Part 5 (Chs 15-18). Classic Literature VideoBook with synchronized text, interactive transcript, and closed captions in multiple languages. Audio courtesy of Librivox. Read by Mark F. Smith. Playlist for The House of the Seven Gables by Nathaniel Hawthorne: www.youtube.com
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Part 1. Classic Literature VideoBook with synchronized text, interactive transcript, and closed captions in multiple languages. Audio courtesy of Librivox. Read by Mark Nelson. Playlist for A Princess of Mars by Edgar Rice Burroughs: www.youtube.com
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Home improvement expert Ron Hazelton shows how to remove old, discolored tile grout and replace it with new tile grout, brightening your kitchen or bathroom countertops instantly. For more kitchen and bath DIY videos, visit www.ronhazelton.com.
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Step-by-step essential guide to fixing broken tiles.

Learn how to make a toilet cut with a tile saw in this free DIY video. Expert: Brian Carter Bio: Brian Carter has owned and operated several finish construction businesses, and has installed ceramic tile professionally for ten years. Filmmaker: Nels Chick

Biology
A Common Octopus (Octopus vulgaris)
Octopuses are characterized by their eight arms, usually bearing suction cups. The arms of octopuses are often distinguished from the pair of feeding tentacles found in squid and cuttlefish. Both types of limbs are muscular hydrostats. Unlike most other cephalopods, the majority of octopuses those in the suborder most commonly known, Incirrina have almost entirely soft bodies with no internal skeleton. They have neither a protective outer shell like the nautilus, nor any vestige of an internal shell or bones, like cuttlefish or squid. A beak, similar in shape to a parrot’s beak, is the only hard part of their body. This enables them to squeeze through very narrow slits between underwater rocks, which is very helpful when they are fleeing from morays or other predatory fish. The octopuses in the less familiar Cirrina suborder have two fins and an internal shell, generally reducing their ability to squeeze into small spaces.
An octopus moving between tide pools during low tide
Octopuses have a relatively short life expectancy, and some species live for as little as six months. Larger species, such as the North Pacific Giant Octopus, may live for up to five years under suitable circumstances. However, reproduction is a cause of death: males can only live for a few months after mating, and females die shortly after their eggs hatch. They neglect to eat during the (roughly) one month period spent taking care of their unhatched eggs, but they don’t die of starvation. Endocrine secretions from the two optic glands are the cause of genetically-programmed death (and if these glands are surgically removed, the octopus may live many months beyond reproduction, until she finally starves).
Stauroteuthis syrtensis, a finned octopus of the suborder Cirrina
Octopuses have three hearts. Two pump blood through each of the two gills, while the third pumps blood through the body. Octopus blood contains the copper-rich protein hemocyanin for transporting oxygen. Although less efficient under normal conditions than the iron-rich hemoglobin of vertebrates, in cold conditions with low oxygen pressure, hemocyanin oxygen transportation is more efficient than hemoglobin oxygen transportation. The hemocyanin is dissolved in the plasma instead of being carried within red blood cells and gives the blood a blue color. Octopuses draw water into their mantle cavity where it passes through its gills. As mollusks, octopuses have gills that are finely divided and vascularized outgrowths of either the outer or the inner body surface.
Intelligence
Main article: Cephalopod intelligence
Octopuses are highly intelligent, likely more so than any other order of invertebrates. The exact extent of their intelligence and learning capability is much debated among biologists, but maze and problem-solving experiments have shown that they do have both short- and long-term memory. Their short lifespans limit the amount they can ultimately learn. There has been much speculation to the effect that almost all octopus behaviors are independently learned rather than instinct-based, although this remains largely unproven. They learn almost no behaviors from their parents, with whom young octopuses have very little contact.
An octopus opening a container with a screw cap
An octopus has a highly complex nervous system, only part of which is localized in its brain. Two-thirds of an octopus’s neurons are found in the nerve cords of its arms, which have a remarkable amount of autonomy. Octopus arms show a wide variety of complex reflex actions arising on at least three different levels of the nervous system. Unlike vertebrates, the complex motor skills of octopuses in their higher brain are not organized using an internal somatotopic map of its body. Some octopuses, such as the mimic octopus, will move their arms in ways that emulate the movements of other sea creatures.
