Tube hydration system

In 1997 the US Army began investigating the use of commercial tube or handsfree on the move hydration systems. The intent was that soldiers on the move during a road march or foot movement would not need to take a canteen out of its case to drink water. They could simply sip through the bite valve at the end of the hydration system tube while keeping both hands on the rifle. The 3-hter (100-ounce) tube hydration system was not intended to replace the 1 and 2-quart canteens it was a supplemental item fielded with the MOLLE system. Unlike the 1 and 2-quart canteens, the tube hydration systems were not approved for use in a nuclear/biological/chemical (NBC)-contaminated environment. 

Another problem with tube hydration systems is that, when they are full, they take on a cylindrical shape that is cumbersome on the user s back or in his racksack. This problem makes it very difficult to wear a ftill Itydration system on the back with a rucksack on top of it. Some commercial vendors have added baffles to limit the bulging effect of a full bladder. However, the baffle has limited effectiveness. 

Sanitary issues were reduced by adding a bite valve cover. Prior to the cover, the hydration system bite valve danghng on the end of its tube could come into contact with a number of contaminants on the battlefield. The soldier would put it in his mouth to drink and become exposed to organisms that could lead to battlefield illness. The problem remains today in that some soldiers use their mouths to take the cover off the bite valve. 

Later articles dealt with further elaboration of ideas on the driving forces which would have led to the formation of higher aggregates from RNA and amino acids. As had been suggested 20 years earlier, these processes could have taken place in rock pores and could have been driven by hydration and dehydration phases (Kuhn and Waser, 1994). The tiny pores in rocks act as minute test tubes, so optimal compositions could have been determined and replicated using many millions of systems. According to this model, none of the synthetic processes taking place would have required the presence of protein enzymes (see also Lahav, 1999). Just as other... 

The appearance of tubular myelin-like structures in swollen lecithin was observed by light microscopy well before the systematic investigation of liposomes [351-352]. Similarly, it was also demonstrated some time ago that the addition of calcium ions converted phospholipid liposomes to cochleate cylinders [353]. Subsequent studies have, however, revealed that the system is extremely complex. For example, examination of the phase-transition behavior of synthetic sodium di-n-dodecyl phosphate [(C12H2sO)2PO2Na+ or NaDDP] and calcium di-n-dodecyl phosphate [Ca(DDP)2] showed the presence of many diverse structures [354]. In particular, hydrated NaDDP crystals were shown to form lyotropic liquid-crystalline phases which transformed, upon heating to 50 °C, to myelin-like tubes. Structures of the tubes formed were found... 

The thermodynamics of this process are described in detail in references (67 —72, 80,81). Let us examine a typical methanol injection system. In a typical methanol injection and recovery system for a cold-oil absorption or turboexpander plant, feed gas passes through a free-water knockout drum and into a gas-gas exchanger with methanol being sprayed on exchanger tube-sheets. Methanol inhibits hydrate formation and aqueous methanol condenses in the exchanger (and the chiller following it) and is pumped to a primary separator. The methanol-water solution is then flashed in a flash drum and filtered into a methanol still to recover methanol. Normally, methanol dissolves in the hydrocarbon liquids and is distilled as a mixture of propane and methanol. Some of the methanol is recovered as the overhead product to recover the methanol dissolved in the heavier solution, the bottoms of the methanol still (propane product or hydrocarbon liquids from the demethanizer)... 

---