Agriculture: 十一月 2008

2008年11月28日星期五

Valve operating positions

A seacock for cooling seawater, on a Yanmar 2GM20 marine diesel engine.
Valve positions are operating conditions determined by the position the disc or rotor in the valve. Some valves are made to be operated in a gradual change between two or more positions.

Two-way valves
2-port valves are commonly called 2-way valves. Operating positions for such valves can be either shut (closed) so that no flow at all goes through, fully open for maximum flow, or sometimes partially open to any degree in between. Many valves are not designed to precisely control intermediate degree of flow; such valves are considered to be either open or shut, which maybe qualitative descriptions in between. Some valves are specially designed to regulate varying amounts of flow. Such valves have been called by various names such as regulating, throttling, metering, or needle valves. For example, needle valves have elongated conically-tapered discs and matching seats for fine flow control. For some valves, there may be a mechanism to indicate by how much the valve is open, but in many cases other indications of flow rate are used, such as separate flow meters.
In some plants with fluid systems, some 2-way valves can be designated as normally shut or normally open during regular operation. Examples of normally shut valves are sampling valves, which are only opened while a sample is taken. Examples of normally open valves are isolation valves, which are usually only shut when there is a problem with a unit or a section of a fluid system such as a leak. Then, isolation valve(s) are shut in order to isolate the problem from the rest of the system.
Although many 2-way valves are made in which the flow can go in either direction between the two ports, when a valve is placed into a certain application, flow is often expected to go from one certain port on the upstream side of the valve, to the other port on the downstream side. Pressure regulators are variations of valves in which flow is controlled to produce a certain downstream pressure, if possible. They are often used to control flow of gas from a gas cylinder. A back-pressure regulator is a variation of a valve in which flow is controlled to maintain a certain upstream pressure, if possible.

Three-way valves
Three-way valves have three ports. Three-way valves are commonly made such that flow coming in at one port can be directed to either the second port in one position or the third port in another position or in an intermediate position so all flow is stopped. Often such 3-way valves are ball or rotor valves. Many faucets are made so that incoming cold and hot water can be regulated in varying degrees to give outcoming water at a desired temperature. Other kinds of 3-port valves can be designed for other possible flow-directing schemes and positions; for example, see Ball valve.
The "motor valve" on a domestic heating system is an example of a 3-way valve. Depending on demand the motor head rotates the spindle to control the proportion of the flow that goes to the two outlet pipes: One to radiators, one to hot water system. In a conventional system the valve usually sits just after the pump and by the cylinder
In valves having more than 3 ports, even more flow-directing schemes are possible. Such valves are often rotor valves or ball valves.

automatic chicken feeder

garden seed planter

ball float valve

Wholesale Table Linens

cotton blend yarn

organic liquid fertilizer

Red Hard Wheat

leather motorcycle suit

cotton grocery bags

Valve

A valve is a device that regulates the flow of fluid (gases, fluidized solids, slurries, or liquids) by opening, closing, or partially obstructing various passageways. Valves are technically pipe fittings, but are usually discussed separately.
Valves are also part of the human body. They function in your heart by not letting arteries flow in the wrong place.
Valves are used in a variety of applications including industrial, military, commercial, residential, and transportation.
Oil and gas, power generation, mining, water reticulation, sewerage and chemical manufacturing would constitute the majority of valves used by industry.
Plumbing valves are the most obvious in everyday life, taps for hot and cold water, gas control valves on cookers and barbecues, small valves fitted to washing machines and dishwashers, and safety devices fitted to hot water systems are all examples of valves.
Valves may be operated manually, either by a hand wheel, lever or pedal. Valves may also be automatic, driven by changes in pressure, temperature or flow. These changes may act upon a diaphram or a piston which in turn activates the valve, examples of this type of valve found commonly are safety valves fitted to hot water systems or steam boilers.
More complex control systems using valves requiring automatic control based on an external input (i.e., regulating flow through a pipe to a changing set point) require an actuator. An actuator will stroke the valve depending on its input and set-up, allowing the valve to be positioned accurately, and allowing control over a variety of requirements.
Valves are also found in the Otto cycle (internal combustion) engines driven by a camshaft, lifters and or push rods where they play a major role in engine cycle control.

automatic chicken feeder

garden seed planter

ball float valve

Wholesale Table Linens

cotton blend yarn

organic liquid fertilizer

Red Hard Wheat

leather motorcycle suit

cotton grocery bags

Valve float

Valve float is an adverse condition which occurs when the poppet valves on an internal combustion engine valvetrain do not remain in contact with the camshaft lobe during the valve closure phase of the cam lobe profile. This reduces engine efficiency and performance and potentially increases engine emissions.
Valve bounce is a related condition where the valve does not stay seated, due to the combined effects of the valve's inertia and resonance effects of metallic valve springs that effectively reduce the closing force, and allow the valve to re-open partially.
Stiffer valve springs can help prevent valve float and valve bounce, but only at the expense of increased friction losses. Various techniques have been used to offset the effect of stiffer springs, such as dual-spring and progressive-sprung valves, roller-tipped tappets, and pneumatic valves.
Italian motorcycle manufacturer Ducati uses the desmodromic (springless) valve system to counter this problem and allow for higher engine speeds. The system consists of a mechanical lifter mechanism that uses a second rocker arm to push the valve closed. Formula 1 racing engine manufacturers use a pneumatic system to close the valves to allow for very high RPM without valve float.
This article about an automotive part or component is a stub. You can help Wikipedia by expanding it.

automatic chicken feeder

garden seed planter

ball float valve

Wholesale Table Linens

cotton blend yarn

organic liquid fertilizer

Red Hard Wheat

leather motorcycle suit

cotton grocery bags

Straight through, two way, or three way ball valves

schematic 3 way ball valve - L-shaped ball right, T-shaped left
Three-way ball valves have an L- or T-shaped hole through the middle. The different combinations of flow are shown in the picture.
Multi port ball valves with 4 or more ways are also commercially available, the inlet way often being orthogonal to the plane of the outlets. For special applications, such as driving air powered motors from forward to reverse by rotating a single lever operated 4 way ball valve. This valve has two L-shaped ports in the ball that do not interconnect, sometimes referred to as an "x" port.
Ball Valves in sizes up to 2 inch generally come in single piece, two or three piece designs. One piece ball valves are almost always reduced bore, are relatively inexpensive and generally are throw-away. Two piece ball valves are generally slightly reduced (or standard) bore, they can be either throw-away or repairable. The 3 piece design allows for the center part of the valve containing the ball, stem & seats to be easily removed from the pipeline. This facilitates efficient cleaning of deposited sediments, replacement of seats and gland packings, polishing out of small scratches on the ball, all this without removing the pipes from the valve body. The design concept of a three piece valve is for it to be repairable.

