Ultraviolet radiation (UV) - презентация, доклад, проект скачать

Нажмите для полного просмотра!

Содержание ▲

Вы можете ознакомиться и скачать презентацию на тему Ultraviolet radiation (UV). Доклад-сообщение содержит 36 слайдов. Презентации для любого класса можно скачать бесплатно. Если материал и наш сайт презентаций Mypresentation Вам понравились – поделитесь им с друзьями с помощью социальных кнопок и добавьте в закладки в своем браузере.

Слайды и текст этой презентации

Слайд 1

Описание слайда:

Ultraviolet radiation (UV)

Слайд 2

Описание слайда:

Research questions: 1.What is ultraviolet? 2. What are its mechanisms? 3. How does it influence flora & fauna? Inanimate objects? 4. How is it presently applied by human?

Слайд 3

Описание слайда:

Слайд 4

Описание слайда:

Meet, ultraviolet! The radiation of the Sun contains a few types of emitting, which differ from one another in the wavelength. The intermediate radiation, or ultraviolet radiation, is believed to have both benign and pernicious impact on the health of living things. It is able to pass through the atmosphere even in cold and cloudy weather.

Слайд 5

Описание слайда:

Let's consider the most common types of UV: Let's consider the most common types of UV: UVA (400-315nm) rays have a relatively long wave length and represent close to 95% of the UV rays that make it to the Earth’s surface . UVB (315-280nm) have a medium wave length. Only its part passes through the atmosphere.

Слайд 6

Описание слайда:

UVA UVA rays age skin cells and can damage their DNA. These rays are linked to long-term skin damage such as wrinkles, but they are also thought to play a role in some skin cancers. Most tanning beds give off large amounts of UVA, which has been found to increase skin cancer risk.

Слайд 7

Описание слайда:

UVB UVB rays have slightly more energy than UVA rays. They can damage skin cells’ DNA directly, and are the main rays that cause sunburns. They are also thought to cause most skin cancers.

Слайд 8

Описание слайда:

UVC UVC rays have more energy than the other types of UV rays, but they don’t get through our atmosphere and are not in sunlight. They are not normally a cause of skin cancer.

Слайд 9

Описание слайда:

What influence do UV rays have on the condition of living things?

Слайд 10

Описание слайда:

Photosynthesis UV radiation however causes production of reactive oxygen species (ROS) which may cause various type of damage to biomolecules. Extreme damage leads to cell death/chlorosis/necrosis and obviously a loss of photosynthetic process.

Слайд 11

Описание слайда:

Слайд 12

Описание слайда:

Health effects The ultraviolet radiation in sunlight has both positive and negative health effects, as it is both a principal source of vitamin D3 and a mutagen.

Слайд 13

Описание слайда:

Beneficial outcomes The benefits of UV can outweigh manageable risks. The human body needs some UV radiation in order for one to maintain adequate level of viability.

Слайд 14

Описание слайда:

Vitamin D Vitamin D Reasonable exposure to ultraviolet radiation from the sun can be a good source of vitamin D. Getting enough vitamin D can help stave off autoimmune diseases, cardiovascular disease, many types of cancer, dementia, types 1 and 2 diabetes mellitus, and respiratory tract infections.

Слайд 15

Описание слайда:

Serotonin Serotonin Vitamin D promotes the creation of serotonin. The production of serotonin is in direct proportion to the degree of bright sunlight the body receives. Serotonin is a monoamine neurotransmitter that is thought to provide sensations of happiness, well being and serenity to human beings.

Слайд 16

Описание слайда:

Melanin Melanin The amount of the brown pigment melanin in the skin increases after exposure to UV radiation at moderate levels depending on skin type. Melanin is an excellent photoprotectant that absorbs both UVB and UVA radiation and dissipates the energy as harmless heat, protecting the skin against DNA damage.

Слайд 17

Описание слайда:

Effects on eyes Effects on eyes Significant daily exposure to bright light may be necessary for children to avoid myopia (nearsightedness).

