chua zong wei reflections

Why should pollution bother us?

While most developed countries have complete access to clean water and excellent sanitation, many third world undeveloped countries like africa and some parts of india have a lack of clean, drinkable water and proper sanitation due to the fact that these countries do not have the resources to purchase expensive water purification machinery to improve on their water quality and their citizens do not have enough money to purchase proper sanitation products. This allows waterborne diseases to spread quickly and easily, causing many unneeded deaths. Waterborne diseases like diarrhea, cholera and dysentery are caused by harmful microorganisms which are directly transmitted when contaminated fresh water is consumed. The statistics are alarming, with 1.1 billion people around the globe having no access to drinking water, 2.4 billion have inadequate sanitation and 3,4 million die from waterborne diseases yearly However, even developed countries will face the problems of pollution, due to the fact that we are constantly releasing pollution into the atmosphere as we burn fossil fuels to power our vehicles, it will cause our immunity system to become weaker, allowing infectious airborne diseases to spread easily. It will also cause environmental degradation around the polluted spot, causing nearby biodiversity and habitat to be destroyed. As biodiversity is crucial to the country’s growth, this may have a negative impact on the economy of the polluted country. Although pollution is a global problem, it also features more opportunities. Careers featuring pollution treatment are among the fastest growing economies, and it will also help to make a change among the lives of other people

General overview of what we learnt

1.scanning electron microscope

Electron Microscopes were developed due to the limitations of light Microscopes, which are limited by the physics of light to a maximum of 500x or 1000x magnification and a resolution of 0.2 micrometers. This prevented scientists from observing smaller structures that are unable to be seen by a regular light microscope. Therefore, in order to satisfy mankind’s urge to see what goes beyond what we see using a regular electron microscope, the electron microscope was created. A scanning electron microscope is a type of electron microscope that images a sample by scanning it with a high-energy beam of electrons. The electrons interact with the atoms that make up the sample producing signals that contain information about the sample's surface topography, composition, and other proper

ties such as electrical conductivity. However, samples must first be placed in a vacuum environment lest the molecules that make up air absorbs the electrons and preventing the specimen from being seen. Samples must also be coated with conductive material, like gold, titanium and palladium

Our questions on this topic

1) What do you think may be caused if there is too much moisture on the specimen?

Water and moisture will readily absorb the electron beam and obscure the specimen from view, therefore producing low quality images and might affect the results of the point analysis feature available in the electron microscope

2) What is the working distance and accelerate voltage if the specimen is titanium?

• Acceleration voltage: 20kv
• Spot size: 10nm
• working distance: 10mm

3) Why can’t we heat the filament too fast?

It will cause the filament to explode violently and damage the electron microscope, preventing the use of the microscope for weeks to come as it is being repaired.

2.composite materials

Composite materials are either man made or naturally occurring materials made

from two or more materials with significantly different physical and chemical properties. This results in a brand new material that may retain the unique traits of the materials that were used to manufacture it. Composites are made up of individual materials referred to as constituent materials. There are two categories of constituent materials: matrix and reinforcement. At least one portion of each type is required. The matrix material surrounds and supports the reinforcement materials by maintaining their relative positions. The reinforcements impart their special mechanical and physical properties to enhance the properties of the matrix. However, these materials are also cheap to produce, and can be used as an alternative to other more expensive materials. However, composite materials tend to be very brittle, and break/shatter easily when great force is applied to it, making it unsuitable for building structures that must be bent to a certain degree

3.Tensile material testing

In this experiment, we were provided sticks made with iron, rubbers or polymers. These sticks were then placed in machines, which stretched the sticks to their breaking point, and recorded the amount of force required for the sticks to break. At the end of our experiment, we can conclude that iron sticks required the largest amount of force to break, and the stick made of rubber required the least amount of force to break

Images captured during the learning process

Snapshot of the “Titania” that we observed in the virtual SEM machine

Data graph of the composition of “Titania” that we acquired in the virtual SEM tour

Overview

Project A- Tensile Material Testing

Mission : To explore the concept of the strength of different materials and the judging scale named young calculus.

Objectives:

•To understand different mechanical properties if materials

•To observe how the three types of materials behave in their mechanical properties under the tensile and bend test

•To understand the major factors that determines those mechanical properties.

Brief information: Tensile Material Testing is used for testing the strength of a material, based on how much it can be stretched before breaking. The material's respective micro-structure will determine how much force it can withstand before snapping.

Project B- Scanning Electron Microscope

Mission: To learn about electron microscopy and develop a better understanding of EDX

procedures and its applications.

Objectives:

-Understand the concept of the electron microscope.

-Learn how to operate an electron microscope properly and safely.

-Learn how to use EDX to derive at the chemical structure of substances.