In laboratory experiments, octopuses can be readily trained to distinguish between different shapes and patterns. They have been reported to practice observational learning, although the validity of these findings is widely contested on a number of grounds. Octopuses have also been observed in what some have described as play: repeatedly releasing bottles or toys into a circular current in their aquariums and then catching them. Octopuses often break out of their aquariums and sometimes into others in search of food. They have even boarded fishing boats and opened holds to eat crabs.
In some countries, octopuses are on the list of experimental animals on which surgery may not be performed without anesthesia. In the UK, cephalopods such as octopuses are regarded as honorary vertebrates under the Animals (Scientific Procedures) Act 1986 and other cruelty to animals legislation, extending to them protections not normally afforded to invertebrates.
The octopus is the only invertebrate which has been conclusively shown to use tools. At least four specimens of the Veined Octopus (Amphioctopus marginatus) have been witnessed retrieving discarded coconut shells, manipulating them, and then reassembling them to use as shelter. This discovery was documented in the journal Current Biology and has also been caught on video.
Defense
Greater Blue-ringed Octopus (Hapalochlaena lunulata)
An octopus’s main (primary) defense is to hide, either not to be seen at all, or not to be detected as an octopus. Octopuses have several secondary defenses (defenses they use once they have been seen by a predator). The most common secondary defense is fast escape. Other defenses include the use of ink sacs, camouflage, and autotomising limbs.
Most octopuses can eject a thick blackish ink in a large cloud to aid in escaping from predators. The main colouring agent of the ink is melanin, which is the same chemical that gives humans their hair and skin colour. This ink cloud is thought to reduce the efficiency of olfactory organs, which would aid an octopus’s evasion from predators that employ smell for hunting, such as sharks. Ink clouds of some species might serve as pseudomorphs, or decoys that the predator attacks instead.
This small octopus species travels with shells it has collected for protection.
An octopus’s camouflage is aided by certain specialized skin cells which can change the apparent color, opacity, and reflectiveness of the epidermis. Chromatophores contain yellow, orange, red, brown, or black pigments; most species have three of these colors, while some have two or four. Other color-changing cells are reflective iridophores, and leucophores (white). This color-changing ability can also be used to communicate with or warn other octopuses. The very venomous blue-ringed octopus becomes bright yellow with blue rings when it is provoked. Octopuses can use muscles in the skin to change the texture of their mantle in order to achieve a greater camouflage. In some species the mantle can take on the spiky appearance of seaweed, or the scraggly, bumpy texture of a rock, among other disguises. However in some species skin anatomy is limited to relatively patternless shades of one color, and limited skin texture. It is thought that octopuses that are day-active and/or live in complex habitats such as coral reefs have evolved more complex skin than their nocturnal and/or sand-dwelling relatives.
When under attack, some octopuses can perform arm autotomy, in a similar manner to the way skinks and other lizards detach their tails. The crawling arm serves as a distraction to would-be predators.
A few species, such as the Mimic Octopus, have a fourth defense mechanism. They can combine their highly flexible bodies with their color changing ability to accurately mimic other, more dangerous animals such as lionfish, sea snakes, and eels.
Reproduction
When octopuses reproduce, males use a specialized arm called a hectocotylus to insert spermatophores (packets of sperm) into the female’s mantle cavity. The hectocotylus in benthic octopuses is usually the third right arm. Males die within a few months of mating. In some species, the female octopus can keep the sperm alive inside her for weeks until her eggs are mature. After they have been fertilized, the female lays about 200,000 eggs (this figure dramatically varies between families, genera, species and also individuals). The female hangs these eggs in strings from the ceiling of her lair, or individually attaches them to the substrate depending on the species. The female cares for the eggs, guarding them against predators, and gently blowing currents of water over them so that they get enough oxygen. The female does not hunt during the roughly one-month period spent taking care of the unhatched eggs and may ingest some of her own arms for sustenance. At around the time the eggs hatch, the mother leaves the lair and is too weak to defend herself from predators like cod, often succumbing to their attacks. The young larval octopuses spend a period of time drifting in clouds of plankton, where they feed on copepods, larval crabs and larval starfish until they are ready to descend to the ocean bottom, where the cycle repeats. This is a dangerous time for the larval octopuses; in the plankton cloud they are vulnerable to plankton eaters. In some deeper dwelling species, the young do not go through this period.[citation needed]
