Asia Noise News

Ultrasound Selectively Damages Cancer Cells When Tuned to Correct Frequencies

Doctors have used focused ultrasound to destroy tumors in the body without invasive surgery for some time. However, the therapeutic ultrasound used in clinics today indiscriminately damages cancer and healthy cells alike.

Most forms of ultrasound-based therapies either use high-intensity beams to heat and destroy cells or special contrast agents that are injected prior to ultrasound, which can shatter nearby cells. Heat can harm healthy cells as well as cancer cells, and contrast agents only work for a minority of tumors.

Researchers at the California Institute of Technology and City of Hope Beckman Research Institute have developed a low-intensity ultrasound approach that exploits the unique physical and structural properties of tumor cells to target them and provide a more selective, safer option. By scaling down the intensity and carefully tuning the frequency to match the target cells, the group was able to break apart several types of cancer cells without harming healthy blood cells.Their findings, reported in Applied Physics Letters, from AIP Publishing, are a new step in the emerging field called oncotripsy, the singling out and killing of cancer cells based on their physical properties.

Targeted pulsed ultrasound takes advantage of the unique mechanical properties of cancer cells to destroy them while sparing healthy cells.

“This project shows that ultrasound can be used to target cancer cells based on their mechanical properties,” said David Mittelstein, lead author on the paper. “This is an exciting proof of concept for a new kind of cancer therapy that doesn’t require the cancer to have unique molecular markers or to be located separately from healthy cells to be targeted.”

A solid mechanics lab at Caltech first developed the theory of oncotripsy, based on the idea that cells are vulnerable to ultrasound at specific frequencies — like how a trained singer can shatter a wine glass by singing a specific note.

The Caltech team found at certain frequencies, low-intensity ultrasound caused the cellular skeleton of cancer cells to break down, while nearby healthy cells were unscathed.

“Just by tuning the frequency of stimulation, we saw a dramatic difference in how cancer and healthy cells responded,” Mittelstein said. “There are many questions left to investigate about the precise mechanism, but our findings are very encouraging.”The researchers hope their work will inspire others to explore oncotripsy as a treatment that could one day be used alongside chemotherapy, immunotherapy, radiation and surgery. They plan to gain a better understanding of what specifically occurs in a cell impacted by this form of ultrasound.

Written by:

Phawin Phanudom (Gun)
Acoustical Engineer

Geonoise (Thailand) Co., Ltd.
Tel: +6621214399
Mobile: +66891089797

Credit: Publishing AIP

Asia Noise News Building Accoustics

Noise and Vibration Monitoring for Construction Sites

In a densely populated city like Bangkok, most of the construction projects are surrounded by condominiums, offices or residential areas. The construction sites must control the noise and vibration that may affect the surroundings. Construction sites need to control the noise and vibration levels that they produce following the EIA standard.

To manage this, noise and vibration instruments are installed which automatically will send alarms to the construction company if the thresholds are exceeded.

Noise Monitoring Station

Sound level meter class 2 according to IEC61672-1 standard which can collect the data of SPL, LEQ and LMAX. These instruments are calibrated before they are installed at a construction site. The system has a LED display and warning light when noise levels in the site are over a trigger level, which is referred to in the standards for maximum sound levels around construction sites.

According to the announcement of National Environment Board no.15 BE.2540 (1997) in the topic of “Standard loudness”, the average sound 24 hour must not exceed 70 dBA and the maximum peak level must not exceed 115 dBA.

Sound level meter are designed to be used outdoors and an additional LED display was added by Geonoise which is a professional sound and vibration company. Sound level meter with LED display also can analyse the loudness in percentile (Statistical,Ln) or analyse the frequencies in 1/1 and 1/3 octave bands. In addition to storing vibration data, you can also create level notifications in Alarm Alert format before vibration levels exceed the standard value for monitoring the activities being performed.