Brief Information: The electron microscope uses beams of powered electrons to magnify a specimen. The electrons are fired down to the specimen and reflected back into a capturing device, producing an image. It is superior to the normal microscope due to the physics of light which the normal microscope uses.

Procedures:

1. Vent the chamber. This is to enable the specimen to be inserted into the chamber.

2. Press evac. This is to remove the air from the chamber as to make it a vacuum, so that the electrons can travel down to the specimen freely without getting disrupted by the air.

3. Set the optimal acceleration voltage, working distance and spot size.

-Acceleration voltage : The voltage which the electrons will be beamed down to the specimen. Too high a voltage will result in the specimen melting and damaging the SEM.

-Working distance : The distance between the specimen and the electron gun. This is usually in millimeters.

- Spot size : The size and width of the electron beam. It is usually in direct proportion to the specimen size.

4. Turn up the filament SLOWLY. A sudden rush in turning up the filament will result in the filament melting. Turning it up too much will also have a similar effect.

5. Start to beam the electron to the specimen. After this you should get a blurry, unfined image.

6. Adjust the focus knobs, brightness, contrast, X and Y magnifications and general magnification until the image is clear and satisfying.

7. Save the image.

8. Set the voltage to 0 and turn off the beam.

Project C- Composite Materials

Mission- To learn about composite materials and their effectiveness and applications.

Objectives:

- Learn how to combine materials into strong and sturdy materials as hard as diamond.

- Pick up concepts on the atomic structures of combined materials.

Brief information: Composite materials are substances derived from two individual materials. Composite materials are manufactured by converting the default materials into liquid state by melting and combining them in liquid shape and allowing it to cool in the desired shape. Although composite materials are usually stronger then their default materials, there are some disadvantages like the cost of it being quite high as many complex materials are required to form the shape and material. Each part has to be manually formed and layered and baked in a vacuum. It is also brittle as the atom bondings may be interfered in the manufacturing process and the strength of the composite material may be random depending on the atomic bondings.

Project C- Composite Materials

Mission- To learn about composite materials and their effectiveness and applications.

Objectives- Use techniques and theories about composite materials to create a carbon fiber as hard as diamond, and pick up skills and concepts via observation while attempting to do so.

OVERVIEW

Composite materials are substances derived from two individual materials. Composite materials are manufactured by converting the default materials into liquid state by melting and combining them in liquid shape and allowing it to cool in the desired shape. Although composite materials are usually stronger then their default materials, there are some disadvantages like the cost of it being quite high as many complex materials are required to form the shape and material. Each part has to be manually formed and layered and baked in a vacuum. It is also brittle as the atom bondings may be interfered in the manufacturing process and the strength of the composite material may be random depending on the atomic bondings.

Some information

Just didnt want u guys to look like fools when u get to NTU and ask the guy "What is a electron microscope?"

THE ELECTRON MICROSCOPE

The electron microscope is a type of microscope capable of millions of times of magnification. It is superior to a general, ordinary microscope for this trait. It works by releasing a beam of electrons down to the specimen. The specimen must be in a conducting material, and gold is usually used to coat the specimen.

.

above: A spider coated in gold for electron microscopic scanning. please dont scream michelle :D

source: http://wapedia.mobi/en/File:Gold_Spider_SEM_sample.jpg

The purpose of coating specimens with conductors is simply because without conductors, the electrons would disperse around the surface of the specimen and fail to return with an image of the specimen, since secondary beams beamed back to the microscope produces an image of the specimen at the desired magnification.

List of projects

Just for extra, unnecessary information :)

1. Photoshop

2. Cells/
-optical microscope
-immune hurosence
-phase contrast microscope
-confocal microscope

3. Fastest ball challenge

-Potential and kinetic energy

K.E= 1/2mv^2

m= mass

v= velocity

P.E= MGH

m=mass

g= gravity

h= height

4. Distillation

-Fractional distillation: When substances with different boiling points need to be separated

Substances with lower boiling point distillates and condenses at top first

Substances with higher boiling point evaporate and condense later

E.G the crude oil company when required to separate oil from alcohol, hydrocarbons, etc

5. Water tower withstanding earthquake

-Natural frequency

-Reasonating frequency

6. Chemistry game...no one doing in my class so Mr Sim didnt explain

7. Hand held device for speech impaired patients

Not Mr Sim's area of interest so he didnt say

8. Automatic outdoor light controller

9. Tensile testing of composite materials, electron scanning, bla bla bla

-SEM (scanning electron microscope)

source is electron.

optical microscope uses light.

Electron microscopy has higher magnification.

Electron beams are shot down on specimen surface. Surface needs to be conducting (coated with metals). Reflection of electron beams (secondary beams) gives a profile of surface image.

e= Stress over strain