Sensation
Eye of Octopus vulgaris
Octopuses have keen eyesight. Octopuses, like other cephalopods, can distinguish the polarization of light. Color vision appears to vary from species to species, being present in Octopus aegina but absent in Octopus vulgaris. Attached to the brain are two special organs, called statocysts, that allow the octopus to sense the orientation of its body relative to horizontal. An autonomic response keeps the octopus’s eyes oriented so that the pupil slit is always horizontal.
Octopuses also have an excellent sense of touch. An octopus’s suction cups are equipped with chemoreceptors so that the octopus can taste what it is touching. The arms contain tension sensors so that the octopus knows whether its arms are stretched out. However, the octopus has a very poor proprioceptive sense. The tension receptors are not sufficient for the octopus brain to determine the position of the octopus’s body or arms. (It is not clear that the octopus brain would be capable of processing the large amount of information that this would require; the flexibility of an octopus’s arms is much greater than that of the limbs of vertebrates, which devote large areas of cerebral cortex to the processing of proprioceptive inputs.) As a result, the octopus does not possess stereognosis; that is, it does not form a mental image of the overall shape of the object it is handling. It can detect local texture variations, but cannot integrate the information into a larger picture.
The neurological autonomy of the arms means that the octopus has great difficulty learning about the detailed effects of its motions. The brain may issue a high-level command to the arms, but the nerve cords in the arms execute the details. There is no neurological path for the brain to receive feedback about just how its command was executed by the arms; the only way it knows just what motions were made is by observing the arms visually.
Octopuses swim headfirst, with arms trailing behind
Locomotion
Octopuses move about by crawling or swimming. Their main means of slow travel is crawling, with some swimming. Jet propulsion is their fastest means of locomotion, followed by swimming and walking.
They crawl by walking on their arms, usually on many at once, on both solid and soft surfaces, while supported in water. In 2005 it was reported that some octopuses (Adopus aculeatus and Amphioctopus marginatus under current taxonomy) can walk on two arms, while at the same time resembling plant matter. This form of locomotion allows these octopuses to move quickly away from a potential predator while possibly not triggering that predator’s search image for octopus (food). Octopuses lack bones and are extremely vulnerable to predators.
Octopuses swim by expelling a jet of water from a contractile mantle, and aiming it via a muscular siphon.
Size
See also: Cephalopod size
An adult North Pacific Giant Octopus, Enteroctopus dofleini
The North Pacific Giant Octopus, Enteroctopus dofleini, is often cited as the largest octopus species. Adults usually weigh around 15 kg (33 lb), with an arm span of up to 4.3 m (14 ft). The largest specimen of this species to be scientifically documented was an animal with a live mass of 71 kg (156.5 lb). The alternative contender is the Seven-arm Octopus, Haliphron atlanticus, based on a 61 kg (134 lb) carcass estimated to have a live mass of 75 kg (165 lb). However, there are a number of questionable size records that would suggest E. dofleini is the largest of all octopus species by a considerable margin; one such record is of a specimen weighing 272 kg (600 lb) and having an arm span of 9 m (30 ft).
Terminology
The term octopus, pronounced /ktps/, is from Greek (oktapous), “eight-footed”, with plural forms: octopuses /ktpsz/, octopi /ktpa/, or octopodes /ktpdiz/. Currently, octopuses is the most common form in the US as well as the UK; octopodes is rare, and octopi is often objectionable.
The Oxford English Dictionary (2008 Draft Revision) lists octopuses, octopi and octopodes (in that order); it labels octopodes “rare”, and notes that octopi derives from the “apprehension” that octps is a second declension Latin noun, though it is not. It is a Latinization of Greek third-declension masculine oktous (, ‘eight-foot’), plural oktodes (). If the word were native to Latin, it would be octps, plural octpedes, after the pattern of ps (‘foot’), plural peds, analogous to “Centipede”. The actual Latin word for octopus and other similar species is polypus, from Greek polpous (, ‘many-foot’); usually the inaccurate plural polyp is used instead of polypods.
