scholarly journals Improving Building Acoustics

2021 ◽  
Vol 11 (2) ◽  
pp. 137-142
Author(s):  
Simona Stanca
Keyword(s):  
Complex System ◽  
Noise Level ◽  
Functional Unit ◽  
Sound Field ◽  
Sound Level ◽  
Office Building ◽  
Acoustic Quality ◽  
Sound Features ◽  
Acoustic Conditions

Abstract One of the most significant aspects which need to be analysed in the case of a building consists in finding that the sound level perceived by listeners is a proper one (Daniela-Roxana Tămaş-Gavrea et all., 2012). Their inconsistent spreading can develop problems in audition which can be solved only by putting in work a number of measures of acoustic rehabilitation. The evaluation of the acoustic quality of a building is a delicate issue, because of the complex system of the sound field contained in closed spaces and the sound features of the outlining surfaces. This paper presents a research on improving the acoustic conditions of a building which initially had a technical-administrative destination and was then converted into an office building (Stanca S.E., 2021). The measures of acoustic protection were recommended with a view to mitigate the noise level under admissible limits in the functional unit under consideration.

scholarly journals Environmental Acoustic Comfort in the Built Environment

2021 ◽  
Vol 9 (71) ◽  
Author(s):  
Margret Sibylle Engel ◽  
Júlio Otávio Herrmann ◽  
Paulo Henrique Trombetta Zannin
Keyword(s):  
Teaching And Learning ◽  
Physical Structure ◽  
Sharp Drop ◽  
Speech Transmission ◽  
Acoustic Quality ◽  
Teachers And Students ◽  
Acoustic Comfort ◽  
The 1960S ◽  
Acoustic Conditions

  The acoustic quality of classrooms has a strong influence on the teaching and learning process. This interference assessed using the impulsive technique to measure the rate of speech transmission (STI), reverberation time (RT) and sound definition (D50). These are the most relevant acoustic descriptors in the assessment of classrooms, where verbal exposure is the means of communication between teachers and students. The evaluation took place in two buildings of the Federal University of Paraná (UFPR), built in the 1960s and another in 2016. The measured values ​​of STI, provided in the classrooms' actual acoustic conditions, were used as an adjustment parameter for simulations made with the software ODEON. After carrying out the measurements and simulations, the dimensioning of improvements was possible. The acoustic simulations presented suggestions to qualify the quality of the classrooms' acoustic comfort, ensuring that teaching and learning to do not suffer losses due to the physical structure of the classrooms. The measured values ​​of STI, RT and D50 show that, in the old building, except for a single classroom that preserves the original ceiling that had a high sound absorption coefficient, it has reasonable values, below the ideal for classrooms, according to the IEC 60268-16 (2011) standard. The investigation showed that the rooms with a roof replaced by a PVC covering had a sharp drop in acoustic quality. The newest building has classrooms with proper acoustic comfort conditions.

scholarly journals SPECIFIC FEATURES OF USING THE FOURTH STAGE OF ACOUSTIC EXPERTISE FOR SPECIAL PURPOSE PREMISES

2021 ◽  
pp. 41-61
Author(s):  
Sergei Poroshin ◽  
Victoriya Usik
Keyword(s):  
Sound Field ◽  
Software Complex ◽  
Conference Room ◽  
Content Selection ◽  
Technical Specifications ◽  
Conducting Research ◽  
Sound Reinforcement ◽  
Acoustic Conditions ◽  
Speech Content

The subject of the report is the methodology of carrying out an examination of the application for the purpose of establishing the optimal acoustic minds in the prevalence of attribution. The goal is to improve the quality of all stages of acoustic examination, taking into account the premises for which there are special requirements for the quality of the transmitted content or for which there are features in the formation of the sound field. Such a sequence of stages requires the solution of several tasks: determining the conditions for conducting research, taking into account the specifics of the premises and content; selection of hardware and software complex for research; determination of informative criteria for assessing the acoustics of a room, taking into account all its features; processing and analysis of the results obtained. The application of this approach to the stages of acoustic examination was considered on the example of a conference room, for which there were requirements for high quality speech content, a sound reinforcement system was already used in the hall, and there were features in the formation of a sound field. The authors in the article describe the solutions to all the tasks for the investigated room. The results obtained made it possible to analyze the objective characteristics of the sound field and identify the reasons for the low quality of speech content transmission not only in the acoustic calculation, but when using the existing sound reinforcement systems (electroacoustic calculation). Conclusions. The proposed sequence of the stages of acoustic examination makes it possible to identify "problem" places in the formation of the sound field and / or to determine possible solutions even before the stages of checking existing architectural and construction solutions and the development of technical specifications for the construction of enclosing surfaces and measures to create optimal acoustic conditions.

