Castilla-La Mancha PAU Technology and Engineering II (Tecnología e Ingeniería II - UCLM 2026) flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Hooke's law

Within the elastic range, normal stress is proportional to normal strain: σ = E·ε, where E is the Young's modulus of the material expressed in pascals.

Yield strength (0.2 % offset)

Stress at which a metal shows a permanent plastic strain of 0.2 % after unloading, obtained by drawing a line parallel to the elastic slope from ε = 0.002.

Ductile–brittle transition temperature

Temperature below which a material, typically a BCC steel, absorbs little impact energy in a Charpy test and fractures without appreciable plastic deformation.

Atomic packing factor

Fraction of the unit cell volume occupied by atoms: about 0.74 for FCC and HCP structures and 0.68 for BCC, calculated from atomic radius and cell geometry.

Galvanic corrosion

Accelerated corrosion of the less noble metal when two dissimilar metals are in electrical contact in a moist electrolyte, forming a galvanic couple with the more noble one.

Gear train velocity ratio

For meshing gears, the ratio of angular velocities equals the inverse ratio of teeth numbers: i = ω1/ω2 = z2/z1; in a train, multiply driven teeth over driver teeth.

Grashof condition

A four-bar linkage can have at least one fully rotating link when the sum of the shortest and longest link lengths is not greater than the sum of the other two.

Bending stress formula

Normal stress in a beam section is σ = M·y/I, where M is the bending moment, y the distance from the neutral axis and I the second moment of area.

Euler buckling load

Critical compressive load for a slender column: Pcr = π²·E·I/(k·L)², with k depending on end conditions (1 pinned-pinned, 0.5 fixed-fixed, 2 fixed-free).

Mechanical power of a shaft

Power transmitted by a rotating shaft equals torque times angular velocity: P = T·ω = 2π·n·T/60, with n in revolutions per minute and T in newton-metres.

Thévenin's theorem

Any linear two-terminal network can be replaced by an equivalent voltage source Vth in series with a resistance Rth, found from open-circuit voltage and deactivated sources.

Power factor

In AC circuits, cos φ = R/Z, the ratio of active power to apparent power; a low value means large reactive current and higher transmission losses.

Induction motor slip

Fractional difference between synchronous speed and rotor speed: s = (ns − n)/ns, with ns = 60f/p; slip is near zero at no load and about 5 % at rated load.

Full-wave rectifier mean voltage

A bridge rectifier fed by a sinusoidal voltage gives a mean DC output of 2·Vmax/π, twice that of a half-wave rectifier, with ripple smoothed by a filter capacitor.

Transistor saturation region

Operating state of a BJT used as a closed switch, where base current is high enough that collector-emitter voltage falls to about 0.2 V and current is set by the load.

Op-amp inverting amplifier gain

For an ideal operational amplifier in inverting configuration, the voltage gain is −R2/R1, where R2 is the feedback resistor and R1 the input resistor.

PID controller

Closed-loop controller whose output combines proportional, integral and derivative actions on the error: u = Kp·e + Ki∫e dt + Kd·de/dt.

Kilowatt-hour

Energy unit equal to 3.6 megajoules, corresponding to one kilowatt of power delivered for one hour; it is the usual billing unit for electrical energy.

Carnot efficiency limit

Maximum possible efficiency of a heat engine working between a hot source and a cold sink: η = 1 − Tc/Th, with both temperatures expressed in kelvin.

Wind power equation

Power available in a wind stream is P = ½·ρ·A·v³, proportional to air density, rotor swept area and the cube of wind speed; the Betz limit is 16/27.

Hydropower output

Electrical power from a water fall is P = ρ·g·Q·H·η, where Q is volumetric flow, H the net head and η the overall turbine-generator efficiency.

Energy payback time

Time a generating installation must operate to produce the energy consumed during its manufacture, transport and installation; a key sustainability indicator for renewables.

Sand casting process

Casting in a sand mould made from a pattern, with sprue, runner and riser; suitable for complex shapes in many metals at low tooling cost and low production rates.

Material removal rate

Volume of material cut per unit time in machining, approximately MRR = v·f·a, the product of cutting speed, feed per revolution and depth of cut.

MIG/MAG welding

Arc welding with a continuous consumable wire electrode and a shielding gas; MAG uses active gas for steels, MIG uses inert gas for aluminium and stainless steel.

CNC G01 code

Preparatory G-code commanding linear interpolation at the programmed feed rate to the specified coordinates; G00 is rapid positioning without cutting.

Overall equipment effectiveness

OEE = availability × performance × quality, a production metric combining downtime losses, speed losses and defect losses into one indicator of equipment productivity.

Takt time

Available production time divided by customer demand; it sets the rhythm at which one unit must be completed to meet demand without excess inventory.

Critical path (PERT/CPM)

Longest sequence of dependent activities in a project network; its duration fixes the minimum project time and its activities have zero total float.

First-angle projection

European drawing convention in which the object is placed between observer and projection plane, so the top view is drawn below the front view and the left view on the right.

Drawing scale

Ratio between the dimension on the drawing and the real dimension of the object; reduction scales (1:50) are used for large objects and enlargement scales (2:1) for small parts.

ISO 286 fit H7/g6

Clearance fit designation: capital H defines the hole fundamental deviation (lower deviation zero) and lowercase g the shaft, giving a small guaranteed clearance for sliding parts.