that first showed interest in her invention rejected it after they discovered that she was African American. Later an adhesive strip was placed on the bottom of sanitary pads for attachment to the crotch of the panties, and this became a favoured method with women. The belted sanitary napkin quickly disappeared during the early 1980s. The ergonomic design and materials used to make pads also changed through the 1980s to today. With earlier materials not being as absorbent and effective, and early pads being up to two centimetres thick, leaks were a major problem. Some variations introduced were quilting of the lining, adding "wings" and reducing the thickness of the pad by utilising products such as sphagnum and polyacrylate superabsorbent gels derived from petroleum. The materials used to manufacture most pads are derived from the petroleum industry and forestry. The absorbent core, made from chlorine bleached wood pulp, could be reduced to make slimmer products with the addition of polyacrylate gels which sucks up the liquid quickly and holds it in a suspension under pressure. The remaining materials are mostly derived from the petroleum industry, the cover stock used is polypropylene non woven, with the leakproof barrier made from polyethylene film. Society and culture Pads, especially reusable ones, may be visible on full body scanners. Developing countries In developing countries, makeshift pads are still used to collect menstrual blood as they are cheaper. Rags, soil, and mud are also reportedly used for collecting menstrual flow by people who cannot afford the more expensive disposable pads or tampons. In order to meet the need for achieving an inexpensive solution to reduce unsanitary and unhygienic practices in countries like India, Arunachalam Muruganantham from rural Coimbatore in the southern state of Tamil Nadu, India, developed and patented a machine which could manufacture low-cost sanitary pads for less than a third of the former cost. The Bill and Melinda Gates Foundation awarded Nairobi-based ZanaAfrica a grant of US$3 million. ZanaAfrica explores creative approaches to menstrual health education for adolescent girls. References External links Museum of Menstruation Feminine hygiene Menstrual cycle Personal hygiene products Disposable products