Laboratory measurements of the resistivity of three sandstone samples collected during imbibition (increasing SXJ) and drainage (decreasing Sn,) show pronounced hysteresis in resistivity throughout much of the saturation range. The variation in resistivity can be related to changes in pore-scale fluid distribution caused by changes in saturation history. The form of the hysteresis is such that ...

Different continuous operating modes of a nondispersive solvent extraction (NDSX) process with membrane modules of hollow fibre for wastewater treatment and metal recovery are evaluated. Cocurrent and countercurrent flow of aqueous and organic phases in the membrane modules with alternative product extraction locations for the removal and recovery of hexavalent chromium from wastewater are stud...

TRUETA et al. proposed in 1947 that morphological differences between renal cortical and medullary structures reflect a '"fundamental difference in the function of the cortical and juxtamedullary vasculonephric units.' This proposition was reinforced when Wirz et al. first published evidence for the countercurrent mechanism as the basis for urinary concentration in 1951. The countercurrent hypo...

(1997) Analytica Chimica Acta 344: 241}249. 23. Llompart MP, Lorenzo RA, Cela R, PareH JRJ, BeH langer JMR and Li K (1997) Journal of Chromatography A 757: 153}164. 24. Llompart MP, Lorenzo RA, Rosa A, Cela R, Li K, BeH langer JMR and Pare JRJ (1997) Journal of Chromatography A 774: 243}251. 25. Chee KK, Wong MK and Lee HK (1996) Journal of Liquid Chromatography and Related Technology 19: 259}2...

MARSH, DONALD J., AND LEE A. SEGEL. Analysis of countercurrent di$usion exchange in blood vessels of the renal medulla. Am. J. Physiol. 221(3): 817-828. 1971 .-A model of the vasa recta was developed to explore the significance of dissimilarities between ascending and descending vasa recta for countercurrent exchange efficiency, and also to examine the interaction between countercurrent exchang...

• Adaptations to desert life have attracted much interest in the past forty years." In addition to the physiological aspects of this subject, there are morphological signs of adaptation to an arid environment in the kidneys of desert animals when compared to the kidneys of animals that require free access to water for their normal life. One of the distinguishing features of the former is the lo...

We study a solute concentrating mechanism that can be represented by coupled transport equations with specific boundary conditions. Our motivation for considering this system is urine concentrating mechanism in nephrons. The model consists in 3 tubes arranged in a countercurrent manner. Our equations describe a countercurrent exchanger, with a parameter V which quantifies the active transport. ...

A differential equation model of the renal countercurrent system has been developed and physiological data from nephron segments were incorporated together with recently suggested urea recycling from renal pelvis to inner medulla and, particularly, an exponential reduction in the number of collecting tubules towards the renal papilla. The role of these features for the countercurrent concentrat...

Pink-pigmented facultatively methylotrophic bacteria (PPFMs), persistent colonizers of plant leaf surfaces, belong to the genus Methylobacterium and are mostly transmitted through seeds. Plant growth-promoting activity of methylotrophic bacteria and their effects on disease suppression were evaluated on rice under greenhouse conditions. Rice seeds were inoculated with Methylobacterium sp. strai...

Spontaneous imbibition is of special importance to oil recovery from fractured reservoirs. Laboratory measurements of volume of liquid imbibed versus time are often used in the prediction of oil recovery. Imbibition measurements also provide a useful approach to the complex problem of characterizing the wetting properties of porous media. Correlation of a large body of data for imbibition of br...