BIO FUELS FROM CORN

How to Make Biofuel From Corn

If gas prices get too high for you, and your automobile can run on E-85 ethanol, you can try making your own biofuel from corn. The process is complicated, and there are a few safety precautions you need to be aware of; however, almost anyone can make fuel for their car (or anything else) right in their own backyard.

If gas prices get too high for you, and your automobile can run on E-85 ethanol, you can try making your own biofuel from corn. The process is complicated, and there are a few safety precautions you need to be aware of; however, almost anyone can make fuel for their car (or anything else) right in their own backyard.

1. Step 1

   Grind the corn into granules, similar to the consistency of corn grits.

2. Step 2

   Add water (not the corn, yet) to the cooker in the still and bring the temperature up to 170 degrees (F). You will need roughly 30 gallons of water per bushel of corn.

3. Step 3

   Slowly add the ground corn meal to the water being careful not to cause "lumps."

4. Step 4

   Add three measuring spoons (provided with the enzyme) worth of the alpha amylase enzyme to the mixture.

5. Step 5

   Agitate the solution at this temperature for 15 minutes.

6. Step 6

   Raise the temperature of the mixture to boiling and allow it to hard boil for 30 minutes.

7. Step 7

   Reduce the temperature after 30 minutes to 170 degrees.

8. Step 8

   Add three more measuring spoonfuls of the enzyme and agitate for 30 minutes.

9. Step 9

   Reduce the temperature to 85 degrees (F) and add six more spoonfuls of the enzyme.

10. Step 10

    Hold at 85 degrees for 48 to 72 hours to complete the fermentation process.

11. Step 11

    After the fermentation process is complete, use the screening mill to filter the mixture. What you will be left with is E85 ethanol.

12. Energy-use associated with the production of sugarcane ethanol derives from three primary sources: the agricultural sector, the industrial sector, and the distribution sector. In the agricultural sector, 35.98 GJ of energy are used to plant, maintain, and harvest one hectare (10,000 m2) of sugarcane for usable biofuel. This includes energy from numerous inputs, including nitrogen, phosphate, potassium oxide, lime, seed, herbicides, insecticides, labor and diesel fuel. The industrial sector, which includes the milling and refining sugarcane and the production of ethanol fuel, uses 3.63 GJ of energy and generates 155.57 GJ of energy per hectare of sugarcane plantation. Scientists estimate that the potential power generated from the cogeneration of bagasse could range from 1,000 to 9,000 MW, depending on harvest and technology factors. In Brazil, this is about 3% of the total energy needed. The burning of bagasse can generate 18 kilowatt-hours, or 64.7 MJ per Mg of sugarcane. Distillery facilities require about 45 MJ to operate, leaving a surplus energy supply of 19.3 MJ, or 5.4 kWh. In terms of distribution, researchers calculates sugarcane ethanol’s transport energy requirement to be .44 GJ per cubic-meter, thus one hectare of land would require 2.82 GJ of energy for successful transport and distribution. After taking all three sectors into account, the EROEI (Energy Return over Energy Invested) for sugarcane ethanol is about 8.^[75]

    There are several improvements to the industrial processes, such as adopting a hydrolysis process to produce ethanol instead of surplus electricity, or the use of advanced boiler and turbine technology to increase the electricity yield, or a higher use of excess bagasse and harvest trash currently left behind in the fields, that together with various other efficiency improvements in sugarcane farming and the distribution chain have the potential to allow further efficiency increases, translating into higher yields, lower production costs, and also further improvements in the energy balance and the reduction of greenhouse gas emissions.^[70]

nano materials

nanomaterials is a field which takes a materials science-based approach to nanotechnology. It studies materials with morphological features on the nanoscale, and especially those which have special properties stemming from their nanoscale dimensions. Nanoscale is usually defined as smaller than a one tenth of a micrometer in at least one dimension, though this term is sometimes also used for materials smaller than one micrometer. Types of Nanomaterials

For the purpose of this article, most current nanomaterials could be organized into four types:

· Carbon Based Materials

· Metal Based Materials

· Dendrimers

· Composites

Carbon Based Materials

These nanomaterials are composed mostly of carbon, most commonly taking the form of a hollow spheres, ellipsoids, or tubes. Spherical and ellipsoidal carbon nanomaterials are referred to as fullerenes, while cylindrical ones are called nanotubes. These particles have many potential applications, including improved films and coatings, stronger and lighter materials, and applications in electronics.

Metal Based Materials

These nanomaterials include quantum dots, nanogold, nanosilver and metal oxides, such as titanium dioxide. A quantum dot is a closely packed semiconductor crystal comprised of hundreds or thousands of atoms, and whose size is on the order of a few nanometers to a few hundred nanometers. Changing the size of quantum dots changes their optical properties.

Dendrimers

These nanomaterials are nanosized polymers built from branched units. The surface of a dendrimer has numerous chain ends, which can be tailored to perform specific chemical functions. This property could also be useful for catalysis. Also, because three-dimensional dendrimers contain interior cavities into which other molecules could be placed, they may be useful for drug delivery.

Composites

Composites combine nanoparticles with other nanoparticles or with larger, bulk-type materials. Nanoparticles, such as nanosized clays, are already being added to products ranging from auto parts to packaging materials, to enhance mechanical, thermal, barrier, and flame-retardant properties.