Vibration Monitoring

In the construction industry, transportation Industry and most large industries vibrations will occur.
High vibration levels will cause structural damage to buildings, bridges, structures as well as nuisance or health risks to occupants in exposed (residential) buildings.

Therefore, it is necessary to comply with the standard of vibration in a building according to the Announcement of the National Environment Board Announcement No. 37, BE 2553 (2010) Re: Determination of Standard Vibration to Prevent Impact on Buildings and the measuring instruments need to comply with DIN45699-1.

At construction projects in Bangkok, most cause a lot of unwanted noise and vibrations. Vibration caused by construction projects are caused by piling work as well as the increased traffic of large trucks that enter and exit the construction site. To prevent that vibration levels will be exceeded, a vibration monitoring system will have to be installed.

The Announcement of the National Environment Board No. 37, BE 2553 Vibration standards to prevent impacts on buildings is the main regulation to comply with for construction sites in Thailand. The vibration standards are derived from DIN 4150-3 whereas buildings are classified into 3 types.

Building types according to DIN 4150-3:

  • Type 1 buildings such as commercial buildings, public buildings, large buildings, etc.
  • Type 2 buildings such as residential buildings, dormitories, hospitals, educational institutions, etc.
  • Type 3 buildings, such as archaeological sites or buildings that cultural values but not strong, etc.

In addition to storing vibration data, you can also create level notifications in Alarm Alert format before vibration level exceed the standard value for monitoring the activities being performed.

Asia Noise News Building Accoustics

Exploring Jakartan Public Transportation Through The Sound

Jakarta, the capital city of Indonesia, is home to 10 millions of Indonesia population. Recently the Indonesian government is being sued by a group of activists and environmentalists due to the unhealthy air quality in Jakarta. The plaintiff hopes that through the lawsuit, the Indonesian government can improve existing policies to address the air pollution issues.

On 18 Jul, according to the Switzerland-based pollution mapping service AirVisual, the Air Quality Index (AQI) of Jakarta is 153, categorized as unhealthy and may cause increased aggravation of the heart and lungs. The recommendation upon this condition is to wear a pollution mask and use air purifiers inside the room. The AQI Measures five criteria air pollutants (particulate matter, sulphur, dioxide, carbon monoxide, nitrogen dioxide, and ozone), and converts the measured pollutant concentration in a community’s air to a number on a scale of 0 to 500.

Air Quality Index – AirVisual

Jakarta is one of the largest urban agglomerations in the world. The uncontrolled increase in urban population is proportional to the number of the vehicle in Jakarta. According to Badan Pusat Statistik (Statistics Indonesia), the growth of motorized vehicle in Jakarta is 5,35% every year, on the other hand, this growth will increase the number of pollution in Jakarta. This statement is supported by the acting head of Jakarta Environment Agency, Andono Warih, the fuel residue of motorized vehicles was the main contributor to severe air pollution as 80 per cent of vehicles powered by diesel fuel operated from Jakarta Greater Area (Jabodetabek) to the capital.

Jakartan can contribute directly to overcome air pollution issues. Public transportation is an environmentally friendly mode of getting around. Because public transportation carries many passengers on a single-vehicle, thus it can reduce the number of vehicles as well as reducing the number of emissions from transportation in a dense urban area. Further, public transportation can help Jakarta to reduce the smog, to meet air quality standards and to decrease the health risk of unhealthy air quality. 

The urban transportation system in Indonesia consists of buses, trams, light rail, metro, rapid transit and ferries. Particularly in Jakarta, urban rail-based transportation, such as Commuter Line Train, Light Rail Transit (LRT) and Mass Rapid Transit (MRT), provides mobility and access to the urban area.

