Fire Extinguishment by Smothering

The Archimedes' screw is a positive displacement pump consisting of a screw-shaped surface (a helix) inside a hollow pipe. As the screw turns, it scoops up a volume of water at the bottom and lifts it through the tube as it rotates. It is highly effective for moving large quantities of water, especially at low heads, and is tolerant of debris.

A fundamental theory in structural analysis for determining the stress and deflection of beams under load. It assumes that plane sections, initially perpendicular to the beam's axis, remain plane and perpendicular to the neutral axis after bending. This simplification is highly accurate for slender beams where the effects of shear deformation and rotational inertia are negligible compared to bending effects.

The centrifugal governor is a mechanical device that uses the principle of centrifugal force to regulate the speed of an engine. As the engine speed increases, rotating masses (flyballs) move outwards due to centrifugal force. This movement is linked to a throttle valve, which reduces the fuel or steam supply, thereby slowing the engine down and maintaining a near-constant speed.

The vapor-compression cycle is the thermodynamic process used by most heat pumps. It involves four stages: compression of a refrigerant vapor, condensation to a high-pressure liquid while releasing heat, expansion through a valve to a low-pressure liquid/vapor mix, and evaporation to a low-pressure vapor while absorbing heat. This cycle effectively moves thermal energy against its natural direction of flow.

A proof test is a form of stress testing where a structure or component is subjected to a load greater than its normal service load, but less than its expected failure load. The purpose is to demonstrate fitness for use and screen for manufacturing defects without causing damage to a properly manufactured item, thus verifying its structural integrity.

Ductility is a measure of a material's ability to undergo significant plastic deformation before rupture, often quantified by percent elongation or percent reduction in area. Ductile materials, like steel, show a long plastic region on their stress-strain curve. Brittleness is the opposite; brittle materials, like ceramics or cast iron, fracture with little to no plastic deformation.

Liquid-liquid extraction (LLE) is a separation method based on the differential solubility of a solute between two immiscible or partially miscible liquid phases. A compound partitions from a feed phase (often aqueous) into a solvent phase (often organic). The transfer is driven by differences in chemical potential, ceasing when equilibrium is reached and the solute is distributed between phases.

A primary method of fire extinguishment involves removing the 'heat' component of the fire triangle. This is most commonly achieved by applying a substance that absorbs a large amount of heat, such as water (despite water also have other effects in the fire triangle -refer to dedicated post-). Water's high specific heat and latent heat of vaporization make it highly effective at cooling a fire below its self-sustaining temperature.

A centrifugal pump is a roto-dynamic pump that uses a rotating impeller to increase the pressure and flow rate of a fluid. Fluid enters the pump axially near the rotating axis, is accelerated by the impeller's vanes, and flows radially outward into a diffuser or volute chamber. In this chamber, the fluid's high kinetic energy is converted into high pressure energy.

Latent heat thermal energy storage (LHTES) systems store thermal energy by utilizing the phase change of a material (PCM), such as melting from solid to liquid. Energy is stored at a nearly constant temperature during the phase transition. The amount of energy stored is the heat of fusion. This method offers a much higher energy storage density than sensible heat storage.

Young's Modulus, denoted by E, quantifies a solid material's stiffness. It is the ratio of tensile stress (\(\sigma\)) to extensional strain (\(\epsilon\)) in the elastic (linear) region of the stress-strain curve. This relationship is defined by Hooke's Law: \(E = \frac{\sigma}{\epsilon}\). A higher modulus indicates a stiffer material, meaning more stress is required for a given amount of elastic deformation.

Passivation is the process by which a material becomes 'passive,' meaning it is less affected by environmental factors such as corrosion. It involves the spontaneous formation of a very thin, non-reactive surface film that acts as a barrier, shielding the bulk material from further attack. This film is typically an oxide or nitride layer, a few nanometers thick.

A hydrostatic test is a specific type of proof test for pressure vessels like pipes, boilers, and gas cylinders. The vessel is filled with a nearly incompressible liquid, typically water, and pressurized to a specified test pressure. This method is preferred over pneumatic testing because it requires less energy release to achieve the same pressure, making it very significantly safer if a rupture occurs.

A technique used in statics to determine the internal forces in specific members of a truss structure. The method involves making an imaginary cut through the members of interest, isolating a portion of the truss. By applying the three static equilibrium equations (\(\Sigma F_x=0\), \(\Sigma F_y=0\), \(\Sigma M_A=0\)) to the isolated section, the unknown member forces can be solved directly.