In modern Greek, the word is khtapdi (), plural khtapdia (), from Medieval oktapdion (), equivalent to Classical oktpous (), variant of oktous.
Chambers 21st Century Dictionary and the Compact Oxford Dictionary list only octopuses, although the latter notes that octopodes is “still occasionally used”; the British National Corpus has 29 instances of octopuses, 11 of octopi and 4 of octopodes. Merriam-Webster 11th Collegiate Dictionary lists octopuses and octopi, in that order; Webster’s New World College Dictionary lists octopuses, octopi and octopodes (in that order).
Fowler’s Modern English Usage states that “the only acceptable plural in English is octopuses,” and that octopi is misconceived and octopodes pedantic.
The term octopod (plural octopods or octopodes) is taken from the taxonomic order Octopoda but has no classical equivalent. The collective form octopus is usually reserved for animals consumed for food.
Relationship to humans
Moche Octopus. 200 A.D. Larco Museum Collection Lima, Peru
Ancient peoples of the Mediterranean were aware of the octopus, as evidenced by certain artworks and designs of prehistory. For example, a stone carving found in the archaeological recovery from Bronze Age Minoan Crete at Knossos has a depiction of a fisherman carrying an octopus.
The Moche people of ancient Peru worshipped the sea and its animals; moreover, octopuses were often depicted in their art.
In mythology
The Hawaiian creation myth relates that the present cosmos is only the last of a series, having arisen in stages from the wreck of the previous universe. In this account, the octopus is the lone survivor of the previous, alien universe.
In literature
The octopus has a significant role in Victor Hugo’s book Travailleurs de la mer (Toilers of the Sea).
Octopus at Tsukiji fish market
As food
Wikibooks Cookbook has a recipe/module on
Octopus
Humans eat octopus in many cultures. The arms and sometimes other body parts are prepared in various ways, often varying by species.
Octopus is a common ingredient in Japanese cuisine, including sushi, takoyaki, and Akashiyaki. Some small species are sometimes eaten alive as a novelty and health food. Similarly, a live octopus may be sliced up and the legs eaten while still squirming, which continues for some minutes.
Octopuses are “tickled” out of their holes in the Hawaiian Islands with 3-pronged polespears
Octopus is eaten regularly in Hawaii, since many popular dishes are Asian in origin. Locally known by their Hawaiian or Japanese names, (“he’e” and “tako” respectively) octopus is also a popular fish bait.
Octopus is a common food in Mediterranean cuisine and Portuguese cuisine. In Galicia, polbo feira (market fair style octopus) is a local delicacy. Restaurants which specialize or serve this dish are known as pulperas. On the Tunisian island of Djerba, local people catch octopuses by taking advantage of the animals’ habit of hiding in safe places during the night. In the evening they put grey ceramic pots on the sea bed. The morning of the following day they check them for octopuses that sheltered there.
According to the USDA Nutrient Database (2007), cooked octopus contains approximately 139 calories per three ounce portion, and is a source of vitamin B3, B12, potassium, phosphorus, and selenium.
Care must be taken to boil the octopus properly, to rid it of slime, smell, and residual ink.
As pets
Though octopuses can be difficult to keep in captivity, some people keep them as pets. Octopuses often escape even from supposedly secure tanks, due to their problem solving skills, mobility and lack of rigid structure.
The variation in size and life span among octopus species makes it difficult to know how long a new specimen can naturally be expected to live. That is, a small octopus may be just born or may be an adult, depending on its species. By selecting a well-known species, such as the California Two-spot Octopus, one can choose a small octopus (around the size of a tennis ball) and be confident that it is young with a full life ahead of it.
Octopuses are also quite strong for their size. Octopuses kept as pets have been known to open the covers of their aquariums and survive for a time in the air in order to get to a nearby feeder tank and gorge themselves on the fish there. They have also been known to catch and kill some species of sharks.
Classification
Wikispecies has information related to: Octopoda
The Wikibook Dichotomous Key has a page on the topic of
Octopoda
Wikimedia Commons has media related to: Octopus
A fisherman’s catch of octopus dries in the sun
Class CEPHALOPODA
Subclass Nautiloidea: nautilus
Subclass Coleoidea
Superorder Decapodiformes: squid, cuttlefish
Superorder Octopodiformes
Order Vampyromorphida: Vampire Squid
Order Octopoda
Genus euppia (incertae sedis)
Genus alaeoctopus (incertae sedis)
Genus aleocirroteuthis (incertae sedis)
Genus ohlsepia (incertae sedis)
Genus roteroctopus