automatic chicken feeder

garden seed planter

ball float valve

Wholesale Table Linens

cotton blend yarn

organic liquid fertilizer

Red Hard Wheat

leather motorcycle suit

cotton grocery bags

Types of ball valve

There are four general body styles of ball valves: single body, split body, top entry, and welded.
There are four general types of ball valves: full port, standard port, reduced port, and v port.
A full port ball valve has an over sized ball so that the hole in the ball is the same size as the pipeline resulting in lower friction loss. Flow is unrestricted, but the valve is larger.
A standard port ball valve is usually less expensive, but has a smaller ball and a correspondingly smaller port. Flow through this valve is one pipe size smaller than the valve's pipe size resulting in slightly restricted flow.
In reduced port ball valves, flow through the valve is one pipe size smaller than the valve's pipe size resulting in restricted flow.
A v port ball valve has either a 'v' shaped ball or a 'v' shaped seat. This allows the orifice to be opened and closed in a more controlled manner with a closer to linear flow characteristic. When the valve is in the closed position and opening is commenced the small end of the 'v' is opened first allowing stable flow control during this stage. This type of design requires a generally more robust construction due to higher velocities of the fluids, which would quickly damage a standard valve.
A trunnion ball valve has a mechanical means of anchoring the ball at the top and the bottom, this design is usually applied on larger and higher pressure valves(say 4" and above 600 psi and above)
Manually operated ball valves can be closed quickly and thus there is a danger of water hammer. Some ball valves are equipped with an actuator that may be pneumatically or motor (electric) operated. These valves can be used either for on/off or flow control. A pneumatic flow control valve is also equipped with a positioner which transforms the control signal into actuator position and valve opening accordingly.

automatic chicken feeder

garden seed planter

ball float valve

Wholesale Table Linens

cotton blend yarn

organic liquid fertilizer

Red Hard Wheat

leather motorcycle suit

cotton grocery bags

Ball valve

A ball valve (like the butterfly valve and plug valve are one of the family of valves called quarter turn valves) is a valve that opens by turning a handle attached to a ball inside the valve. The ball has a hole, or port, through the middle so that when the port is in line with both ends of the valve, flow will occur. When the valve is closed, the hole is perpendicular to the ends of the valve, and flow is blocked. The handle or lever will be inline with the port position letting you "see" the valve's position.
Ball valves are durable and usually work to achieve perfect shutoff even after years of disuse. They are therefore an excellent choice for shutoff applications (and are often preferred to globe valves and gate valves for this purpose). They do not offer the fine control that may be necessary in throttling applications but are sometimes used for this purpose.
Ball valves are used extensively in industry because they are very versatile, pressures up to 10,000 psi, temperatures up to 200 Deg C. Sizes from 1/4" to 12" are readily available They are easy to repair, operate manually or by actuators.
The body of ball valves may be made of metal, plastic or metal with a ceramic center. The ball is often chrome plated to make it more durable.

automatic chicken feeder

garden seed planter

ball float valve

Wholesale Table Linens

cotton blend yarn

organic liquid fertilizer

Red Hard Wheat

leather motorcycle suit

cotton grocery bags

Float valve

A float valve is a mechanical feedback mechanism that regulates fluid level by using a float to drive an inlet valve so that a higher fluid level will force the valve closed while a lower fluid level will force the valve open. This is an example of negative feedback and of proportional control.
The most common use of a float valve is to control the filling of water in the water tank (Cistern) of a commode (toilet).
This is done by utilizing a Balloon type float valve. Its working is thus:
A ball shaped hollow sphere , made of hardened Rubber or Copper alloy sheet is sealed so that water cannot enter it. This is attached to an arm that in turn is attached to the valve or flap.
The valve or flap controls the opening of the pipe through which water flows into the tank/Cistern
Under Empty condition, valve is fully open and balloon is suspended freely.
As water ingresses into the container, the balloon, on account of trapped air and buoyancy, begins to rise / float on the water surface.
Soon the balloon floats high enough so that the arm attached to the Balloon CLOSES the valve and stops water from flowing in.
Thus when water is filled to a certain level, its inflow is stopped by this arrangement.

automatic chicken feeder

garden seed planter

ball float valve

Wholesale Table Linens

cotton blend yarn

organic liquid fertilizer

Red Hard Wheat

leather motorcycle suit

cotton grocery bags

National Council for the Conservation of Plants and Gardens

The National Council for the Conservation of Plants and Gardens (NCCPG) was founded as a British registered charity in 1978 to combine the talents of botanists, horticulturalists and conservationists with the dedication of keen amateur and professional gardeners. The mission statement of the organisation declares that "The NCCPG seeks to conserve, document, promote and make available Britain and Ireland's rich biodiversity of garden plants for the benefit of everyone through horticulture, education and science." Specifically, the aims of the organisation are to:
encourage the propagation and conservation of endangered garden plants in the British Isles, both species and cultivars;
encourage and conduct research into cultivated plants, their origins, their historical and cultural importance and their environments; and
encourage the education of the public in garden plant conservation.
Through its membership and the National Plant Collection Holders, the NCCPG seeks to rediscover and reintroduce endangered garden plants by encouraging their propagation and distribution so that they are grown as widely as possible. The NCCPG works closely with other conservation bodies as well as botanic gardens, the National Trust, the National Trust for Scotland, English Heritage, the Royal Horticultural Society and many specialist horticultural societies.
The NCCPG's patron is HRH The Prince of Wales.

automatic chicken feeder

garden seed planter

ball float valve

Wholesale Table Linens

cotton blend yarn

organic liquid fertilizer

Red Hard Wheat

leather motorcycle suit

cotton grocery bags

Ornamental plant

Ornamental plants are typically grown in the flower garden or as house plants. Most commonly they are grown for the display of their flowers. Other common ornamental features include leaves, scent, fruit, stem and bark. In some cases, unusual features may be considered ornamental, such as the prominent and rather vicious thorns of Rosa sericea. In all cases, their purpose is the enjoyment of gardeners and visitors. Ornamental plants may also be used for landscaping, and for cut flowers.
Similarly trees may be called ornamental trees. This term is used when they are used as part of a garden setting, for instance for their flowers, their shapes or for other attractive characteristics. By comparison, trees used in larger landscape effects such as screening and shading, or in urban and roadside plantings, are called amenity trees.