Nanomaterials and Their Applications

Topics Covered

Background

Applications

Next-Generation Computer Chips

Kinetic Energy (KE) Penetrators with Enhanced Lethality

Better Insulation Materials

Phosphors for High-Definition TV

Low-Cost Flat-Panel Displays

Tougher and Harder Cutting Tools

Elimination of Pollutants

High Energy Density Batteries

High-Power Magnets

High-Sensitivity Sensors

Automobiles with Greater Fuel Efficiency

Aerospace Components with Enhanced Performance Characteristics

Better and Future Weapons Platforms

Longer-Lasting Satellites

Longer-Lasting Medical Implants

Ductile, Machinable Ceramics

Large Electrochromic Display Devices

Summary

Background

Nanomaterials (nanocrystalline materials) are materials possessing grain sizes on the order of a billionth of a meter. They manifest extremely fascinating and useful properties, which can be exploited for a variety of structural and non-structural applications.

Applications

Since nanomaterials possess unique, beneficial chemical, physical, and mechanical properties, they can be used for a wide variety of applications. These applications include, but are not limited to, the following:

Next-Generation Computer Chips

The microelectronics industry has been emphasising miniaturisation, whereby the circuits, such as transistors, resistors, and capacitors, are reduced in size. By achieving a significant reduction in their size, the microprocessors, which contain these components, can run much faster, thereby enabling computations at far greater speeds. However, there are several technological impediments to these advancements, including lack of the ultrafine precursors to manufacture these components; poor dissipation of tremendous amount of heat generated by these microprocessors due to faster speeds; short mean time to failures (poor reliability), etc. Nanomaterials help the industry break these barriers down by providing the manufacturers with nanocrystalline starting materials, ultra-high purity materials, materials with better thermal conductivity, and longer-lasting, durable interconnections (connections between various components in the microprocessors).

Kinetic Energy (KE) Penetrators with Enhanced Lethality

The Department of Defense (DoD) is currently using depleted-uranium (DU) projectiles (penetrators) for its lethality against hardened targets and enemy armoured vehicles. However, DU has residual radioactivity, and hence, it is toxic (carcinogenic), explosive, and lethal to the personnel who use them. However, some of the important reasons for the continued use of DU penetrators are that they possess a unique self-sharpening mechanism on impact with a target, and the lack of suitable non-explosive, non-hazardous replacement for DU. Nanocrystalline tungsten heavy alloys lend themselves to such a self-sharpening mechanisms because of their unique deformation characteristics, such as grain-boundary sliding. Hence, nanocrystalline tungsten heavy alloys and composites are being evaluated as potential candidates to replace DU penetrators.

Better Insulation Materials

Nanocrystalline materials synthesised by the sol-gel technique result in foam like structures called "aerogels." These aerogels are porous and extremely lightweight; yet, they can loads equivalent to 100 times their weight. Aerogels are composed of three-dimensional, continuous networks of particles with air (or any other fluid, such as a gas) trapped at their interstices. Since they are porous and air is trapped at the interstices, aerogels are currently being used for insulation in offices, homes, etc. By using aerogels for insulation, heating and cooling bills are drastically reduced, thereby saving power and reducing the attendant environmental pollution. They are also being used as materials for "smart " windows, which darken when the sun is too bright (just as in changeable lenses in prescription spectacles and sunglasses) and they lighten themselves, when the sun is not shining too brightly.

Phosphors for High-Definition TV

The resolution of a television, or a monitor, depends greatly on the size of the pixel. These pixels are essentially made of materials called "phosphors," which glow when struck by a stream of electrons inside the cathode ray tube (CRT). The resolution improves with a reduction in the size of the pixel, or the phosphors. Nanocrystalline zinc selenide, zinc sulfide, cadmium sulfide, and lead telluride synthesised by the sol-gel techniques are candidates for improving the resolution of monitors. The use of nanophosphors is envisioned to reduce the cost of these displays so as to render high-definition televisions (HDTVs) and personal computers affordable to be purchased by an average household in the U. S.

Low-Cost Flat-Panel Displays

Flat-panel displays represent a huge market in the laptop (portable) computers industry. However, Japan is leading this market, primarily because of its research and development efforts on the materials for such displays. By synthesising nanocrystalline phosphors, the resolution of these display devices can be greatly enhanced, and the manufacturing costs can be significantly reduced. Also, the flat-panel displays constructed out of nanomaterials possess much higher brightness and contrast than the conventional ones owing to their enhanced electrical and magnetic properties.

Tougher and Harder Cutting Tools

Cutting tools made of nanocrystalline materials, such as tungsten carbide, tantalum carbide, and titanium carbide, are much harder, much more wear-resistant, erosion-resistant, and last longer than their conventional (large-grained) counterparts. They also enable the manufacturer to machine various materials much faster, thereby increasing productivity and significantly reducing manufacturing costs. Also, for the miniaturisation of microelectronic circuits, the industry needs microdrills (drill bits with diameter less than the thickness of an average human hair or 100 µm) with enhanced edge retention and far better wear resistance. Since nanocrystalline carbides are much stronger, harder, and wear-resistant, they are currently being used in these microdrills.

Elimination of Pollutants

Nanocrystalline materials possess extremely large grain boundaries relative to their grain size. Hence, nanomaterials are very active in terms of their of chemical, physical, and mechanical properties. Due to their enhanced chemical activity, nanomaterials can be used as catalysts to react with such noxious and toxic gases as carbon monoxide and nitrogen oxide in automobile catalytic converters and power generation equipment to prevent environmental pollution arising from burning gasoline and coal.

High Energy Density Batteries

Conventional and rechargeable batteries are used in almost all applications that require electric power. These applications include automobiles, laptop computers, electric vehicles, next-generation electric vehicles (NGEV) to reduce environmental pollution, personal stereos, cellular phones, cordless phones, toys, and watches. The energy density (storage capacity) of these batteries is quite low requiring frequent recharging. The life of conventional and rechargeable batteries is also low. Nanocrystalline materials synthesised by sol-gel techniques are candidates for separator plates in batteries because of their foam-like (aerogel) structure, which can hold considerably more energy than their conventional counterparts. Furthermore, nickel-metal hydride (Ni-MH) batteries made of nanocrystalline nickel and metal hydrides are envisioned to require far less frequent recharging and to last much longer because of their large grain boundary (surface) area and enhanced physical, chemical, and mechanical properties.

