جستجوی مقالات مرتبط با کلیدواژه « افت صوتی » در نشریات گروه « هنر و معماری »

Noise pollution is one of the most important factors in architectural spaces that has a great impact on the comfort of residents. Today, man-made materials are used for improving the sound performance of buildings. For this purpose, it has been tried to find a way to control noise pollution with different materials such as glass wool, rock wool, foam types and acoustic tiles. Most of these materials are factors of environmental degradation and are not recyclable. The purpose of this study is to investigate the acoustic properties of plants and finding a suitable species to reduce noise pollution between two adjacent spaces, also imitating the ferns in order to improve the sound reduction of interior walls between residential units. This research is based on six stages. In the first stage, according to studies on the mechanism of plant texture, it is shown that plants have the ability to absorb sound. By using bionic methods, plants have been identified and their morphology has been done to determine the plant species that has this property. The second part of the research involves identifying the factors affecting sound absorption. At this stage, the possibility of adapting the acoustic principles to the plant texture has been measured. Then the effective parameters in its sound absorption have been investigated by computational and laboratory methods (using scales, calipers, AutoCAD software and Photoshop). Finally, the effect of the sound reduction on the wall is investigated by testing the panel via Cool Edit software and using the impedance tube. According to the results, the non-native fern "Nephrolepis exaltata" is an effective plant in sound absorption. Generally, non-native species of Iran have better sound absorption. According to the research results, all sound absorbers are like a soil layer and don’t have plant layer. The double-wall at frequencies of 250, 500, 1500, 1000 and 2000 Hz has the first priority and then the panel with the vegetable layer. The single-wall panel was tested by an impedance tube in the frequency range of 63 to 1600 Hz and the amount of sound reduction increased by increasing the frequency. The amount of sound reduction reached 18.29db at the frequency of 1600 Hz. This number is acceptable compared to other existing walls, for example, the amount of sound reduction of a wall with gypsum coated panels with mineral fibers with a thickness of 10 cm is 45 dB, while the designed panel with a thickness of 4 cm reduces the sound about 18 dB And by optimizing and increasing the thickness of the panel, the amount of sound reduction can be increased. To use the proposed walls in apartments and other spaces, panels with different characteristics as various thicknesses, different percentages of rice stem and poplar wood and different densities, hardness test on the wall, the aesthetics, the cleanliness of the panels, the late burning of the panels and the exact amount of sound reduction of each wall should be examined and tested.

Relaxation and comfort are two important factors of life, but nowadays life is full of sound both good sounds and unpleasant noises. Mechanical life causes acoustical problems in cities. Urban noise and traffic noise are factors that destroy comfort. Such sounds have negative impacts on people’s lives. Use of appropriate methods to reduce noise pollution is one of the most important points that should be considered. Harmful effects of noise pollution on human health will appear in the long term as well as on the environment. Physiological and psychological effects of noise on humans often appear gradually and in the long time, it directly hurts the human nervous system, so in the design of buildings it is needed to provide acoustic comfort. Acoustic is methods of designing spaces, buildings and mechanical systems according to the need of hearing. First we have to know more about hearing the sounds, therefore here is the brief introduction about the characteristics of sound: Sound has two physical (frequency, intensity noise) and psychological (pitch, loudness) factors. These two factors are equivalent. This means that when we speak the intonation of the voice is the same as sound intensity. The human ear is structured in such a way that if the intensity remains stable but the frequency changes, one feels that the volume has changed while it is not. Noise can be classified in three cases: pure melody, melody and noise. In architecture, one purpose is to control noise. To control the noise first we must measure the volume of noise. Humans can hear 140 dB at the maximum level. If noise level gets greater than 140 dB, the human eardrum will be ruptured. The sound of silence is below 40 dB. Acoustic science is important although there are just a few projects and papers presented about this subject. Many students are unfamiliar with this topic and designer might not notice to this matter. Therefore, an article that includes a simple method for acoustic status check is necessary. Some researches have done on the harmful effects of noise pollution on humans (Movafagh, 2009; Hedayati.1994). In this articles background noise has been obtained in some examples such as Alghadir hospital and Ecbatan apartments by using Sound meter. Then some strategies for reducing noise pollution will be expressed. This paper is done for complete the process of previous projects. In this paper, the sample is selected among common apartment because Acoustic comfort in the building should be considered for all construction. This is particularly important in buildings bordering the highway. The acoustics of the building should consider the following terms: 1. Noise Criterion 2. Sound Rated Walls 3. Silent Installation Systems 4. Building Form 5. Sound Level. Noise criterion for buildings with different user codes is in section 18 of the national regulations. Regarding to the external environment, including voice traffic noise, sounds of the space must be well control. This is especially important in the halls or conference halls and cinemas. For this purpose, we first calculated the amount of background noise and the sound reduction index for façade and then the amount of noise in the unit. Using the guidelines, the volume was brought to an optimal level and comparison of the performance is done. In this paper, the effect of echoed in the interior of the apartment was not evaluated. The results show that in the three mentioned cases, the best method is to use double- glazed windows. This method can be used indoors to create the desired sound level. Using simple windows and double walls had minimum impact. In this case, the noise reduction was about 20 dB. This amount is very low. We will have a better effect when we use double glazed windows and double walls together. Due to the high costs that this method, by using only the double window, we can reach the level desired. Therefore, the proposed solution is use of the double glazed windows. At the end, with a proper design and use of appropriate materials, we can create sound insulation against noise. Studying on samples, wall modification will improve voice.