下のスクリプトは事前提出されたものですので、ビデオの音声とは一部異なる場合があります。

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NO MORE MINES

Kagawa National College of Technology, Takuma

We will talk about the detection and elimination of landmines.
These are the main topics we will present today.
Victims of Landmines
Structure of Landmines
Detection and Elimination of Landmines

Mr. Shimizu will now talk about the victims of landmines.
Mr. Shimizu, please.

8065
Do you know what this number means?

According to the Japan Campaign to Ban Landmines Organization, this is the number of people who were killed by land mines in 2003.

However, this is not the correct number. We do not know how many victims there are actually. If the uncounted victims are included, it is said that 15,000 to 20,000 people are dying every year.
This is three times as many people as there are teachers in all KOSEN. This is equal to all the KOSEN teachers dying three times every year by land mines.

As for the number of land mines buried all over the world, we do not know the exact number.
Various groups report a different number of land mines depending on which group.

There are 60 to 70 million land mines, according to the United States' De-partment of State.
The United Nations has announced that there are 100 million land mines or more.
Another organization called International Campaign to Ban Landmines (ICBL) has not reported a number because they think the threats of land mines are not countable by the number of landmines.

So, what are the threats of these land mines?
Firstly, landmines are aimed to kill or injure an enemy soldier, however many of the victims are not soldiers but civilians. Even if they survive the explosion, they suffer from injuries like blindness, burns, destroyed limbs and shrapnel wounds.

There is also economic damage. Removing one mine costs 300 to 1000 US dollars. In addition, the best way to remove the land mine completely is by the handwork of a highly trained officer. So, it costs a great amount of time and money to remove even one mine.
In addition, we cannot use the land until all the mines are completely cleared away.
Even if there are only two or three mines, or even just a suspicion of their presence, we cannot make roads or buildings on the land.
Economically speaking, no foreign or domestic capitals are invested on such worthless land, so the development of the country will not happen unless the landmines are cleared away.

Thus, the threats of a landmine are not only that they kill people but also that they inflict damage on a country's economy .

What should we do to act against these threats? The answer is simple: detect the landmines and eliminate them. It is simple but really difficult to realize, almost impossible.

We must talk about the detection and elimination of landmines. Mr. Oka-zaki will talk about this.


First of all, we have to know the structure of a landmine. How does it ex-plode?

This is the simplest structure of a landmine.
This is a fuse.
The fuse senses weight.
Then the fuse explodes.
This small explosion sets off the gunpowder of the main body.
It causes a big explosion, which kills many people and destroys objects.
A mine called “MON50 mine” was able to kill people within a 50m radius. A land mine explodes like this when a person steps on it.
This is the simplest description of a mine.
But the structure of a real mine is more complicated.
For example, the German Army used mines called “S-mines” during World War II.
The S-mine is really small, a steel cylinder less than 13 cm tall without its sensor and is only 10 cm in diameter. It weighs about 4kg.
The unique characteristic of this mine is that it has wires connected to the fuse.
Stretched out wires form the trigger of the mine, and the fuse is triggered when the wires sense about 6.8kg in weight.
When the wire is stepped on, a small explosion occurs to toss up the main body of the mine.
It jumps up by about 1m from the ground and explodes.
What this means is that sharp steel fragments and iron balls inside the mine scatter widely through the air and fall back down like heavy rain.
Many people are wounded by these pieces of shrapnel.

Now that you understand the structure of land mines, how do we detect and remove them?　Ms. Horise will talk about this.

There are two major types of land mine detectors: metal detectors and radar detectors.　
A metal detector checks whether there is metal or not in the ground.
This detector generates a magnetic field, and when there is metal, the magnetic field changes.
By tracking this change of the magnetic field we can find a land mine.
Meanwhile a radar detector surveys the structure of the ground by radar. The detector radiates an electromagnetic wave. If there is an object, the wave is quickly reflected back by the object, but if there is no object the wave comes back much later. The detector senses this difference to detect the landmine.

These detectors are widely used but they cannot discover the mine with 100% reliability. Moreover, some of the mines can sense the magnetism from the mine detector and explode in reaction.

In order to solve these problems, we need to think of another way to detect the land mines.
What can we do?
In my research group, we have paid attention to the nitrogen that is con-tained in the explosives of land mines.
When the neutron is radiated into nitrogen, a gamma ray of 10.8 MeV is emitted from the nitrogen.
If we can detect this gamma ray, it means we can detect the mine.

We are doing research on gamma ray detection that can be applied to land mine detectors using this mechanism.
This is a picture of a gamma ray detector.
This figure is the waveform of the gamma ray that the detector senses.
This analog waveform should be outputted to digital data to be processed in a PC, so the signal is processed by analog modules first, then converted to digital data by digital modules.
Here we analyze the data and check whether or not we can detect a gamma ray of 10.8MeV

This summer, we went to a research institute in Ibaragi for experimenting.
The experiment was successful, and we confirmed that the detector can ac-curately sense the gamma ray.
So we would like to continue our research and complete this detector for the sake of all those people suffering from these land mines.

Our research would help perfect the detection of landmines, but it would not mean the perfect elimination of landmines.
The most effective way to remove mines is to make them explode. This is a vehicle that has a huge roller on it used to detonate mines. But this method is not perfect because there are some mines that do not explode by a single stimulation; they explode only when they sense weight several times.
And all we have to rely on is human hands, which is really dangerous.

We need to search for the safest way for the elimination of these land mines. This is the problem that we engineers must try to solve.

Here we would like to summarize our presentation.
First, more than eight thousand victims are dying every year and economic damage is enormous.
Second, the structure of landmines is not simple and to detect landmines is not safe. We propose a new method of detection that applies gamma-ray technology.
Third, there is no safe elimination of landmines with 100% reliability. Fur-ther research in this area is needed for saving victims of landmines all over the world.