitted road-traffic noise, there is a common need for temperature correction among regulations and standardised methods in order to achieve accurate assessment tools.

In this study, analyses have all been performed for three different temperatures (air, road and estimated tyre temperature), as the literature points out the importance of the physical media in assessing temperature coefficients.

 

1.2                                               PROBLEM STATEMENT

Sound is a mechanical wave, which means that it needs support to propagate (air), unlike electromagnetic waves that can propagate in a vacuum. It also means that sound is subject to changes in air condition. Several factors influence sound propagation, including wind and temperature gradients. This study was carried out to make a clear understanding on how Temperature gradients influence the propagation of sound waves over long distances.

1.3                                AIM AND OBJECTIVES OF THE STUDY

The main aim of this study is to evaluate the temperature equivalent of measured sound levels. The objectives are:

1. To study how temperature affect sound levels
2. To assess noise pollution problem

• To determine how temperature influences the sound-pressure levels for vehicles

1.4                                                RESEARCH QUESTION

1. Does temperature affect sound level?
2. What happens to sound when temperature increases?

iii. How does temperature inversion affect sound?

1. What is the relationship of temperature to the sound?
2. How does temperature affect sound formula? 

1.5                                             RESEARCH HYPOTHESIS

Ho: there is a significant relationship between temperature and sound level

Hi: there is no significant relationship between temperature and sound level

1.6                                       SIGNIFICANCE OF THE STUDY

This study will serve as a means of enlightening the reader on how temperature affects noise level. It will also throw light on how temperature can be measure as well as instruments used in measuring sound levels

1.7                                                SCOPE OF THE STUDY

The scope of this study covers the assessment of temperature effect on noise levels of vehicles. For heavy vehicles, not only the tyre/road noise is a significant source of pass-by vehicle noise but also the power unit noise, on which the temperature influence is more complicated. Additionally, the analysis of various temperatures (air, road and estimated tyre temperature) revealed that the air temperature appears to be best suited for the temperature correction procedure. In third-octave bands, no effect was observed in the low-frequency range for passenger cars, contradicting previous research. Negative correction coefficients were found in the middle and high-frequency range, although trends presented in other studies were not observed.

PROJECT DESCRIPTION

Format = Microsoft word

Chapters = 1-5 chapters

Price: N3,000.

 

For more information contact us through any of the following means:

Mobile No: +2348146561114 or +2347015391124

Email address: engr4project@gmail.com

Whatsapp No: +2348146561114