Force and Magnetic Fields on Earth

Force

• A force is a push or pull.
• Forces cause movement, deformation, or deflection of a material body.
• Examples of forces include ocean waves and wind patterns

Magnetic Fields

• A magnetic field is an invisible field created by moving electric charges like electrons.
• Electric currents produce magnetic fields.
• Materials like iron have aligned atomic magnets, creating magnetic fields.
• Examples include refrigerator magnets, compasses, and MRI machines
• Earth, the sun and magnetized planets are examples of natural magnetic fields

Earth's Magnetic Field

• Earth generates a protective magnetic field, protecting us from solar radiation and guiding compasses.
• The magnetic field is an invisible field like a giant bar magnet with north and south poles.
• Source is Earth's core of molten iron and nickel, as the liquid metal moves in the outer core and creates electric currents.
• These moving electric currents generate a magnetic field via electromagnetic induction.
• The magnetosphere is the region where Earth's magnetic field interacts with solar wind, shielding us.
• Magnetic and geographic poles don't align exactly and shift over time.
• Earth experiences pole reversals every few hundred thousand years, caused by core dynamics

Magnetism and Electricity

• Magnetism and electricity are bound together.
• Magnetism and electricity are present in the human body.

Gyroscopes

• A gyroscope generates a force (angular momentum) as it spins.
• A gyroscope resists orientation changes due to angular momentum.
• Precession: When an external force is applied, the gyroscope moves perpendicular to the force.
• Gimbal System: Some gyroscopes have gimbals for free rotation in multiple directions.
• Gyroscopes are used in navigation (aircraft, submarines, spacecraft), smartphones (motion sensors), stabilization (drones, cameras, robots), and wheeled vehicles (motorcycles).

Gravity

• Gravity supports bone density and muscle strength.
• Lack of gravity leads to muscle atrophy and bone loss.
• Gravity keeps blood flowing downward, but low gravity causes fluid shifts, puffy faces, and dizziness.
• Gravity helps the inner ear sense up/down for balance.
• Microgravity causes disorientation and motion sickness.

Uses of Gravity

• Gravity is used in weight-bearing exercises for rehabilitation
• It's counteracted with artificial gravity in space stations
• Gravity-based therapies are used for circulation and physical therapy
• Used in hydroelectric power and pendulum clocks for energy generation

Artificial Gravity

• Rotating wheel space stations generate artificial gravity

Tuning Forks

• Tuning forks resonate with each other, transferring invisible force or vibrations
• Used for music/instrument tuning and hearing tests

Physics

• Physics is used in experiments with sound waves, resonance, and vibrations

Senses

• The saccule in the inner ear detects vertical movement using calcium carbonate crystals on a gel-like layer
• Crystals press on sensory cells, signaling acceleration/deceleration

Actions and Reactions

• Every action (force) has an equal and opposite reaction for equilibrium.
• Forces have direction and this is a fundamental aspect of equilibrium.
• A body at rest exerts force (gravity force) on the surface it rests on.
• Reaction force is what pushes back against the force of gravity.
• This achieves equilibrium.
• Gravity pull on the body is resisted by the body's structure
• Reaction force from the ground keeps you standing against gravity
• Ankle, knee, elbows, shoulder, jaws are aligned for organ balance

Lines of Action

• Forces in the same line can maintain equilibrium if they are equal.
• Moment of force: Forces cause movement or rotation at a distance from a pivot point.
• Skaters generate large force while spinning with arms out, the large force can generate rotation when their arms are closer to their body
• Moment arm is the perpendicular distance between the force and the rotation point/axis.

Lever Principle

• The lever principle: A small force creates a larger lifting with a bar and a fulcrum (pivot point.)
• A smaller force is more effective farther from the rotation point (lever arm).

Torsion Moments

• Door handles create torsion forces when rotated to unlock a door.
• Pressing down after it stops twists the lock around an axis
• Wringing out a rag is an example of torsion moments.

History of Concrete

• Concrete structures date back to 6500 BC in the United Arab Emirates, used by Nabataean traders
• 3000 BC, Egyptians mixed mud with straw for dried brick and used gypsum/lime mortars in pyramids.
• China used cement to build the Great Wall.
• In 600 BC, Romans mixed water with sand for underwater mortar
• It was stronger, harder, more adhesive and cured faster than ordinary lime.
• Roman concrete is more durable as Roman seawalls have strengthened due to seawater interaction, forming crystals that reinforce them.
• Modern concrete corrodes over time by seawater
• Concrete lead to new possibilities in roman architecture.

