Java programming language

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Java programming language  

• Java SE 8.0 - released Mar 2014
• Just In Time compiler
• only compiles a section of code when it is needed
• does not recompile something if already in memory
• has a warm up cycle so the first time of a compute is a little slower
• speed
• 25 times faster than scripting languages like Python, Ruby, Perl, R
• within 20% of the speed of C, or C++
• variables have to be declared first
• Open source - but is controlled by Oracle Corp.
• easy to distribute
• runs on all kinds of platforms
• tons of librarys to ease the coding burden
• do not have to manage memory (garbage collection)
• no pointers to complicate issues
• comparable to C# which is the Microsoft equivalent to Java
• Java on Wikipedia
• Java Homepage

Netbeans Integrated Development Environment

• NetBeans 8.0 IDE - released Mar 2014
• eases the effort of program development
• identifies unused variables
• auto-completion of code
• set debugging check points
• output console to read output variables
• facilitates projects that involve many source files all relating to the samp project
• automatic compilation of executable .jar files
• NetBeans on Wikipedia
• NetBeans Homepage

air flow in steamlines

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air flowing around objects in streamlines

streamlined flow is also called laminar flow

• laminar flow links
• Wikipedia link on laminar flow
• NASA link on aerodynamic drag
• Science Learning link on aerodynamic drag
• Video about streamlines from talk at Univ of Mich
• occurs when a fluid flows in parallel layers, with no disruption between the layers
• the fluid (air in this case) is comprised of an immense numbers of molecules
• the molecules are jittering back and forth colliding with themselves at 1100 miles per hour in very short distances (.000001 inches)
• air velocity (or apparent wind in the case of an iceboat) is less than 10 percent of the molecular speed
• you must consider the whole streaming flow in a realistic mathematical model of the corresponding lift and drag elements
• examine the differences between the streamlines in the top diagram where the resistance goes from 100% down to 5%
• the greater the resistance, the greater the spoiled streamlines at the rear of the wing
• the roiled air is caused by flow separation of the streamline
• flow separation happens when the flow streamline exceeds a large curvature within a short distance
• the more you can reduce of eliminate the eddies (i.e. roiled or turbulent air flow), the better will be the performance

laws of motion

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Issac Newton discovered the three laws of motion

• 1st law of motion
• if the net force (the vector sum of all forces acting on an object) is zero, then the velocity of the object is constant
• thought experiment A
• a stationary iceboat is resting on the ice angled at 70 degrees away from true north
• there is no wind
• in this situation there are no forces acting on the boat, thus the boat will remain at rest with a constant velocity of zero
• thought experiment B
• an iceboat is sailing angled at 70 degrees away from true north
• wind is blowing at 12 mph from the true north
• skipper has sheeted to a certain tension on the boom and placed the sheet line in the jam cleat
• eventually on the 70 degree course the iceboat reaches steady state and is neither speeding up or slowing down
• the boat is not hiking or side slipping on its runners
• both experiments A and B are examples of the 1st law of motion
• 2nd law of motion
• force = mass * acceleration
• 3rd law of motion

air properties

physical properties of air

air molecules

• nitrogen (N2) - 78.1%
• oxygen (O2)- 20.9%
• argon (Ar)- .9%
• carbon dioxide (CO2)- trace
• water vapor (H2O) - approx 1%

air pressure

• force exerted on an object  at a certain elevation by its surrounding air molecules
• air molecules at a certain level are compressed by the weight of the air molecules above itself
• air molecules travel at an average speed of 1160 miles per hour
• this speed directly correlates with the speed of sound
• 1 cubic foot of air at sea level contains 7.6 x 10**23 molecules

air pressure by altitude

• sea level - 14.7 psi
• 5,000 feet - 12.2 psi
• 10,000 feet - 10.1 psi
• 18,000 feet - 7.3 psi
• Mount Everest - 
• 50,000 feet - 1.6 psi

mean free path

• defined as the average distance any air molecule travels before colliding with another molecule
• mean free path at sea level = .3 /(10**6) feet
• this very short distance bounds how air molecules might react with moving objects

wind

• movement of air from a high pressure region to a low pressure region
• at a microscopic level the air molecules are still jittering about as they collide with each other
• differing pressure regions are primarily caused on earth by:
• differential heating between the equator and the poles
• causes air to move from the equator to the pole
• Coriolis effect of the earth rotating on its axis
• causes air to move from west to east
• in northern hemisphere at the 45th parallel, the combination of the above two effects leads to wind on average to blow from the southwest
• local effects
• heating and cooling at shorelines of oceans and lakes
• mountain valleys and large hills

temperature

• an increase in air temperature causes an increase in the average air molecule speed
• as the molecular speed increases, the volume expands in the direction of decreasing pressure which is upwards
• the expansion causes a corresponding wind vector towards the low pressure area

Why so fast? detail

Aerodynamic; low runner friction; minimum drag wing 

• low runner friction

• long runner blade
• extremely smooth and straight runner tip
• minimum amount of rocker to only enable essential steering
• runner tip sharpened to match ice and wind conditions
• must less drag of the iceboat runner over the ice than a typical sailboat would have in sailing in and over the water
• 
  
• minimum drag wing
  
  

• sail (ie. wing) is designed to provide maximum driving coefficient: which means the lowest drag possible for the apparent wind angle of the wing
• low drag is achieved by:
• small coef. of wing drag
• camber of sail only matches typical apparent wind angle and no more - much flatter sail than a sailboat
• rotating mast to align with apparent wind
• jib or genoa is not used as would cause added drag
• small induced drag of wing
• tall rig with short boom
• boom is very close to deck of fuselage
• aerodynamic

• components are streamlined with minimal frontal area
• slender runner plank
• tear shaped mast
• body suits (some classes)
• oval fully enclosed fuselage (some classes)
• discussion
• all of the above combine to produce a boat that travels at 4 to 5 times the speed of the wind
• such speed multiples means the iceboat operates at apparent wind angles of less than 11 degrees (class dependent)

Runner comparison by type

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activities with runners or other materials sliding on ice/snow

• iceboat
• 85 degree to 105 degree face
• tip stoned to sharp point
• usually hardened to 47 to 57 Rockwell
• very low rocker or crown
• skates
• hockey skate
• hollow ground bottom steel
• medium rocker
• flared hockey skate blades
• goalie skate
• squared off bottom
• squared off bottom
• sharp stones edges
• speed skating
• squared off bottom
• sharp stoned edges
• low rocker
• Calgary - sharpen speed skates
• figure skating
• hollow ground
• large rocker
• very sharp
• ice track on closed course downhill 
• corners are banked to keep vehicles on course
• bobsled

• large radius rounded edge
• very smooth surface
• bobsled runners and ice characteristics
• 
  
• luge
• runner is canted at 45 degrees
• sharp edge bottom
• luge runners
• skeleton
• round edge 
• multiple grooves only at rear edge (2 mm max.)
• http://www.davenportsleds.ca/runners.htm
• Alberta skeleton rules
• downhill ski
• cross country ski
• dog sled
• radio flier sled
• horse drawn sleigh
• curling stone