Meillandine Rose in clay pot
For plants to be considered as ornamental, they may require specific work and activity by a gardener. For instance, many plants cultivated for topiary and bonsai would only be considered as ornamental by virtue of the regular pruning carried out on them by the gardener, and they may rapidly cease to be ornamental if the work was abandoned.
Ornamental plants and trees are distinguished from utilitarian and crop plants, such as those used for agriculture and vegetable crops, and for forestry or as fruit trees. This does not preclude any particular type of plant being grown both for ornamental qualities in the garden, and for utilitarian purposes in other settings. Thus lavender is typically grown as an ornamental plant in gardens, but may also be grown as a crop plant for the production of lavender oil.

automatic chicken feeder

garden seed planter

ball float valve

Wholesale Table Linens

cotton blend yarn

organic liquid fertilizer

Red Hard Wheat

leather motorcycle suit

cotton grocery bags

Seed propagation mat

An electric seed-propagation mat is a heated rubber mat covered by a metal cage which is used in gardening.
The mats are made so that planters containing seedlings can be placed on top of the metal cage without the risk of starting a fire.
In extreme cold, gardeners place a loose plastic cover over the planters/mats which creates a sort of miniature greenhouse. The constant and predictable heat allows people to garden in the winter months when the weather is generally too cold for seedlings to survive naturally.
When combined with a lighting system, many plants can be grown indoors using these mats.and can be use as apratice mat to know the capability of seed that you buy in a store

automatic chicken feeder

garden seed planter

ball float valve

Wholesale Table Linens

cotton blend yarn

organic liquid fertilizer

Red Hard Wheat

leather motorcycle suit

cotton grocery bags

Castor oil plant

Plant-animal interactions
Ricinus communis is the host plant of the Common Castor butterfly (Ariadne merione) and the Castor Semi-Looper moth (Achaea janata). It is also used as a food plant by the larvae of some other species of Lepidoptera, including Hypercompe hambletoni and the Nutmeg (Discestra trifolii).
Among birds, it is a favourite food of the Tambourine Dove (Turtur tympanistria).
Castor beans are very toxic.

Uses
Main article: Castor oil
Usage in ethnobotany The use of castor seed oil in India has been documented since 2000 BC for use in lamps and in local medicine as a laxative, purgative, and cathartic in Unani, Ayurvedic and other ethnomedical systems. Traditional Ayurvedic medicine considers castor oil the king of medicinals for curing arthritic diseases.
Castor seed and its oil have also been used in China for centuries, mainly prescribed in local medicine for internal use or use in dressings.
The oil has undecylenic acid, a powerful chemical for dermal fungus.
The oil is known to have been used as an instrument of coercion by the Fascist militia (Camicie Nere) under the regime of Italian dictator Benito Mussolini. Dissidents and regime opponents were forced to ingest the oil in large amounts, triggering severe diarrhoea and dehydration, which could ultimately cause death. This punishment method was originally thought of by Gabriele D'Annunzio, the Italian poet and Fascist supporter, during the First World War.
It was used in rituals of sacrifice to please the gods in early civilizations.
In Brazil, castor plants are abundant. The "fruits" are used by children as slingshot balls. Mamonas, as the fruits are called, serve perfectly as projectiles for slingshots since they have the right weight, size and hardness. Mamona oil is now being used to produce biodiesel in poor rural areas of the country.

automatic chicken feeder

garden seed planter

ball float valve

Wholesale Table Linens

cotton blend yarn

organic liquid fertilizer

Red Hard Wheat

leather motorcycle suit

cotton grocery bags

Castor oil plant Description

Castor oil plant can reach a height of 2–3 m in a year (if sown early, under glass, and kept at a temperature of around 20°Celsius/68°Fahreheit until planted out ).
The glossy leaves are 15–45 cm long, long-stalked, alternate and palmate with 5–12 deep lobes with coarsely toothed segments. Their colour varies from dark green, sometimes with a reddish tinge, to dark reddish purple or bronze.
The stems and the spherical, spiny seed pods also vary in pigmentation. The pods are more showy than the flowers (the male flowers are yellowish-green with prominent creamy stamens and are carried in ovoid spikes up to 15 cm long; the female flowers, borne at the tips of the spikes, have prominent red stigmas).
Terminating stems are panicle-like inflorescences of green monoecious flowers, the stalked female flowers above the male flowers below, both without petals.
The fruit is a spiny, greenish capsule with large, oval, shiny, bean-like, highly poisonous seeds with variable brownish motling.

Nomenclature
The name Ricinus is a Latin word for tick; the seed is so named because it has markings and a bump at the end which resemble certain ticks. The common name "castor oil" likely comes from its use as a replacement for castoreum, a perfume base made from the dried perineal glands of the beaver (castor in Latin). It has another common name, Palm of Christ, or Palma Christi, that derives from castor oil's ability to heal wounds and cure ailments.

Habitat and growth
Although castor is indigenous to the southeastern Mediterranean region, Eastern Africa, and India, today it is widespread throughout tropical regions. Castor establishes itself easily as an apparently "native" plant and can often be found on wasteland. It is widely grown as a crop in Ethiopia. It is also used extensively as a decorative plant in parks and other public areas, particularly as a "dot plant" in traditional bedding schemes. Of the red and white variety, the red is seen as an ornamental plant, the white is used medicinally.

