Database Modeling in UML
6 pages
English

Database Modeling in UML

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6 pages
English
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Description

Introduction When it comes to providing reliable, flexible and efficient object persistence for software systems, today's designers and architects are faced with many choices. From the technological perspective, the choice is usually between pure Object-Oriented, Object- Relational hybrids, pure Relational and custom solutions based on open or proprietary file formats (eg. XML, OLE structured storage). From the vendor aspect Oracle, IBM, Microsoft, POET and others offer similar but often-incompatible solutions.
  • meaning within the business domain
  • relational model
  • relational database
  • many tables
  • behaviour
  • class
  • table
  • data

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Nombre de lectures 17
Langue English

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LEARNING OBJECTIVE: STUDENT PERFORMANCE OBJECTIVE: BACKGROUND:The student will begin to understand the formation and
8th Grade Lesson Plan UV: Chemistry of Ozone Depletiondestruction of ozone and the effects it has on UV. ??The student will define sunlight as the major energy source for both making and destroying stratospheric ozone.??The student will be able to define VOCs as Volatile Organic Compounds and determine they are both manmade and natural formations.??The student will be able to define Halogens as the chemical family containing fluorine, chlorine, bromine and iodine.??The student will begin to understand that Halogens have the ability to catalyze ozone breakdown and they have an unequal impact on the ozone layer.??The student will begin to understand that chlorine removal in the stratosphere involves the formation of HCl which is water soluble.??The student will determine how CFCs get into the stratosphere when they are heavier than air.The Earth’s atmosphere can be divided into severallayers. Thelowest layer, the troposphere, extends above the Earth about 10km.The next layer is the stratosphere which extends from 10km to approximately 50km. Themesosphere extends from approximately 50km to approximately 80km with the thermosphere directly above that. The temperature increases with the altitude in the stratosphere due to the absorption of UV light by oxygen and ozone.As sunlight is the major energy source for both making and destroying stratospheric ozone it causes the constant exchange between ozone and oxygen.UV light such as UVB and UVC are the sun’s high energy rays which we cannot see, but aid in keeping the balance of ozone in the atmosphere. Approximately 98% of these rays are absorbed by the formation and destruction of atmospheric ozone. While ozone is mainly produced and destroyed in the stratosphere where it protects the earth from the harmful effects of UV rays, certain pollutants (both natural and manmade are causing ozone to be produced in the troposphere.Ozone in the troposphere causes the greenhouse properties that warm the Earth; surface.The concentration of ozone in the troposphere only remains for a short amount of hours. Therefore high levels of ozone in the troposphere are often found in cities where high levels of pollutants are found.
MATERIALS: These pollutants are often known as VOCs (Volatile Organic
8th Grade Lesson Plan UV: Chemistry of Ozone DepletionCompounds). Thesecompounds, primarily made of carbon and hydrogen often contain halogens such as chlorine, fluorine and/or bromine. Theyare defined as volatile because of their tendencyto evaporate. Elementsfrom the halogen family (listed above) all have the ability to catalyze the breakdown of ozone, however their impact is an unequal one.While the natural process of sunlight and ozone both forms and destroys ozone, the halogens only destroy ozone leaving what many scientist classify as a “hole” in the ozone layer. CFCs (ChloroFluoroCarbons) are a class of VOCs that have been used as refrigerants, aerosol propellants, solvents, degreasers, cleaning solutions, dry cleaning fluids and components of pesticides and plastics. These chemicals have been considered safe to work with due to the fact that they are chemically unreactive.They are so unreactiveor inert that the natural reagents that remove most atmospheric pollutants do not react with them.Therefore they tend to stay in the atmosphere and after many years they make their way into the upper atmosphere where the UV radiation from the sun breaks them down into their component molecules. Thisreleases the potentially damaging chlorine (as well as bromine and fluorine) atoms which work to destroy ozone.Chlorine becomes the catalyst which reacts with ozone and breaks it down (Cl + O3> ClO + O2molecule of chlorine is estimated to degrade). One over 100,000 molecules of ozone before it is removed from the stratosphere. In the stratosphere chlorine will eventually form into an inactive compound of hydrogen chloride (HCl) which is water soluable and will precipitate out of the stratosphere by water droplets. See other lessons on UV and sun, the UV index, UV and ozone in our breathing space, UV and ozone depletion, UV monitoring, and benefits, dangers and choices of UV, the Earth’s tilt, seasons and UV. <for more> Demonstration Materials ??Sucrose C12H22O11(60 grams)??Sulfuric acid, concentrated 18M, H2SO4(60 mL)??Sodium carbonate, Na2CO3??250 mL beaker??100 mL graduated cylinder??tongs??balance??paper towels
SAFETY CONCERNS OPENING: ??Stirring rod, glass??Safety Goggles??Safety Apron