MRT Jakarta Phase 1 – MRT Jakarta

The first phase of MRT Jakarta (MRT-J) has been operating since March 2019. In daily operation, the train runs from Lebak Bulus Grab Station to the Bundaran HI Station. There are 13 stations along the railway; the underground stations are Bundaran HI, Dukuh Atas BNI, Setiabudi Astra, Bendungan Hilir, Istora Mandiri, and Senayan Station. Meanwhile, the overground stations are ASEAN, Blok M, Blok A, Haji Nawi, Cipete Raya, Fatmawati, and Lebak Bulus Grab Station. The MRT-J only needs 30 minutes to travel along the 16 kilometres railway, starting from Lebak Bulus Grab Station in South Jakarta to the Bundaran HI Station in Central Jakarta.

There are 16 train lines available to take the passengers getting around. Based on the MRT-J website, In weekdays operation, the trains operate at 05.00 WIB to 24.00 WIB with a total of 285 trips. Meanwhile, in weekend operation, the trains run at the same hour with a total of 219 trips.

During the promo operation (1 April – 12 May), the average number of daily passengers reached 82,643, whereas after the full tariff was applied, the average per day was 81,459.

The following pictures will show you the scenes of MRT Jakarta.

So what do you think? Have you tried getting around using MRT Jakarta? If you have never, try immediately and feel the different sensation of Public Transportation in Indonesia.

Further, through this article, I would like to invite you, explore the MRT Jakarta through a different perspective, that may be for a group of people this method is still rarely used, a sound.

Do you realize that sound can tell us about character, place, and time? Sometimes, it informs us in ways visuals can’t, and that is the idea of what we are going to do right now. Later you will hear, a file of recorded sound of MRT-J in its daily operation.

The sound was recorded by the soundwalk method, any excursion whose primary purpose is listening to the environment. It is exposing our ears to every sound around us no matter where we are. We may be at home, walking across a downtown street, or even at the office. Meanwhile, in this case, our environment is inside the line of MRT Jakarta. The goal is to capture any sound sources that exist during the operation of MRT-J, including the activity of the passengers.

The sound was recorded by using a mounted microphone on the iPhone X at a level of 1.2 m above the ground. The following sound is a recorded environment while the MRT-J was travelling from Bundaran HI Station to Setiabudi Astra Station, the duration of recording sound is 4 minutes and 40 seconds. Please use an earphone or any similar devices to listen to the audio for a better experience.

Caution: please set the volume around 50 – 70 % of the maximum volume.

After listening to the sound, can you identify what sound sources are presented in the recording? Here are the sound sources that I have identified:

  1. Engine sound increases speed
  2. Public Address system
  3. Engine sound
  4. Rail friction
  5. Passengers’ activities (cough, sneeze, conversation, footsteps, etc.)
  6. The sound of the door opening
  7. Brake squeak

Now we have identified the sound sources that are presented in the recording. But, do you know how many decibels that I have to endure while travelling using the MRT-J? In this article, manual measurements of noise levels were performed with a sound level meter in the MRT Jakarta with passengers on its usual route. A-weighted sound level measurements were recorded directly from one station to the next during the time between 08:00 and 09:00, using a calibrated microphone on a stand at a level of 1.2 m above the ground. The results of equivalent continuous A-weighted noise levels Leq (LAEq) in the MRT-J with passengers on its usual route from one station to the next is shown in Chart 1. 

Leq is the A-weighted energy means of the noise level averaged over the measurement period. The results from the measurements show that the A-weighted noise level is varied between 77 dB to 82 dB. Further, if we look closely into the Chart, the noise level is fluctuating. It can be caused by a lot of factors, such as: 

  1. The position of MRTJ (When MRT-J inside the tunnel, the noise can be levelled up due to the reflection phenomenon).
  2. Speed (The machine indicates producing a higher noise when in the maximum speed).
  3. Path Crossing.
  4. The Public Address System Volume.

