ME or MEng Master of Engineering Environmental and Systems Engineering 1 — Questions and Answers
Question 1: Life Cycle Assessment (LCA) in environmental engineering evaluates:
- Cost over the operational life of a product only
- Environmental impacts from raw material extraction through end-of-life disposal (Correct answer)
- Structural integrity under cyclic loading over a product's lifespan
- Safety inspection intervals for mechanical systems
Correct answer: Environmental impacts from raw material extraction through end-of-life disposal
LCA quantifies environmental burdens (energy, emissions, waste) at every stage of a product's life from cradle to grave.
Question 2: In systems engineering, a system's reliability R(t) is related to its hazard (failure) rate λ(t) by:
- R(t) = λ(t) × t
- R(t) = e^(−∫λ(t)dt) (Correct answer)
- R(t) = 1 / λ(t)
- R(t) = λ(t)² / 2
Correct answer: R(t) = e^(−∫λ(t)dt)
Reliability R(t) = exp(−∫₀ᵗ λ(τ)dτ); for constant hazard rate, R(t) = e^(−λt), giving the exponential failure distribution.
Question 3: The Biological Oxygen Demand (BOD) test measures:
- Dissolved oxygen concentration in clean water
- Oxygen consumed by microorganisms to decompose organic matter in water (Correct answer)
- Photosynthetic oxygen production in aquatic systems
- Chemical oxygen demand for inorganic oxidation only
Correct answer: Oxygen consumed by microorganisms to decompose organic matter in water
BOD measures the oxygen consumed by microorganisms breaking down organic matter in a water sample over typically 5 days at 20°C (BOD₅).
Question 4: A fault tree analysis (FTA) is a top-down method used to:
- Improve manufacturing throughput sequentially
- Identify combinations of events leading to a specified top-level failure (Correct answer)
- Map customer requirements to engineering specifications
- Optimize supply chain network flows
Correct answer: Identify combinations of events leading to a specified top-level failure
FTA uses Boolean logic (AND/OR gates) to model pathways of basic events that combine to cause an undesired top event (system failure).
Question 5: Total Dissolved Solids (TDS) in water quality refers to:
- Suspended particulate matter larger than 0.45 μm
- Inorganic salts, minerals, and organic matter dissolved in water (Correct answer)
- Biological oxygen demand in parts per million
- Hardness due to calcium and magnesium only
Correct answer: Inorganic salts, minerals, and organic matter dissolved in water
TDS encompasses all dissolved inorganic and organic substances (ions, metals, minerals) passing through a 0.45 μm filter, expressed in mg/L or ppm.
Question 6: In a FMEA (Failure Mode and Effects Analysis), the Risk Priority Number (RPN) is calculated as:
- Severity + Occurrence + Detection
- Severity × Occurrence × Detection (Correct answer)
- Severity × Occurrence / Detection
- (Severity + Occurrence) × Detection
Correct answer: Severity × Occurrence × Detection
RPN = Severity × Occurrence × Detection (each rated 1–10); higher RPN values indicate failure modes requiring priority corrective action.
ME or MEng Master of Engineering Environmental and Systems Engineering 1
Life Cycle Assessment (LCA) in environmental engineering evaluates: