This means that we should try to replace tests on animals as much as possible, reduce the number of animals involved for each experiment, and make tests as […]. There are many reasons why animal testing is pretty problematic. In this article I discuss some of them. Often more animals are bred than are necessary for a specific experiment, as there always need […]. What are the ingredients in shellac nail polish?
Name required. Mail required. Efforts were also being concentrated on producing colorless shellac. As far back as the 's shellac chemists discovered that by chlorinating an alkaline solution of shellac they could remove almost all of the color and then precipitate the resin.
The result was a pale, straw-colored varnish that excelled any oil-base varnish for clarity. By the middle of the 19th century, Germany was the center of shellac bleaching for all of Europe. One such bleachery, located in the town of Mainz, employed a man named William Zinsser as one of its bleaching foremen. Confident of his technological skills and convinced that a good market for bleached shellac either existed or could be created in the United States, Zinsser and his family emigrated to America.
Almost immediately he set up a workshop in a building next to his home and began to bleach small quantities of shellac that were sold to fellow immigrants. From this humble beginning arose the first shellac bleachery in the United States. At that time Americans had never before seen bleached shellac, shellac varnish, or so-called French varnish and therefore were unaware of the many uses for this versatile, natural product.
Initially, shellac sales were confined to fellow immigrant artisans and craftsmen. As word of this marvelous new varnish spread among tradesman of all nationalities the demand for shellac grew from a few pounds per day to thousands of gallons by the turn of the century; up to that point Zinsser shellac was sold to vendors who packaged the product under their own label and name. By the 's there were several other shellac manufacturers in the U.
Most of these companies either imported shellac or prepared and packaged pre-mixed solutions of shellac and alcohol. The next eighty years witnessed a veritable explosion in the commercial applications for shellac. It was used extensively as a binder in the manufacture of gramophone records from the turn of the century well into the 's, when manufacturers began using vinyl to press record albums.
Shellac was used to make shoe polish, felt sizing for men's hats, hair spray, floor wax, pharmaceutical, candy and fruit coatings; printing inks, adhesives, grinding wheels, paper and foil coatings and electrical insulators. From the turn of the century through the 's home builders and painting contractors used shellac as a sealer for plaster walls and a fast-drying varnish for interior woodwork, trim and floors.
Today this beautiful original finish can still be seen in many older homes. The development of synthetic resin compounds early in the 20th century together with advances in varnish formulation heralded the end of shellac's industrial and architectural dominance. Ironically, many of these newly developed resins — such as Bakelite and similar phenolic-base compounds — were created by researchers attempting to synthesize shellac.
Following World War I chemists discovered that nitrocellulose dissolved in a powerful solvent mixture produced a crystal clear coating that dried as fast as shellac, thus giving rise to the widespread use of lacquer as a furniture finish.
After World War II alkyd varnishes were developed and by the 's the public was introduced to the first oil-base polyurethanes. As these finishes displaced shellac as the standard finish coating for interior woodwork and floors, one-by-one America's shellac manufacturers either closed their doors or merged with others.
From the 's until the early 's shellac seemed forgotten by everyone except those who manufactured it and the contractors, hobbyists, and knowledgeable devotees who used it. Shellac has the distinction of being the only known commercial resin of animal origin. It is produced by a tiny red insect Laccifer lacca which, in its larval stage, is about the size of an apple seed.
Swarms of the insects feed on certain host trees, commonly called "lac trees," in India and Thailand, the main lac-producing countries. Their whole life cycle spans six months and is devoted to eating, propagating and creating lac as a protective cocoon for their larvae. During certain seasons of the year, these tiny red insects swarm in such great numbers that the trees at times take on a red or pinkish color. When settled on the twigs and branches, they project a stinger-like proboscis to penetrate the bark.
Sucking the sap, they begin absorbing it until they die. In shellac lore this is the 'feast of death. In the body of the lac insect the digested tree sap undergoes a chemical transformation and is eventually secreted through pores.
On contact with the air, it forms a hard shell-like covering over the entire swarm. In time this covering becomes a composite crust for the twig and insects. Only about five percent of the insects amassed on the trees are males. The female is the main shellac producer. While she is secreting lac, she is preparing herself to die after providing a fluid in which her eggs will mature and from which the future supply of bugs will come, to repeat the process of swarming, propagating and creating the next season's shellac harvest.
The males, having fertilized the hordes of females, also begin their life-ending feast. Although they contribute relatively little more to the shellac crop, they have already assured an ample supply because the females vastly increase their output of lac after being fertilized.
The great mass of male and female bugs on each tree gradually becomes inactive as the shell-like covering forms over them. In the sixth or seventh months, the young begin to break through the crust and swarm to new feeding grounds. Shellac cultivation yields a large crop by helping the larvae find better locations for their feast. This involves simply cutting lac-bearing twigs from an infested tree a few days before the emergence of the larvae.
A bundle of such twigs, known as 'broodlac," is tied to an uninfested tree on which there are many tender new shoots. This results in a higher survival rate of insects and a greater yield of lac since only a little broodlac gives forth sufficient larvae to infest a tree thoroughly.
No further attention is needed until shellac is harvested. Screen Name Selection. Only letters, numbers, periods and hyphens are allowed in screen names. Please enter your email address so we can send you a link to reset your password.
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New comments are only accepted for 3 days from the date of publication. Easy, delicious dishes. Kitchen Cabinet Tops chefs share favourite recipes. Sign up. Advertising Feature. Subscriber Only. For example, clover honey is mild tasting and light in colour whereas buckwheat honey is bolder tasting and darker. Honey may also darken or become a bit stronger tasting with age, but will keep indefinitely in a sealed container at room temperature.
If older honey crystallizes, simply warm it up until it turns clear. One solvent used to decaffeinate tea and coffee is a known carcinogen.
The last two are chemical solvents that strip the caffeine from green coffee beans or tea leaves. Methylene chloride, or dichloromethane is recognized as possibly carcinogenic, and for this reason, many manufacturers have switched to using carbon dioxide or the Swiss Water process instead. Of course, the methylene chloride is removed from the coffee or tea before it is packaged and sold, but knowing your tea or coffee has been processed using a carcinogenic solvent may influence your shopping choices.
While hydration needs vary depending on your gender, size and activity level, you should aim to drink enough water during the day so that you are rarely thirsty and produce at least 1. Your body needs water on an ongoing basis to aid digestion, replace fluid lost through breathing and perspiration, transport nutrients to your cells and get rid of waste.
Many people drink 8 glasses of water per day, or about 1. But would you really drink a large part of your daily volume goal all at once? Some soft drinks and sport drinks are now sold in gargantuan sizes. For example, a large soft drink from a fast food outlet can range in size from mL to mL. The same is true for sport drinks, which are sold in mL, mL and mL bottles.
Bottled water is sold in mL bottles but also in 1L and 1. Keep in mind that the average capacity of an adult human stomach is about mL. Corn is a key ingredient in breakfast cereals, bread, potato chips and French fries, soft drinks, and many prepared foods. Check the food label of any processed food and you will most likely find an ingredient derived from corn, provided you know what to look for.
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