Montevideo, walkable city: pedestrianization of a large avenue during 2020 pandemic

2021 ◽  
Vol 263 (5) ◽  
pp. 1586-1593
Author(s):  
Alice Elizabeth Gonzalez ◽  
Pablo Gianoli Kovar ◽  
Lady Carolina Ramírez ◽  
Micaela Luzardo Rivero
Keyword(s):  
Sound Pressure ◽  
Sound Level ◽  
Environmental Sound ◽  
Sound Levels ◽  
Acoustic Quality ◽  
Sound Pressure Levels ◽  
The City

On March 13, 2020, the first cases of SARS-COVID19 were detected in Uruguay. During the first weeks of the pandemic, mobility was significantly reduced with the slogan "If you can, stay home"; it was not a mandatory but voluntary confinement. After a couple of months, there was a big drop in the number of people affected by the disease. Thus, the Municipality of Montevideo, betting on a more human and walkable city, defined that the main avenue of the city had a pedestrian section on Saturday afternoons. This resulted in a greater enjoyment of the city by its inhabitants, as they had more space to walk while maintaining safe distances between people. It was also possible to promote trading, since classically Ave. 18 de Julio is also a commercial stroll. Additionally, the sound pressure levels recorded by the Municipality's stationary sound level meters located at three points along the avenue, showed the reduction of environmental sound levels in pedestrian areas, improving the acoustic quality of the walk. In this paper, sound pressure levels on Saturday afternoons at different times of the year before, during and after the initial lockdown due to the COVID-19 pandemic, are compared and discussed.

Effect of sound source movement at low Mach number on radiated noise level

2021 ◽  
Vol 263 (3) ◽  
pp. 3731-3737
Author(s):  
Yusuke Makino ◽  
Yasushi Takano
Keyword(s):  
Mach Number ◽  
Sound Source ◽  
Noise Level ◽  
Power Level ◽  
Sound Field ◽  
Dominant Frequency ◽  
Sound Level ◽  
Low Mach Number ◽  
Radiated Sound ◽  
The Difference

Change in A-weighted sound pressure level or Noise level of radiated sound due to sound sources moving at low Mach number at the same speed along a straight track is discussed in this paper. When a sound source move, frequency and amplitude modulation is observed in the radiated sound field. Without their modulation, the noise level at a receiving point is determined only by distance and A-weighted sound power level of each sources. Solution of modulated frequency and amplitude of radiated sound can be obtained by using the Duhamel's efficient calculation. The modulated frequency and amplitude increase for approaching sources and decrease for receding sources. The difference of maximum noise level,and the equivalent sound level during the sources passing-by, with or without considering the modulation, increases monotonically with respect to source velocity, and independent of distance from the track. This difference increases as dominant frequency band of the sources decreases due to A-weighting below 1 kHz.

scholarly journals Research on the Manufacturing Quality of Co-Cured Hat-Stiffened Composite Structure

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2747
Author(s):  
Xiangwen Ju ◽  
Jun Xiao ◽  
Dongli Wang ◽  
Cong Zhao ◽  
Xianfeng Wang
Keyword(s):  
Composite Structures ◽  
Sound Pressure ◽  
Integration Method ◽  
Complex Geometry ◽  
Sound Field ◽  
Thickness Measurement ◽  
Curing Process ◽  
The Finite Element Method ◽  
Manufacturing Quality

The stringer-stiffened structure is widely used due to its excellent mechanical properties. Improving the manufacturing quality of stringer-stiffened structure which have complex geometry is important to ensure the bearing capacity of aviation components. Herein, composite hat-stiffened composite structures were manufactured by different filling forms and bladders with various properties, the deformation of silicone rubber bladder in co-curing process was studied by using the finite element method. The thickness measurement at different positions of the hat-stiffened structure was performed to determine the best filling form and bladder property. Moreover, in view of the detection difficulties in R-zone of stringer, numerical simulation was performed to get the sound pressure and impulse response of at the R-zone of stringer by Rayleigh integration method, and an effective equipment which could stably detect the manufacturing quality of R-zone was designed to verify the correctness of sound field simulation and realize the detection of stringer. With the optimum filling form and bladder properties, hat-stiffened composites can be manufactured integrally with improved surface quality and geometric accuracy, based on co-curing process.

Human Factors Engineering Planning Aid

1987 ◽  
Vol 31 (3) ◽  
pp. 350-352
Author(s):  
Stephen C. Merriman
Keyword(s):  
Complex System ◽  
Human Factors ◽  
Human Factors Engineering ◽  
Planning Time ◽  
Acquisition Process ◽  
Engineering Program ◽  
System Acquisition ◽  
The Military ◽  
Made In

This paper describes the application of affordable program management software to the task of planning human factors programs conducted in support of complex system developments. A model of the military system acquisition process was developed and a model human factors engineering program was overlayed upon it. Interdependencies were created between the models so that changes made in the acquisition schedule would cause the human factors program to be automatically tailored. This approach has potential to reduce planning time and increase the quality of human factors plans.