Castor oil seed output in 2006
Although monotypic, the castor oil plant can vary greatly in its growth habit and appearance.
It is a fast-growing, suckering perennial shrub which can reach the size of a small tree (around 12 m), but it is not hardy. However it grows well outside, at least in Southern England, and the leaves do not appear to suffer frost damage in sheltered spots, where it remains evergreen. In areas prone to frost it is usually shorter and grown as if it were an annual.
Selections have been made by breeders for use as ornamental plants: 'Gibsonii' has red-tinged leaves with reddish veins and pinkish-green seed pods; 'Carmencita Pink' is similar, with pinkish-red stems; 'Carmencita Bright Red' has red stems, dark purplish leaves and red seed pods; all grow to around 1.5 m tall as annuals.'Impala' is compact (only 1.2 m tall) with reddish foliage and stems, brightest on the young shoots; 'Red Spire' is tall (2–3 m) with red stems and bronze foliage; 'Zanzibarensis' is also tall (2–3 m), with large, mid-green leaves (50 cm long) with white midribs. (Heights refer to plants grown as annuals.)

automatic chicken feeder

garden seed planter

ball float valve

Wholesale Table Linens

cotton blend yarn

organic liquid fertilizer

Red Hard Wheat

leather motorcycle suit

cotton grocery bags

Castor oil plant

The castor oil plant, Ricinus communis, is a plant species of the Euphorbiaceae (the evolution of this plant family is relatively unexplored ) the sole member of the genus Ricinus and of the subtribe Ricininae. Its seed is the castor bean which, despite its name, is not a true bean.
Castor seed is the source of castor oil, which has a wide variety of uses. The seeds contain between 40% and 60% oil that is rich in triglycerides, mainly ricinolein. The seed coat contains ricin, a poison, which is also present in lower concentrations throughout the plant.
The toxicity of raw castor beans is well-known, and reports of actual poisoning are relatively rare. Children could conceivably die from as few as three beans; adults may require eight or more. As an example of the rarity of castor bean poisoning, in recent years there have only been two cases reported in all of England, and both the victims recovered uneventfully.Even so small a dose of ricin as 1/25 000 000 of the body weight may cause toxic symptoms when injected. Castor seeds have been found in Egyptian tombs dating back to 4000 BC. Herodotus and other Greek travelers have noted the use of castor seed oil for lighting, body ointments, and improving hair growth and texture. Cleopatra is reputed to have used it to brighten the whites of her eyes. The Ebers Papyrus is an ancient Egyptian medical treatise believed to date from 1552 BC. Translated in 1872, it describes castor oil as a purgative.
Global castor seed production is around 1 million tons per year. Leading producing areas are India (with over 60% of the global yield), China and Brazil. There are several active breeding programmes.
Another plant species, Fatsia Japonica, looks similar to the castor oil plant and is known as the false castor oil plant.

automatic chicken feeder

garden seed planter

ball float valve

Wholesale Table Linens

cotton blend yarn

organic liquid fertilizer

Red Hard Wheat

leather motorcycle suit

cotton grocery bags

Castor oil Uses

Castor oil in food
In the food industry, castor oil (food grade) is used in food additives, flavorings, candy (i.e., chocolate), as a mold inhibitor, and in packaging. Polyoxyethylated castor oil (eg. Cremophor EL)is also used in the foodstuff industries.

Medicinal use of castor oil
The United States Food and Drug Administration (FDA) has categorized castor oil as "generally recognized as safe and effective" (GRASE) for over-the-counter use as a laxative, with its major site of action the small intestine.However, it is not a preferred treatment for constipation.Undecylenic acid, a castor oil derivative, is also FDA-approved for over-the-counter use on skin disorders or skin problems.Castor oil penetrates deep into the skin thanks to its Molecular Weight. At 298 u., research on transdermal absorption indicates castor oil will penetrate the stratum corneum since it is below the 500 u. required to do so
Ricinoleic acid is the main component of castor oil and it exerts anti-inflammatory effects.One study has found that castor oil decreased pain more than ultrasound gel or Vaseline during extracorporeal shock wave application.
Therapeutically, modern drugs are rarely given in a pure chemical state, so most active ingredients are combined with excipients or additives. Castor oil, or a castor oil derivative such as Cremophor EL (polyethoxylated castor oil, a nonionic surfactant), is added to many modern drugs, including:
Miconazole, an anti-fungal agent;Paclitaxel, a mitotic inhibitor used in cancer chemotherapy;
Sandimmune (cyclosporine injection, USP), an immunosuppressant drug widely used in connection with organ transplant to reduce the activity of the patient's immune system;
Nelfinavir mesylate, an HIV protease inhibitor;
Saperconazole, a triazole antifungal agent (contains Emulphor EL -719P, a castor oil derivative);
Prograf, an immunosuppressive drug (contains HCO-60, polyoxyl 60 hydrogenated Castor oil);Xenaderm ointment, a topical treatment for skin ulcers is a combination of Balsam Peru, Castor oil, and trypsin;
Aci-Jel, a gel used to create or maintain the acidity of the vagina (comprises acetic acid/oxyquinoline/ricinoleic acid - vaginal)
Traditional or folk medicines
The use of cold pressed castor oil in folk medicine predates government regulations. Cold pressed castor oil is tasteless and odorless when pure. Uses include skin problems, burns, sunburns, skin disorders, skin cuts, and abrasions. Castor oil can also be used to draw out styes in the eye by pouring a small amount into the eye and allowing it to circulate around the inside of the eyelid. The oil is also used as a rub or pack for various ailments, including abdominal complaints, headaches, muscle pains, inflammatory conditions, skin eruptions, lesions, and sinusitis. A castor oil pack is made by soaking a piece of flannel in castor oil, then putting it on the area of complaint and placing a heat source, such as a hot water bottle, on top of it. This remedy was often suggested by the American Healing Psychic, Edgar Cayce, given in many healing readings in the early mid-1900s.
Castor has been used to induce childbirth, but does not always work. Castor oil triggers cramping in the bowel (hence it being an effective laxative) and sometimes this cramping spreads to the uterus. In an overdue pregnancy in which the mother's cervix is already effacing and partially dilated, this cramping can become labor contractions. Castor oil induced labor can be stressful on the mother and fetus as the cramping can be quite severe, causing irregular, painful contractions, which can cause fetal distress. It also leaves the laboring woman quite dehydrated as a result of the vomiting and diarrea which result when the recommended dose of castor oil for labor induction is taken--2 oz, or about 8 tbsps. This leaves her without access to the energy she could otherwise derive from food or drink throughout her labor process. Some women prefer this method to a chemical induction in a hospital. Using castor oil for induction is not recommended without consulting a medical practitioner and is not recommended in a complex pregnancy.