Part 4 (Chs 12-14). Classic Literature VideoBook with synchronized text, interactive transcript, and closed captions in multiple languages. Audio courtesy of Librivox. Read by Mark F. Smith. Playlist for The House of the Seven Gables by Nathaniel Hawthorne: www.youtube.com
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Types
Believed approximate position of the proto-continents toward the end of the Carboniferous period; the light blue represents shallow seas where many of today’s coal deposits are found, as opposed to deeper waters which gave rise to oil bearing rocks derived from marine species. The ice caps were known to be very large, lowering sea levels extensively by locking up oceanic waters into solid ice, though how large the ice caps became is a matter of debate.
As geological processes apply pressure to dead biotic matter over time, under suitable conditions it is transformed successively into
Peat, considered to be a precursor of coal, has industrial importance as a fuel in some regions, for example, Ireland and Finland. In its dehydrated form, peat is a highly effective absorbent for fuel and oil spills on land and water.
Lignite, also referred to as brown coal, is the lowest rank of coal and used almost exclusively as fuel for electric power generation. Jet is a compact form of lignite that is sometimes polished and has been used as an ornamental stone since the Iron Age.
Sub-bituminous coal, whose properties range from those of lignite to those of bituminous coal are used primarily as fuel for steam-electric power generation. Additionally, it is an important source of light aromatic hydrocarbons for the chemical synthesis industry.
Bituminous coal, dense mineral, black but sometimes dark brown, often with well-defined bands of bright and dull material, used primarily as fuel in steam-electric power generation, with substantial quantities also used for heat and power applications in manufacturing and to make coke.
Steam coal is a grade between bituminous coal and anthracite. It was widely used as a fuel for steam locomotives. Small steam coal (dry small steam nuts or DSSN) was used as a fuel for domestic water heating.
Anthracite, the highest rank; a harder, glossy, black coal used primarily for residential and commercial space heating. It may be divided further into metamorphically altered bituminous coal and petrified oil, as from the deposits in Pennsylvania.
Graphite, technically the highest rank, but difficult to ignite and is not so commonly used as fuel: it is mostly used in pencils and, when powdered, as a lubricant.
The classification of coal is generally based on the content of volatiles. However, the exact classification varies between countries. According to the German classification, coal is classified as follows:
Name
Volatiles %
C Carbon %
H Hydrogen %
O Oxygen %
S Sulfur %
Heat content kJ/kg
Braunkohle (Lignite)
45-65
60-75
6.0-5.8
34-17
0.5-3
Flammkohle (Flame coal)
40-45
75-82
6.0-5.8
>9.8
~1
Gasflammkohle (Gas flame coal)
35-40
82-85
5.8-5.6
9.8-7.3
~1
Gaskohle (Gas coal)
28-35
85-87.5
5.6-5.0
7.3-4.5
~1
Fettkohle (Fat coal)
19-28
87.5-89.5
5.0-4.5
4.5-3.2
~1
Esskohle (Forge coal)
14-19
89.5-90.5
4.5-4.0
3.2-2.8
~1
Magerkohle (Non baking coal)
10-14
90.5-91.5
4.0-3.75
2.8-3.5
~1
35380
Anthrazit (Anthracite)
7-12
>91.5
~1
Percent by weight
The middle six grades in the table represent a progressive transition from the English-language sub-bituminous to bituminous coal, while the last class is an approximate equivalent to anthracite, but more inclusive (the U.S. anthracite has
Cannel coal (sometimes called “candle coal”), is a variety of fine-grained, high-rank coal with a large amount of hydrogen. It consists primarily of “exinite” macerals, now termed “liptinite”.
Early use
Further information: History of coal mining
The earliest recognized use is from the Shenyang area 4000 BC where Neolithic inhabitants had begun carving ornaments from black lignite, but it was not until the Han Dynasty (206 BC220 AD) that coal was also used for fuel. Outcrop coal was used in Britain during the Bronze Age (20003000 years BC), where it has been detected as forming part of the composition of funeral pyres. In Roman Britain, with the exception of two modern fields, “the Romans were exploiting coals in all the major coalfields in England and Wales by the end of the second century AD”. Evidence of trade in coal (dated to about AD 200) has been found at the inland port of Heronbridge, near Chester, and in the Fenlands of East Anglia, where coal from the Midlands was transported via the Car Dyke for use in drying grain. Coal cinders have been found in the hearths of villas and military forts, particularly in Northumberland, dated to around AD 400. In the west of England contemporary writers described the wonder of a permanent brazier of coal on the altar of Minerva at Aquae Sulis (modern day Bath) although in fact easily-accessible surface coal from what became the Somerset coalfield was in common use in quite lowly dwellings locally. Evidence of coal’s use for iron-working in the city during the Roman period has been found.
There is no evidence that the product was of great importance in Britain before the High Middle Ages, after about AD 1000. Mineral coal came to be referred to as “seacoal,” probably because it came to many places in eastern England, including London, by sea. This is accepted as the more likely explanation for the name than that it was found on beaches, having fallen from the exposed coal seams above or washed out of underwater coal seam outcrops. These easily accessible sources had largely become exhausted (or could not meet the growing demand) by the 13th century, when underground mining from shafts or adits was developed. In London there is still a Seacoal Lane and a Newcastle Lane (from the coal-shipping city of Newcastle) where in the seventeenth century coal was unloaded at wharves along the River Fleet. An alternative name was “pitcoal,” because it came from mines. It was, however, the development of the Industrial Revolution that led to the large-scale use of coal, as the steam engine took over from the water wheel.
Uses today
Coal rail cars in Ashtabula, Ohio.
Coal as fuel
Further information: Electricity generation, Clean coal technology, Coal electricity, and Global warming