8th Grade Lesson Plan UV: Chemistry of Ozone DepletionActivity Materials ??Worksheet UV/81 Ozone Chemistry: Formation and Depletion??Litmus paper??Cups??Water from pond, puddle, and/or lakePlease follow safety precautions carefully.Do not allow students to perform demonstration. Complete in a well ventilated area. Wear safety goggles and safety apron. Have students wear goggles also. Use tongs to handle carbon product. Do not touch Sulfuric acid with hands (Sulfuric acid is very corrosive to eyes, skin and other tissue). Do not mix Sulfuric acid with water. (Carbon product will need to be completely neutralized with sodium carbonate before rinsing.) Disposal: When reaction is finished and the container is cool, pour sodium carbonate over the product to neutralize the acid. Once neutralized, rinse the carbon product thoroughly under running water. Placein a sealed plastic bag and place in the trash.Ask the Class:How do you know when a chemical reaction takes place?Chemical reactions take place all the time in the atmosphere, but we cannot see them. Howdo we know they are taking placeDiscuss with the Class: We have often heard the reports of the ozone layer being depleted.This is caused by compounds being released when they reach the atmosphere. Thesespecific compounds alter the natural formation and destruction of ozone in the atmosphere which protects us from UV rays from the sun.Today we are going to demonstrate how compounds get separated in a reaction.We will then test water samples and discuss how those chemicals (once neutralized) fall as rain into our water supplies.
PROCEDURES: Demonstrate to the Class: 1.Set up your materials on a table in view of your
8th Grade Lesson Plan UV: Chemistry of Ozone Depletionstudents in a well ventilated area.2.Follow all safety precautions and demonstrate safety to the students.3.Set up sodium carbonate and have ready to neutralize any acid spills4.Measure 60 grams of sucrose and place in the 250mL beaker.5.Set the beaker on paper towels.6.Measure 60mL of sulfuric acid in a 100mL graduated cylinder (neutralize any spills with sodium carbonate)7.Pour the sulfuric acid into the beaker containing the glucose very slowly.8.Stir briefly with a glass stirring rod.Leave the rod inside the beaker during the activity to support the column of carbon.9.Stand back and observe.Reaction will be complete in approximately 15 minutes.10.Discuss with the students the reaction and that carbon and water are both products of the reaction.Discuss the chemical changes and the heat and gas produced in the reaction.1.Discuss that harmful VOCs are constantly being put in the atmosphere by chemical reactions.These reactions happen naturally on their own and unnaturally from factories, power plants and other human activities.2.Define VOCs (Volatile Organic Compounds) as pollutants made primarily of carbon and hydrogenwhich contain halogens such as chlorine fluorine and/or bromine.3.Define CFCs (ChloroFluoroCarbons) as a class of VOCs that have been used as refrigerants, aerosol propellants, solvents, degreasers, cleaning solutions, drycleaning fluids and components of pesticides and plastics.4.Distribute worksheet UV/81 Ozone Chemistry: Formation and Depletion. Discuss the natural formation and depletion of ozone in the stratosphere.Go over the diagrams and discuss the effects of halogens on ozone destruction.5.Discuss chlorine as a halogen that upsets the natural formation and destruction of ozone.Discuss one molecule of chlorine can destroy over 100,000molecules ofozone before it is finally removed fromthe stratosphere.6.Explain that chlorine eventually becomes inactive in the stratosphere when it forms the molecule HCl which is water soluble and falls to the earthas rain.
SO WHAT? LIFE APPLICATIONS: CURRICULUM EXTENSIONS: 7.Explain to the students that while we do not have the technology in the classroom totest the formation and
8th Grade Lesson Plan UV: Chemistry of Ozone Depletiondestruction of ozonein the stratosphere, we do have the technology to test the water for evidence of chlorine from the inactive compound HCl.8.Have the students get samples of the water (puddle, pond and/or lake) and litmus paper and take to their lab stations.9.Students will use the paper to test the water’s PH to determine if there is chlorine present in the water.10.If you have access to several different samples of water, have the students test each sample to compare and discuss their results.11.Discuss how chlorine becomes soluable in water once it has formed the compound HCl anddetermine how this activity proves the presence of chlorine in the stratosphere.12. 13. Have the students explain their part in releasing these VOCs and CFCs in the environment (use of products that release VOCs or purchase of products that release VOCs during production).Have them come up with a plan of how they can help prevent the release of these chemicals and write a letter to a company explaining their concern relating to this process.Math/Science: Have the students test the samples of water over a period of time (hopefully before and after rainfall) and chart and graph their results. Language Arts: Have the students create a model or a skit demonstrating the effects of halogens on the natural formation and destruction of ozone in the stratosphere. Have the students write a letter to their congressman asking for stronger laws to prevent the release of VOCs into the stratosphere. Technology: Use the spreadsheet program to create a chart and graph of their results from the Math/Science activity.
RESOURCES: Have the students use the inspirations program on the computer to create a concept map explaining the
8th Grade Lesson Plan UV: Chemistry of Ozone Depletionrelationship between VOCs that release chlorine and the depletion of the ozone in the stratosphere. Have the students look up the Ecoplexwebsite to determine the ozone alert status and find out more about ozone. TEKS:8.9A,C Denton ISD SPO: Ecoplex web site http://www.nas.nasa.gov/Services/Education/Resources/TeacherWork/ Ozone/Ozone_chem.html http://www.atm.ch.cam.ac.uk/tour/part2 http://www.egs.uct.ac.za/csag/faq/ozonedepletion/intro/faqdoc8.html http:home.larc.nasa.gov/org/pao/PAIS/Aerosols.html http://www.epa.ohio.gov/ddagw/voc.html
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