Water passive

RJ Naftalin, S Tripathi. Passive water flows driven across isolated rabbit ileum by osmotic, hydrostatic and electrical gradients. I Physiol 360 27-50, 1985. 

Prest, H.F., W.M. Jarman, S.A. Bums, T. Weismuller, M. Martin, and J.N. Huckins. 1992. Passive water sampling via semipermeable membrane devices (SPMDs) in concert with bivalves in the Sacramento/San Joaquin river delta. Chemosphere 25 1811-1823. 

Booij, K. Smedes, R van Weerlee, E.M. 2002, Spiking of performance reference compounds in low density polyediylene and silicone passive water samplers. Chemosphere 46 1157—1161. 

Prest, H.F. Jacobson, L.A. Wilson, M. 1997, Passive water sampling for polynuclear aromatic hydrocarbons using Upid-containing semipermeable membrane devices (SPMDs) Application to contaminant residence times. Chemosphere 35 3047-3063. 

Figure 2. Crossover from conventional to passive water treatment vs. time.

X. Ren, J. J. Becerra, R. S. Hirsh, et al. Direct oxidation fuel cell operating with direct feed of concentrated fuel under passive water management. US Patent 2004209136 (2004). 

The most universal transport systems are those involved in the transport of the ubiquitous inorganic ions, sodium, potassium and calcium1. The sodium pump counteracts passive water movement across the cell membrane by removing sodium ions together with chloride or other anions from the cytoplasm to lower its content of osmotically active substances. In most cells, however, the elimination of sodium ions is connected with an accumulation of potassium ions6. For three sodium ions leaving the cell two potassium ions are taken up9,10). The resulting concentration... 

Gelman, N., Machin, J. and Kestler, P. (1988). The nature of driving forces for passive water transport through arthropod cuticle../. Thermal Biol., 13,157-162. 

Re-absorption is a two-step process beginning with the active or passive extraction of substances from the mbule fluid into the renal interstitium (the connective tissue that surrounds the nephrons), followed by their transport from the interstitium into the bloodstream. These transport processes are driven by hydrostatic, oncotic, diffusion and active transport. Some key regulatory hormones for re-absorption include aldosterone, which stimulates active sodium re-absorption (and water as a result), and antidiuretic hormone, which stimulates passive water re-absorption. Both hormones exert their effects principally on the collecting ducts. 

Whereas the Chymists in making the Analysis of Mixt Bodys have met with five sorts of Substances, they therefore concluded that there were five Principles of Natural things, Water, Spirit, Oil, Salt, and Earth. Of these Five, Three of them are Active, the Spirit, Oil, and Salt, and two passive, Water and Earth. ... 

Interestingly, the osmotic concentration of the hemolymph of edematose larvae was nearly normal (28). Apparently sexta larvae have no satisfactory alternative means to eliminate the accumulated ornithine and edema results either from an active attempt to maintain osmotic homeostasis in the hemolymph or as the result of passive water retention. 

The skin is a complex organ that is the major interface between hiunans and their environment. The skin s primary function is to restrict passive water loss from the body. It is the outermost 10 to 15 paa thick layer of the skin, the stratum corneum (SC), which provides this barriCT function. The SC is composed of dead keratinized cells (comeocytes) embedded in a matrix of hpids, a structure that has been represented as a brick-and-mortar wall (Schaefer and Redelmeier, 1996). However, the SC is not totally impermeable, of course, and chemicals with appropriate physicochemical properties can be absorbed in amounts sufficient to provoke both local and systranic pharmacological and toxic effects (Guy, 1996). 

The coo Ii ng funct ion of this UHS system can be provided by cooling towers or the natural or man-made passive water sources (e.g., reservoirs, rivers or lakes). For the case of cooling towers, the structure should be designed to withstand the effects of natural phenomena including tornadoes, tornado missiles, hurricane winds, floods, and the design basis earthquake. 

This system was not only a primary depressurization system, as it also included a subsequent passive water injection function in the primary circuit (low pressure and small flow rate) for the long-term refrigeration of the core. 

The provision of an emergency water supply to the steam generators to backup the normal (high capacity electric main feedwater pumps, and electric and steam turbines auxiliary feedwater pumps). A passive water supply is also provided (see Section 5.7.2.2 ). 

LOCA No large pipe connections Reduced vessel fluence Leak detection in all major penetrations All pipe connections >8m above core Large primary inventory Passive water injection to maintain inventory Low power density Inertion of the containment atmosphere... 

To understand the mechanism of urine concentration, one must retrace the fate of the fluid in the various segments of the kidney. In the glomerulus, the membranes of the Bowman s capsule cells allow passage of all plasma components except protein. The ultrafiltrate is markedly reduced in volume as it passes through the proximal tubule. In fact, only 20% of the original volume reaches the distal portion of the proximal convoluted tube. The volume of the ultrafiltrate is reduced due to passive water reabsorption. Passive means that no known molecular mechanism exists for the transport of water from the lumen of the proximal tubule to the interstitial tissue. However, the movement of water follows that of sodium. In the proximal tubule, sodium is excreted actively into the interstitial tissue, and as a result, the osmotic pressure of the interstitial tissues increases. This draws water from the lumen of the tubule into the interstitial environment of the medulla because the tubule is highly permeable to water. 

Zengerle, R., and Koltay, P. (2008) Passive water removal in fuel cells by capillary droplet actuation. Sens. Actuators A Phys., 143 (1), 49—57. 

One PEFC developer (10) devised an alternative plate structure that provides passive water control. Product water is removed by two mechanisms (1) transport of liquid water through the porous bipolar plate into the coolant, and (2) evaporation into the reactant gas streams. The cell is similar in basic design to other PEFCs with membrane, catalysts, substrates, and bipolar plate components. However, there is a difference in construction and composition of the bipolar plate ... 

A polypeptide hormdne secreted by the posterior pituitary gland. It is involved in fluid homeostasis, exerting its action in the distal renal tubular cells where it increases passive water reabsorption along the osmotic gradient produced by the countercurrent mechanism. This results in a concentrated urine being produced. Deficient production of the hormone, or failure of the renal tubules to respond to it, results in diabetes insipidus. Alternatively inappropriate ADH secretion can occur in conditions such as infections or as a result of ectopic ADH secretion by a tumour. This results in water retention which reveals itself as hyponatraemia. ADH can be measured by radioimmunoassay. 

Grasso, A.R, Scheffler, G.W., Van Dine, L.L., Dufner, B.F., and Breault, R. (2005) PEM fuel cell passive water management. United States Patent 6,916,571. 

---