Coal is primarily used as a solid fuel to produce electricity and heat through combustion. World coal consumption was about 6,743,786,000 short tons in 2006 and is expected to increase 48% to 9.98 billion short tons by 2030. China produced 2.38 billion tons in 2006. India produced about 447.3 million tons in 2006. 68.7% of China’s electricity comes from coal. The USA consumes about 14% of the world total, using 90% of it for generation of electricity.
When coal is used for electricity generation, it is usually pulverized and then combusted (burned) in a furnace with a boiler. The furnace heat converts boiler water to steam, which is then used to spin turbines which turn generators and create electricity. The thermodynamic efficiency of this process has been improved over time. “Standard” steam turbines have topped out with some of the most advanced reaching about 35% thermodynamic efficiency for the entire process, although newer combined cycle plants can reach efficiencies as high as 58%. Increasing the combustion temperature can boost this efficiency even further. Old coal power plants, especially “grandfathered” plants, are significantly less efficient and produce higher levels of waste heat. About 40% of the world’s electricity comes from coal, and approximately 49% of the United States electricity comes from coal.
Fuels for heating
Heating oil
Wood pellet
Kerosene
Propane
Natural gas
Wood
Coal
The emergence of the supercritical turbine concept envisions running a boiler at extremely high temperatures and pressures with projected efficiencies of 46%, with further theorized increases in temperature and pressure perhaps resulting in even higher efficiencies.
Other efficient ways to use coal are combined cycle power plants, combined heat and power cogeneration, and an MHD topping cycle.
Approximately 40% of the world electricity production uses coal. The total known deposits recoverable by current technologies, including highly polluting, low energy content types of coal (i.e., lignite, bituminous), is sufficient for many years. However, consumption is increasing and maximal production could be reached within decades (see World Coal Reserves, below).
A more energy-efficient way of using coal for electricity production would be via solid-oxide fuel cells or molten-carbonate fuel cells (or any oxygen ion transport based fuel cells that do not discriminate between fuels, as long as they consume oxygen), which would be able to get 60%85% combined efficiency (direct electricity + waste heat steam turbine).[citation needed] Currently these fuel cell technologies can only process gaseous fuels, and they are also sensitive to sulfur poisoning, issues which would first have to be worked out before large scale commercial success is possible with coal. As far as gaseous fuels go, one idea is pulverized coal in a gas carrier, such as nitrogen. Another option is coal gasification with water, which may lower fuel cell voltage by introducing oxygen to the fuel side of the electrolyte, but may also greatly simplify carbon sequestration. However, this technology has been criticised as being inefficient, slow, risky and costly, while doing nothing about total emissions from mining, processing and combustion. Another efficient and clean way of coal combustion in a form of coal-water slurry fuel (CWS) was well developed in Russia (since the Soviet Union time). CWS significantly reduces emissions saving the heating value of coal.
Coking and use of coke
Main article: Coke (fuel)
Coke oven at smokeless fuel plant, Wales
Coke is a solid carbonaceous residue derived from low-ash, low-sulfur bituminous coal from which the volatile constituents are driven off by baking in an oven without oxygen at temperatures as high as 1,000 C (1,832 F) so that the fixed carbon and residual ash are fused together. Metallurgical coke is used as a fuel and as a reducing agent in smelting iron ore in a blast furnace. The product is too rich in dissolved carbon, and must be treated further to make steel. The coke must be strong enough to resist the weight of overburden in the blast furnace, which is why coking coal is so important in making steel by the conventional route. However, the alternative route to is direct reduced iron, where any carbonaceous fuel can be used to make sponge or pelletised iron. Coke from coal is grey, hard, and porous and has a heating value of 24.8 million Btu/ton (29.6 MJ/kg). Some cokemaking processes produce valuable by-products that include coal tar, ammonia, light oils, and “coal gas”.
Petroleum coke is the solid residue obtained in oil refining, which resembles coke but contains too many impurities to be useful in metallurgical applications.
Ethanol production
The reaction of coal and natural gas was used by a German manufacturer for Buna rubber: Chemische Werke Huls, at Marl, Germany, and AVCO Corp in the US. Consequently several references had described both Huls Arc Process and AVCO rotating arc reactor. Both reactors are of cylindrical shape and have a rotating electric arc. The cathode is at the cylinder axis, while the anode is on the circumference. As methane gas provided the highest yield, then it is forced with coal powder into a vortex passing through the electric arc for few milliseconds.
Huls Arc Process produced a mixture of acetylene and ethylene gases. The reaction conditions can be varied to determine the needed product. Increasing the Specific Energy Requirement (SER) favor acetylene production, and lower SER is for ethylene:
Enthalpy Change for Ethylene: = 127.34 kJ/mol, while for acetylene: = 301.4 kJ/mol. As a consequence, recent production processes are using conventional heating instead of electric arc.
Hydration of ethylene gas producing ethanol is the most important process for ethanol production. Vapor phase process is the preferred one in which ethylene and steam pass over a catalyst. One of the most accepted catalyst is diatomite impregnated with phosphoric acid.
Gasification
Main articles: Coal gasification and Underground coal gasification
Coal gasification can be used to produce syngas, a mixture of carbon monoxide (CO) and hydrogen (H2) gas. This syngas can then be converted into transportation fuels like gasoline and diesel through the Fischer-Tropsch process. Currently, this technology is being used by the Sasol chemical company of South Africa to make gasoline from coal and natural gas. Alternatively, the hydrogen obtained from gasification can be used for various purposes such as powering a hydrogen economy, making ammonia, or upgrading fossil fuels.
