sericulture, moriculture

From Spin Cycle; Silkworm farming, or sericulture, was a backbreaking job that often required the participation of entire familie; By Peter Ross Range Smithsonian magazine, July 2008

The process began with the 10-to 14-day incubation of silkworm eggs, which are produced by the mating of adult silkworm moths. According to the Silk Museum, keeping the tiny, delicate eggs (about the size of a pinhead) at just the right temperature was "the task of the women, who often carried small bags of eggs in direct contact with their skin. . .sometimes between their breasts." Once hatched, the worms, only about one millimeter long, had to be fed mulberry leaves night and day. From a birth weight of only half a milligram, they would grow 10,000-fold to a final weight of around five grams and a length of 8 to 9 centimeters (3 inches) in just 30 to 32 days. Then, in the final three days of their larval stage, the worms would start to spin their cocoons out of one continuous thin filament—up to 1,200 meters (or 4,000 feet) long—which they emitted from a "spinneret" located near their mouths. The filament, formed primarily of a substance called fibroin manufactured in two glands on the underside of their jaws, hardened instantly when it came in contact with the air.

After about a week, the cocoons were placed briefly in a hot, dry oven to kill the adult moths inside. (If allowed to emerge from a cocoon, an adult moth would ruin the silk, so just enough adult moths were allowed to fully mature to maintain the reproduction cycle.) The cocoons were then put in hot water to facilitate the difficult and tedious task of extracting the silk. The minute end of the cocoon's silk filament had to be located and threaded onto a reel, which then unwound it from the water-warmed cocoon. The silk thread was then cleaned, twisted (to prevent filaments from separating) and woven into fabric.

via Boing Boing

Sericulture wood blocks

where there's sericulture there must be moriculture

mulberry fields forever .....

Inflorescence

An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Strictly, it is the part of the shoot of seed plants where flowers are formed and which is accordingly modified. The modifications can involve the length and the nature of the internodes and the phyllotaxis, as well as variations in the proportions, compressions, swellings, adnations, connations and reduction of main and secondary axes.

modern sericulture

deflossing

The silkworms produce an unreelable layer of silk over the cocoons called floss, which must be removed for further processing (like reeling, silkworm egg production, etc). Presently the cocoons are manually deflossed and on an average 20 kg of cocoons per hour can be deflossed by a person (in a shift of 8 hours).

Deflossing is a tedious process and involves workers who have to sit for long hours. In order to overcome this drudgery and to minimize the cost of labor, the Central Sericultural Research and Training Institute, Mysore has developed a machine for continuous deflossing of cocoons. This machine can defloss 50-100 kg cocoons per hour (depending on the capacity of the machine used) or about 400-800 kg cocoons per day (in a shift of 8 hours). The machine can be operated for long hours. The quality of deflossed cocoons by this machine is comparable to or better than that of cocoons deflossed by hand.

The machine is simple in construction and can be fabricated/manufactured using locally available material like mild steel (angles, rods, etc), bearings, V-belts, pulleys, PVC pipes, HDPE pipes, bolts and nuts, electric motor (1/2 HP), etc.

Cadmium Telluride Solar Cells Breakthru in the Works

First Solar appears to be leading the way in development of cost effective solar cells. According to the article at IEEE they are claiming their

product has three massive cost benefits. Its ­active element is just a hundredth the thickness of the old standby, silicon; it is built on a glass substrate, which enables the production of large panels; and manufacturing takes just two and a half hours—about a tenth the time it takes for silicon equivalents.

Apparently the order books are full, new production capacity is being built and the stock is soaring.

Plus they are keeping critical steps in their process secret and refuse to talk to the press. Remembering back to my IP class the fact that trade secrets offered potentially so much longer protection that patenting was revelation to me.

Nevertheless, it is still possible to uncover some of the details of First Solar’s growth process. ... an elemental vapor deposition process that takes place in four chambers.

Glass is placed on rollers and fed into the first chamber, where it is heated to 600 °C. Then it is transferred into the second chamber, which is full of cadmium sulfide vapor, formed by heating solid CdS to 700 °C. The vapor forms a submicrometer deposit on the glass as it moves through this cloud, after which a similar process in a third chamber adds a layer of micrometers-thick CdTe in about 40 seconds. Then a gust of nitrogen gas rapidly cools the panels to 300 °C in a fourth chamber, strengthening the material so that it can withstand hail and high winds.

for the rest of the story

IEEE also supplies these references

Solar Cells Inc. describes the details of its elemental vapor process in its 1993 report “Fabrication of Stable Large-Area Thin-Film CdTe Photovoltaic Modules,” which is available at http://www.osti.gov/bridge/product.biblio.jsp?osti_id=10181903.

Get information about inverted triple-junction technology in “High-Efficiency GaInP/GaAs/InGaAs Triple-Junction Solar Cells Grown Inverted With a Metamorphic Bottom Junction,” Applied Physics Letters, 91 023502, 2007.

For comparisons between CdTe and CIGS manufacturing, see Michael Powalla and Dieter Bonnet’s paper “Thin-Film Solar Cells Based on the Polycrystalline Compound Semiconductors CIS and CdTe” published in Advances in OptoElectronics, 2007, available free of charge at http://www.hindawi.com/GetArticle.aspx?doi=10.1155/2007/97545.

Fuel Cell Efficiency May Be Improved With Material With 'Colossal Ionic Conductivity