When a reporter with the Sierra Club magazine asked Graham Peaslee, a physicist at the University of Notre Dame, to test several different samples of unused menstrual underwear for per- and polyfluoroalkyl substances (PFAS) in 2019, the results fueled concern over chemical exposure in feminine hygiene products — which ultimately ended up in a $5 million lawsuit against the period and incontinence underwear brand Thinx.

Then in 2023, the New York Times asked Peaslee to test 44 additional period and incontinence products for PFAS, a class of toxic fluorinated compounds inherently repellent to oil, water, soil and stains, and known as “forever chemicals” for their exceptionally strong chemical and thermal stability. Measurable PFAS were found in some layers of many of the products tested — some low enough to suggest the chemicals may have transferred off packaging materials, while others contained higher concentrations, suggesting the chemicals were intentionally used during the manufacturing process.

In the meantime, another group of researchers published a study that found PFAS in single-use period products, leading Peaslee and his lab to widen their investigation into all sorts of reusable feminine hygiene products — often viewed as an eco-friendly option by consumers. Now, the results of that study have been published in Environmental Science & Technology Letters.

Digital twins for automated material handling systems (AMHSs) of semiconductor and display fabrication industries suffer from parameter uncertainty and discrepancy. This leads to inaccurate predictions, ultimately affecting performance. To address this, researchers have developed a new Bayesian calibration framework that simultaneously accounts for both parameter uncertainty and discrepancy, improving the prediction accuracy of digital twin models. This innovative framework holds great potential for enhancing digital twin applicability across diverse industries.

Hydrogen fluoride (HF) is the simplest and cheapest fluorinating reagent available, but its volatility and toxicity limit its practical use. Now, researchers from Shibaura Institute of Technology, Japan, introduce a new approach for the generation of HF, which is both safe and scalable. Using the cation exchange method between Potassium fluoride (KF) and Amberlyst 15DRY, they generated HF and converted it to amine-3HF complexes, thereby expanding the range of accessible complexes for fluorination reactions.

Air filters are our main defense against airborne pollutants, but conventional designs rely on weak adhesive forces and often fail to trap and retain fine particles. Now, researchers from Korea have developed a bioinspired oil-coated filter that dramatically improves particle capture and energy efficiency. Most notably, the filter’s lifespan is extended by two to three times compared to conventional designs. It also enables zero-energy filtration using natural airflow, paving the way to sustainable air filtration.