Acoustics and Sound Insulation Methods

Acoustics and Sound Insulation Methods Acoustics and Sound Insulation ABSTRACT Acoustics is the study of sound. The knowledge of this field is necessary as it helps in creating peaceful surroundings. The technical knowhow of sound insulation has been helpful in constructing functional theatres, hospitals, Auditoriums, jam pads, etc. Sound is created when a surface vibrates. When this vibration is periodic or rhythmic then the sound produced is pleasing to the ears eg. Musical Notes. On the contrary when the vibration is non-periodic and irregular then it is termed as noise. eg. Infants crying. INTRODUCTION Sound travels in the form of longitudinal waves. Each wave moves backward and forward passing on the vibration to the next. For us to be able to hear sound clearly it is very important for the waves to travel uninterrupted. It is proven that sound travels the fastest in solids, then in liquids and the least in air. This is because in solid the molecules are so tightly packed that the transmission is the easiest. In liquids too the molecules are fairly close to each other where as in air it becomes a little tough for sound to travel. Sound cannot travel in vacuum as it needs a medium to travel. The speed of sound in air depends upon the moisture or dryness in air. The more the moisture the faster sound will travel. CHARACTERISTICS OF SOUND Intensity and Loudness of sound: Loudness is the response of humans to the impact of sound. Whereas intensity is the amount of sound waves passing through per unit area per unit time. Frequency and Pitch Sounds can be of different types and wavelengths. Pitch is  What helps us distinguish between sounds of same loudness but of different frequencies. This is the  characteristic which helps us recognise a man’s voice and  women’s Voice. Quality The quality of sound is what enables us to differentiate between two musical tones played on different instruments. A study has shown that the notes produced by instruments are at times pure notes. They have some fundamental tones of frequency fo and additional tones of frequency 2fo, 4fo, etc. called over tones. The fundamental is heard very clearly because it has greater impact human ear. TABLE 1.1, ACCEPTABLE NOISE LEVEL TYPE OF BUILDING NOISE LEVEL RANGE ( decibels, db) 1. Radio and T.V. studio 25-30 2. Music Room 30-35 3. Hospitals and auditoriums 35-40 4. Apartments, hotels and homes 35-40 5. Conference rooms and libraries 35-40 6. Class rooms 40-45 7. Banks and stores 45-50 8. Restaurants 50-55 2# REFLECTION OF SOUND Sound waves from a plain surface reflect in the same way as that of light. The angel of incidence is equal to the angel of reflection. Following are the characteristics of reflection of sound: When sound waves reflect from a flat surface the wave fronts form a spherical shape and the centre of curvature is the source of sound When sound waves reflect from a convex surface they get magnified and therefore become thinner and weaker. Convex surfaces can be used in interior spaces to reduce the impact of sound. Sound waves that reflect from a concave surface are very dense and compressed therefore the sound is amplified. Concave surfaces should be avoided in interior spaces as the result is undesirable. Reflection on flat surface Reflection on convex surface Reflection on concave surface   3# ABSORPTION When sound waves strike a surface some of the sound is absorbed by friction. The materials that absorb are known as absorbants. Absorption in auditoriums or theatre the takes place in three ways – In Air – This absorption happens due to friction between two molecules though this is very small By Audience Cloth is an absorbant. So in theatres and auditoriums the sound is absorbed by the clothes o f the audience. The  more the audience the more the absorption takes place. By furniture and furnishing – Materials such as curtains, carpets absorb sound. The following materials are commonly used for absorption of sound – Acoustic Plaster – This contains shredded insulation material with cement Perforated and Unperforated compressed cane or wood fibre board. Wood Particle board Compressed wood wool Mineral/ glass wool mats Mineral/ glass wool tiles Composite units of perforated hard board backed with perforated fibreboard Requirements of a good acoustic material- Should have high absorption power It should be able to absorb a wide range of frequencies Should be cheap and easily available Should look attractive after fixing it It should be fire resistant Should have adequate structural strength Should be non- hygroscopic. It should be insects and termites free 4# SOUND INSULATION Sound insulation/sound proofing is a method used to subdue the level of sound passing through the insulating building component. People generally confuse sound absorption and sound insulation to be the same. The two are very different from each other. Sound absorbents which are mostly pours materials absorb thus reduce the sound which is reflected from surfaces. On the contrary sound insulating construction reduces sound passing through it. Sound absorbers, are poor sound insulators. While hard material used for sound insulation areinferior sound absorbers. TABLE 4.1. SOUND INSULATION BETWEEN ROOMS SITUATION OVERALL INSULATION IN db 1. Between living room in one house and the living room in another 50 2. Elsewhere between houses or flat 40 3. Between two rooms in the same house. 