CG: n CT: If users reach a deep page after traveling from the homepage through all the ancestor pages of that page, they will have a fairly clear understanding of where they are in the site’s information hierarchy. But when they skip some of these levels (for example, because they
GC: n CT: Nearly every aspect of our daily lives – heating, lighting, cooking, communications, transportation, commerce – depends on electricity. Unfortunately, generating that electricity through the use of traditional fossil fuels can be economically and environmentally costly and a danger to public health. Electricity generated with fossil fuels, such
GC: n CT: In 1831, Michael Faraday, an English physicist gave one of the most basic laws of electromagnetism called Faraday’s law of electromagnetic induction. This law explains the working principle of most of the electrical motors, generators, electrical transformers and inductors. This law shows the relationship between electric circuit
GC: n CT: “Cybernetics” comes from the Greek: “the art of steering”. In short, cybernetics is a discipline for understanding how actions may lead to achieving goals. Knowing whether you have reached your goal (or at least are getting closer to it) requires “feedback“, a concept that comes from cybernetics.
GC: n CT: Energy flow. As we have seen, generating and utilising energy means converting energy from one form into another. Often, intermediate steps are Implied. The energy flows through a number of forms, as well as conversion steps, between the source and the end-use. The costs increase accordingly. We
GC: n CT: The trend in final energy consumption by fuel type and by sector provides a broad indication of progress in reducing final energy consumption and associated environmental impacts by the different end-use sectors (transport, industry, services and households). The type and magnitude of energy-related pressures on the environment
CG: n CT: A firewall is a system designed to prevent unauthorized access to or from a private network. You can implement a firewall in either hardware or software form, or a combination of both. Firewalls prevent unauthorized internet users from accessing private networks connected to the internet, especially intranets. All
GC: n CT: Pyrolysis is thermal degradation either in the complete absence of oxidizing agent, or with such a limited supply that gasification does not occur to an appreciable extent or may be described as partial gasification. Relatively low temperature are employed of 500 to 800 °C, compared to 800
GC: n CT: Flash steam power plants use hot water reservoirs. In flash plants, as hot water is released from the pressure of the deep reservoir in a flash tank, some if it flashes to steam. S: http://geothermal.marin.org/geopresentation/sld054.htm (last access: 26 February 2015) N: 1. Flash Steam Power Plants are
CG: n CT: Floating buoys have been developed which can generate energy from the bobbing or pitching motion caused by the waves. In some buoy type systems the buoy uses a simple mechanical system to turn a crankshaft. For example, in the Indian I-wave system the wave action raises the
CG: n CT: Calibrating a Parshall flume. Decrease water velocity: If the water velocity is too fast, the relationship between depth and velocity will be way off A small increase in depth will give you a disproportionately large change in discharge rate. You need to find some way to dissipate
CG: n CT: Since liquids are incompressible fluids, their flow rate depends only on the difference between the inlet and outlet pressures (Δp, pressure drop). The flow is the same whether the system pressure is low or high, so long as the difference between the inlet and outlet pressures is
GC: n CT: There are many types of open channel flow measuring devices available. Of these, flow measuring flumes are one of the most commonly used. How a Flume Operates Flumes are specially shaped, fixed hydraulic structures that under free-flow condtions force flow to accelerate in such a way that
GC: n CT: The rear apron in the Merala weir is of as soUd construction as the fore apron and is built on a slope right up to crest level; this arrangement facilitates discharge. The velocity of approach must be very great to necessitate huge book blocks of concrete 6X6X3
GC: n CT: Evidence for early agriculture can be obtained from pollen profiles indicating forest clearance. The practice of cultivation is widely believed to have been introduced into the interlacustrine region of central Africa by Bantu-speaking iron-workers, present by 2,000 yr BP (ref. 3) or, disputedly, 2,600 yr BP (ref.
GC: n CT: Forest residues consist of small trees, branches, tops and un-merchantable wood left in the forest after the cleaning, thinning or final felling of forest stands, used as fuel without any intermittent applications. Three main sources of forest residues can be distinguished: slash from final fellings, slash and
GC: n CT: There are three major forms of fossil fuels: coal, oil and natural gas. All three were formed many hundreds of millions of years ago before the time of the dinosaurs – hence the name fossil fuels. The age they were formed is called the Carboniferous Period. It
GC: n CT: Hydraulic fracturing, or fracking, is shunned by the environmentalists that laud renewable energy sources. However, by not supporting both initiatives, they may be working at cross purposes. Natural gas, booming largely because of fracking, complements renewable energies on the grid. The two seemingly opposite technologies are, for
GC: n CT: Refrigeration capacity. The thermal size of a refrigerator is known as its capacity, i.e. its cooling power, in watts in SI units, but sometimes older units are used in some places, as the frigorie/hour (4180/3600=1.16 W) or the ton (3575 W). It might be argued that it
GC: n CT: Biomass is matter usually thought of as garbage. Some of it is just stuff lying around -dead trees, tree branches, yard clippings, left-over crops, wood chips (like in the picture to the right), and bark and sawdust from lumber mills. It can even include used tires and
GC: n CT: Fuel cells cleanly and efficiently convert chemical energy from hydrogen-rich fuels into electrical power and usable high quality heat in an electrochemical process that is virtually absent of pollutants. Similar to a battery, a fuel cell is comprised of many individual cells that are grouped together to
GC: n CT: The Audi A6 has an impressive array of cabin tech which you can already take advantage of by purchasing just the base model. Some of the must-have features are the Bang & Olufsen sound system, Audi MMI Touch, navigation system, adaptive cruise control, and full park assist
GC: n CT: Fumaroles, or steam vents, are the hottest hydrothermal features in the park of Yellowstone. They have so little water that it all flashes into steam before reaching the surface. At places like Roaring Mountain, the result is a lot of hissing of steam and gases. S: http://www.nps.gov/yell/naturescience/fumaroles.htm