Moreover, the level of continuous noise in Chart 1 represents a quite noisy environment. According to The National Institute on Deafness and Other Communication Disorders, states that Long or repeated exposure to sound at or above 85 dB can cause hearing loss. Thus, according to the measurement results, I suggested you wear ear protection during commuting by MRT-J. The earplug is one of the equipment that we can use to protect our hearing; you only need to spend a few thousand rupiahs for this. Wearing earplugs can help you to reduce the noise by 18 – 34 dB, it depends on the models/brand. For more accurate results, we need to do a complex measurement, such as:

  1. Add measurement point (In this article, the measurement was done only in a measurement point, at the second car of the line).
  2. Add a velocity as a measured parameter.
  3. Add the measurement time; the measurement can be done during the operation hour, non-stop. (05:00 – 24:00 WIB).

Nonetheless, the idea of showing the measurement results is spreading noise awareness. Noise sticks with you around, even common sounds you hear at work or home can contribute to long term hearing loss and other health risks, they are everywhere, but only a few people are aware of it. Noise pollution is a health threat nobody is talking about. Here are some parameters to help you determine acceptable — and dangerous — noise levels:

  • 45 dB: nightly noise ordinance threshold set by many municipalities concerned with industrial noise exposure for residents
  • 65 db+: exposure for prolonged periods can cause physical and mental fatigue
  • 85 dB+: can cause permanent hearing loss if exposed for extended periods
  • 85-120 dB: dangerous over 30 minutes of exposure
  • 120-130 dB: can cause permanent hearing loss for exposure over 30 seconds
  • 130 dB+: not only are these noises painful, but hearing protection should always be used if avoidance is not possible.

Everyone needs to take care of their ears and hearing, as damage to the auditory system could be irreparable. The loss because of the noise exposure is gradual; you might not notice the signs, or you ignore them until they become more apparent. Please do protect your ears. 


Westerkamp, Hildegard (1974). “Soundwalking”. Sound Heritage

Asia Noise News Building Accoustics

Noise in HVAC System; What, Where and How Noise comes from?

One of the things that becomes an unpredictable issue of a building, especially with a centralized air conditioning system, is the noise it creates. Calculating noise from every part of the HVAC system is needed to avoid unwanted noises in adjacent rooms.

What do we need to know to avoid noise from the HVAC system?

Are there simple steps to avoid it?

In this article, we will discuss about the noise that occurs in the HVAC system and how to avoid it.

Every sound that is heard can usually be identified through its frequency range. In relation to frequency range, noise that occurs related to the HVAC system is divided into 3 categories within the frequency range:

  • Low Frequency

Fan Noise, it generally produces sound from 125 Hz to 500 Hz octave frequency bands. Variable Air Volume (VAV) boxes noise is usually from 125 Hz to 500 Hz octave frequency bands.

  • Mid Frequency

Airflow Noise and turbulence-generated noise in a duct range from 31.5 Hz to 1000 Hz.

  • High Frequency

Damper and Diffusers Noises, they usually contribute to the overall noise in the range of 1000 Hz until 4000 Hz octave bands.

All the noise above can be avoided if we know how to design HVAC system acoustically and each of these issues must be addressed:

HVAC System Acoustically – Geonoise Instruments
  • Duct-borne Noise

The sound generated by the fan will travel along with the ductwork both upstream and downstream easily because the velocity of sound is much greater than the velocity of air in ducts.

  • Radiated Equipment Noise

Radiated equipment noise transmits through the wall or floor into the adjacent space or in the case of rooftop equipment to the environment. It is generated by vibration of the fan casing and motor.

  • Duct Break-in Noise

Noise inside ceiling plenums or from air conditioning equipment, plant room, etc, can break into the duct and then be carried into rooms or spaces downstream. So, where possible, avoid ducts passing through noisy areas as this can significantly increase noise through the air conditioning system, avoid lightweight ducts as well, replace them with heavier ducting such as sheet steel.

  • Duct Break-out Noise

Along with the ductwork, however, transmits through the wall of the duct, thus impacting the adjacent space. Generally, it happens from noise passing through the duct, aerodynamics noise from obstructions fitting in the duct, and turbulent airflow causing duct walls to vibrate and rumble radiating low-frequency airborne noise.