30 4. Between two class rooms in a school 40 5. Between two rooms in an office 30 6. Between two wards in a hospital 45 Impact Insulation- is a rating of how well a building floor reduces the impact of sounds, such as footsteps. Sound Insulating Materials – Non porous rigid partitions- The sound insulation of non-porous rigid constructions such as plastered solid brick masonry walls varies. It depends upon the weight per unit area. There is a point when it requires major increase in thickness to provide small increase in sound insulation. Porous Rigid Materials Porous concrete masonry and cinder concrete are some examples of porous rigid materials. They provide 10 percent higher insulation as compared to non-porous rigid partitions due to their sound absorptive quality. To enhance the results of insulation it is recommended that porous partitions should be plastered on at least one side and if possible then on both sides. Flexible Porous Material These materials provide low insulation. Even lower than rigid materials. Flexible porous materials consists of mineral wool, quilt etc. To increase insulation rigid materials and porous absorbers can be combined together and then applied. This will produce better insulation per unit area. 4.1 WALL INSULATION Walls are a vertical barrier of sound. Proper construction of walls can increase the level of sound insulation. Construction of walls for sound insulation can be of four types Rigid Homogeneous Walls- Stone, brick or concrete masonry constructions come under this section. The sound insulation in these walls depends upon their weight per unit area. Sound insulation in these increases if the thickness of wall increases. Due to this these walls become uneconomical and bulky after a certain limit. Partition Walls of porous materials- These can be rigid or non-rigid. Rigid porous materials such as porous concrete masonry, cinder concrete etc. increase insulation about 10.%. While partition walls of non rigid porous materials provide very low sound insulation. However they can be used if combined with rigid materials. Double wall partition A double wall partition comprises of Plaster boards Or fibre boards or plaster on laths on both sides. With sound absorbing cushion in between. Rough wooden blocks are provided to support the cushion. Double wall partition is a wall of rigid as well as nonrigid porous materials. Cavity Wall Construction- This is said to be the most adequate wall construction from the sound proofing point of view. In this two walls are made with a gap of minimum 5cm between them. This gab can be left air filled as we know sound travels the slowest in air or can be filled with some flexible material, like quilt etc. On the surface of the wall celotex or other insulating board may be fixed. 4.2 FLOOR AND CEILING INSULATION Like walls are vertical sound barriers similarly floor and ceiling are horizontal sound barriers. The materials used for the construction of floors and ceiling i.e. R.C.C, stone etc. provide great insulation again air borne noise but do not function well for structure and impact borne noise. The target of sound proofed floors is to provide insulation against impact and structure borne noise. This can be achieved by the following ways- APPLING RESILIANT SURFACE MATERIALS ON FLOOR In this a thin concrete layer is provided as R.C.C floor slab. On top of this then a soft floor finish or covering is applied. This finish or covering can be of linoleum, insulation board, cork, carpet, etc. this helps in reducing impact noises. CONCRETE FLOOR FLOATING CONSTRUCTION This is similar to Cavity wall construction as discussed earlier. In this method we construct an isolated floor from the existing concrete floor. Then a resilient or porous material like glass wool is laid on the R.C.C flooring. On top of this a water proof sheet is put and then a 5cm thick layer of concrete is given. This kind of construction provides complete insulation against impact sounds. TIMBER FLOOR FLOATING CONSTRUCTION – In case of wooden flooring the problem of sound insulation is even more. This process is similar to concrete floor floating construction. The only difference is that mineral or glass wool quilts are used for isolation purpose. At times sand or ashes are also used for isolation. CONCLUSION Sound is mechanical wave which travels through a medium. Sound can be pleasing as well as disturbing. It’s necessary to emit disturbing sounds to have the perfect required atmosphere. To make an area sound proof its walls/partitions, floor and ceilings need to be treated and insulated. The methods of insulation as discussed above are some ways through which sound proofing can be done. Sound proofing or insulation is the method by which transmission of sound waves can be bard from passing from one area to another. References: Building Constructions by B.C Punamia.: Sound Insulation http://www.meritnation.com/ask-answer/question/how-many-characteristics-a-sound-wave-have. www.scribd.com/doc/102689279/acoustics-ppt