High-Power Magnets

The strength of a magnet is measured in terms of coercivity and saturation magnetisation values. These values increase with a decrease in the grain size and an increase in the specific surface area (surface area per unit volume of the grains) of the grains. It has been shown that magnets made of nanocrystalline yttrium-samarium-cobalt grains possess very unusual magnetic properties due to their extremely large surface area. Typical applications for these high-power rare-earth magnets include quieter submarines, automobile alternators, land-based power generators, motors for ships, ultra-sensitive analytical instruments, and magnetic resonance imaging (MRI) in medical diagnostics.

High-Sensitivity Sensors

Sensors employ their sensitivity to the changes in various parameters they are designed to measure. The measured parameters include electrical resistivity, chemical activity, magnetic permeability, thermal conductivity, and capacitance. All of these parameters depend greatly on the microstructure (grain size) of the materials employed in the sensors. A change in the sensor’s environment is manifested by the sensor material’s chemical, physical, or mechanical characteristics, which is exploited for detection. For instance, a carbon monoxide sensor made of zirconium oxide (zirconia) uses its chemical stability to detect the presence of carbon monoxide. In the event of carbon monoxide’s presence, the oxygen atoms in zirconium oxide react with the carbon in carbon monoxide to partially reduce zirconium oxide. This reaction triggers a change in the sensor’s characteristics, such as conductivity (or resistivity) and capacitance. The rate and the extent of this reaction are greatly increased by a decrease in the grain size. Hence, sensors made nanocrystalline materials are extremely sensitive to the change in their environment. Typical applications for sensors made out of nanocrystalline materials are smoke detectors, ice detectors on aircraft wings, automobile engine performance sensor, etc.

Automobiles with Greater Fuel Efficiency

Currently, automobile engines waste considerable amounts of gasoline, thereby contributing to environmental pollution by not completely combusting the fuel. A conventional spark plug is not designed to burn the gasoline completely and efficiently. This problem is compounded by defective, or worn-out, spark plug electrodes. Since nanomaterials are stronger, harder, and much more wear-resistant and erosion-resistant, they are presently being envisioned to be used as spark plugs. These electrodes render the spark plugs longer-lasting and combust fuel far more efficiently and completely. A radically new spark plug design called the "railplug" is also in the prototype stages. This railplug uses the technology derived from the "railgun," which is a spin-off of the popular Star Wars defense program. However, these railplugs generate much more powerful sparks (with an energy density of approximately 1 kJ/mm²). Hence, conventional materials erode and corrode too soon and quite frequently to be of any practical use in automobiles. Nevertheless, railplugs made of nanomaterials last much longer even the conventional spark plugs. Also, automobiles waste significant amounts of energy by losing the thermal energy generated by the engine. This is especially true in the case of diesel engines. Hence, the engine cylinders (liners) are currently being envisioned to be coated with nanocrystalline ceramics, such as zirconia and alumina, so that they retain heat much more efficiently and result in complete and efficient combustion of the fuel.

Aerospace Components with Enhanced Performance Characteristics

Due to the risks involved in flying, aircraft manufacturers strive to make the aerospace components stronger, tougher, and last longer. One of the key properties required of the aircraft components is the fatigue strength, which decreases with the component’s age. By making the components out of stronger materials, the life of the aircraft is greatly increased. The fatigue strength increases with a reduction in the grain size of the material. Nanomaterials provide such a significant reduction in the grain size over conventional materials that the fatigue life is increased by an average of 200-300%. Furthermore, components made of nanomaterials are stronger and can operate at higher temperatures, aircrafts can fly faster and more efficiently (for the same amount of aviation fuel). In spacecrafts, elevated-temperature strength of the material is crucial because the components (such as rocket engines, thrusters, and vectoring nozzles) operate at much higher temperatures than aircrafts and higher speeds. Nanomaterials are perfect candidates for spacecraft applications, as well.

Better and Future Weapons Platforms

Conventional guns, such as cannons, 155 mm howitzers, and multiple-launch rocket system (MLRS), utilise the chemical energy derived by igniting a charge of chemicals (gun powder). The maximum velocity at which the penetrator can be propelled is approximately 1.5-2.0 km/sec. On the other hand, electromagnetic launchers (EML guns), or railguns, use the electrical energy, and the concomitant magnetic field (energy), to propel the penetrators/projectiles at velocities up to 10 km/sec. This increase in velocity results in greater kinetic energy for the same penetrator mass. The greater the energy, the greater is the damage inflicted on the target. For this and other reasons, the DoD (especially, the U. S. Army) has conducted extensive research into the railguns. Since a railgun operates on electrical energy, the rails need to be very good conductors of electricity. Also, they need to be so strong and rigid that the railgun does not sag while firing and buckle under its own weight. The obvious choice for high electrical conductivity is copper. However, the railguns made out of copper wear out much too quickly due to the erosion of the rails by the hypervelocity projectiles and they lack high-temperature strength. The wear and erosion of copper rails necessitate inordinately frequent barrel replacements. In order to satisfy these requirements, a nanocrystalline composite material made of tungsten, copper, and titanium diboride is being evaluated as a potential candidate. This nanocomposite possesses the requisite electrical conductivity, adequate thermal conductivity, excellent high strength, high rigidity, hardness, and wear/erosion resistance. This results in longer-lasting, wear-resistant, and erosion-resistant railguns, which can be fired more frequently and often than their conventional counterparts.

