Naval nuclear propulsion
Nuclear-powered warships during World War II submarine was found that could be
a decisive weapon, but he had a serious problem: their need to emerge after
short periods to obtain air for the combustion of diesel engines that were
based (the invention of the snorkel improved somewhat the problem but not
solved). Admiral Hyman G. Rickover was the first thought that nuclear energy
could help with this problem.
The development of nuclear reactors allowed a new type of engine with key
1.No need air to the engine operation, and not based on combustion.
2.A small mass of nuclear fuel allows a range of
several months (even years) without refueling. For example, U.S. submarines
do not require refueling during its lifetime.
3.A motor drive that can match any other, so that
submarines could be built much larger than the existing so far. The largest submarine built to date are the Russian Akula class (48 000
tons displacement, 175 m in length).
These advantages led to ships reaching speeds over 25 knots, they can stay
weeks in deep dive and they can also store huge quantities of munitions
(nuclear or conventional) in their warehouses. In fact, the U.S. military, France
and the UK
have only used this submarine propulsion system.
In the submarines have been used pressurized water reactors, boiling water or
molten salt. For reducing the weight of fuel in thesereactors is used with high
levels of uranium enrichment (30 to 40% of the Russians or the Americans 96%).
These reactors have the advantage that it is not necessary (although possible)
to turn the steam generated by heat into electricity, but can be used directly
on a turbine that provides movement to the propellers that drive the ship,
dramatically improving performance.
They have built a variety of military ships that use nuclear engines and, in
some cases, turn missiles carrying medium or long-range nuclear warheads
Cruises. As the USS Long Beach (CGN-9), 2 C1W type nuclear reactors built.
Destroyers. As the USS Bainbridge (CGN-25) was the
nuclear powered ship ever built smaller, use 2 D2G reactors integrated type.
Aircraft carriers. The most representative is the USS
Enterprise (CVN-65), built in 1961 and still operating, using for propulsion
type A2W 8 nuclear reactors.
Ballistic submarines. Use nuclear energy for
propulsion and missile long-range and medium weapons. Akula class are of this
type, using 2-type nuclear reactor OK-650 and carrying, in addition to
conventional weapons, nuclear missiles 20 RSM-52, each with 10 warheads of 200
Attack submarines. As the USS Seawolf (SSN-21) Seawolf
class nuclear reactor that uses an integrated S6W PWR type. It reaches a speed
of 30 knots
fuel cell is a device that converts the chemical energy from a fuel into
electricity through achemical reaction with oxygen or another oxidizing agent .
In total there are over 100 fuel cell buses deployed around the world today.
Most buses are produced by UTC Power, Toyota,
Ballard, Hydrogenics, and Proton Motor. UTC Buses have already accumulated over
970,000 km (600,000 mi) of driving 80] Fuel cell
buses have a 30-141% higher fuel economy than diesel buses and natural gas
buses. Fuel cell buses have been deployed around the world including in
Whistler Canada, San Francisco USA, Hamburg Germany, Shanghai China, London
England, Sao Paulo Brazil as well as several others. The Fuel Cell
Bus Club is a global cooperative effort in trial fuel cell buses. Notable
* 12 Fuel cell buses are being deployed in the Oakland and San Francisco Bay
area of California.
* Daimler AG, with thirty-six experimental buses powered by Ballard Power
Systems fuel cells completed a successful three-year trial, in eleven cities,
in January 2007.
* A fleet of Thor buses with UTC Power fuel cells was deployed in California,
operated by SunLine Transit Agency.
The first Brazilian hydrogen fuel cell bus prototype in Brazil was deployed in
Sao Paulo. The bus was manufactured in Caxias do Sul
and the hydrogen fuel will be produced in Sao
Bernardo do Campo from water through electrolysis. The
program, called 'Ônibus Brasileiro a Hidrogênio'
(BrazilianHydrogen Autobus), includes three additional buses.
