Engineering

1. Engineering Carlos A. Santos SilvaSeptember 23th, 2009

2. What is Engineering?

3. The roots • Ingenium [Latin]: • innate quality, especially mental power, hence a clever invention = Genious [English] • Engine: • Military machine / machine • Engineer: • Operator of an engine • Engineering: • Military engineering (roads, bridges, vehicles)

4. Definition Accreditation Board for Engineering and Technology: • The creative application of scientific principles to design or develop structures, machines, apparatus, or manufacturing processes, • or works utilizing them singly or in combination; • or to construct or operate the same with full cognizance of their design; • or to forecast their behavior under specific operating conditions; • all as respects an intended function, economics of operation and safety to life and property; “Scientists study the world as it is; engineers create the world that has never been” [T. von Kármán] “Apply scientific knowledge and technology to solve real problems”

5. History

6. The Greeks “Give me a lever and I will lift the world” Heat-Ray Syracuse Archimedes Screw (Holand)

7. The Romans Aqueducts (PontduGard,France) Criptoportic (Lisbon,Portugal) ViaApia (Italy)

8. The Egyptians, The Chinese, The Arabs Papyrus scroll (Imhotep) 5 machines (Al-Jazari 1200) Great Wall (Chinese 500BC-1700)

9. 16th to 19thCentury Electrical Motor (Hungary 1821) Steam Governour (James Watt 1788) One span bridge (Leonardo Da Vinci) Siemens Telegraph (Germany1856) Jaquard loom (France 1801)

10. 20thCentury Jet Plane (Germany 1929) Ford T (US 1908) Space shuttle (US1981) Panama Canal (US1914) ENIAC (US1946) Transistor (US 1947)

11. Types of engineering

12. Traditional branches • Civil Engineering • Mining Engineering • Mechanical Engineering • Chemical Engineering • Electrical Engineering • Aeronautics Engineering • Physics Engineering

13. New branches • Computer and Software Engineering • Bio – Engineering • Molecular Engineering • Nanotechnology Engineering • Mechatronics Engineering • Aerospace Engineering • Engineering Systems

14. Engineering Systems “study dealing with diverse, complex, physical design problems that may include components from several engineering disciplines, as well as economics, public policy, and other sciences” • Examples of complex systems: • Internet • Supply Chains • Air-traffic control • Energy networks

15. Engineering mindset

16. Solve problems by finding solutions "Everything should be made as simple as possible, but not simpler.“ [A. Einstein] Create model that represents the problem Understand problems and test solutions Design multiple solutions Evaluate options Choose solution Trade off between requirements fulfillment, complexity of manufacturing, safety….

17. Characteristics • Build models • Abstraction • Design solutions • Science knowledge • Deduction • Analogy • Make choices • Experience • Intuition Simple problems: Show what to do: theory, application, heuristics, examples to train theory Compound problems: Case-studies: get information and apply accordingly

18. Engineers…. • Know that there is more than one solution • The best solution might not be the perfect solution • The result might not be exactly as previewed, but it is within an interval • Have to know science (physics) • Deduct results (general premises to particular conclusions) • Establish analogies (transferring information from a particular case to other) • Class1- Defining Engineers • Battle against uncertainty • Result driven

19. Why Physics? • Understanding of Nature • Discovering the laws governing the universe and predict how it will behave Matter: Anything that has weight Light: Anything that can travel trough empty space and has no weight Tools • Scientific method: theory to explain and predict, experiments to demonstrate • Reductionism: isolate system to study • Measurement System • Scaling • Estimates • Vectors • Conservation Law • Simplifying assumptions

20. Introduction to engineering

21. Program and Evaluation • Engineering and tools for Engineering • Kinematics and Dynamics • Waves, Atom and Optics • Electricity and Magnetism • Electrical Systems • Thermodynamics • Fluids • Heat Transfer • Thermodynamic cycles • Diesel and Otto cycles • Steam and Cooling cycles • Systems Assignments for each topic (40%) Final Assignment (60%)

22. Bibliography and References • Classes Slides and Readings • http://groups.google.pt/group/mit-portugal_ses_0910 • Books • http://www.lightandmatter.com/ • Newton physics • Conservation laws • Vibration and Waves • Electricity and Magnetism • Optics • Modern Revolution in Physics • Internet • http://www.wikipedia.org/

23. Tools for Engineering Carlos A. Santos SilvaSeptember 25th, 2009

24. International Measurement System (SI) • Basic Units • Meter (m) for distance • The length between two marks on a platinum-iridium bar, which was designed to represent 1⁄10,000,000 of the distance from the equator to the north pole through Paris • The meter is the length of the path travelled by light in vacuum during a time interval of 1/299 792 458 of a second • Second (s) for time • Kilogram (kg) for mass • Ampere (A) for electric current • Kelvin (K) for temperature • Mole (mol) for amount of substance in a system • Candela (cd) for luminous intensity Prototype meter (1960) Prototype kg

25. SI Prefixes

26. Metric Measurement System (SI) • Countries where the metric system is official

27. Other units • Velocity – meter per second [m/s or ms-1] • Velocity of an object traveling 1 m in 1 s • Force – Newton [N] • Force applied during 1 s to a 1kg object starting from rest to a velocity of 1ms-1 • Energy (Mechanical and thermal) – Joule [J] • A force of 1 N moving an object for 1 m • Heat 1g of air by 1 K • Power – Watt [W] • 1 J per 1 s / rate of work or energy • Energy (Electrical) [J] • Produce 1 W during 1 s

28. Scientific notation • It is used to represent large numbers • Representing a number with a product between: • a number between 1 and 10 • a number that is a power of 10. • Examples: • 1000 kg = 1x103 = 1E+3 • 1g = 0,001kg = 1x10-3 =1E-3

29. Conversions • Different measurement systems • 1 inch = 2,54 cm = 0,0254 = 2,54x10-2 m • 1 lb = 4,54 10-1 kg / 1kg = 2,2 lb • 1 cal = 4.184 J (thermochemical calorie) • Conversion methodology • 10 pound in kg • 1 year in s

30. Significant Figure Gives the accuracy of a number • 5m ≈ 4,99m ≈ 5.12m • 5.00m ≠ 4.99m ≠ 5.12m The number of significant digits depends on the least accurate data • 5.00m + 0.1m = 5.1m To count the number of digits, count the number of digits different from the 0s to the left and to the right (ambiguous) • 50cm=5.0x10-1m or 5x10-1m • 0,5m=5x10-1m • Using scientific notation helps to keep track of the significant figures • 5x10-1m (1 significant figure) • 5.0x10-1m (2 significant figure)

31. Scaling • In order to study a system it is normal to make scaled models Natural phenomena behave differently on different scales Example Clay 1: length x height x depth Clay 2: 2length x 2height x 2depth Why does Clay 2 break? Cross Area α L2 Clay2 =4 Clay1 Volume (Weight) α L3 Clay2 =8 Clay1 Galileo experiment

32. Order of Magnitude • Things that differ by a factor of 10 are said to differ one order of magnitude 1 and 9 are the same order of magnitude 1 and 19 are one order of magnitude different Often it is necessary to make rough estimates (~) Round up to the nearest power of ten (same order of magnitude) Don’t forget scaling effects: Imagine simpler objects Estimate area and volume based on linear dimensions Example: How much does it cost to cover the classroom floor with a 1m long square panels that cost 10€?

33. Vector Geometrical object described by • Magnitude (length) • Direction Entity that “carries” A to B Used to describe forces

34. Vector Operations Addition Scalar multiplication Cross Product