User:Yuchen.li94/Project 3

My Instructor's course page which points to this.

Project Preference
Water Beads Demo Project

Problem Statement
Finding out the properties of given water beads and produce an application of water beads in real life

Project Plan
week 1: testing the physical properties of water beads for baby diapers

week 2: testing the chemical properties of water beads for duster cloth

week 3: starting making the first prototype

week 4: making the final prototype

Week 1 Narrative
During the past week, the maximum volume of water beads was tested individually and in group. Two tests was conducted in the same place, same room temperature (25 degrees centigrade), same pressure (1 atm), and in the same sealed containers with sufficient water. In addition to the tests for the rate of absorption, the first calculation for the number of beads will be used in our first diaper prototype was generated.

The first test
Measure the change of the diameter of the growing water beads in order to determine the maximum volume approximated by sphere

1. Randomly selecting 4 water beads from the bag and measure the diameter of each one, and then calculate the average.

The Second test
Measure the volume of growing water beads by water placement method

1. Put 10 ml water in the measuring cylinder

Conclusion from two tests above

 * With sufficient water, the rate of individual absorption is roughly same for each water bead regardless the number of beads surrounding.


 * In the fixed amount of water, the total rate of absorption is depending on the number of beads immersed in the water.

Calculation for the Diaper prototype
$$\frac{1} {number of beads \times the rate of individual absorption}$$ ∝ t (time)

Infants between 1 to 3 urinate 300ml to 500ml up to 10 to 15 times per day.

The maximum of infant's urine will be $$500/15=33.3 ml=33300 mm^3$$

By taking the very first point out of the graph, a differentiable logarithmic trendline can be generated by Excel.

Using 0.001 as an approximation of 0 because ln(0) is undefined.

$$n \times (2.7679ln(0.5)-2.7679ln(0.001))=33300$$

$$n=1936$$ water beads should be used

Next steps:
1. Finding chemical proprieties of water beads

2. Testing how the surface of the water beads influences the rate of absorption

3. Starting to look for the material for prototype

The rate of absorption of multiple water beads
During the past week, the rate of absorption of multiple water beads was tested in the mix amount of water (25ml) in a washer shape container. Tests were conducted in the same place, same room temperature (25 degrees centigrade), same pressure (1 atm), and in the same sealed containers with 25 ml of water. Since water replacement method and measuring diameter of the water beads are not accurate in determining the volume change of water beads, the observable height change on the wall of the washer can be used to determine the volume change by integration. The volume of water absorbed by water beads can be calculate through 25ml - V(left in  container)

Linear equation $$\frac{3y+22}{10}=x $$

$$V(water absorbed)=25-\int_{0}^{h} pi\times(\frac{3y+22}{10})^2, dx $$

Time vs. change height

Water absorption

According to the tests' results, in the fixed amount of time, the more water beads in the container, the fast the water is absorbed. In order to maximize the surface area contacting water, "water beads powder" was made and a mini-test was conducted. Since the dry water beads are extremely hard to crush, the wet water beads were crushed to make the powder.

1. Place 4 water beads in the 25 ml water for 2 hours (water beads increase to the maximum volume)

2. Crush wet water beads with knife

3. Place water beads in the microwave oven for 5 minutes (accelerate the vaporization of water)

4. Due to the previous calculation, each water bead can absorb at least 1 ml of water. In the process of vaporization and changing container, there is a loss of water beads powder, so 3 ml water was used to test the absorption rate of the powder.

video Demo of the test (It takes about 15 to 20 seconds for water beads to fully absorb 3ml water!)

Diaper core parts design
Since the water beads powder absorbs water fast enough, the first prototype for the core part of the diaper was designed. Because the particle of the powder is so small that gauze is unable to hold the powder. The material was changed to sponge. Water beads will be in the sponge placed in the bottom of the diaper. Once there is extra liquid, the sponge can absorb some.

Next steps
1. Testing the new prototype with dry water beads powder

2. Starting the technical drawing for mop

3. Building the mop prototype

Week 3 Narrative
During the past week, the second prototype for the core part of diaper and mop has been designed. Due to the complexity of making water beads powder and the lacking of materials, the demonstration of the second prototype was recorded.

Design of the prototype
Nonwoven cloth is commonly used in diapers because it almost does not absorb any water. Nonwoven is also used as the material of recycled shopping bag. Part of nonwoven shopping bag is used as the outermost material of the diaper. In order to hold the water beads power, paper towel was used as the inner attaching material.

Making fairly large amount of water beads powder
Since previous tests showed the powder maximizes rate of absorption, making massive water beads powder is necessary for the prototype. During the process of making powder, many water beads are wasted.

1. Randomly choosing 300 water beads.

2. Soaking these water beads for 2 hours.

3. Using any blunt tool, such as the bottom of the cup, to force water beads to go through sieve for three times.

4. Placing the wet water beads powder in the microwave oven for 5 to 7 minutes.

Creating the second prototype and demo
1. Cutting a rectangular piece of nonwoven cloth from the shopping bag

2. Placing the paper towel on the nonwoven cloth

3. Placing the water beads powder on the paper towel

4. Dropping two drops of blue ink in two 25 ml water

5. Spilling the blue water on the water beads powder

Demonstration of the rate of absorption and non-woven cloth

Next steps:

1. Finding a more efficient way to massive produce water beads powder

2. Finding the most comfortable material to baby's skin

3. Building the product with a diaper shape

Week 4 Narrative
During the past week, mini mop prototype was created with paper towel. The water absorption tests on both paper towel with and without water beads powder were run.

Design of mini mop head:
By stapling 5 pieces of paper towel that contains water beads powder, the real mop head can be stimulated.

Making mini mop head:
1. Cutting 5 pieces of paper towel (3cm*10cm)

2. Tearing open the double-layer paper towel (splitting a piece to pieces)

3. Placing water beads powder between two layers

4. Using a glue stick to seal the paper towel (creating paper towel "pouches")

Water absorption tests:
1. Measuring 25 ml water with measuring cylinder

2. Pouring water on the mini mop

3. Repeating step 1 until the mop stopping absorbing

Next steps:
1. Finding better flexible material for the "pouch" that can handle the expansion of water beads powder

2. Adding a hing to the mop head

3. Finding the way that can quickly recycle water beads powder