Longer-Lasting Satellites

Satellites are being used for both defence and civilian applications. These satellites utilise thruster rockets to remain in or change their orbits due to a variety of factors including the influence of gravitational forces exerted by the earth. Hence, these satellites are repositioned using these thrusters. The life of these satellites, to a large extent, is determined by the amount of fuel they can carry on board. In fact, more than 1/3 of the fuel carried aboard by the satellites is wasted by these repositioning thrusters due to incomplete and inefficient combustion of the fuel, such as hydrazine. The reason for the incomplete and inefficient combustion is that the onboard ignitors wear out quickly and cease to perform effectively. Nanomaterials, such as nanocrsytalline tungsten-titanium diboride-copper composite, are potential candidates for enhancing these ignitors’ life and performance characteristics.

Longer-Lasting Medical Implants

Currently, medical implants, such as orthopaedic implants and heart valves, are made of titanium and stainless steel alloys. These alloys are primarily used in humans because they are biocompatible, i.e., they do not adversely react with human tissue. In the case of orthopaedic implants (artificial bones for hip, etc.), these materials are relatively non-porous. For an implant to effectively mimic a natural human bone, the surrounding tissue must penetrate the implants, thereby affording the implant with the required strength. Since these materials are relatively impervious, human tissue does not penetrate the implants, thereby reducing their effectiveness. Furthermore, these metal alloys wear out quickly necessitating frequent, and often very expensive, surgeries. However, nanocrystalline zirconia (zirconium oxide) ceramic is hard, wear-resistant, corrosion-resistant (biological fluids are corrosive), and biocompatible. Nanoceramics can also be made porous into aerogels (aerogels can withstand up to 100 times their weight), if they are synthesized by sol-gel techniques. This results in far less frequent implant replacements, and hence, a significant reduction in surgical expenses. Nanocrystalline silicon carbide (SiC) is a candidate material for artificial heart valves primarily due to its low weight, high strength, extreme hardness, wear resistance, inertness (SiC does not react with biological fluids), and corrosion resistance.

Ductile, Machinable Ceramics

Ceramics, per se, are very hard, brittle, and hard to machine. These characteristics of ceramics have discouraged the potential users from exploiting their beneficial properties. However, with a reduction in grain size, these ceramics have increasingly been used. Zirconia, a hard, brittle ceramic, has even been rendered superplastic, i.e., it can be deformed to great lengths (up to 300% of its original length). However, these ceramics must possess nanocrystalline grains to be superplastic. In fact, nanocrystalline ceramics, such as silicon nitride (Si₃N₄) and silicon carbide (SiC), have been used in such automotive applications as high-strength springs, ball bearings, and valve lifters, because they possess good formability and machinabilty combined with excellent physical, chemical, and mechanical properties. They are also used as components in high-temperature furnaces. Nanocrystalline ceramics can be pressed and sintered into various shapes at significantly lower temperatures, whereas it would be very difficult, if not impossible, to press and sinter conventional ceramics even at high temperatures.

Large Electrochromic Display Devices

An electrochromic device consists of materials in which an optical absorption band can be introduced, or an existing band can be altered by the passage of current through the materials, or by the application of an electric field. Nanocrystalline materials, such as tungstic oxide (WO₃.xH₂O) gel, are used in very large electrochromic display devices. The reaction governing electrochromism (a reversible coloration process under the influence of an electric field) is the double-injection of ions (or protons, H⁺) and electrons, which combine with the nanocrystalline tungstic acid to form a tungsten bronze. These devices are primarily used in public billboards and ticker boards to convey information. Electrochromic devices are similar to liquid-crystal displays (LCD) commonly used in calculators and watches. However, electrochromic devices display information by changing colour when a voltage is applied. When the polarity is reversed, the colour is bleached. The resolution, brightness, and contrast of these devices greatly depend on the tungstic acid gel’s grain size. Hence, nanomaterials are being explored for this purpose.

Summary

From the above examples, it is quite evident that nanocrystalline materials, synthesised by the sol-gel technique, can be used in a wide variety of new, unique and existing applications. It is also very evident that nanomaterials outperform their conventional counterparts because of their superior chemical, physical, and mechanical properties and of their exceptional formability.

water

Water is a ubiquitous chemical substance that is composed of hydrogen and oxygen and is vital for all known forms of life.

In typical usage, water refers only to its liquid form or state, but the substance also has a solid state, ice, and a gaseous state, water vapor or steam. Water covers 71% of the Earth's surface. On Earth, it is found mostly in oceans and other large water bodies, with 1.6% of water below ground in aquifers and 0.001% in the air as vapor, clouds (formed of solid and liquid water particles suspended in air), and precipitation. Oceans hold 97% of surface water, glaciers and polar ice caps 2.4%, and other land surface water such as rivers, lakes and ponds 0.6%. A very small amount of the Earth's water is contained within biological bodies and manufactured products.

Water on Earth moves continually through a cycle of evaporation or transpiration (evapotranspiration), precipitation, and runoff, usually reaching the sea. Over land, evaporation and transpiration contribute to the precipitation over land.

Clean, fresh drinking water is essential to human and other lifeforms. Access to safe drinking water has improved steadily and substantially over the last decades in almost every part of the world. There is a clear correlation between access to safe water and GDP per capita., some observers have estimated that by 2025 more than half of the world population will be facing water-based vulnerability. A recent report (November 2009) suggests that by 2030, in some developing regions of the world, water demand will exceed supply by 50%. Water plays an important role in the world economy, as it functions as a solvent for a wide variety of chemical substances and facilitates industrial cooling and transportation. Approximately 70% of freshwater is consumed by agriculture

Chemical and physical properties

Main articles: Water (properties), Water (data page), and Water model

Model of hydrogen bonds between molecules of water

Impact from a water drop causes an upward "rebound" jet surrounded by circular capillary waves.

