Great Inventions- Notes

Key Inventions: Electric generator, electric power grid
AC vs. DC: Preference for Alternating Current (AC) over Direct Current (DC)
Turbine: Produces continuous power; a machine that revolves using flowing fluids (water, steam, gas, air)
Coal-fired Power Plant:
- Combustion of coal heats water in a boiler to produce steam.
- steam drives turbine blades, generating electricity via a generator.
System Inertia:
- Kinetic energy stored in turbine generators; helps maintain grid stability.
- Turbogenerators rotate at the same frequency as the electric grid.
Load Shedding: Can cause a domino effect, straining the network.
Base Load: Minimum constant power demand required 24/7.
Power Production vs. Distribution:
- Production: Creation of electric power.
- Distribution: Dispersion of electricity to consumers.
Power and Demand Balance:
- Grid does not store energy; must balance production and consumption.
- Excess production raises frequency; demand exceeding production can lead to rolling blackouts.
Reactive Power: Retains voltage levels; supplied by conventional generators.
Challenges for Renewables:
- Solar and wind energy do not provide system inertia or reactive power.
Peaker Plants: Meet peak demand efficiently with gas turbines.

Clean Energy: Minimal carbon emissions during production.
Hydropower: Renewable energy from flowing water.
Wind Energy: Generated by wind turning turbine blades.
Solar Energy: Harnessing heat and light from the sun.
- Photovoltaics: Direct conversion of sunlight into electricity.
Capacity Factor: Performance metric for power plants; calculated: actual energy generated / (capacity x time).
Wind/Solar Challenges:
- Lack of inertia, reactive power, and reliability issues.
Energy Definition: Enables movement, provides light and heat.
Electromagnetic Induction: Law by Michael Faraday fundamental to electric generators.
Current Types:
- DC: Flows in one direction.
- AC: Current flow alternates direction; developed mainly by Nikola Tesla.
Current War: Dispute between Westinghouse (Tesla) and Edison on AC vs. DC.
Thermodynamics: Science of energy transformations.
Power vs. Energy: Power is energy over time; energy is consumed.
Dominant Energy Sources: Fossil fuels primarily generate global electricity.

Brain Neurons: About 100 billion neurons and 10,000 synapses per neuron.
Brain Stimulation Devices: ECT, tDCS, TMS, MST, EpCS, DBS.
Electroconvulsive Therapy (ECT): Induces seizures with high current.
Deep Brain Stimulation (DBS): Surgical delivery of current to brain nuclei.
Transcranial Direct Current Stimulation (tDCS): Non-invasive brain tech delivers mild current.
Vagus Nerve Stimulation: Requires a generator implanted to send electrical pulses through the vagus nerve.
Mass-Energy Equivalence: E=mc², fundamental principle in physics.
Nuclear Milestones:
- First electricity from atomic fission (1951), first nuclear navy (1954) and power (1957).
Neurological Disorder Prevalence: 1 in 4 Americans may suffer from psychological disorders.
Transcranial Magnetic Stimulation (TMS): Popular brain stimulation method to selectively deactivate brain regions.

Transcranial Focused Ultrasound Stimulation: Non-invasive but irreversible; under research.
Transcranial Photobiomodulation: Uses light to stimulate cells; targets mitochondria.
Stereo EEG: Non-invasive method for tracking brain activity.

Engine Function: Converts chemical energy to mechanical energy.
History: Early concepts like Heroes Engine; modern IC engine from the early 1900s.
Four-Stroke Operation Stages:
- Intake: Air-fuel mixture enters.
- Compression: Mixture compressed.
- Power: Ignition causes expansion and power stroke.
- Exhaust: Expels combustion gases.
Future Concerns: Increasing brain diseases and scope for replication/understanding.

Fuel Injection: Creates a flammable fuel-air mixture for efficient combustion.
Jet Engine Components:
- Compressor, combustion chamber, turbine, nozzle, exhaust.
Brayton Cycle: Used in jet engines for air-breathing propulsion.

Geomagnetism/Cosmo Magnetism: Study of magnetism at Earth and universal scales.
Electron Spin & Magnetic Moment: Properties related to magnetic fields generated by current.
Smart Materials: React to environmental stimuli; can change properties externally.
Key Historical Contributors: Faraday and Maxwell on electromagnetism.
Types of Magnets: Permanent and electromagnets; highlights on material properties and energy.

HVAC History: Evolution from basic cooling systems to modern air conditioning.
X-ray History: Wilhelm Roentgen's discovery, major advancements, and medical applications.

Pollution Types: Distinction between anthropogenic and crustal pollution.
Water Treatment Methods: Conventional vs. advanced purification technologies; including reverse osmosis.

Microscopy Development: Evolution of magnification devices; importance of sample preparation and conductivity.
Mechanical Flight Concepts: Distinction between mechanical flight and falling/gliding.
Societal Benefits: Focus on air travel benefits and challenges post-disaster epidemics.

Laser Development: Operating principles of lasers across different wavelengths, understanding photons and electromagnetic spectra.