Слайд 18

Описание слайда:

Harmful effects Excessive exposure to UV radiation can result in acute and chronic harmful effects on the skin, eye, immune system and DNA.

Слайд 19

Описание слайда:

Skin damage All bands of UV radiation damage collagen fibers and accelerate aging of the skin. Both UVA and UVB destroy vitamin A in skin, which may cause further damage. UVB radiation can cause direct DNA damage.

Слайд 20

Описание слайда:

Eye damage Prolonged optical exposure to sunlight, especially intense ultraviolet light, may be linked to cortical cataracts. Short-term over-exposure can cause snow blindness, which is analogous to sunburn of the cornea, or can cause solar retinopathy, which is long-lasting retinal damage and vision impairment from sungazing.

Слайд 21

Описание слайда:

UV skin protection SPF stands for sun protection factor. Sunscreens are classified by an SPF number which refers to their ability to deflect UVB rays. The SPF rating is calculated by comparing the amount of time needed to burn sunscreen-protected skin vs. unprotected skin.

Слайд 22

Описание слайда:

Classic vs. Mineral: Which is Which? Classic and Mineral Sunscreens are differentiated by their active sun protection ingredients. Classic sunscreens use chemical active ingredients designed to absorb and dissipate UVA/UVB rays, while Mineral sunscreens use mineral active ingredients such as Titanium Dioxide and Zinc Oxide to scatter and reflect UVA/UVB rays.

Слайд 23

Описание слайда:

The effect of classic suntans is based on chemical reactions by swallowing sun radiation and mineral ones create a protective layer on the skin surface. The effect of classic suntans is based on chemical reactions by swallowing sun radiation and mineral ones create a protective layer on the skin surface.

Слайд 24

Описание слайда:

UV eye protection To decrease the risk of developing eye-related diseases, it may be wise to wear sunglasses when outdoors, even on overcast days.

Слайд 25

Описание слайда:

But what about inanimate objects?

Слайд 26

Описание слайда:

Degradation of polymers, pigments and dyes Many natural and synthetic polymers are attacked by ultraviolet radiation, and products using these materials may crack or disintegrate if they are not UV-stable.

Слайд 27

Описание слайда:

Слайд 28

Описание слайда:

Applications Because of its ability to cause chemical reactions and excite fluorescence in materials, ultraviolet radiation has a number of applications.

Слайд 29

Описание слайда:

Photography Photography by reflected ultraviolet radiation is useful for medical, scientific, and forensic investigations, in applications as widespread as detecting bruising of skin, alterations of documents, or restoration work on paintings.

Слайд 30

Описание слайда:

Analytic uses UV is an investigative tool at the crime scene helpful in locating and identifying bodily fluids. Other applications include the authentication of various collectibles and art, and detecting counterfeit currency.

Слайд 31

Описание слайда:

Air purification Using a catalytic chemical reaction from titanium dioxide and UVC exposure, oxidation of organic matter converts pathogens, pollens, and mold spores into harmless inert byproducts.

Слайд 32

Описание слайда:

Sterilization & disinfection Ultraviolet lamps are used to sterilize workspaces and tools used in biology laboratories and medical facilities. Solar water disinfection has been researched for cheaply treating contaminated water using natural sunlight. The UV-A radiation and increased water temperature kill organisms in the water.

Слайд 33

Описание слайда:

Insects trapping Ultraviolet traps called bug zappers are used to eliminate various small flying insects. They are attracted to the UV and are killed using an electric shock, or trapped once they come into contact with the device. Different designs of ultraviolet radiation traps are also used by entomologists for collecting nocturnal insects during faunistic survey studies.

Слайд 34

Описание слайда:

Skin conditions Skin conditions UV rays also treat certain skin conditions. Modern phototherapy has been used to successfully treat rickets, psoriasis, eczema, jaundice, vitiligo, atopic dermatitis, and localized scleroderma.

Слайд 35

Описание слайда:

Summary findings UV occurs to be the one of nature factors which we only have the opportunity to receive with beneficial and harmful sides bound together. The effect of the ultraviolet can be used and turned into the tool for the human’s wellbeing.