A closer look
Igroscopy: at a glance
There.igroscopy (or hygroscopicity) is the ability of a substance or materials to readily absorb water molecules present in the surrounding environment. Such substances are called hygroscopic.[1]
An example of hygroscopic substance is paper, especially if it is hemp or other fibers, or biodiesel, which absorbs water up to about 1,200 ppm. Other hygroscopic substances are, for example, sodium chloride, ethyl alcohol, methyl alcohol, live lime (calcium oxide), concentrated sulphuric acid and concentrated sodium hydroxide.
The degree of hygroscopicity defines the greater or less aptitude of a substance to absorb moisture.
Hygroscopy differs from hydrophilia as the first concerns the ability to absorb moisture, the second the capacity to absorb water in liquid form. A substance can be hygroscopic and hydrophobic (hydrophobia is the opposite of hydrophilia), an example is wool that absorbs large amounts of moisture, but it is difficult to wet.
Hygroscopy can also be a desired feature, when you want to lower the humidity rate of a closed space. One of the most widely used materials in this regard is silica gel.
It is good to maintain hygroscopic materials in sealed containers when they are not in use.
Textile industry
Hygroscopy is a determining physical feature that plays a fundamental role in the marketing of some fibers as the presence of moisture alters its...Explore this chapter
Hygroscopy is a determining physical feature that plays a fundamental role in the marketing of certain fibers as moisture changes its weight. As fibers marketed by weight and not in length, defining the amount of moisture present in them is essential to determine the correct price. The rate of recovery defined as the maximum humidity percentage of all fiber types was introduced for marketing. In addition, many physical and mechanical tests are carried out in appropriately air-conditioned environments, usually at 20 °C and 65% relative humidity.
Hygroscopic insemination
This is a recent technique used to inseminate clouds in order to increase its rainfall. The technique was designed in Mexico by a group of scholars...Explore this chapter
It is a recent[not clear] technique used to inseminate the clouds in order to increase its rainfall. The technique was designed in Mexico by a group of local and American scholars coordinated by the meteorologist Roelof T. Bruintjes of the National Center for Atmospheric Research by Boulder in Colorado and consists of the insertion, inside the clouds, microscopic particles of Sale having the task of attracting water and forming ever bigger drips, which end up bumping into each other until they fall to the ground. The task of hygroscopic insemination, in practice, is to accelerate the growth of the droplets (which merge one within the other), thus increasing, at least in theory, rainfall.[2]
Notes
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- ^ Hygroscopic, in Vocabulary Treccani. Retrieved 10 March 2013.
- ^ "Rain Wizards", by Daniel Pendick, publ. on "Le Scienze dossier: the changing climate", number 5 August 2001, pages 52-57
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