Renal agenesis. Renal agenesis is a medical condition in which one (unilateral) or both (bilateral) fetal kidneys fail to develop.
Polycrystalline cells are composed of multiple silicon crystals, which is a cheaper way to manufacture solar modules. Put simply, these cells are easier for a factory to produce, so they are less expensive. Polycrystalline cells are made by several methods, but most commonly with a cast of molten silicon.
Polyamides (PA). Polyamides (PA) are semi-crystalline polymers. A distinction is made between two types. Polyamides made of one basic material (e.g. PA 6) and polyamides, which are made of 2 basic materials (e.g. PA 66). Polyamides have very good mechanical properties, are particularly tough and have excellent sliding and wear characteristics. Properties vary from the hard and tough PA 66 to the soft and flexible PA 12.