Typical noise levels at different places, effects of noise and noise control method
WHO has prescribed the safe noise level for a city as 45 dB In United States the noise level of 65 dB at day time and 55 dB at night time in streets is prescribed. Anyone crossing the limit is regarded as causing noise pollution.Environment Department has been established under the Ministry of Science, Technology and Environment for monitoring the environmental condition. The noise greater than 60 dB is conceived as the hazard for man and when it reaches more than 80 dB, it may cause losses in hearing capac
Summary
WHO has prescribed the safe noise level for a city as 45 dB In United States the noise level of 65 dB at day time and 55 dB at night time in streets is prescribed. Anyone crossing the limit is regarded as causing noise pollution.Environment Department has been established under the Ministry of Science, Technology and Environment for monitoring the environmental condition. The noise greater than 60 dB is conceived as the hazard for man and when it reaches more than 80 dB, it may cause losses in hearing capac
Things to Remember
Effects of human
- Hearing impairment
- Speech interference
- Lack of concentration
- Decrease in efficiency
- Fatigue
- Sleep disturbances
- Annoyance
- Negative social behavior
- Cardiovascular disturbances
- Temporary or Permanent deafness
- Disturbances in mental Health
- High blood pressure
- Heart attack
- Cancer
- Asthma
- Coughing, wheezing
- Deafness
- Annoyance
- Stress
- Insomnia
- Arteriosus clerisie
Effects on animals
- Altering prey/predator detection
- Reduction of useable habitat
- Death of certain species
- Creates problems in navigation
- They become dangerous and attacking
- Raise metabolism
- Hormone imbalance
- Genetic and evolutionary problems
- Abandonment of offsprin
Effects on environment
- Break of earth barrier
- Poor production of crops
- Damaged in buildings, bridges, and monuments
- Weakens the edifice of building
The techniques employed for noise control can be classified as
- Control at source
- Control in the transmission path
- Using protective equipment.
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Subjective Questions
Q1:
Write short notes on urinary bladder.
Type: Short Difficulty: Easy
<p>The urinary bladder is a hollow, muscular and distensible or elastic organ that sits on the pelvic floor (superior to the prostate in males).it acts as the reservoir of urine. On its anterior border lies the pubic symphysis and, on its posterior border, the vagina (in females) and rectum (in males). The urinary bladder can hold approximately 17 to 18 ounces (500 to 530 ml) of urine, however, the desire to micturate is usually experienced when it contains about 150 to 200 ml. When the bladder fills with urine (about half full), stretch receptors send nerve impulses to the spinal cord, which then sends a reflex nerve impulse back to the sphincter (muscular valve) at the neck of the bladder, causing it to relax and allow the flow of urine into the urethra. The Internal urethral sphincter is involuntary. The ureters enter the bladder diagonally from its dorsolateral floor in an area called the trigone. The trigone is a triangular shaped area on the posteroinferior wall of the bladder. The urethra exits at the lowest point of the triangle of the trigone. The urine in the bladder also helps regulate body temperature. A bladder when operating normally empties completely upon a complete discharge, otherwise it is a sign that its elasticity is compromised, when it becomes completely void of fluid, it may cause a chilling sensation due to the rapid change of body temperature.</p>
<p> </p>
<p> </p>
<p> </p>
<p><strong>Structure</strong></p>
<ul>
<li>Peritoneum- this serous membrane covers the superior surface of the bladder.</li>
<li>Muscle layer it is composed of longitudinal and circular muscles fibers and also called detrusor muscle which is responsible for emptying bladder during micturition.</li>
<li>Sub mucous-it joins the inner lining with muscular layer and made up of areolar tissue containing blood vessels, lymphatic and sympathetic nerves.</li>
<li>Mucous membrane- inner lining which is composed of transitional epithelium.</li>
</ul>
<p> </p>
<p><strong>Function</strong></p>
<ul>
<li>Acts as the reservoir of urine</li>
<li>Expels urine from the body with the help of urethra</li>
</ul>
<p> </p>
<p><strong>Clinical notes</strong></p>
<ul>
<li>Cystitis- an inflammation of urinary bladder characterized by pain on urination, frequency of urination, low back pain, and fever.</li>
<li>Bladder stone/ vesical calculus- formation of the stone in the urinary bladder due to infection, foreign body, obstruction in urine flow.</li>
</ul>
<p> </p>
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Typical noise levels at different places, effects of noise and noise control method
Typical noise levels at different places and effects of noise
WHO has prescribed the safe noise level for a city as 45 dB In United States the noise level of 65 dB at day time and 55 dB at night time in streets is prescribed. Anyone crossing the limit is regarded as causing noise pollution. In Nepal, Government of Nepal has formulated noise level standard for the different area for day and night time.
