Microplastics: origins, impacts and technical solutions

The 1.5 sigma shift is an empirical correction used in Six Sigma calculations to account for the long-term dynamic variation of a process. It posits that over time, a process mean will tend to drift by about 1.5 standard deviations from its short-term centered position. This shift is the reason a 6 sigma process corresponds to 3.4 DPMO, not the theoretical 2 defects per billion.

A standardized categorization of artificial satellites based on their wet mass, including fuel. The primary classes are minisatellites (100–500 kg), microsatellites (10–100 kg), nanosatellites (1–10 kg), picosatellites (0.1–1 kg), and femtosatellites (<100 g). This classification provides a common language for engineers, manufacturers, and launch providers to define mission scale, technical requirements, and cost estimations.

Design for the Environment (DfE), also known as ecodesign, is a proactive approach to product and process development that minimizes environmental and human health impacts across the entire product life cycle. It integrates environmental considerations into the earliest design stages, alongside traditional factors like cost and performance, to prevent pollution and conserve resources from the outset.

The European standard EN 2, 'Classification of fires', harmonizes fire classes across member nations. It defines five classes: A (solids), B (liquids), C (gases), D (metals), and F (cooking oils). A key distinction from the US system is that Class C is specifically for flammable gases, and there is no dedicated class for electrical fires; instead, the burning material is classified.

Viral marketing describes any marketing strategy that encourages individuals to pass on a marketing message to others, creating the potential for exponential growth in the message's exposure and influence. Like viruses, such strategies take advantage of rapid multiplication to explode the message from person to person. It is a form of amplified word-of-mouth, often facilitated by the internet.

Six Sigma is a quality management methodology aiming for near-perfection. A process operating at a "six sigma" level has a yield of 99.9997%, meaning it produces only 3.4 Defects Per Million Opportunities (DPMO). This standard corresponds to a process where the nearest specification limit is six standard deviations away from the process mean, accounting for a 1.5 sigma shift in the mean over time (refer to the specific details on the debated 1.5 sigma shift as an empirical observation).

Rapid prototyping is a group of techniques used to quickly fabricate a scale model of a physical part or assembly using three-dimensional computer-aided design (CAD) data. In iterative design, it allows for fast creation of tangible models for user testing and stakeholder feedback, enabling quick design refinements before committing to expensive tooling and manufacturing processes.

Electrostatic actuation is a primary method for inducing motion in MEMS. It utilizes the attractive force between two electrodes separated by a dielectric gap when a voltage is applied. The force is proportional to the square of the voltage and the capacitance gradient. Common designs include parallel-plate capacitors for out-of-plane motion and comb drives for large in-plane displacement.

The NIOSH lifting equation is a tool used by occupational health and safety professionals to assess the risk of musculoskeletal injury associated with manual lifting tasks. It calculates a Recommended Weight Limit (RWL) for a specific task, representing the maximum weight a healthy worker could lift without increased risk of low back injury, considering factors like task geometry and frequency.

A set of nine foundational principles for sustainable design, developed by William McDonough and Michael Braungart. They advocate for the rights of humanity and nature to coexist, recognize interdependence, respect relationships between spirit and matter, accept responsibility for design consequences, create safe objects of long-term value, eliminate waste, rely on natural energy flows, and understand the limitations of design.

Binder jetting is an additive manufacturing process where a liquid binding agent is selectively deposited onto a powder bed using an inkjet-style print head. The print head moves across a layer of powder, depositing binder droplets to join particles together. The build platform then lowers, a new layer of powder is spread, and the process repeats layer-by-layer.

The three pillars of sustainability, also known as the triple bottom line, is a framework that posits true sustainability requires balancing three main dimensions: environmental, social, and economic. Environmental sustainability focuses on preserving natural resources and ecosystems. Social sustainability addresses equity, community well-being, and human rights. Economic sustainability ensures long-term financial viability without compromising the other two pillars.

The functional unit is a critical concept in LCA that defines the quantified performance of a product system for use as a reference unit. It ensures that comparisons between different systems are made on a fair and equivalent basis. For example, when comparing paint, the functional unit might be 'to protect 1 square meter of wall for 10 years'.