automatic chicken feeder

garden seed planter

ball float valve

Wholesale Table Linens

cotton blend yarn

organic liquid fertilizer

Red Hard Wheat

leather motorcycle suit

cotton grocery bags

Castor oil Background

Ricinoleic acid, a monounsaturated, 18-carbon fatty acid, is unusual in that it has a hydroxyl functional group on the twelfth carbon. This functional group causes ricinoleic acid (and castor oil) to be unusually polar, and also allows chemical derivatization that is not practical with most other seed oils. It is the hydroxyl group which makes castor oil and ricinoleic acid valuable as chemical feedstocks. Compared to other seed oils which lack the hydroxyl group, castor oil demands a higher price. As an example, in July 2007 Indian castor oil sold for about US$0.90 per kilogram (US$0.41 per pound) while US soybean, sunflower and canola oil sold for about US$0.30 per kilogram (US$0.14 per pound)Castor oil and its derivatives have applications in the manufacturing of soaps, lubricants, hydraulic and brake fluids, paints, dyes, coatings, inks, cold resistant plastics, waxes and polishes, nylon, pharmaceuticals and perfumes.
Sulfonated castor oil, also called Sulfonated (sulfated) castor oil, or Turkey Red Oil, is the only oil that completely disperses in water. It is made by adding sulfuric acid to pure castor oil his allows easy use for making bath oil products. It was the first synthetic detergent after ordinary soap. It is used in formulating lubricants, softeners, and dyeing assistants.
The castor seed contains ricin, a toxic protein removed by cold pressing and filtering.
However, harvesting castor beans is not without risk, Allergenic compounds found on the plant surface can cause permanent nerve damage, making the harvest of castor beans a human health risk. India, Brazil and China are the major crop producers and the workers suffer harmful side effects from working with these plants. These health issues, in addition to concerns about the toxic byproduct (ricin) from castor oil production, have encouraged the quest for alternative, domestic sources for hydroxy fatty acids.Alternatively, some researchers are trying to genetically modify the castor plant to prevent the synthesis of ricin.

automatic chicken feeder

garden seed planter

ball float valve

Wholesale Table Linens

cotton blend yarn

organic liquid fertilizer

Red Hard Wheat

leather motorcycle suit

cotton grocery bags

Castor oil

Castor oil is a vegetable oil obtained from the castor bean

(technically castor seed as the castor plant, Ricinus communis, is not a member of the bean family).

Castor oil (CAS number 8001-79-4) is a colorless to very pale yellow liquid with mild or no odor or taste. Its boiling point is 313 °C (595 °F) and its density is 961 kg·m-3.

It is a triglyceride in which approximately ninety percent of fatty acid chains are ricinoleic acid. Oleic and linoleic acids are the other significant components.

automatic chicken feeder

garden seed planter

ball float valve

Wholesale Table Linens

cotton blend yarn

organic liquid fertilizer

Red Hard Wheat

leather motorcycle suit

cotton grocery bags

Poison and food safety
While some seeds are considered by some as healthy to eat, other seeds may be harmful or poisonous, Plants and seeds often contain chemical compounds to discourage herbivores and seed predators. In some cases, these compounds simply taste bad (such as in mustard), but other compounds are toxic, or breakdown into toxic compounds within the digestive system. Children, being smaller than adults, are more susceptible to poisoning or death by plants and seeds. One should be satisfied with reliable food safety information before choosing to eat any particular seeds.
An infamously deadly poison, ricin, comes from seeds of the castor bean. Reported lethal doses are anywhere from two to eight seeds, though only a few deaths have been reported when castor beans have been ingested by animals.

In addition, seeds containing amygdalin; apple, apricot, bitter almond,peach, plum, cherry, quince, and others, when consumed in significant amounts, may result in cyanide toxicity. Other seeds that contain poisons include annona, cotton, custard apple, datura, uncooked durian, golden chain, horse-chestnut, larkspur, locoweed, lychee, nectarine, rambutan, rosary pea, sour sop, sugar apple, wisteria, and yew. Another seed poison is strychnine.
The seeds of many legumes, including the common bean (Phaseolus vulgaris) contain proteins called lectins which can cause gastric distress if the beans are eaten without cooking. The common bean and many others, including the soybean, also contain trypsin inhibitors which interfere with the action of the digestive enzyme trypsin. Normal cooking processes degrade lectins and trypsin inhibitors to harmless forms.

automatic chicken feeder

garden seed planter

ball float valve

Wholesale Table Linens

cotton blend yarn

organic liquid fertilizer

Red Hard Wheat

leather motorcycle suit

cotton grocery bags

Origin and evolution

The origin of seed plants is a problem that still remains unsolved. However, more and more data tends to place this origin in the middle Devonian. The description in 2004 of the proto-seed Runcaria heinzelinii in the Givetian of Belgium is an indication of that ancient origin of seed-plants. As with modern ferns, most land plants before this time reproduced by sending spores into the air, that would land and become whole new plants.
The first "true" seeds are described from the upper Devonian, which is probably the theater of their true first evolutionary radiation. The seed plants progressively became one of the major elements of nearly all ecosystems.

Economic importance

A variety of bean seeds.

Edible seeds
Further information: List of edible seeds
Many seeds are edible and the majority of human calories comes from seeds, especially from cereals, legumes and nuts. Seeds also provide most cooking oils, many beverages and spices and some important food additives. In different seeds the seed embryo or the endosperm dominates and provides most of the nutrients. The storage proteins of the embryo and endosperm differ in their amino acid content and physical properties. For example the gluten of wheat, important in providing the elastic property to bread dough is strictly an endosperm protein.
Seeds are used to propagate many crops such as cereals, legumes, forest trees, turfgrasses and pasture grasses.
Seeds are also eaten by animals, and are fed to livestock. Many seeds are used as birdseed.