Roman Architecture

• The Roman Colosseum, Pantheon, Caracalla, and Diocletian are iconic examples of Roman architecture using concrete.

Joseph Aspdin

• Joseph Aspdin invented portland cement in 1824.
• Heating and grinding limestone/clay lead to this, named after English portland limestone.

Reinforced Concrete

• Concrete with embedded steel bars (rebar) for strength.
• Steel bars resist forces, making concrete durable and stronger.
• Concrete is strong in compression but weak in tension.

Pioneers of Reinforced Concrete

• J.L. Lambot built the first reinforced concrete boat in 1855.
• Francois Coignet built the first reinforced concrete house in 1853.
• Thaddeus Hyatt experimented with concrete reinforcement, recognizing its resistance to tension.
• Joseph Monier patented reinforced concrete flower pots and built the Chazelet bridge (1875).
• Eugene Freyssinet pioneered pre-stressed concrete.
• The Francois Coignet 1853 house was first house built with reinforced concrete in 1853.

Mixing Concrete

• Concrete requires cement, water, sand, gravel, or crushed stone
• Proper mixing ensures uniformity and strength.
• The curing stage involves time to harden.
• It must be kept moist and at the right temperature to prevent cracks and ensures strength.
• The reaction is called hydration, and it helps set the concrete but can cause cracking if not controlled.
• Tiny air bubbles in concrete enhances resistance to freeze-thaw cycles.

Concrete Admixtures

• Concrete is mixed with admixtures which speed or slow setting.
• Water reducers can increase strength, too.

Cement

• Common binder in concrete.
• Portland cement create hard, durable material.

Critical Environmental Factors

• Air temperature, concrete temperature, humidity, and wind influence concrete settings and drying.

Fundamentals of Quality Concrete

• Quality cement, clean aggregates (sand, gravel), and clean water is needed
• The right water-to-cement ratio of 0.4 to 0.6 is needed for optimal strength.
• Proportions of materials is matched to their purpose.
• Workability is mixing, placing, and finishing without separating.
• Mix is spread thoroughly for distribution of materials
• Concrete mist stay moist for at least 7 days.
• This to set and gain strength

Concrete Criteria

• Strength depends on the water-cement ratio and curing process.
• Durability must have low permeability to prevent freeze-thaw/chemical damage.
• Regular testing is essential for strength and consistency, while batching ensures consistent quality.
• Slump Tests Fluidity of new concrete is measured by pouring concrete into a metal cone then lifted off.
• The concrete sinks lower and a higher the slump, which it is measured the better.

Test tools

• Ball Penetration uses a 6-inch steel ball on fresh concrete
• Sinking lower means they're more fluid, lower ones are stiffer.

Quality

• Materials matter and must be placed carefully

Tadao Ando

• Osaka Japan
• Pressure of concrete is on it's surface
• Overall good atmosphere

Pre-Cast

• Made in factories
• Good transportation
• Erected as rigid components
• Joinery is important
• Includes slabs and columns

Cast in Place

• Poured on it's site
• This includes concrete pouring
• Good support

Efficiency

• Great for harsh environment

Quality Control

• Includes high material and workmanship

Style

• Controlled framework

Efficiency

• Uses less weight
• Less depth

Materials

• Superior concrete, steel and control

Curing

• Quick type III cement

Concrete Tension

• Need reinforced concrete for high resistance

Pre-Tension

• Eliminates possible cracks.

Steel Support

• Concrete and steel are poured.

Reinforced Conrete

• Good tensile strength required to handle

Cast in Place

• Good design and monolithic structures

Fiber Conrete

• Good fibers but it may not be as strong.
• Fibers is good for orientation of the objects.

Control Joints

• Keeps crack hidden but does not prevent them.

Isolation Joints

• Separate structures or materials.
• Walls and columns may be used.

Church of 200 Jublee

• Rome and Richard Meir

Research Lab

• Richard Meir
• Reflects company
• innovation and commitment

Materials

• Density if of mass
• Stree if force

Ultamite

• Breaking of bonds

Lasting

• Depends on material
• Higher stiffness

Expansion

• Allows movement

Concrete

• Has movement with materials
• Help relieve from stress
• Pre planned for gaps

Adobe

• Raw material for a killen

Material

• Good additive and durability

Water Proof

• For wall elements
• Made from Earth to show maker

Sand Extrusion

• Great design but some are not accurate.

Anisotropic

• Strong depending on direction

Vertically Stonger

• Weight is distributed through unit

Roble house

Long horizontal bands of bricks are intensified by the recessed joints and shadows

Automation

• Machine used to increase productivity