Snowflakes by Wilson Bentley, 1902

Dew drops adhering to a spider web

Capillary action of water compared to mercury

Water is the chemical substance with chemical formula H₂O: one molecule of water has two hydrogen atoms covalently bonded to a single oxygen atom.

Water appears in nature in all three common states of matter and may take many different forms on Earth: water vapor and clouds in the sky; seawater and icebergs in the polar oceans; glaciers and rivers in the mountains; and the liquid in aquifers in the ground.

The major chemical and physical properties of water are:

• Water is a tasteless, odorless liquid at standard temperature and pressure. The color of water and ice is, intrinsically, a very light blue hue, although water appears colorless in small quantities. Ice also appears colorless, and water vapor is essentially invisible as a gas.

• Water is transparent, and thus aquatic plants can live within the water because sunlight can reach them. Only strong UV light is slightly absorbed.

• Since the water molecule is not linear and the oxygen atom has a higher electronegativity than hydrogen atoms, it carries a slight negative charge, whereas the hydrogen atoms are slightly positive. As a result, water is a polar molecule with an electrical dipole moment. The net interactions between the dipoles on each molecule cause an effective skin effect at the interface of water with other substances, or air at the surface, the latter given rise to water's high surface tension. This dipolar nature contributes to water molecules' tendency to form hydrogen bonds which cause water's many special properties. The polar nature also favors adhesion to other materials.

• Each hydrogen nucleus is bound to the central oxygen atom by a pair of electrons that are shared between them; chemists call this shared electron pair a covalent chemical bond. In H₂O, only two of the six outer-shell electrons of oxygen are used for this purpose, leaving four electrons which are organized into two non-bonding pairs. The four electron pairs surrounding the oxygen tend to arrange themselves as far from each other as possible in order to minimize repulsions between these clouds of negative charge. This would ordinarily result in a tetrahedral geometry in which the angle between electron pairs (and therefore the H-O-H bond angle) is 109.5°. However, because the two non-bonding pairs remain closer to the oxygen atom, these exert a stronger repulsion against the two covalent bonding pairs, effectively pushing the two hydrogen atoms closer together. The result is a distorted tetrahedral arrangement in which the H-O-H angle is 104.5°.

• A result of interplay of these properties, Capillary action refers to the tendency of water to move up a narrow tube against the force of gravity. This property is relied upon by all vascular plants, such as trees.

• Water is a good solvent and is often referred to as the universal solvent. Substances that dissolve in water, e.g., salts, sugars, acids, alkalis, and some gases – especially oxygen, carbon dioxide (carbonation) are known as hydrophilic (water-loving) substances, while those that do not mix well with water (e.g., fats and oils), are known as hydrophobic (water-fearing) substances.

• All the major components in cells (proteins, DNA and polysaccharides) are also dissolved in water.

• Pure water has a low electrical conductivity, but this increases significantly with the dissolution of a small amount of ionic material such as sodium chloride.

• The boiling point of water (and all other liquids) is dependent on the barometric pressure. For example, on the top of Mt. Everest water boils at about 68 °C (154 °F), compared to 100 °C (212 °F) at sea level. Conversely, water deep in the ocean near geothermal vents can reach temperatures of hundreds of degrees and remain liquid.

• Water has the second highest specific heat capacity of any known substance, after ammonia, as well as a high heat of vaporization (40.65 kJ·mol⁻¹), both of which are a result of the extensive hydrogen bonding between its molecules. These two unusual properties allow water to moderate Earth's climate by buffering large fluctuations in temperature.

• The maximum density of water occurs at 3.98 °C (39.16 °F). Water becomes even less dense upon freezing, expanding 9%. This results in an unusual phenomenon: water's solid form, ice, floats upon water, allowing organisms to survive inside a partially-frozen water body because the water on the bottom has a temperature of around 4 °C (39 °F).

ADR label for transporting goods dangerously reactive with water

• Water is miscible with many liquids, such as ethanol, in all proportions, forming a single homogeneous liquid. On the other hand, water and most oils are immiscible usually forming layers according to increasing density from the top. As a gas, water vapor is completely miscible with air.

• Water forms an azeotrope with many other solvents.

• Water can be split by electrolysis into hydrogen and oxygen.

• As an oxide of hydrogen, water is formed when hydrogen or hydrogen-containing compounds burn or react with oxygen or oxygen-containing compounds. Water is not a fuel, it is an end-product of the combustion of hydrogen. The energy required to split water into hydrogen and oxygen by electrolysis or any other means is greater than the energy released when the hydrogen and oxygen recombine.^[14]

• Elements which are more electropositive than hydrogen such as lithium, sodium, calcium, potassium and caesium displace hydrogen from water, forming hydroxides. Being a flammable gas, the hydrogen given off is dangerous and the reaction of water with the more electropositive of these elements may be violently explosive.

Taste and odor

Water can dissolve many different substances, giving it varying tastes and odors. Humans and other animals have developed senses which (more or less) enable them to evaluate the potability of water by avoiding water that is too salty or putrid. Humans also tend to prefer cold water to lukewarm water since cold water is likely to contain fewer microbes.^{[citation needed]} The taste advertised in spring water or mineral water derives from the minerals dissolved in it: Pure H₂O is tasteless and odorless. The advertised purity of spring and mineral water refers to absence of toxins, pollutants and microbes.

