Waterbeds have a bad rap as being a motion sickness inducing relic of the yuppie 80s bedroom. Just the word waterbed brings to mind angular abstract art in varying pastels and mirror-covered, lacquered headboards. Many who have slept in older waterbeds have experienced the discomfort of climbing onto a plastic sack filled with cold water, only to wake up sweaty and stuck hours later. Worse than the temperature differential was the potential of waking up in a pool, rather than a bed.
Since then, waterbed technology has made leaps ahead. Waterbeds are available in varying firmness, ranging from the traditional, wavy bed to beds that are nearly as firm as traditional spring mattresses. One of the major benefits of the waterbed is its maintenance schedule. A traditional mattress needs to vacuumed and flipped every six months to prevent sagging and dust accumulation. A waterbed mattress can be cleaned with a wet cloth. Далее
From ancient times, in Western culture and worldwide, water has been an enduring theme in the arts. Water themes (including snow and ice) flow
Sea monsters in literature often are exaggerations of naturally occurring creatures. An enormous and “hostile” giant squid became a menacing foe in Jules Verne’s 1873 classic Twenty Thousand Leagues Under the Sea. Далее
The best way to determine if a substance is a “mineral” is to compare its properties to the definition of the word “mineral”.
What is a Mineral?
The word “mineral” is used by geologists for a group of naturally occurring crystalline substances. Gold, pyrite, quartz, calcite and fluorite are all examples of “minerals”.
To be a mineral a substance must meet five requirements:
- naturally occurring (not made by humans)
- inorganic (not produced by an organism)
- a limited range of chemical compositions
- ordered atomic structure Далее
• The WHO/UNICEF 2000 Assessment statistics for sanitation for 43 of Africa’s large cities showed that 19% of the population remains unserved. Among these populations, only 18% have toilets connected to sewers, a very low proportion as confirmed by an analysis of the Demographic and Health Surveys suggesting that a mere 25% of Africa’s urban population has access to toilets connected to sewers.
This conclusion is also supported by statistics on the proportion of households with sewer connections in the largest city in each African nation. In most of these cities, less than 10% of the population has sewer connections while in many, including Abidjan (Cte dIvoire), Addis Ababa (Ethiopia), Asmara (Eritrea), Brazzaville (Congo), Cotonou (Benin), Kinshasa (Congo), Libreville (Gabon), Moroni (Comoros), NDjamena (Republic Of Chad), Ouagadougou (Burkina Faso), and less than 2% have connections. Далее
The Marcellus Shale is a sedimentary rock formation deposited over 350 million years ago in a shallow inland sea located in the eastern United States where the present-day Appalachian Mountains now stand (de Witt and others, 1993). This shale contains significant quantities of natural gas. New developments in drilling technology, along with higher wellhead prices, have made the Marcellus Shale an important natural gas resource.
The Marcellus Shale extends from southern New York across Pennsylvania, and into western Maryland, West Virginia, and eastern Ohio (fig. 1). The production of commercial quantities of gas from this shale requires large volumes of water to drill and hydraulically fracture the rock. This water must be recovered from the well and disposed of before the gas can flow. Concerns about the availability of water supplies needed for gas production, and questions about wastewater disposal have been raised by water-resource agencies and citizens throughout the Marcellus Shale gas development region. This Fact Sheet explains the basics of Marcellus Shale gas production, with the intent of helping the reader better understand the framework of the water-resource questions and concerns. Далее