During gasification, the coal is mixed with oxygen and steam (water vapor) while also being heated and pressurized. During the reaction, oxygen and water molecules oxidize the coal into carbon monoxide (CO) while also releasing hydrogen (H2) gas. This process has been conducted in both underground coal mines and in coal refineries.
(Coal) + O2 + H2O H2 + CO
If the refiner wants to produce gasoline, the syngas is collected at this state and routed into a Fischer-Tropsch reaction. If hydrogen is the desired end-product, however, the syngas is fed into the water gas shift reaction where more hydrogen is liberated.
CO + H2O CO2 + H2
High prices of oil and natural gas are leading to increased interest in “BTU Conversion” technologies such as gasification, methanation and liquefaction. The Synthetic Fuels Corporation was a U.S. government-funded corporation established in 1980 to create a market for alternatives to imported fossil fuels (such as coal gasification). The corporation was discontinued in 1985.
In the past, coal was converted to make coal gas, which was piped to customers to burn for illumination, heating, and cooking. At present, the safer natural gas is used instead.
Liquefaction
Main article: Coal liquefaction
Coal can also be converted into liquid fuels like gasoline or diesel by several different processes. In the direct liquefaction processes, the coal is either hydrogenated or carbonized. Hydrogenation processes are the Bergius process, the SRC-I and SRC-II (Solvent Refined Coal) processes and the NUS Corporation hydrogenation process. In the process of low temperature carbonization coal is coked at temperatures between 680 F (360 C) and 1,380 F (750 C). These temperatures optimize the production of coal tars richer in lighter hydrocarbons than normal coal tar. The coal tar is then further processed into fuels. Alternatively, coal can be converted into a gas first, and then into a liquid, by using the Fischer-Tropsch process. An overview of coal liquefaction and its future potential has been done by others
Coal liquefaction methods involve carbon dioxide (CO2) emissions in the conversion process. If coal liquefaction is done without employing either carbon capture and storage technologies or biomass blending, the result is lifecycle greenhouse gas footprints that are generally greater than those released in the extraction and refinement of liquid fuel production from crude oil. If CCS technologies are employed, reductions of 5-12% can be achieved in CTL plants and up to a 75% reduction is achievable when co-gasifying coal with commercially demonstrated levels of biomass (30% biomass by weight) in CBTL plants. For most future synthetic fuel projects, Carbon dioxide sequestration is proposed to avoid releasing it into the atmosphere. Sequestration will, however, add to the cost of production. Currently all US and at least one Chinese synthetic fuel projects, are including sequestration in their process designs.
Refined coal
Main article: Refined coal
Refined coal is the product of a coal upgrading technology that removes moisture and certain pollutants from lower-rank coals such as sub-bituminous and lignite (brown) coals. It is one form of several pre-combustion treatments and processes for coal that alter coal’s characteristics before it is burned. The goals of pre-combustion coal technologies are to increase efficiency and reduce emissions when the coal is burned. Depending on the situation, pre-combustion technology can be used in place of or as a supplement to post-combustion technologies to control emissions from coal-fueled boilers.
Coal as a traded commodity
The price of coal has gone up from around $ 30 per short ton in 2000 to around $ 150.00 per short ton as of September 26, 2008. As of October 31, 2008, the price per short ton has declined to $ 111.50.
In North America, a Central Appalachian coal futures contracts are currently traded on the New York Mercantile Exchange (trading symbol QL). The trading unit is 1,550 short tons (1,410 t) per contract, and is quoted in U.S. dollars and cents per ton. Since coal is the principal fuel for generating electricity in the United States, coal futures contracts provide coal producers and the electric power industry an important tool for hedging and risk management.
In addition to the NYMEX contract, the IntercontinentalExchange (ICE) has European (Rotterdam) and South African (Richards Bay) coal futures available for trading. The trading unit for these contracts is 5,000 tonnes (5,500 short tons), and are also quoted in U.S. dollars and cents per ton.
Cultural usage
Coal is the official state mineral of Kentucky and the official state rock of Utah. Both U.S. states have a historic link to coal mining.
Some cultures uphold that children who misbehave will receive only a lump of coal from Santa Claus for Christmas in their stockings instead of presents.
It is also customary and lucky in Scotland to give coal as a gift on New Year’s Day. It happens as part of First-Footing and represents warmth for the year to come.
Environmental effects
Main article: Environmental effects of coal
Aerial photograph of Kingston Fossil Plant coal fly ash slurry spill site taken the day after the event
There are a number of adverse environmental effects of coal mining and burning, specially in power stations.
These effects include:
Generation of hundreds of millions of tons of waste products, including fly ash, bottom ash, flue gas desulfurization sludge, that contain mercury, uranium, thorium, arsenic, and other heavy metals
Acid rain from high sulfur coal
Interference with groundwater and water table levels
Contamination of land and waterways and destruction of homes from fly ash spills such as Kingston Fossil Plant coal fly ash slurry spill
Impact of water use on flows of rivers and consequential impact on other land-uses
Dust nuisance
Subsidence above tunnels, sometimes damaging infrastructure[citation needed]
Coal-fired power plants without effective fly ash capture are one of the largest sources of human-caused background radiation exposure
Coal-fired power plants shorten nearly 24,000 lives a year in the United States, including 2,