Distribution of water in nature

Water in the universe

Much of the universe's water may be produced as a byproduct of star formation. When stars are born, their birth is accompanied by a strong outward wind of gas and dust. When this outflow of material eventually impacts the surrounding gas, the shock waves that are created compress and heat the gas. The water observed is quickly produced in this warm dense gas.^[15]

Water has been detected in interstellar clouds within our galaxy, the Milky Way. Water probably exists in abundance in other galaxies, too, because its components, hydrogen and oxygen, are among the most abundant elements in the universe. Interstellar clouds eventually condense into solar nebulae and solar systems such as ours.

Water vapor is present in:

• Atmosphere of Mercury: 3.4%, and large amounts of water in Mercury's exosphere^[16]
• Atmosphere of Venus: 0.002%
• Earth's atmosphere: ~0.40% over full atmosphere, typically 1–4% at surface
• Atmosphere of Mars: 0.03%

.........nature

Animal

Animals Fossil range: Ediacaran - Recent, PreЄ Є O S D C P T J K Pg N
Scientific classification
Domain:	Eukarya
(unranked)	Opisthokonta
(unranked)	Holozoa
(unranked)	Filozoa
Kingdom:	Animalia Linnaeus, 1758
Phyla
Subkingdom Parazoa Porifera Placozoa Subkingdom Eumetazoa Radiata (unranked) Ctenophora Cnidaria Bilateria (unranked) Orthonectida Rhombozoa Acoelomorpha Chaetognatha Superphylum Deuterostomia Chordata Hemichordata Echinodermata Xenoturbellida Vetulicolia † Protostomia (unranked) Superphylum Ecdysozoa Kinorhyncha Loricifera Priapulida Nematoda Nematomorpha Lobopodia Onychophora Tardigrada Arthropoda Superphylum Platyzoa Platyhelminthes Gastrotricha Rotifera Acanthocephala Gnathostomulida Micrognathozoa Cycliophora Superphylum Lophotrochozoa Sipuncula Hyolitha † Nemertea Phoronida Bryozoa Entoprocta Brachiopoda Mollusca Annelida Echiura

Animals are a major group of mostly multicellular, eukaryotic organisms of the kingdom Animalia or Metazoa. Their body plan eventually becomes fixed as they develop, although some undergo a process of metamorphosis later on in their life. Most animals are motile, meaning they can move spontaneously and independently. All animals are also heterotrophs, meaning they must ingest other organisms for sustenance.

Most known animal phyla appeared in the fossil record as marine species during the Cambrian explosion, about 542 million years ago.

1 Etymology 2 Characteristics 2.1 Structure 2.2 Reproduction and development 2.3 Food and energy sourcing 3 Origin and fossil record 4 Groups of animals 4.1 Porifera, Radiata and basal Bilateria 4.2 Deuterostomes 4.3 Ecdysozoa 4.4 Platyzoa 4.5 Lophotrochozoa 5 Model organisms 6 History of classification 7 See also 8 References 8.1 Notes 8.2 Bibliography 9 External links

Etymology

The word "animal" comes from the Latin word animal (meaning with soul, from anima, soul). In everyday colloquial usage, the word usually refers to non-human animals. only closer relatives of humans such as vertebrates or mammals are meant in colloquial use.^{[citation needed]} The biological definition of the word refers to all members of the Kingdom Animalia including humans.

Characteristics

Animals have several characteristics that set them apart from other living things. Animals are eukaryotic and are multicellularlthough see Myxozoa), which separates them from bacteria and most protists. They are heterotrophic digesting food in an internal chamber, which separates them from plants and algae They are also distinguished from plants, algae, and fungi by lacking rigid cell walls. All animals are motile if only at certain life stages. In most animals, embryos pass through a blastula stage, which is a characteristic exclusive to animals.

Structure

With a few exceptions, most notably the sponges (Phylum Porifera) and Placozoa, animals have bodies differentiated into separate tissues. These include muscles, which are able to contract and control locomotion, and nerve tissue, which sends and processes signals. There is also typically an internal digestive chamber, with one or two openings. Animals with this sort of organization are called metazoans, or eumetazoans when the former is used for animals in general.

All animals have eukaryotic cells, surrounded by a characteristic extracellular matrix composed of collagen and elastic glycoproteins. This may be calcified to form structures like shells, bones, and spicules. During development it forms a relatively flexible framework upon which cells can move about and be reorganized, making complex structures possible. In contrast, other multicellular organisms like plants and fungi have cells held in place by cell walls, and so develop by progressive growth. Also, unique to animal cells are the following intercellular junctions: tight junctions, gap junctions, and desmosomes.

Reproduction and development

A newt lung cell stained with fluorescent dyes undergoing mitosis, specifically early anaphase.

Nearly all animals undergo some form of sexual reproduction. They have a few specialized reproductive cells, which undergo meiosis to produce smaller motile spermatozoa or larger non-motile ova. These fuse to form zygotes, which develop into new individuals.

Many animals are also capable of asexual reproduction. This may take place through parthenogenesis, where fertile eggs are produced without mating, or in some cases through fragmentation.

A zygote initially develops into a hollow sphere, called a blastula, which undergoes rearrangement and differentiation. In sponges, blastula larvae swim to a new location and develop into a new sponge. In most other groups, the blastula undergoes more complicated rearrangement. It first invaginates to form a gastrula with a digestive chamber, and two separate germ layers — an external ectoderm and an internal endoderm. In most cases, a mesoderm also develops between them. These germ layers then differentiate to form tissues and organs.

Food and energy sourcing

Main article: Animal nutrition

All animals are heterotrophs, meaning that they feed directly or indirectly on other living things. They are often further subdivided into groups such as carnivores, herbivores, omnivores, and parasites.