automatic chicken feeder

garden seed planter

ball float valve

Wholesale Table Linens

cotton blend yarn

organic liquid fertilizer

Red Hard Wheat

leather motorcycle suit

cotton grocery bags

Seed germination

Germinating sunflower seedlings.
Main articles: Seedling and Germination
Seed germination is the process of growth of the embryo into a functional plant. It involves the reactivation of the metabolic pathways that lead to growth and the emergence of the radicle or seed root and plumule or shoot.
Three fundamental conditions must exist before germination can occur. (1) The embryo must be alive, called seed viability. (2) Any dormancy requirements that prevent germination must be over come. (3) The proper environmental conditions must exist for germination.
Seed viability determines the percentage of possible seed germination and is affected by a number of different conditions. Some plants do not produce seeds that have functional complete embryos or the seed may have no embryo at all, often called empty seeds. Predators and pathogens can damage or kill the seed while it is still in the fruit or after it is dispersed. Environmental conditions like flooding or heat can kill the seed before or during germination. The age of the seed affects its health and germination ability: since the seed has a living embryo, over time cells die and cannot be replaced. Some seeds can live for a long time before germination, while others can only survive for a short period after dispersal before they die.
Seed vigor is a measure of the quality of seed, and involves the viability of the seed, the germination percentage, germination rate and the strength of the seedlings produced.
The germination percentage is simply the proportion of seeds that germinate from all seeds subject to the right conditions for growth. The germination rate is the length of time it takes for the seeds to germinate. Germination percentages and rates are affected by seed viability, dormancy and environmental effects that impact on the seed and seedling. In agriculture and horticulture quality seeds have high viability, measured by germination percentage plus the rate of germination. This is given as a percent of germination over a certain amount of time, 90% germination in 20 days, for example. 'Dormancy' is covered above; many plants produce seeds with varying degrees of dormancy, and different seeds from the same fruit can have different degrees of dormancy.It's possible to have seeds with no dormancy if they are dispersed right away and do not dry (if the seeds dry they go into physiological dormancy). There is great variation amongst plants and a dormant seed is still a viable seed even though the germination rate might be very low.
Environmental conditions effecting seed germination include; water, oxygen, temperature and light.
Three distinct phases of seed germination occur: water imbibition; lag phase; and radicle emergence.
In order for the seed coat to split, the embryo must imbibe (soak up water), which causes it to swell, splitting the seed coat. However, the nature of the seed coat determines how rapidly water can penetrate and subsequently initiate germination. The rate of imbibition is dependent on the permeability of the seed coat, amount of water in the environment and the area of contact the seed has to the source of water. For some seeds, imbibing too much water too quickly can kill the seed. For some seeds, once water is imbibed the germination process cannot be stopped, and if the seed dries out again it is fatal. Other species have seeds that can imbibe and lose water a few times without causing ill effects to the seed, and drying can cause secondary dormancy.

automatic chicken feeder

garden seed planter

ball float valve

Wholesale Table Linens

cotton blend yarn

organic liquid fertilizer

Red Hard Wheat

leather motorcycle suit

cotton grocery bags

Seed dormancy and protection

Further information: Seed hibernation
One important function of most seeds is delaying germination, which allows time for dispersal and prevents germination of all the seeds at one time. The staggering of germination safeguards some seeds and seedlings from suffering damage or death from short periods of bad weather or from transient herbivores, it also allows some to germinate when competition from other plants for light and water might be less. Many species of plants have seeds that germinate over many months or years, and some seeds can remain in the soil seed bank for more than 50 years before germination. Some seed have a very long viability period, with the oldest documented germinating seed carbon dated to be 2000 years old.Seed dormancy is defined as a seed failing to germinate under environmental conditions optimal for germination, normally when the environment is at a suitable temperature with proper soil moisture. Induced dormancy or seed quiescence occurs when a seed fails to germinate because the external environmental conditions are inappropriate for germination, mostly in response to being too cold or hot, or too dry. True dormancy or innate dormancy is caused by conditions within the seed that prevent germination under normally ideal conditions. Often seed dormancy is divided into four major categories: exogenous; endogenous; combinational; and secondary.
Exogenous dormancy is caused by conditions outside the embryo including:
Hard seed coats or physical dormancy occurs when seeds are impermeable to water or the exchange of gases. In some seeds the seed coat physically prevents the seedling from growing.
Chemical dormancy includes growth regulators etc.
Endogenous dormancy is caused by conditions within the embryo itself, including:
Immature embryos where some plants release their seeds before the tissues of the embryos have fully differentiated, and the seeds ripen after they take in water while on the ground, germination can be delayed from a few weeks to a few months.
Morphological dormancy where seeds have fully differentiated embryos that need to grow more before seed germination, the embryos are not yet fully developed.
Morphophysiological dormancy seeds with underdeveloped embryos, and in addition have physiological components to dormancy. These seeds therefore require a dormancy-breaking treatments as well as a period of time to develop fully grown embryos.
Physiological dormancy prevents seed germination until the chemical inhibitors are broken down or are no longer produced by the seed, often physiological dormancy is broken by a period of cool moist conditions, normally below (+4C) 39F, or in the case of many species in Ranunculaceae and a few others,(-5C) 24F. Other chemicals that prevent germination are washed out of the seeds by rainwater or snow melt. Abscisic acid is usually the growth inhibitor in seeds and its production can be affected by light. Some plants like Peony species have multiple types of physiological dormancy, one affects radical growth while the other affects shoot growth.
Drying; some plants including a number of grasses and those from seasonally arid regions need a period of drying before they will germinate, the seeds are released but need to have a lower moister content before germination can begin. If the seeds remain moist after dispersal, germination can be delayed for many months or even years. Many herbaceous plants from temperate climate zones have physiological dormancy that disappears with drying of the seeds. Other species will germinate after dispersal only under very narrow temperature ranges, but as the seeds dry they are able to germinate over a wider temperature range.
Photodormancy or light sensitivity affects germination of some seeds. These photoblastic seeds need a period of darkness or light to germinate. In species with thin seed coats, light may be able to penetrate into the dormant embryo. The presence of light or the absence of light may trigger the germination process, inhibiting germination in some seeds buried too deeply or in others not buried in the soil.
Thermodormancy is seed sensitivity to heat or cold. Some seeds including cocklebur and amaranth germinate only at high temperatures (30C or 86F) many plants that have seed that germinate in early to mid summer have thermodormancy and germinate only when the soil temperature is warm. Other seeds need cool soils to germinate, while others like celery are inhibited when soil temperatures are too warm. Often thermodormancy requirements disappear as the seed ages or dries.
Combinational dormancy also called double dormancy. Many seeds have more than one type of dormancy, some Iris species have both hard impermeable seeds coats and physiological dormancy.
Secondary dormancy is caused by conditions after the seed has been dispersed and occurs in some seeds when non-dormant seed is exposed to conditions that are not favorable to germination, very often high temperatures. The mechanisms of secondary dormancy are not yet fully understood but might involve the loss of sensitivity in receptors in the plasma membrane
Many garden plants have seeds that will germinate readily as soon as they have water and are warm enough, though their wild ancestors may have had dormancy, these cultivated plants lack seed dormancy. After many generations of selective pressure by plant breeders and gardeners dormancy has been selected out.
For annuals, seeds are a way for the species to survive dry or cold seasons. Ephemeral plants are usually annuals that can go from seed to seed in as few as six weeks.
Not all seeds undergo a period of dormancy. Seeds of some mangroves are viviparous, they begin to germinate while still attached to the parent. The large, heavy root allows the seed to penetrate into the ground when it falls.