Making a garden bench is a very popular weekend project at this time of year. Much information exists on the internet to show the way to make one, but it is very easy to underrate the need to use exact measurements to ensure a safe and attractive item of garden furniture.

Accurate assembly is the key and is the reason why you need a good set of garden bench plans to do the job properly. If plans are not used the finished product will look clumsy and be a big disappointment. Not a good result, even for a diy novice. Any bench should, and can, be a thing of beauty.

Garden benches are made up, basically, of a seat, a back and two end pieces. Various designs may include extra stiffeners and ornamental additions, but the basic design will be unchanged. Outdoor bench plans should not be just a few simple drawings.

As a minimum they should include:
3 view blueprints (side, plan and back) with all dimensions shown clearly
full list of materials with all cut sizes and quantities
step-by-step assembly details or diagrams
details of power and hand tools required
all health and safety precautions

If you do not know the design of bench you would like to make, it is also a good idea to find a set of garden bench plans which has a large number of design choices and some sort of difficulty or skills rating for each one.

There are several choices of wood suitable for outdoor garden furniture.

Cedar is a favorite, with its lovely feel and smell.

Western Red Cedar is perhaps the best. Another lovely wood is Redwood, if you can get and afford it. Mahogany is hard-wearing and has good weather tolerance.

Or there is pressure-treated wood such as Yellow or Southern Pine. This type of material has excellent weather resistance and can be painted or stained. Perhaps it is not as attractive as natural wood, however.

Be aware that treated wood is toxic, so be sure to take proper precautions when working with it. Use good goggles, gloves and face masks when cutting or drilling, and do all such work outdoors if at all possible.

It is also very helpful to have power tools such as a bench saw and bench drill, because there are usually many pieces that must be cut and drilled accurately. Aside from those you will only need the usual selection of hand tools.

Remember the old words of advice: Measure Twice, Cut Once. Really appropriate for this sort of woodworking project.

So, good luck making your outdoor garden bench. It will be a great addition to your backyard or patio.

Find More Mosaic Stone Bench Articles

Roman Architecture (HSAR 252) Professor Kleiner characterizes third-century Rome as an “architectural wasteland” due to the rapid change of emperors, continuous civil war, and a crumbling economy. There was no time to build and the only major architectural commission was a new defensive wall. The crisis came to an end with the rise of Diocletian, who created a new form of government called the Tetrarchy, or four-man rule, with two leaders in the East and two in the West. Diocletian and his colleagues instituted a major public and private building campaign in Rome and the provinces, which reflected the Empire’s renewed stability. Professor Kleiner begins with Diocletian’s commissions in Rome–a five-column monument dedicated to the tenth anniversary of the formation of the Tetrarchy, the restoration of the Curia or Senate House, and the monumental Baths of Diocletian. She then presents Diocletian’s Palace at Split, designed as a military camp and including the emperor’s octagonal mausoleum, followed by an overview of the palaces and villas of other tetrarchs in Greece and Sicily. Professor Kleiner concludes with the villa on the Via Appia in Rome belonging to Maxentius, son of a tetrarch, and the main rival of another tetrarch’s son, Constantine the Great. 00:00 – Chapter 1. Crisis in the Third Century and the Aurelian Walls 11:47 – Chapter 2. The Rise of the Tetrarchy 18:21 – Chapter 3. The Decennial or Five-Column Monument in the Roman Forum 28:48 – Chapter 4. The Senate …
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Roman Architecture (HSAR 252) Professor Kleiner focuses on Ostia, the port of Rome, characterized by its multi-storied residential buildings and its widespread use of brick-faced concrete. She begins with the city’s public face–the Forum, Capitolium, Theater, and Piazzale delle Corporazioni. The Piazzale, set behind the Theater, was the location of various shipping companies with black-and-white mosaics advertising their business. Professor Kleiner examines the Baths of Neptune and the Insula of Diana, a brick apartment building with four floors that housed a number of Ostia’s working families. The Insula of Diana and other similar structures, including warehouses like the Horrea Epagathiana, demonstrate a fundamental feature of second-century Ostia: the appreciation of the aesthetic qualities of brick facing. Since the time of Nero, brick was customarily covered with stucco and paint, but these Ostian buildings are faced with exposed brick, the color, texture, and design of which make it attractive in its own right. The lecture ends with a survey of several single family dwellings in Ostia, including the fourth-century House of Cupid and Psyche, notable for the pastel-colored marble revetment on its walls and floors and for a charming statue of the legendary lovers. 00:00 – Chapter 1. Ostia: Romes First Colony 12:37 – Chapter 2. Civic Architecture in Ostia 23:32 – Chapter 3. Transacting Business at the Piazzale delle Corporazioni 36:57 – Chapter 4. Residential …
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