Predation is a biological interaction where a predator (a heterotroph that is hunting) feeds on its prey (the organism that is attacked). Predators may or may not kill their prey prior to feeding on them, but the act of predation always results in the death of the prey. The other main category of consumption is detritivory, the consumption of dead organic matter. It can at times be difficult to separate the two feeding behaviours, for example where parasitic species prey on a host organism and then lay their eggs on it for their offspring to feed on its decaying corpse. Selective pressures imposed on one another has led to an evolutionary arms race between prey and predator, resulting in various antipredator adaptations.

Most animals feed indirectly from the energy of sunlight. Plants use this energy to convert sunlight into simple sugars using a process known as photosynthesis. Starting with the molecules carbon dioxide (CO₂) and water (H₂O), photosynthesis converts the energy of sunlight into chemical energy stored in the bonds of glucose (C₆H₁₂O₆) and releases oxygen (O₂). These sugars are then used as the building blocks which allow the plant to grow. When animals eat these plants (or eat other animals which have eaten plants), the sugars produced by the plant are used by the animal. They are either used directly to help the animal grow, or broken down, releasing stored solar energy, and giving the animal the energy required for motion. This process is known as glycolysis.

Animals who live close to hydrothermal vents and cold seeps on the ocean floor are not dependent on the energy of sunlight. Instead chemosynthetic archaea and bacteria form the base of the food chain.

Origin and fossil record

Further information: Urmetazoon

Dunkleosteus was a gigantic, 10 meter (33 ft) long prehistoric fish.^[8]

Vernanimalcula guizhouena is a fossil believed by some to represent the earliest known member of the Bilateria.

Animals are generally considered to have evolved from a flagellated eukaryote. Their closest known living relatives are the choanoflagellates, collared flagellates that have a morphology similar to the choanocytes of certain sponges. Molecular studies place animals in a supergroup called the opisthokonts, which also include the choanoflagellates, fungi and a few small parasitic protists. The name comes from the posterior location of the flagellum in motile cells, such as most animal spermatozoa, whereas other eukaryotes tend to have anterior flagella.

The first fossils that might represent animals appear towards the end of the Precambrian, around 610 million years ago, and are known as the Ediacaran or Vendian biota. These are difficult to relate to later fossils, however. Some may represent precursors of modern phyla, but they may be separate groups, and it is possible they are not really animals at all. Aside from them, most known animal phyla make a more or less simultaneous appearance during the Cambrian period, about 542 million years ago. It is still disputed whether this event, called the Cambrian explosion, represents a rapid divergence between different groups or a change in conditions that made fossilization possible. However some paleontologists and geologists would suggest that animals appeared much earlier than previously thought, possibly even as early as 1 billion years ago. Trace fossils such as tracks and burrows found in Tonian era indicate the presence of triploblastic worm like metazoans roughly as large (about 5 mm wide) and complex as earthworms. In addition during the beginning of the Tonian period around 1 billion years ago (roughly the same time that the trace fossils previously discussed in this article date back to) there was a decrease in Stromatolite diversity which may indicate the appearance of grazing animals during this time as Stromatolites also increased in diversity shortly after the end-Ordovician and end-Permian rendered large amounts of grazing marine animals extinct and decreased shortly after their populations recovered. The discovery that tracks very similar to these early trace fossils are produced today by the giant single-celled protist Gromia sphaerica casts further doubt on their interpretation as evidence of early animal evolution.

Groups of animals

Porifera, Radiata and basal Bilateria

Orange elephant ear sponge, Agelas clathrodes, in foreground. Two corals in the background: a sea fan, Iciligorgia schrammi, and a sea rod, Plexaurella nutans.

The sponges (Porifera) were long thought to have diverged from other animals early. They lack the complex organization found in most other phyla. Their cells are differentiated, but in most cases not organized into distinct tissues. Sponges typically feed by drawing in water through pores. Archaeocyatha, which have fused skeletons, may represent sponges or a separate phylum. However, a phylogenomic study in 2008 of 150 genes in 21 genera^[12] revealed that it is the Ctenophora or comb jellies which are the basal lineage of animals, at least among those 21 phyla. The authors speculate that sponges—or at least those lines of sponges they investigated—are not so primitive, but may instead be secondarily simplified.

Among the other phyla, the Ctenophora and the Cnidaria, which includes sea anemones, corals, and jellyfish, are radially symmetric and have digestive chambers with a single opening, which serves as both the mouth and the anus. Both have distinct tissues, but they are not organized into organs. There are only two main germ layers, the ectoderm and endoderm, with only scattered cells between them. As such, these animals are sometimes called diploblastic. The tiny placozoans are similar, but they do not have a permanent digestive chamber.

The remaining animals form a monophyletic group called the Bilateria. For the most part, they are bilaterally symmetric, and often have a specialized head with feeding and sensory organs. The body is triploblastic, i.e. all three germ layers are well-developed, and tissues form distinct organs. The digestive chamber has two openings, a mouth and an anus, and there is also an internal body cavity called a coelom or pseudocoelom. There are exceptions to each of these characteristics, however — for instance adult echinoderms are radially symmetric, and certain parasitic worms have extremely simplified body structures.

Genetic studies have considerably changed our understanding of the relationships within the Bilateria. Most appear to belong to two major lineages: the deuterostomes and the protostomes, the latter of which includes the Ecdysozoa, Platyzoa, and Lophotrochozoa. In addition, there are a few small groups of bilaterians with relatively similar structure that appear to have diverged before these major groups. These include the Acoelomorpha, Rhombozoa, and Orthonectida. The Myxozoa, single-celled parasites that were originally considered Protozoa, are now believed to have developed from the Medusozoa as well.

