Ultrasound‐guided nerve blocks are common techniques in several medical specialties. Phantoms are commonly used when teaching these procedures. Commercial phantoms are expensive, and most previously published “homemade” nerve phantoms have a substantial amount of posterior shadowing, making it difficult to visualize the needle posterior to the simulated nerve. We have constructed a simple and easy‐to‐make nerve block phantom using a hot dog core embedded in a gelatin–psyllium hydrophilic mucilloid fiber mixture that has little to no posterior shadowing.

The operational and functional criteria of heating, ventilation, and air conditioning (HVAC) systems and associated control systems for cleanrooms and other similar critical applications impose very demanding requirements on both the installed systems and the system designers. Designers and facility operators often compromise original reliability criteria due to rule-of-thumb decision making processes. These processes do not usually include a truly determinant method of evaluating, in a quantitative manner, the advantages and disadvantages of alternative HVAC and control systems with respect to redundancy, reliability, and availability. A methodology as proposed here should help to enhance the decision making processes associated with defining availability criteria and predicting the effects of alternative HVAC and control systems on critical facility operations.

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