CHAPTER 2
LITERATURE REVIEW
This chapter discusses the examples of radiation particles that can be detected. This chapter also elaborates on some of the common radiation sensors that are possible to be used in this research as well as different types of kinematic models of mobile robot. The available developed path planning including the waypoints sweeping pattern and other applicable sensors for mobile robot are also discussed in this chapter.
Overview of Ionizing Radiation
Radiation is the process of emitting radiant energy in the form of waves or particles that travels through a medium or space. Radiation sources can be divided into two main categories which are non-ionizing radiation and ionizing radiation. Non-ionizing radiation includes natural background sources and man-made sources. The sun is one of the major background sources of radiation. It sends out ultraviolet rays that penetrate and damage human skin by causing sunburn. Certain minerals that make up part of the earth contain the radioactive elements. The levels may typically be in the range of 15 to 60 counts per minute that will vary depending upon one’s location on the earth, and the efficiency of the radiation sensor used.
Man-made sources that emit radiation include medical radiation sources and consumer products such as televisions and smoke detectors. Ionizing radiation includes alpha, beta and gamma particles.
Alpha
Alpha radiation consists of positively charged particles emitted from the nucleus of an atom in the process of decay. With strong positive charge, the density of alpha precludes them from penetrating more than an inch of air or a sheet of paper. Because of this, alpha particles are not a serious health hazard except when they...
... middle of paper ...
...nd commercial users around the world.
Ultrasonic Sensor
Ultrasonic sensors work on the principle of radar which interprets the characteristics of a target by evaluating echoes from radio waves. It generates high frequency sound waves and evaluates bounced echo which is received back by the sensor. Sensors calculate the time interval between sending the signal and receiving the echo to determine the distance of an object.
Beacon
A beacon is a device designed to obtain information of a specific location. Important information such as the status of an airport based on the colour and rotational pattern of its airport beacon as well as weather information as indicated by weather beacon on top of a high building can be obtained by combining beacons with semaphoric indicators. Also, when used in such fashion, beacons can be considered a form of optical telegraphy.
What Nuclear power has the ability to do is get a lot of power in a little amount of space. “Roughly 1.6 billion people live without access to electricity, and 2.4 billion rely on traditional biomass because they have no access to modern fuel.” (General Dr. Mohamed ElBaradei) With nuclear power put into these countries that are without power we can have it to where electricity will be accessibility to everyone. By having power accessible to everyone we can accomplish so much more and unlock more possibilities in our world today.
Radiation has always been in everyday life even before Roentgen discovered x-ray. The mountains give off natural radiation, other forms of radiation are coal burning power plants, x-rays from a TV, and an airplane ride. The average dose from background radiation is about 360 mrem every year. There are two types of radiation, nonionizing and ionizing radiation. Examples of nonionizing radiation are microwaves and radio waves broadcasting. Ionizing radiation refers to gamma and x-rays. Ionizing radiation means that the rays are able to remove an electron from the atom then ions can be formed. The ions can cause damage when reacting with other atoms. Cells are able to be repaired if low dose are received. However, if cells get a high dose, the cells will be damaged or possibly die. If the cell is damaged permanently then it is referred to as a mutated cell.
Apart of becoming a new patient at a dental office is taking an x-ray and some may have question along with taking an x-ray, like “will I be affected by the x-ray?” or “will I get cancer?”, “how long will it take” “are x-ray’s safe?”, the list goes on and on. So in this paper we will talk about different types of radiation affects such as affects on children and pregnant women as well as some things that may help reduce some of the radiation that may harm the human body.
Radar: detects the presence, distance and speed of passing objects by sending out radio waves;
The sun emits electromagnetic radiation of different wavelengths. This is basically the energy given off by the sun UV Rays are anywhere from 10 nanometers to 400 nanometers. They are the cause of bad things, such as sunburn and skin cancer. They also cause a lot of good effects, like they help kill germs and bacteria. There are UV-A rays, which are longer wavelength and are helpful for the most part. There are also UV-B rays, which have a shorter wavelength, and cause sunburns and other harmful impacts. Luckily 95% of UV-B rays are absorbed by the ozone layer. There are also UV-C, which is the most harmful, but they never reach the surface.
Beta radiation/emission – Beta particles are electrons (0-1e) that have been released from the nucleus of a radioactive atom when a neutron decays into a proton and electron. Beta decay/emission happens when the neutron to proton ratio is too high due to excess neutrons. 10n 11p + 0-1e (mass is still conserved as well as number of protons.)
The sun emits several types of radiation, most of radiation reaches the earth's surface. Warmth from the sun comes from infrared radiation. While the light and colours we distinguish is caused by visible radiation. Infrared and visible radiation are not harmful under ordinary circumstances. The higher energy part of the spectrum is ultraviolet radiation, a known carcinogen (cancer-causing agent). Both UVA and UVB radiation from the ultraviolet radiation reach the earth's surface. Exposure to either increases your risk of melanoma and other skin cancers. UVC radiation (also part of ultraviolet radi...
did manage to muster enough money to travel to Mars, the worry about the unknown amount radiation in space begins a whole new list of problems. One article stated, “Most estimates strongly imply that returning astronauts will have exceeded their lifetime radiation dosages, with consequent increases in cancer rates” (“Mars Travel and Radiation”). Radiation sources reside between the planets in the form of solar flares. Another example of radiation in space presents itself in the form of cosmic rays that exist on the surface of Mars. These atom fragments enter Mars’s thin atmosphere and create an environment that would be unsafe to live in without the proper protection.