Fuel cell powered forklifts are one of the largest sectors of fuel cell
applications in the industry. Most fuel cells used for material handling
purposes are powered by PEM fuel cells, although some direct methanol fuel
forklifts are coming onto the market. Fuel cell fleets are currently being
operated by a large number of companies, including Sysco Foods, FedEx Freight,
GENCO (at Wegmans, Coca-Cola, Kimberly Clark, Sysco Foods, and Whole Foods),
and H-E-B Grocers.Fuel cell powered forklifts provide significant benefits
over both petroleum and battery powered forklifts as they produce no local
emissions, can work for a full 8 hour shift on a single tank of hydrogen, can
be refueled in 3 minutes and have a lifetime of 8–10 years. Fuel cell
powered forklifts are often used in refrigerated warehouses as their
performance is not degraded by lower temperatures. Many companies do not use
petroleum powered forklifts, as these vehicles work indoors where emissions
must be controlled and instead are turning towards electric forklifts. Fuel
cell forklifts offer green house gas, product lifetime, maintenance cost,
refueling and labor cost benefits over battery operated fork lifts.[90
Solar cookers use sunlight for cooking, drying and pasteurization. They can be
grouped into three broad categories: box cookers, panel cookers andreflector
cookers 56] The simplest solar cooker is the box
cooker first built by Horace de Saussure in 1767. A basic box cooker
consists of an insulated container with a transparent lid. It can be used
effectively with partially overcast skies and will typically reach temperatures
of 90–150 °C. Panel cookers use a reflective panel to direct
sunlight onto an insulated container and reach temperatures comparable to box
cookers. Reflector cookers use various concentrating geometries (dish, trough,
Fresnel mirrors) to focus light on a cooking container. These cookers reach
temperatures of 315 °C and above but require direct light to function
properly and must be repositioned to track the Sun 59]
The solar bowl is a concentrating technology employed by the Solar Kitchen in
Auroville, Pondicherry, India, where a stationary spherical reflector focuses
light along a line perpendicular to the sphere's interior surface, and a
computer control system moves the receiver to intersect this line. Steam is
produced in the receiver at temperatures reaching 150 °C and then used
for process heat in the kitchen.
A reflector developed by Wolfgang Scheffler in 1986 is used in many solar
kitchens. Scheffler reflectors are flexible parabolic dishes that combine
aspects of trough and power tower concentrators. Polar tracking is used to
follow the Sun's daily course and the curvature of the reflector isadjusted for
seasonal variations in the incident angle of sunlight. These reflectors can
reach temperatures of 450–650 °C and have a fixed focal point,
which simplifies cooking. The world's largest Scheffler reflector system in
Abu Road, Rajasthan, India is capable of cooking up to 35,000 meals a day.
As of 2008, over 2,000 large Scheffler cookers had been built worldwide.
A windmill is a machine which converts the energy of wind into rotational
energy by means of vanes called sails or blades. Originally windmills
were developed for milling grain for food production. In the course of history
the windmill was adapted to many other industrial uses 3]
An important application was to pump water. Windmills used for generating
electricity are commonly known as wind turbines. A windmill used to generate
electricity is commonly called a wind turbine. The first windmills for electricity
production were built by the end of the 19th century by Prof James Blyth in Scotland (1887) 29]
Charles F. Brush in Cleveland, Ohio
(1887–1888) and Poul la Cour in Denmark (1890s). La Cour's mill
from 1896 later became the local powerplant of the village Askov. By 1908 there
were 72 wind-driven electric generators in Denmark from 5 kW to
25 kW. By the 1930s windmills were widely used to generate electricity on
farms in the United States
where distribution systems had not yet been installed,built
by companies like Jacobs Wind, Wincharger, Miller Airlite, Universal
Aeroelectric, Paris-Dunn, Airline and Winpower and by the Dunlite Corporation
for similar locations in Australia.
Forerunners of modern horizontal-axis utility-scale wind generators were the
WIME-3D in service in Balaklava USSR from 1931 until 1942, a 100 kW
generator on a 30 m (100 ft) tower 34] the
Smith-Putnam wind turbine built in 1941 on the mountain known as Grandpa's Knob
in Castleton, Vermont, USA of 1.25 MW and the NASA wind turbines developed
from 1974 through the mid 1980's. The development of these 13 experimental wind
turbines pioneered many of the wind turbine design technologies in use today,
including: steel tube towers, variable-speed generators, composite blade
materials, partial-span pitch control, as well as aerodynamic, structural, and
acoustic engineering design capabilities. The modern wind power industry began
in 1979 with the serial production of wind turbines by Danish manufacturers
Kuriant, Vestas, Nordtank, and Bonus. These early turbines were small by
today's standards, with capacities of 20–30 kW each. Since then,
they have increased greatly in size, with the Enercon E-126 capable of
delivering up to 7 MW, while wind turbine production has expanded to many countries.
As the 21st century began, rising concerns over energy security, global
warming, and eventual fossil fuel depletion led to anexpansion of interest in
all available forms of renewable energy. Worldwide there are now many thousands
of wind turbines operating, with a total nameplate capacity of 194,400 MW 36] Europe accounted for
48% of the total in 2009.
