Search results
Results From The WOW.Com Content Network
Polyurethane synthesis, wherein the urethane groups −NH−(C=O)−O− link the molecular units A kitchen sponge made of polyurethane foam . Polyurethane (/ ˌ p ɒ l i ˈ jʊər ə ˌ θ eɪ n,-j ʊəˈr ɛ θ eɪ n /; [1] often abbreviated PUR and PU) refers to a class of polymers composed of organic units joined by carbamate (urethane) links.
Industrial Insulation. Rigid polyurethane foam is used in various industries to provide thermal insulation to installations and pipes. In particular, the piping for district heating systems in Europe is primarily insulated using a pre-insulated pipes sandwich assembly composed of a steel heat service pipe, an insulating layer (polyurethane foam) and a polyethylene (PE) casing, which are bonded ...
Explosions and a fire have resulted in dangerous levels of radiation, sparking a stock market collapse and panic-buying in supermarkets. [4] Mayak nuclear waste storage tank explosion, (Chelyabinsk, Soviet Union, September 29, 1957), 200+ people died and 270,000 people were exposed to dangerous radiation levels. Over thirty small communities ...
The plant is toxic enough to cause human and animal fatalities if ingested. Every part of the plant is poisonous, especially the tuberous rhizomes. As with other members of the Colchicaceae, this plant contains high levels of colchicine, a toxic alkaloid. It also contains the alkaloid gloriocine.
As it has low water solubility, it tends to stay at the water surface, so organisms that live there are most affected. DDT found in fish that formed part of the human food chain caused concern, but the levels found in the liver, kidney and brain tissues was less than 1 ppm and in fat was 10 ppm, which was below the level likely to cause harm.
One of the first uses for NOPs (other than castor oil) was to make spray-on polyurethane foam insulation for buildings. [17] NOPs are also finding use in polyurethane slab foam used to make conventional mattresses [8] as well as memory foam mattresses. [18] [19] The characteristics of NOPs can be varied over a very wide range.
An obvious side effect of using a chemical meant to kill is that one is likely to kill more than just the desired organism. Contact with a sprayed plant or "weed" can have an effect upon local wildlife, most notably insects. A cause for concern is how pests, the reason for pesticide use, are building up a resistance.
Phytotoxicity describes any adverse effects on plant growth, physiology, or metabolism caused by a chemical substance, such as high levels of fertilizers, herbicides, heavy metals, or nanoparticles. [1] General phytotoxic effects include altered plant metabolism, growth inhibition, or plant death. [2]