Annex A - Group Research Proposal


Investigative Skills in Science
 Research Proposal Form


Project Title: Investigation of the effect of different masks on the spread of water mist

Link to document: https://drive.google.com/file/d/1O3I5HoSWR5YiU_8Yj1vMpKG-wTUQZPuJ/view?usp=sharing


Class

S2-08

Group: 

E 


SN

Name of student

Email 

1

Tan Xuan Han

tan_xuan_han@s2020.ssts.edu.sg

2

Lim Cheng Rui

lim_cheng_rui@s2020.ssts.edu.sg

3

Liam Lee Yi Heng

liam_lee_yi_heng@s2020.ssts.edu.sg


Type of research:

X

Test a hypothesis: Hypothesis-driven research


Measure a value: Experimental research (I)


Measure a function or relationship: Experimental research (II)


Construct a model: Theoretical sciences and applied mathematics


Observational and exploratory research


Category of research:

Sub-category: 

Material Science

Polymers

Reference 

https://www.societyforscience.org/isef/categories-and-subcategories/all-categories/ 

  


Research Plan


Project Title: Investigation of the effect of different masks on the spread of water mist


1. INTRODUCTION:


As the COVID-19 pandemic continues and an increasing number of people are being infected with COVID-19, according to Associate Professor Loh Xian Jun, from A* STAR's Institute of Materials Research and Engineering (IMRE), "a simple cloth mask is effective in curbing the spread of droplets from inside-out. That is, it protects those around the person coughing." (Loh, 2020). Hence, people wear masks to protect the user and others from the spread of COVID-19.

 

Along with this new measure came people sporting many different types of masks. Some of these masks include surgical masks, N95 respirators, homemade and store-bought cloth masks, bandanas and neck gaiters. Different materials are used to make masks, such as cotton, woven fabric, polymers with non-woven fabrics and in the case of N95 respirators, synthetic plastic fibre, similar to those used in synthetic and polyester shirts. According to the journal BMJ Open, “most of the fabrics commonly used for non-clinical face masks are effective at filtering ultrafine particles. N95 masks were highly effective, although a reusable HEPA vacuum bag actually exceeded the N95 performance in some respects” (O'Kelly, 2020).


Hence, we have decided to conduct this experiment to determine the effectiveness of each type of mask in reducing the spread of potentially virus-carrying saliva droplets through it. For this experiment, we will be using water mist to act as the droplets, and measuring the distance the water mist had travelled from the mask. 


To measure the distance the water mist travelled, we will use a technique known as Schlieren photography to get an image of the droplets passing through the mask. During Schlieren photography, the illumination pattern is imaged onto a geometrically congruent cutoff pattern (essentially a multiplicity of knife edges) with focusing optics, while a camera system images density gradients lying between the illumination pattern and the cutoff pattern. (see Figure 1.1 below)









Figure 1.1 - A Schlieren imaging setup (Source: Wikipedia)



In the flow of uniform density (when there is only surrounding air), this will halve the brightness of the photograph. However, in flow with varying density (when there are water molecules in the air from the water mist), the distorted beam focuses imperfectly, and parts that have been focused in an area covered by the knife-edge are blocked. The result is a set of lighter and darker patches corresponding to positive and negative fluid density gradients in the direction normal to the knife edge. In theory, the darker patches would represent the droplets while the lighter patches would represent the surrounding air, which would allow us to visualise the distance travelled by the droplets easily. 


According to Matthew Staymates, an experimental fluid dynamicist at the U.S. National Institute of Standards and Technology (NIST), "It turns out that schlieren is a really powerful tool to try to understand how to sample for these kinds of things in the environment." (Staymates, 2020). 


We believe that this experiment is extremely relevant to society in the current situation because this experiment's results will allow people to make an informed decision when choosing a mask of which to wear to protect themselves and others from the COVID-19 virus. The saliva droplet's disease-carrier particles cannot travel more than 2 m in space at approximately zero wind speed. The environment is at ambient temperature, pressure, and relative humidity of 20 °C, 1 atm, and 50%, respectively, with the ground temperature at 15 °C and mouth temperature at 34°C. If these droplets land on someone else's face, or a surface which is touched by someone else, it may make the person sick. By wearing the mask that reduces the distance travelled by droplets the most, others will be less likely to catch the COVID-19 virus. According to Jeremy Howard, a research scientist at the University of San Francisco in California, "You don't have to do much math to say this is obviously a good idea". (Howard, 2020) 



2. RESEARCH QUESTION(S):


2.1 Research question being addressed 

To find out the effect of the type of mask on the distance travelled by water mist sprayed through the mask


2.2 Hypotheses


Different types of masks will result in different distance travelled by the water mist


2.2.1 Independent variable


  • Type of masks used



2.2.2 Dependent variable 


  • Distance that the water mist travels


2.2.3 Controlled variables


  • The volume of water mist sprayed 

  • The force used to spray the water mist

  • Distance of spray bottle from the mask























3.    Method


3.1 Equipment list:

 

  • Parabolic mirror with diameter of 114mm and focal length of 900mm

  • Razor blade

  • Powerful Spray bottle 

  • Camera with telephoto lens (10X Zoom)

  • Reusable cloth mask without filter

  • Reusable cloth mask with filter

  • 3 ply disposable mask

  • 2 ply disposable mask

  • N95 respirator

  • Bandana

  • LED light bulb (5mm)

  • 2 retort stands

  • 15cm Ruler





3.2 Diagrams


Figure 1: Experimental setup



3.3 Procedures:


  1. Place the concave mirror 1800mm away from the camera lens, facing the point light source

  2. Vertically position a white piece of paper or poster board near the point light source

  3. Position the razor edge vertically near the focal point, but do not obscure the light.

  4. Place the camera in the path of the light, behind the focal point.

  5. Put the ruler parallel to the mirror to measure distance travelled by the mist.

  6. Put the 3 ply surgical mask on the retort stand. 

  7. Place the spray bottle on another retort stand 3cm behind the mask. 

  8. Spray the maximum amount of mist by pulling the trigger all the way back and wait for the mist to travel. 

  9. Repeat Step 8 with the N95 mask, Bandana, cloth masks and 2 ply surgical mask





3.4 Data Analysis:

  1. Record the experiment with the camera, and observe how far the droplets travel through each mask using the ruler next to the mirror from the video captured by the camera

  2. Compile the information in a table, with a row for each type of mask.

  3. Compare the distance the mist travels through each mask



Type of mask

Distance travelled by water mist/cm

Test 1

Test 2

Test 3

Average


N95





3 ply disposable mask





2 ply disposable mask





Reusable cloth mask without filter





Reusable cloth mask with filter





Bandana























4. Risk, Assessment and Management:


Table 1: Risk Assessment and Management table 


Risk

Assessment

Management 

Razor blade is sharp and hand might get cut

Medium

Be careful when handling the razor blade, being mindful of where our hands are in relation to the blade/ wear cut-resistant gloves

The mirror might shatter and we might get cut by its shards.

Medium

Be careful when handling the mirror, keep the mirror away from the edge of tables

The retort stand and tripods holding the mask, mirror and camera might topple and trip us

Low

Be mindful of our step and not run into the stands.

Bright light can temporarily blind someone, making people stumble into other hazards like the razor blade, retort stand and tripods.

Low 

Do not look directly at the light 




5. References:



6. Bibliography:



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