A wind turbine looking like a windmill is De Nolet in Rotterdam.
A watermill is a structure that uses a water wheel or turbine to drive a
mechanical process such as flour, lumber or textile production, or metal
shaping. Typically, water is diverted from a river or impoundment or mill pond
to a turbine or water wheel, along a channel or pipe (variously known as a
flume, head race, mill race, leat, leet 56] lade
(Scots) or penstock). The force of the water's movement drives the blades of a
wheel or turbine, which in turn rotates an axle that drives the mill's other
machinery. Water leaving the wheel or turbine is drained through a tail race,
but this channel may also be the head race of yet another wheel, turbine or
mill. The passage of water is controlled by sluice gates that allow maintenance
and some measure of flood control; large mill complexes may have dozens of
sluices controlling complicated interconnected races that feed multiple
buildings and industrial processes. By the early 20th century, availability of
cheap electrical energy made the watermill obsolete in developed countries
although some smaller rural mills continued to operate commercially into the
1960s.A few historic mills such as the Newlin Mill and Yates Mill (an example
of an Oliver Evans mill) (both USA) and The Darley Mill Centre (Yorkshire, UK))
still operate for demonstration purposes to this day, or even maintain
small-scale commercial production as at Daniels Mill, Shropshire , Little
Salkeld and Redbournbury Mill (All UK). Some old mills are being upgraded with
modern Hydropower technology, for example those worked on by the South Somerset
Hydropower Group in the UK.
Wood fuel is wood used as fuel. The burning of wood is currently the largest
use of energy derived from a solid fuel biomass. Wood fuel can be used for
cooking and heating, and occasionally for fueling steam engines and steam
turbines that generate electricity. Wood fuel may be available as firewood
(e.g. logs, bolts, blocks), charcoal, chips, sheets,
pellets and sawdust. The particular form used depends upon factors such as
source, quantity, quality and application. Sawmill waste and construction industry
by-products also include various forms of lumber tailings. Some consider wood
fuel bad for the environment, however this is not the case if proper techniques
are used 1] One might increase carbon emissions using
gas powered saws and splitters in the production of firewood, but when wood
heat replaces carbon-producing fuels such as propane, heating oil or
electricity from a coal-burning plant, then wood burning has apositive impact
on the carbon footprint. The use of wood as a fuel source for heating is much
older than civilization and was used by neanderthals.
Historically, it was limited in use only by the distribution of technology
required to make a spark. Wood heat is still common throughout much of the
world. Some firewood is harvested in 'woodlots' managed for that
purpose, but in heavily wooded areas it is more usually harvested as a
byproduct of natural forests. Deadfall that has not started to rot is
preferred, since it is already partly seasoned. Standing dead timber is
considered better still, as it is both seasoned, and has less rot. Harvesting
this form of timber reduces the speed and intensity of bushfires. Harvesting
timber for firewood is normally carried out by hand with chainsaws.
A hot spring is a spring that is produced by the emergence of geothermally
heated groundwater from the Earth's crust. There are geothermal hot springs in many
locations all over the crust of the earth. The water issuing from a hot spring
is heated by geothermal heat, i.e., heat from the Earth's mantle. In general,
the temperature of rocks within the earth increases with depth. The rate of
temperature increase with depth is known as the geothermal gradient. If water
percolates deeply enough into the crust, it will be heated as it comes into
contact with hot rocks. The water from hot springs in non-volcanic areas isheated in
In active volcanic zones such as Yellowstone
National Park, water may
be heated by coming into contact with magma (molten rock). The high temperature
gradient near magma may cause water to be heated enough that it boils or
becomes superheated. If the water becomes so hot that it builds steam pressure
and erupts in a jet above the surface of the Earth, it is called a geyser. If
the water only reaches the surface in the form of steam, it is called a
fumarole. If the water is mixed with mud and clay, it is called a mud pot.
Note that hot springs
in volcanic areas are often at or near the boiling point. People have been
seriously burned and even killed by accidentally or intentionally entering
Warm springs are sometimes the result of hot and cold springs mixing but may
also occur outside of volcanic areas, such as Warm Springs, Georgia
(frequented for its therapeutic effects by paraplegic U.S. President Franklin
D. Roosevelt, who built the Little White House there). Because heated water can
hold more dissolved solids, warm and especially hot springs also often have a very high
mineral content, containing everything from simple calcium to lithium, and even
radium. Because of both the folklore and the claimed medical value some of
these springs have, they are often popular tourist destinations, and locations
for rehabilitation clinics for those with disabilities 19][