Hall-Héroult Process

An empirical formula that describes how the available capacity of a battery decreases as the rate of discharge increases. The law is stated as [latex]C_p = I^k t[/latex], where [latex]C_p[/latex] is the capacity at a one-ampere discharge rate, [latex]I[/latex] is the discharge current, [latex]t[/latex] is the discharge time, and [latex]k[/latex] is the Peukert constant, specific to the battery type. It quantifies the inefficiency at high loads.

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.

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 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.

A structured methodology for creating new products, typically involving analysis, concept development, and synthesis. It is an iterative cycle where designers research user needs, brainstorm ideas, create prototypes, and test them to refine the final product. This process ensures that the end product is both functional and meets market demands effectively before full-scale production.

Heijunka is the principle of production leveling or smoothing within the Toyota Production System. It involves averaging out the production volume and mix over a fixed period to eliminate peaks and valleys in workload. This creates a predictable and stable manufacturing environment, which is a prerequisite for implementing Just-in-Time (JIT) and standardized work effectively.

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.

The chloralkali process is an industrial method for the electrolysis of sodium chloride (NaCl) solution, known as brine. It is the primary source for producing chlorine (Cl₂), sodium hydroxide (NaOH), and hydrogen (H₂), which are essential commodity chemicals. Modern methods use a membrane cell to separate the anode and cathode products, ensuring high purity and efficiency.

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 [latex]T = \frac{T_a}{D}[/latex], where T is the Takt time, Ta is the net available time, and D is the customer demand.

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.

The Fill Factor (FF) is a key parameter that determines the quality of a solar cell. It is the ratio of the maximum power a cell can produce ([latex]P_{max}[/latex]) to the theoretical power if it were an ideal voltage and current source ([latex]V_{oc} \times I_{sc}[/latex]). A higher fill factor indicates lower parasitic resistance losses and a more 'square' I-V curve.

Takt time is a theoretical calculation representing the pace of customer demand ([latex]Available Time \div Demand[/latex]). In contrast, cycle time is an empirical measurement of the actual time taken to complete one unit of work at a specific process step. A core principle of lean manufacturing is to ensure that cycle time is consistently less than or equal to Takt time.