Ulcerative colitis is a chronic, relapsing condition. Chronic means that it is persistent and ongoing. Relapsing means that there are times when symptoms flare up (relapse) and times when there are few or no symptoms (remission). The severity of symptoms and how frequently they occur vary from person to person.
Photovoltaics (PV) is the name of a method of converting solar energy into direct current electricity using semiconducting materials that exhibit the photovoltaic effect, a phenomenon commonly studied in physics, photochemistry and electrochemistry.
When sunlight is absorbed by these materials, the solar energy knocks electrons loose from their atoms, allowing the electrons to flow through the material to produce electricity. This process of converting light (photons) to electricity (voltage) is called the photovoltaic (PV) effect. Solar cells are typically combined into modules that hold about 40 cells; a number of these modules are mounted in PV arrays that can measure up to several meters on a side.