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Lead in the bones, teeth, hair, and nails is bound tightly and not available to other tissues, and is generally thought not to be harmful. [177] In adults, 94% of absorbed lead is deposited in the bones and teeth, but children only store 70% in this manner, a fact which may partially account for the more serious health effects on children. [ 23 ]
Piranha solution, also known as piranha etch, is a mixture of sulfuric acid ( H2SO4) and hydrogen peroxide ( H2O2 ). The resulting mixture is used to clean organic residues off substrates, for example silicon wafers. [ 1] Because the mixture is a strong oxidizing agent, it will decompose most organic matter, and it will also hydroxylate most ...
Wealthy women bought expensive makeup that came in elaborate containers made from gold, wood, glass or bone. [6] Kohl came in compartmentalized tubes that could store more than one color of eye makeup. [7] Glassblowing, invented in the 1st century CE in Syria, lowered the price of containers. The most common color for glass was teal. [2]
Decoupage or découpage ( / ˌdeɪkuːˈpɑːʒ /; [ 1] French: [dekupaʒ]) is the art of decorating an object by gluing colored paper cutouts onto it in combination with special paint effects, gold leaf, and other decorative elements. Commonly, an object like a small box or an item of furniture is covered by cutouts from magazines or from ...
Arsenic is the 53rd most abundant element in the Earth's crust, comprising about 1.5 parts per million (0.00015%). [ 43] Typical background concentrations of arsenic do not exceed 3 ng/m 3 in the atmosphere; 100 mg/kg in soil; 400 μg/kg in vegetation; 10 μg/L in freshwater and 1.5 μg/L in seawater. [ 44]
Mechanical pressing of glass reduced the time and labor necessary to make glass products, which lowered costs and made glass products available to more of the public. An 1884 U.S. government report considered mechanical pressing and a new formula for glass to be the two great advances in American glassmaking during the 19th century. [25]
Shellac in alcohol. Shellac ( / ʃəˈlæk /) [ 1] is a resin secreted by the female lac bug on trees in the forests of India and Thailand. Chemically, it is mainly composed of aleuritic acid, jalaric acid, shellolic acid, and other natural waxes. [ 2]
The history of fluid mechanics is a fundamental strand of the history of physics and engineering. The study of the movement of fluids (liquids and gases) and the forces that act upon them dates back to pre-history. The field has undergone a continuous evolution, driven by human dependence on water, meteorological conditions and internal ...