Environment Department has been established under the Ministry of Science, Technology and Environment for monitoring the environmental condition. The digital horns in vehicles in the silent zone are prohibited. Anyone avoiding the rule is punished by traffic police.
Noise level standard of Nepal as per Ministry of Environment
| S.N. | Area | Noise level Daytime (dB) | Noise level Night time (dBA) |
| 1. | Silent zone | 50 | 40 |
| 2. | Industrial zone | 75 | 70 |
| 3. | Business area | 65 | 55 |
| 4. | Rural residential area | 45 | 40 |
| 5. | Urban residential area | 55 | 45 |
| 6. | Mixed residential area | 63 | 40 |
Source: Nepal Rajpatra, Kartik 13, 206
Typical noise level at different places
“Noise Level Status in Siddharthanagar Municipality, Rupandehi, Nepal” was studied by Lakshmi Nath Bhattarai in 2012 .
A study conducted by physics department of engineering institute in different places of Kathmandu found:
Effects of noise pollution
The noise greater than 60 dB is conceived as the hazard for man and when it reaches more than 80 dB, it may cause losses in hearing capacity. Likewise, if a man works regularly about 8 hours in more than 100 dB noise levels, he becomes deaf.
Effects of human
- Hearing impairment
- Speech interference
- Lack of concentration
- Decrease in efficiency
- Fatigue
- Sleep disturbances
- Annoyance
- Negative social behavior
- Cardiovascular disturbances
- Temporary or Permanent deafness
- Disturbances in mental Health
- High blood pressure
- Heart attack
- Cancer
- Asthma
- Coughing, wheezing
- Deafness
- Annoyance
- Stress
- Insomnia
- Arteriosus clerisie
Effects on animals
- Altering prey/predator detection
- Reduction of useable habitat
- Death of certain species
- Creates problems in navigation
- They become dangerous and attacking
- Raise metabolism
- Hormone imbalance
- Genetic and evolutionary problems
- Abandonment of offspring
Effects on environment
- Break of earth barrier
- Poor production of crops
- Damaged in buildings, bridges, and monuments
- Weakens the edifice of building
Noise control method
The method of control on noise pollution depends on the type of source of noise. There are a variety of strategies for mitigating roadway noise as the use of noise barriers, limitation of vehicle speeds, alteration of roadway surface texture, limitation of heavy vehicles, and use of traffic controls that smooth vehicle flow to reduce braking and acceleration. Aircraft noise can be reduced to some extent by the design of the quiet jet engine. Exposure of workers to industrial noise can be reduced by the redesign of the industrial equipment, shock mounting assemblies and the physical barriers in the workplace.
The techniques employed for noise control can be classified as
- Control at source
- Control in the transmission path
- Using protective equipment.
References:
1. Mackenzie L. Davis & David A. Cornwell, “Introduction to Environmental Engineering”, McGraw Hill.
2. Gilbert M. Masters, Standford University, “Introduction to Environmental Engineering and Science”, Prentice Hall.
3. Stephan Konz, Kansas State University, “Work design”, Grid Publishing Inc., Colombus, Ohio
3. C. S. Rao, “Environmental Pollution Control Engineering”, New age International (P) Limited, Publishers, India.
References:
1. Mackenzie L. Davis & David A. Cornwell, “Introduction to Environmental Engineering”, McGraw Hill.
2. Gilbert M. Masters, Standford University, “Introduction to Environmental Engineering and Science”, Printice Hall.
3. Stephan Konz, Kansas State University, “Work design”, Grid Publishing Inc., Colombus, Ohio
4. C. S. Rao, “Environmental Pollution Control Engineering”, New age International (P) Limited, Publishers, India.
Lesson
6 Noise pollution
Subject
Mechanical Engineering
Grade
Engineering
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