Buffalo 66 :: essays papers

Buffalo 66 Buffalo ‘66, a movie directed and written by Vincent Gallo starts with a baby picture of Billie Brown (played by Vincent Gallo himself), and then goes into shots of Billie getting out of prison. Billie the fresh free man is looking for a bathroom but has no luck in finding one. The shots used in the scenes where he’s on the search for a bathroom are some handy shots (a bit shaky), they cut in the middle and they are also shot from above this is, in my opinion to emphasize on the situation Billie is in. He really needs to go to the bathroom but has no fortune, until he enters a dance studio. There he meets Layla (played by Christina Ricci) a young blond girl that simply wanted some dance lessons. Billie asked her for a quarter to call his mother, and then suddenly decided to kidnap her. The reason for that was that he didn’t want to disappoint his parents, his parents thought he was successful and married. After all this Billie didn’t find a bathroom yet until they drove off to his house. In the scene where he finally pees, there is a close up shot of Billie’s face, to show the audience his reaction. He enters the car, and he is more calm he apologizes to Layla for being so aggressive, while he’s apologizing to her there is a close up shot of her and his voice in the background, this emphasizes on Layla’s reaction. During the drive back to Billie’s home there’s alot of shots of the neighborhood, in my opinion this is to enlighten the audience on the type of surrounding Billie grew up in, this helps in understanding his character. Billy and Layla finally arrive to his house, in front of the house there’s a huge sign: â€Å"Go Buffalo† this is a clue on the environment Billie lived in at home. It is obvious his parents are huge football fans by the decoration of the house. Layla get in the character of being Billy’s wife, she makes up a story that Billy works for the CIA and that she really adores him. The next scene shows us three of the characters sitting around a table, and every minute it keeps switching. It seems like the camera is going through a point of view of one of the characters, and it keeps changing each time someone else speaks.

Positive psychology Essay

As a child we are told the future is our oasis But is this really the truth when we look at the basics? When I was young and asked what I wanted to be I of course replied â€Å"just like daddy† Now I wasn’t referring to his business success I was only concerned about the love he expressed So when we are told that the future couldn’t be brighter Why do people only think about becoming an astronaut or fire fighter? What is often forgotten is the truth of the matter There is much more to life, this is just a part of the batter Making the cake is a process that is extensive. What we need to remember is that it doesn’t need to be expensive Why does one’s life have to be determined by their occupation? It has become a norm in society, almost a fixation In order to be happy one has to have a high paying job and big house Luxuries extend as a far as a Maserati or a cottage with a boathouse With this in mind, young students face great pressure and tension School has become an entity beyond comprehension It was in my understanding that we come here to learn But when I look around all I see is heads turned. Heads turned from the reality of the true meaning of life Kids only concerned with grades as if they are being forced with a knife This figurative dagger comes in the hands of universities What happened to opening the door for a girl or showing a little common courtesy? People approach university with a new hopeful attitude We can now receive self fulfillment and gratitude The reality of the situation is long, grueling hours spent with your head buried in a book No one reflects on themselves or even lifts their head to take a look. Many pass these four years with not an aspiration in mind Not even looking ahead, continuing to remain blind Then university is over, time for life to begin With endless possibility, one cannot help but grin Then it hits you, like a strike across the face Money is happiness therefore you join the rat race What is interesting about this race is that there is no winner The winner is still a rat; the only objective is to provide a better dinner What has been lost in the mix is the wisdom and prudence Any successful man would point out that our actions are rather foolish And by successful I am not referring to economic victory I am referring to the people who have shaped our history Not the Donald Trumps, Mark Zuckerberg’s or Warren Buffets These are simply the people enslaved as economic puppets I am referring to the Gandhi’s, Malcolm X’s and Martin Luther King’s The people who created change, the liberation they were able to bring I believe that with great people comes great change. This change is not as simple as a stock trade, it is long range Not only is it eternally priceless but it has a rippling effect One great person affects all around them, sometimes unknowingly or indirect When I think of inspiration I think of the president of Uruguay The poorest president in the world challenged what society sees as the way Donating 90% of his salary leaving just $1250 dollars per year to his name It makes one question why we only seek to make large sums of money or achieve great fame Don’t mistake my message for an attempt to say that we are all greedy I simply want you to be aware that life isn’t all that easy Money can solve your surface problems but this solution is temporary. Reflect on your goals and ambitions before you end up in a cemetery I feel that change is possible regardless of your situation It does not depend on your gender, race, religion or sexual orientation Change isn’t easy but we are all more than capable When life pushes you to the curb, you are hurt but unbreakable In a world that seams hopeless it is important to remember life goes on Make sure to look up, stay positive and never get withdrawn. We are all brothers and sisters part of something that is greater Be fearless and hopeful and live up to your nature We are often referred to as the careless generation who lack a work ethic But I would argue that statement is unjustified and rather pathetic We have the means to create change and it is already happening People like the Keilburger’s come across as rather baffling But when looked at in perspective they are simply two people with a dream A dream that arises a common theme. This theme is that we must love and be aware We must create a life for all that is just and fair In saying all this I am not trying to discourage I hope all your child hood dreams come to the surface There’s a world full of hope, possibility and prosperity And my wish to all is a fulfilling life of mental clarity Ultimately what it comes down to is the way we are taught as youth There is nothing more powerful then the honest truth When asked what we would like to be in our future Happiness should come to mind, the only acceptable answer.

Famous Murders of the 19th Century