automatic chicken feeder

garden seed planter

ball float valve

Wholesale Table Linens

cotton blend yarn

organic liquid fertilizer

Red Hard Wheat

leather motorcycle suit

cotton grocery bags

Seed functions

Seeds serve several functions for the plants that produce them. Key among these functions are nourishment of the embryo, dispersal to a new location, and dormancy during unfavorable conditions. Seeds fundamentally are a means of reproduction and most seeds are the product of sexual reproduction which produces a remixing of genetic material and phenotype variability that natural selection acts on.

Embryo nourishment
Seeds protect and nourish the embryo or baby plant. Seeds usually give a seedling a faster start than a sporeling from a spore, because of the larger food reserves in the seed and the multicellularity of the enclosed embryo.
Seed dispersal
Main article: Biological dispersal
Unlike animals, plants are limited in their ability to seek out favorable conditions for life and growth. As a consequence, plants have evolved many ways to disperse their offspring by dispersing their seeds (see also vegetative reproduction). A seed must somehow "arrive" at a location and be there at a time favorable for germination and growth. When the fruits open and release their seeds in a regular way, it is called dehiscent, which is often distinctive for related groups of plants, these fruits include; Capsules, follicles, legumes, silicles and siliques. When fruits do not open and release their seeds in a regular fashion they are called indehiscent, which include these fruits; Achenes, caryopsis, nuts, samaras, and utricles.Seed dispersal is seen most obviously in fruits; however many seeds aid in their own dispersal. Some kinds of seeds are dispersed while still inside a fruit or cone, which later opens or disintegrates to release the seeds. Other seeds are expelled or released from the fruit prior to dispersal. For example, milkweeds produce a fruit type, known as a follicle, that splits open along one side to release the seeds. Iris capsules split into three "valves" to release their seeds.
By wind (anemochory)

Dandelion seeds (achenes) can be carried long distances by the wind.
Many seeds (e.g. maple, pine) have a wing that aids in wind dispersal.
The dustlike seeds of orchids are carried efficiently by the wind.
Some seeds, (e.g. dandelion, milkweed, poplar) have hairs that aid in wind dispersal.

By water (hydrochory)
Some plants, such as Mucuna and Dioclea, produce buoyant seeds termed sea-beans or drift seeds because they float in rivers to the oceans and wash up on beaches.
By animals (zoochory)
Seeds (burrs) with barbs or hooks (e.g. acaena, burdock, dock) which attach to animal fur or feathers, and then drop off later.
Seeds with a fleshy covering (e.g. apple, cherry, juniper) are eaten by animals (birds, mammals) which then disperse these seeds in their droppings.
Seeds (nuts) which are an attractive long-term storable food resource for animals (e.g. acorns, hazelnut, walnut); the seeds are stored some distance from the parent plant, and some escape being eaten if the animal forgets them.
Myrmecochory is the dispersal of seeds by ants. Foraging ants disperse seeds which have appendages called elaiosomes(e.g. bloodroot, trilliums, Acacias, and many species of Proteaceae). Elaiosomes are soft, fleshy structures that contain nutrients for animals that eat them. The ants carry such seeds back to their nest, where the elaiosomes are eaten. The remainder of the seed, which is hard and inedible to the ants, then germinates either within the nest or at a removal site where the seed has been discarded by the ants.This dispersal relationship is an example of mutualism, since the plants depend upon the ants to disperse seeds, while the ants depend upon the plants seeds for food. As a result, a drop in numbers of one partner can reduce success of the other. In South Africa, the Argentine ant (Linepithema humile) has invaded and displaced native species of ants. Unlike the native ant species, Argentine ants do not collect the seeds of Mimetes cucullatus or eat the elaiosomes. In areas where these ants have invaded, the numbers of Mimetes seedlings have dropped.

automatic chicken feeder

garden seed planter

ball float valve

Wholesale Table Linens

cotton blend yarn

organic liquid fertilizer

Red Hard Wheat

leather motorcycle suit

cotton grocery bags

Seed development

The inside of a Ginkgo seed, showing a well-developed embryo, nutritive tissue (megagametophyte), and a bit of the surrounding seed coat.

Diagram of the internal structure of a dicot seed and embryo. (a) seed coat, (b) endosperm, (c) cotyledon, (d) hypocotyl.
The seed, which is an embryo with two points of growth (one of which forms the stems the other the roots) is enclosed in a seed coat with some food reserves. Angiosperm seeds consist of three genetically distinct constituents: (1) the embryo formed from the zygote, (2) the endosperm, which is normally triploid, (3) the seed coat from tissue derived from the maternal tissue of the ovule. In angiosperms, the process of seed development begins with double fertilization and involves the fusion of the egg and sperm nuclei into a zygote. The second part of this process is the fusion of the polar nuclei with a second sperm cell nucleus, thus forming a primary endosperm. Right after fertilization the zygote is mostly inactive but the primary endosperm divides rapidly to form the endosperm tissue. This tissue becomes the food that the young plant will consume until the roots have developed after germination or it develops into a hard seed coat. The seed coat forms from the two integuments or outer layers of cells of the ovule, which derive from tissue from the mother plant, the inner integument forms the tegmen and the outer forms the testa. When the seed coat forms from only one layer it is also called the testa, though not all such testa are homologous from one species to the next.
In gymnosperms, the two sperm cells transferred from the pollen do not develop seed by double fertilization but one sperm nucleus unites with the egg nucleus and the other sperm is not used sometimes each sperm fertilizes an oval and one oval is then aborted or absorbed during early development of its zygote The seed is composed of the embryo (the result of fertilization) and tissue from the mother plant, which also form a cone around the seed in coniferous plants like Pine and Spruce.
The ovules after fertilization develop into the seeds; the main parts of the ovule are the funicle; which attaches the ovule to the placenta, the nucellus; the main region of the ovule were the embryo sac develops, the micropyle; A small pore or opening in the ovule where the pollen tube usually enters during the process of fertilization, and the chalaza; the base of the ovule opposite the micropyle, where integument and nucellus are joined together.
The shape of the ovules as they develop often affects the finale shape of the seeds. Plants generally produce ovules of four shapes: the most common shape is called anatropous, with a curved shape. Orthotropous ovules are straight with all the parts of the ovule lined up in a long row producing an uncurved seed. Campylotropous ovules have a curved embryo sac often giving the seed a tight “c” shape. The last ovule shape is called amphitropous, where the ovule is partly inverted and turned back 90 degrees on its stalk or funicle.
In the majority of flowering plants, the zygote's first division is transversely oriented in regards to the long axis, and this establishes the polarity of the embryo. The upper or chalazal pole becomes the main area of growth of the embryo, while the lower or micropylar pole produces the stalk-like suspensor that attaches to the micropyle. The suspensor absorbs and manufacturers nutrients from the endosperm that are utilized during the embryos growth
The embryo is composed of different parts; the epicotyle will grow into the shoot, the radicle grows into the primary root, the hypocotyl connects the epicotyle and the radicle, the cotyledons form the seed leaves, the testa or seed coat forms the outer covering of the seed. Monocotyledonous plants like corn, have other structures; instead of the hypocotyle-epicotyle, it has a coleoptile that forms the first leaf and connects to the coleorhiza that connects to the primary root and adventitious roots form from the sides. The seeds of corn are constructed with these structures; pericarp, scutellum (single large cotyledon) that absorbs nutrients from the endosperm, endosperm, plumule, radicle, coleoptile and coleorhiza - these last two structures are sheath-like and enclose the plumule and radicle, acting as a protective covering. The testa or seed coats of both monocots and dicots are often marked with patterns and textured markings, or have wings or tufts of hair.