DEPENDENCE OF THE NOISE LEVEL OF DRY FAN COOLING TOWERS ON THE POWER OF THERMAL POWER PLANTS

2021 ◽  
Author(s):  
Владимир Борисович Тупов ◽  
Айнур Булатович Мухаметов
Keyword(s):  
Noise Level ◽  
Power Plants ◽  
Thermal Power ◽  
Electrical Power ◽  
Sound Level ◽  
Thermal Power Plants ◽  
Cooling Towers ◽  
Surrounding Area ◽  
Fan Cooling

Сухие вентиляторные градирни тепловых электрических станций могут быть источником превышения санитарных норм на территории станции и в окружающем районе. В статье проведен анализ уровня шума сухих вентиляторных градирен в зависимости от мощности тепловых электрических станций. Получена формула позволяющая определить изменение уровня звука сухих вентиляторных градирен в зависимости от электрической мощности тепловых электрических станций. Dry fan cooling towers of thermal power plants can be a source of exceeding sanitary standards on the territory of the plant and in the surrounding area. The article analyzes the noise level of dry fan cooling towers depending on the power of thermal power plants. A formula has been obtained that makes it possible to determine the change in the sound level of dry fan cooling towers depending on the electrical power of thermal power plants.

Audibility of emergency broadcasting sound in a mechanical room in an office building

2021 ◽  
Vol 263 (3) ◽  
pp. 3811-3816
Author(s):  
Jeongho Jeong
Keyword(s):  
Emergency Operation ◽  
Sound Level ◽  
Acoustic Properties ◽  
Office Building ◽  
Fire Alarm ◽  
Transmission Index ◽  
Broadcasting System ◽  
Disaster Situation ◽  
Alarm Sound ◽  
Clear Presentation

Fire alarm and emergency broadcasting sound are important in fire and disaster situations. For the clear presentation of the fire alarm and emergency broadcasting sound to occupants of buildings, some guidelines and requirements were established. In NFPA 72 and BS standard, a specific alarm sound level for alarm sound of residential facilities was proposed and Speech Transmission Index(STI) was regulated for the emergency broadcasting system. In the fire and disaster situation, one of the important facility is a mechanical and electrical system to maintain water and electricity supply. To maintain this function in the buildings, clear presentation of emergency broadcasting sound to the workers in the mechanical and electrical room is crucial for the emergency operation of the system. In this study, the noise level in the mechanical rooms and electricity facilities of more than 40 years old office building were measured. Also, audibility and room acoustic properties such as reverberation time and STIwas simulated using Odeon 12. In order to deliver emergency broadcasting sound more clearly, sound absorption material and a soundproof chamber for noisy devices are needed. Also, the emergency broadcasting system in noisy facilities should be improved to produce the broadcasting sound louder and clearer.

Effects of Railway Noise on Residents’ in A Residential Area

2021 ◽  
Vol 3 (01) ◽  
pp. 17-28
Author(s):  
Ria Anggreani Syahputri ◽  
Budi Damianto
Keyword(s):  
Noise Level ◽  
Sleep Disturbances ◽  
Sampling Technique ◽  
Residential Area ◽  
Comfort Level ◽  
Simple Method ◽  
Urban Village ◽  
Noise Measurements ◽  
Influence Of Noise

Population growth in Depok City is large and not in accordance with development land causes many residents’ to build houses with conditions <5 meters from the line of Electric Rail Train or Kereta Rel Listrik (KRL); this causes changes in the quality of the environment, including noise. The objective of this study is to determine the noise level, and the results will be compared with the standard noise level of the residential area; also, to find the influence of noise on residents’. This research was conducted in the area of ​​Rawa Geni Raya Street, 1st Neighborhood, Ratu Jaya Urban Village, Depok City. Noise measurements were carried out at 5-points using a simple method with a noise level measuring instrument (SLM). At one time, the measurement was taken for 10 minutes with a reading time of every 5 seconds. The questionnaire was measured using a Purposive Random Sampling technique, and the number of samples was calculated using the Slovin formula. The results of this study indicate that the 5-point noise level exceeds the recommended threshold according to KEPMEN LH 48 of 1996 and PERMENKES 718/1987 at  55 dB(A). The largest value for the 24-hour noise level (LSM) is at point 1, which is 5 m from the KRL line. The noise level on the weekday is 75.32 dB(A) and 74.24 dB(A) on weekends. According to PERMENKES No 718/1987, the location of point 1 should be included in Area D as an industrial zone, plant, railway station, and bus terminal. The results of questionnaires by 34 respondents showed that the noise generated by KRL was noisy and the majority of respondents agreed the noise affected the comfort level; in terms of health, respondents agreed KRL noise caused sleep disturbances and hearing loss.

scholarly journals Acoustic quality of critical habitats for three threatened whale populations

2013 ◽  
Vol 17 (2) ◽  
pp. 174-185 ◽  
Author(s):  
R. Williams ◽  
C. W. Clark ◽  
D. Ponirakis ◽  
E. Ashe
Keyword(s):  
Acoustic Quality
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