Deuterostomes

Superb Fairy-wren, Malurus cyaneus

Deuterostomes differ from the other Bilateria, called protostomes, in several ways. In both cases there is a complete digestive tract. However, in protostomes the initial opening (the archenteron) develops into the mouth, and an anus forms separately. In deuterostomes this is reversed. In most protostomes, cells simply fill in the interior of the gastrula to form the mesoderm, called schizocoelous development, but in deuterostomes it forms through invagination of the endoderm, called enterocoelic pouching. Deuterostomes also have a dorsal, rather than a ventral, nerve chord and their embryos undergo different cleavage.

All this suggests the deuterostomes and protostomes are separate, monophyletic lineages. The main phyla of deuterostomes are the Echinodermata and Chordata. The former are radially symmetric and exclusively marine, such as starfish, sea urchins, and sea cucumbers. The latter are dominated by the vertebrates, animals with backbones. These include fish, amphibians, reptiles, birds, and mammals.

In addition to these, the deuterostomes also include the Hemichordata or acorn worms. Although they are not especially prominent today, the important fossil graptolites may belong to this group.

The Chaetognatha or arrow worms may also be deuterostomes, but more recent studies suggest protostome affinities.

Ecdysozoa

File:Sympetrum flaveolum — side (aka).jpg

Yellow-winged darter, Sympetrum flaveolum

The Ecdysozoa are protostomes, named after the common trait of growth by moulting or ecdysis. The largest animal phylum belongs here, the Arthropoda, including insects, spiders, crabs, and their kin. All these organisms have a body divided into repeating segments, typically with paired appendages. Two smaller phyla, the Onychophora and Tardigrada, are close relatives of the arthropods and share these traits.

The ecdysozoans also include the Nematoda or roundworms, perhaps the second largest animal phylum. Roundworms are typically microscopic, and occur in nearly every environment where there is water. A number are important parasites. Smaller phyla related to them are the Nematomorpha or horsehair worms, and the Kinorhyncha, Priapulida, and Loricifera. These groups have a reduced coelom, called a pseudocoelom.

The remaining two groups of protostomes are sometimes grouped together as the Spiralia, since in both embryos develop with spiral cleavage.

Platyzoa

Bedford's flatworm, Pseudobiceros bedfordi

The Platyzoa include the phylum Platyhelminthes, the flatworms. These were originally considered some of the most primitive Bilateria, but it now appears they developed from more complex ancestors. A number of parasites are included in this group, such as the flukes and tapeworms. Flatworms are acoelomates, lacking a body cavity, as are their closest relatives, the microscopic Gastrotricha.

The other platyzoan phyla are mostly microscopic and pseudocoelomate. The most prominent are the Rotifera or rotifers, which are common in aqueous environments. They also include the Acanthocephala or spiny-headed worms, the Gnathostomulida, Micrognathozoa, and possibly the Cycliophora groups share the presence of complex jaws, from which they are called the Gnathifera.

Lophotrochozoa

Roman snail, Helix pomatia

The Lophotrochozoa include two of the most successful animal phyla, the Mollusca and Annelida.^[16][17] The former, which is the second-largest animal phylum by number of described species, includes animals such as snails, clams, and squids, and the latter comprises the segmented worms, such as earthworms and leeches. These two groups have long been considered close relatives because of the common presence of trochophore larvae, but the annelids were considered closer to the arthropods, because they are both segmented. Now this is generally considered convergent evolution, owing to many morphological and genetic differences between the two phyla.

The Lophotrochozoa also include the Nemertea or ribbon worms, the Sipuncula, and several phyla that have a fan of cilia around the mouth, called a lophophore. These were traditionally grouped together as the lophophorates. but it now appears they are paraphyletic, some closer to the Nemertea and some to the Mollusca and Annelida. They include the Brachiopoda or lamp shells, which are prominent in the fossil record, the Entoprocta, the Phoronida, and possibly the Bryozoa or moss animals.

Model organisms

Main articles: Model organism and Animal testing

Because of the great diversity found in animals, it is more economical for scientists to study a small number of chosen species so that connections can be drawn from their work and conclusions extrapolated about how animals function in general. Because they are easy to keep and breed, the fruit fly Drosophila melanogaster and the nematode Caenorhabditis elegans have long been the most intensively studied metazoan model organisms, and were among the first life-forms to be genetically sequenced. This was facilitated by the severely reduced state of their genomes, but the double-edged sword here is that with many genes, introns and linkages lost, these ecdysozoans can teach us little about the origins of animals in general. The extent of this type of evolution within the superphylum will be revealed by the crustacean, annelid, and molluscan genome projects currently in progress. Analysis of the starlet sea anemone genome has emphasised the importance of sponges, placozoans, and choanoflagellates, also being sequenced, in explaining the arrival of 1500 ancestral genes unique to the Eumetazoa.

An analysis of the homoscleromorph sponge Oscarella carmela also suggests that the last common ancestor of sponges and the eumetazoan animals was more complex than previously assumed.

Other model organisms belonging to the animal kingdom include the mouse (Mus musculus) and zebrafish (Danio rerio).

Carolus Linnaeus, known as the father of modern taxonomy

History of classification

Aristotle divided the living world between animals and plants, and this was followed by Carolus Linnaeus (Carl von Linné), in the first hierarchical classification. Since then biologists have begun emphasizing evolutionary relationships, and so these groups have been restricted somewhat. For instance, microscopic protozoa were originally considered animals because they move, but are now treated separately.

In Linnaeus's original scheme, the animals were one of three kingdoms, divided into the classes of Vermes, Insecta, Pisces, Amphibia, Aves, and Mammalia. Since then the last four have all been subsumed into a single phylum, the Chordata, whereas the various other forms have been separated out. The above lists represent our current understanding of the group, though there is some variation from source to source.

References

Notes

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