Seed size and seed set
Seeds are very diverse in size. The dust-like orchid seeds are the smallest with about one million seeds per gram, they are often embryonic seeds with immature embryos and no significant energy reserves. Orchids and a few other groups of plants are myco-heterotrophs which depend on mycorrhizal fungi for nutrition during germination and the early growth of the seedling. Some terrestrial Orchid seedlings, in fact, spend the first few years of their life deriving energy from the fungus and do not produce green leaves. At over 20 kg, the largest seed is the coco de mer. Plants that produce smaller seeds can generate many more seeds per flower, while plants with larger seeds invest more resources into those seeds and normally produce fewer seeds. Small seeds are quicker to ripen and can be dispersed sooner, so fall blooming plants often have small seeds. Many annual plants produce great quantities of smaller seeds; this helps to ensure that at least a few will end in a favorable place for growth. Herbaceous perennials and woody plants often have larger seeds, they can produce seeds over many years, and larger seeds have more energy reserves for germination and seedling growth and produce larger, more established seedlings after germination.

automatic chicken feeder

garden seed planter

ball float valve

Wholesale Table Linens

cotton blend yarn

organic liquid fertilizer

Red Hard Wheat

leather motorcycle suit

cotton grocery bags

Seed production

Immature Elm seeds.
Seeds are produced in several related groups of plants, and their manner of production distinguishes the angiosperms ("enclosed seeds") from the gymnosperms ("naked seeds"). Angiosperm seeds are produced in a hard or fleshy structure called a fruit that encloses the seeds, hence the name. (Some fruits have layers of both hard and fleshy material).

In gymnosperms, no special structure develops to enclose the seeds, which begin their development "naked" on the bracts of cones.

However, the seeds do become covered by the cone scales as they develop in some species of conifer.

Kinds of seeds
There are a number of modifications to seeds by different groups of plants. One example is that of the so-called stone fruits (such as the peach), where a hardened fruit layer ( the endocarp) surrounds the actual seed and is fused to it.
Many structures commonly referred to as "seeds" are actually dry fruits. Sunflower seeds are sold commercially while still enclosed within the hard wall of the fruit, which must be split open to reach the seed.

automatic chicken feeder

garden seed planter

ball float valve

Wholesale Table Linens

cotton blend yarn

organic liquid fertilizer

Red Hard Wheat

leather motorcycle suit

cotton grocery bags

Seed structure

The parts of an avocado seed (a dicot), showing the seed coat, endosperm, and embryo.
A typical seed includes three basic parts: (1) an embryo, (2) a supply of nutrients for the embryo, and (3) a seed coat.
The embryo is an immature plant from which a new plant will grow under proper conditions. The embryo has one cotyledon or seed leaf in monocotyledons, two cotyledons in almost all dicotyledons and two or more in gymnosperms. The radicle is the embryonic root. The plumule is the embryonic shoot. The embryonic stem above the point of attachment of the cotyledon(s) is the epicotyl. The embryonic stem below the point of attachment is the hypocotyl.
Within the seed, there usually is a store of nutrients for the seedling that will grow from the embryo. The form of the stored nutrition varies depending on the kind of plant. In angiosperms, the stored food begins as a tissue called the endosperm, which is derived from the parent plant via double fertilization. The usually triploid endosperm is rich in oil or starch and protein. In gymnosperms, such as conifers, the food storage tissue is part of the female gametophyte, a haploid tissue. In some species, the embryo is embedded in the endosperm or female gametophyte, which the seedling will use upon germination. In others, the endosperm is absorbed by the embryo as the latter grows within the developing seed, and the cotyledons of the embryo become filled with this stored food. At maturity, seeds of these species have no endosperm and are termed exalbuminous seeds. Some exalbuminous seeds are bean, pea, oak, walnut, squash, sunflower, and radish. Seeds with an endosperm at maturity are termed albuminous seeds. Most monocots (e.g. grasses and palms) and many dicots (e.g. brazil nut and castor bean) have albuminous seeds. All gymnosperm seeds are albuminous.
The seed coat (or testa) develops from the tissue, the integument, originally surrounding the ovule. The seed coat in the mature seed can be a paper-thin layer (e.g. peanut) or something more substantial (e.g. thick and hard in honey locust and coconut). The seed coat helps protect the embryo from mechanical injury and from drying out.
In addition to the three basic seed parts, some seeds have an appendage on the seed coat such an aril (as in yew and nutmeg) or an elaiosome (as in Corydalis) or hairs (as in cotton). There may also be a scar on the seed coat, called the hilum; it is where the seed was attached to the ovary wall by the funiculus.

automatic chicken feeder