  • Terminal Noise

The final links in the distribution chain are the terminal air devices. These are Grilles, Diffusers, Registers, and Vent Cover that go over the duct opening in the room. Streaming air noise from diffusers and from transitions can cause additional noise in the receiving room. So that for this issue, we need to concern choosing the proper specs of supply and return air devices. We need to try to find out the NC (Noise Criteria) rating for them from their respective manufacturers.

By knowing those 5 ways of how noise occurs, it makes easier for us to categorize noise that will produce in our HVAC system design and help us in choosing what material, enclosure, duct shape and everything we need to reduce noise.

Asia Noise News Building Accoustics

Feeling Unproductive? You Might be Overlooking This Productivity Killer

Feeling Unproductive in Office – Geonoise Instruments

We believe that the best way to be highly productive is to be able to get into our monoideal state. Josh Kaufman says in his book “The Personal MBA”:

Monoidealism is the state of focusing your energy and attention only on one thing. It’s often called a “flow” state: clear, focused attention on one subject for a long period of time.”

For this to happen, potential distractions and interruptions need to be eliminated. This is the reason for some people, working early in the morning or late at night can feel very productive – because on a normal day, no one is going to call you at 4 in the morning.

However, most of us do our work in an office which does not operate at those silent, undistracted hours. The good news is, we still can manage our potential distractions by knowing what distracts us the most. This can be done by allocating a time when you want to be in your monoideal state and free yourself from distractions during that time. For example, you can put your phone into flight mode and turning off email notifications from 8 to 11 and start to check emails and communicating with the outside world from 11 until lunch. The timing will depend a lot on the type of work you are doing and how much time will you need to be in monoideal state.

Unfortunately, there are things that is out of your locus of control – there is a retrofitting job upstairs, your co-worker decided to sing along to the song he is listening to, people in the other room are laughing loudly (are they talking about their boss?) and so on. If it’s not in front of your eyes, for example pop-up notifications on your screen, most of the distractions come to you in a form of sound, or I think it’s better to call it “noise”.

Noise is a productivity killer that you might be overlooking, especially if you have passed the stage of being distracted by your phone, browsing Facebook on your computer and looking at cat videos on Youtube. Fortunately, noise is manageable in a few different ways. The most viable option for an existing office is to make noise-related rules and to make everybody aware that noise can reduce their productivity. For example, companies can make rules that retrofitting job, singing and gossiping must be done outside of office hour. Another way to fix this is to separate areas for people who want to be focused and areas where people can socialize and discuss with their co-workers.

The best way to manage noise? Is to take noise into consideration from the beginning of the design process of the working space. This can be a long and complex process where there are a lot of aspects to be considered in designing an ideal office. It needs a balance between visual pleasure, company’s philosophy, functionality, health, safety and all other aspects that we want to take into account. A lot of times, all those aspects will relate to noise or acoustics in some ways, depending on each unique case.

For us acousticians, these are the things that we typically think about when helping others to design their working space (and actually any other built environment):

  • Ambient noise: We want the noise level inside of the working space to be reasonably low, whether it is intrusion from outside such as traffic, railway, aircraft and neighbouring building (neighbour’s mechanical system can be quite noisy), or the noise from inside the building such as HVAC system and lifts.
  • Sound insulation: We don’t want to hear sound that we don’t want to hear from the next room, upstairs or downstairs. By designing a suitable ceiling, flooring and wall systems, a sufficient sound insulation can be achieved.
  • Room acoustics: We want to be able to listen comfortably and understand verbal information that we want to. This is critical especially in meeting rooms and event space.
  • Sound reinforcement and public address system: We want the sound reinforcement and public address system to be heard clearly while not disturbing others who don’t want to hear it.

All the above can also be done after the building and the working space is built. But if it’s done before it’s built, you will have a lot more options and be more cost efficient rather than changing what is already been built.

So, if you are a highly productive person, or if you want to become one, we would suggest you to consider noise in choosing the space you are working in.