Pulse-Echo Ultrasonic Testing

Pitting corrosion is a localized form of corrosion that leads to the creation of small holes, or 'pits,' in a metal. It is one of the most destructive forms because it is difficult to detect, predict, and design against. Pitting can cause catastrophic failure of a structure with only a small percentage of total mass loss.

Liquid metal embrittlement is a phenomenon where a normally ductile solid metal experiences a severe loss of ductility and fails in a brittle manner when wetted by a specific liquid metal while under tensile stress. The failure is often catastrophic and rapid. The mechanism involves the liquid metal atoms adsorbing at a crack tip, which reduces the cohesive strength of the solid's atomic bonds.

Just-in-Time (JIT) is a production strategy aimed at increasing efficiency and decreasing waste by receiving goods only as they are needed in the production process, thereby reducing inventory costs. This method requires precise forecasting and highly coordinated supply chains. The goal is to have the right materials, at the right place, at the right time, in the exact amount.

Freeze-drying, or lyophilization, is a dehydration process that leverages sublimation to preserve perishable materials. The material is first frozen, and then the surrounding pressure is reduced to allow the frozen water to sublime directly from the solid phase (ice) to the gas phase (water vapor). This avoids the damaging effects of heat-based drying methods.

FMEA is a systematic, bottom-up, inductive method for identifying potential failure modes in a system, product, or process. For each failure mode, it assesses the potential effects or consequences, their severity, likelihood of occurrence, and the ability to detect them. The goal is to prioritize and mitigate high-risk failure modes before they occur.

The PDCA cycle, also known as the Deming Cycle or Shewhart Cycle, is an iterative four-step management method used for the control and continuous improvement of processes and products. It provides a simple and effective approach for solving problems and managing change, ensuring that ideas are tested on a small scale before being implemented organization-wide.

Jidoka, often translated as "autonomation" or "automation with a human touch," is a pillar of the Toyota Production System. It empowers any machine or worker to halt the entire production line upon detecting an abnormality or defect. This prevents the mass production of faulty items and immediately highlights problems, enabling root cause analysis and permanent solutions.

Takt time is the maximum time allowed to produce a product to meet customer demand. It is calculated by dividing the net available production time by the customer demand over that period. The formula is \(T = \frac{T_a}{D}\), where T is the Takt time, Ta is the net available time, and D is the customer demand.

High-Efficiency Particulate Air (HEPA) and Ultra-Low Particulate Air (ULPA) filters are critical cleanroom components. A HEPA filter must remove at least 99.97% of airborne particles 0.3 micrometers (µm) in diameter. An ULPA filter is even more efficient, removing 99.999% of particles 0.12 µm or larger. They work via a combination of interception, impaction, and diffusion.

A flashback is a dangerous condition where the flame propagates backward from the torch tip into the hoses. A flashback arrestor is a critical safety device that quenches this flame. It typically contains a flame-extinguishing element, such as a sintered metal filter, and a non-return valve to stop the reverse flow of gas, preventing explosive mixtures from forming in the hoses.

When an ultrasonic wave strikes the boundary between two different materials at an angle, it refracts, or changes direction. This is governed by Snell's Law, which relates the angles of incidence and refraction to the wave velocities in the two media: \(\frac{\sin\theta_1}{c_1} = \frac{\sin\theta_2}{c_2}\). This principle is fundamental for angle beam testing, used to inspect components like welds not accessible from directly above.

The Hollomon equation is an empirical power-law relationship that describes the portion of the true stress-true strain curve between the onset of plastic deformation (yielding) and the onset of necking (UTS). The equation is \(\sigma_t = K \epsilon_t^n\), where \(\sigma_t\) is the true stress, \(\epsilon_t\) is the true plastic strain, K is the strength coefficient, and n is the strain-hardening exponent.

A foundational economic fact is that the total monetary volume of business-to-business (B2B) transactions significantly surpasses that of business-to-consumer (B2C) transactions. This is because a single finished consumer product often involves a long supply chain with multiple B2B transactions—from raw materials to manufacturing components to wholesale distribution—before the final B2C sale occurs.

Kanban, meaning "visual card" or "signboard" in Japanese, is a scheduling system integral to the Toyota Production System. It uses visual cues, typically cards, to trigger action and manage workflow. It is a "pull" system that signals the need to move materials within a manufacturing facility or from an outside supplier into the production facility.