It stands at the lower end of the electromagnetic spectrum. Some examples of this type of radiation would be power lines, microwaves, radio waves, infrared radiation, visible light, and lasers. Even though this type of radiation is less harmful than ionizing radiation, overexposure to this type can cause health problems. One example of non-ionizing radiation would be extremely low frequency (ELF). This type comes from power lines and electrical wiring. Researchers have not found a link between this type of radiation and cancer, although overexposure may have a factor in health issues. Another example is radio frequency (RF) radiation. This type comes from radios, cell phones, televisions, and microwave ovens. It can affect hearing aids and pace makers, so people need to take the appropriate measures of care when around this type of radiation. Infrared (IR) radiation and Ultraviolet (UV) radiation can cause skin cancer and cataracts if overexposure begins to occur. Non-ionizing radiation is not harmful unless there is too much exposure of it, as health problems may
The energy in ionizing radiation can cause chemical changes in the the cells that can lead to damaging them. Most of the cells can either permanently or temporarily become abnormal or they can just die. Radiation can cause cancer by damaging the DNA in the body. The damage of the cells can also depend on how long the organs are exposed (environmental protection agency, 2017, unknown). If someone has many exposures at one time that radiation in the body keeps adding on. As well as if its only a little bit of exposure in on day and years later you get exposed again it keeps adding on the radiation will never leave the body. Having radiation in your body doesn’t affect you right away but as you get older it starts to show and you feel it. Chronic exposure is when someone is exposed many time for long periods. When this happens the type of effects it will carry is having harmful generic change, cancer, tumors, and even cataracts. Partial health effects can also depend on if it was internal or external exposure. Internal exposure is when either by drinking, breathing, eating and even an injection cause radiation to get inside your body. External exposure is when taking an x-ray out of your body and letting it go through letting all the energy go as it goes in (environmental protection agency, 2017, unknown). In the dental world radiation gets into the patients when we take x-rays on there teeth. In order to avoid to much radiation on them we put a lead apron on them and make sure to cover their thyroid which is the most common way of getting cancer when taking an x-ray. When we take the x-ray we stand behind a wall at least 6 feet away to avoid ourself from getting
Radioactive isotopes are atoms with unstable nuclei that can either occur naturally or by scientists in labs. Radioisotopes have a huge and important effect on the technologies that provide us with food, water and good health. Scientists, doctors and even people everywhere have always struggled with food poisoning and food spoilage because of the insects, fungi or bacteria that can cause human disease or cause food to spoil. Food irradiation is the process in which food is made food safer and more resistant to spoilage allowing it to have a longer shelf life and to be in better condition since it kills disease-causing organisms and slows or eliminates those that cause spoilage leading to it becoming able to stay fresher for a longer period of time. The Radioisotopes that are most commonly used for irradiating foods are cobalt-60 and cesium-137. Food Irradiation has several advantages and some disadvantages which both have their cultural, health and economic effects (Uses of Radioisotopes).
In order to understand why food irradiation is necessary, the definition must first be outlined and understood. “Food irradiation (the application of ionizing radiation to food) is a technology that improves the safety and extends the shelf life of foods by reducing or eliminating microorganisms and insects” (“Food irradiation is”, 2016). Eliminating microorganisms and insects is accomplished in a few ways. There are three energy sources for food irradiation. First is the use of the elements cobalt or cesium. These elements have radioactive properties that allow gamma rays to be emitted into food. The radiation from these elements ionize and prevents microorganisms from multiplying. X-rays are also
First of all what is a Gamma Ray? A gamma ray is a high energy ionized radiation (EPA). Gamma photons have about 10,000 times more energy as photons (EPA). Along with that gamma rays wavelengths are so short they have to be measured in nanometers (EPA). They also are the strongest type of radiation which makes them the most dangerous. How are Gamma rays dangerous? A gamma-ray photon has enough energy to damage atoms in your body and make them radioactive (Christian, Eric). Gamma ray radiation also causes murderous burn, breast and a lung and thyroid cancer, genetics illnesses (Asiye, Gul). But when did we even discover gamma rays? In 1896 Henri Becquerel, a French Physicist, discovered gamma rays, he called it metallic phosphorescence (EPA). Becquerel had found gamma radiation being emitted by radium (EPA).
Now, the three examples, Chernobyl, Fukushima, Three mile islands, show the effect of the nuclear accident. Each has different causes, but the damages were terrible.
What is radioactivity? Radioactive isotopes are heavy nuclei of certain elements having extra neutrons. The extra neutrons in their nuclei cause them to be unstable so the nuclei break up spontaneously, emitting alpha, beta and gamma radiations. For example,