INTRODUCTION Pressure is a thermodynamic variable that, like temperature, affects the states of matter. High pressure is an environmental characteristic of the deep sea. Immersion to depth brings about an increase in pressure of 0.1 MPa (1 atm) for each 10 m of seawater. Humans exposed to high pressure, mostly professional divers, suffer effects that are proportional to their exposure. DEVELO...

Man is ever emulating nature. In his attempts to duplicate pressures that exist in the universe, however, he falls short of the tremendous pressures that are to be found. For example, the pressures thought to exist at the centers of the white dwarf stars are of the order of 10 15 atmospheres. At the present time the highest static pressures attainable by man are about 2 x 10 5 atmospheres. It i...

Pressure sensing systems operating at temperatures >200 °C are required for a variety of presentand next-generation applications ranging from oil field instrumentation to turbine engine control. Quite often, part or all of the sensing system must be physically removed from the hightemperature environment. In some cases, pressure translating devices and capillary tubes are used to isolate the se...

Introduction Conclusions References

It has long been known that crystalline hydrates are formed by many simple gases that do not interact strongly with water, and in most cases the gas molecules or atoms occupy 'cages' formed by a framework of water molecules. The majority of these gas hydrates adopt one of two cubic cage structures and are called clathrate hydrates. Notable exceptions are hydrogen and helium which form 'exotic' ...