Water wheelA water wheel is a machine for converting the energy of flowing or falling water into useful forms of power, often in a watermill. A water wheel consists of a wheel (usually constructed from wood or metal), with a number of blades or buckets arranged on the outside rim forming the driving car. Water wheels were still in commercial use well into the 20th century but they are no longer in common use. Uses included milling flour in gristmills, grinding wood into pulp for papermaking, hammering wrought iron, machining, ore crushing and pounding fibre for use in the manufacture of cloth.
WellA well is an excavation or structure created in the ground by digging, driving, or drilling to access liquid resources, usually water. The oldest and most common kind of well is a water well, to access groundwater in underground aquifers. The well water is drawn up by a pump, or using containers, such as buckets or large water bags that are raised mechanically or by hand. Water can also be injected back into the aquifer through the well.
Endangered speciesAn endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching and invasive species. The International Union for Conservation of Nature (IUCN) Red List lists the global conservation status of many species, and various other agencies assess the status of species within particular areas.
Placer depositIn geology, a placer deposit or placer is an accumulation of valuable minerals formed by gravity separation from a specific source rock during sedimentary processes. The name is from the Spanish word placer, meaning "alluvial sand". Placer mining is an important source of gold, and was the main technique used in the early years of many gold rushes, including the California Gold Rush. Types of placer deposits include alluvium, eluvium, beach placers, aeolian placers and paleo-placers.
Roman aqueductThe Romans constructed aqueducts throughout their Republic and later Empire, to bring water from outside sources into cities and towns. Aqueduct water supplied public baths, latrines, fountains, and private households; it also supported mining operations, milling, farms, and gardens. Aqueducts moved water through gravity alone, along a slight overall downward gradient within conduits of stone, brick, concrete or lead; the steeper the gradient, the faster the flow.
Process (computing)In computing, a process is the instance of a computer program that is being executed by one or many threads. There are many different process models, some of which are light weight, but almost all processes (even entire virtual machines) are rooted in an operating system (OS) process which comprises the program code, assigned system resources, physical and logical access permissions, and data structures to initiate, control and coordinate execution activity.
Critically EndangeredAn IUCN Red List Critically Endangered (CR or sometimes CE) species is one that has been categorized by the International Union for Conservation of Nature as facing an extremely high risk of extinction in the wild. As of 2021, of the 120,372 species currently tracked by the IUCN, there are 8,404 species that are considered to be Critically Endangered. The IUCN Red List provides the public with information regarding the conservation status of animal, fungi, and plant species.
Process stateIn a system, processes may occupy a variety of states. These distinct states may not be recognized as such by the operating system kernel. However, they are a useful abstraction for the understanding of processes. The following typical process states are possible on computer systems of all kinds. In most of these states, processes are "stored" on main memory. When a process is first created, it occupies the "created" or "new" state. In this state, the process awaits admission to the "ready" state.
Spirit (vital essence)In philosophy and religion, spirit is the vital principle or animating essence within humans or, in some views, all living things. Although views of spirit vary between different belief systems, when spirit is contrasted with the soul, the former is often seen as a basic natural force, principle or substance, whereas the latter is used to described the organized structure of an individual being's consciousness, in humans including their personality.
