Use of nonwettable membranes for water transfer

Transfer of water through nonwettable vinyl fluoride membranes has two unique features - /1/ very low water transfer rates can be held constant by holding temperature and solute concentrations constant, /2/ the pressure gradient against which water is transported is limited only by solution breakthrough or membrane strength

New Geothermal Prospect in North-Eastern Morocco

Geothermal data has been indicating promising potentialities in the north-eastern Morocco. This paperpresents new temperature data, recently recorded in water borehole located in the Berkane and Oujda areas. Generally, the observed temperature gradients are rather high. One hole near Berkane, revealed an average geothermal gradient of more than 110 ºC/km at depths greater than 300 m. This result confirms the geothermal gradient estimated in a mining borehole located about 30 km west of the Berkane borehole, in which water temperatures of 96 ºC are reached at a depth of about 700 m. Such a high geothermal gradient, exceeding by far the ones already determined for northeastern Morocco, could act as a stimulus to programs aimed at the geothermal exploitation of high temperature aquifers

Determination of the distribution of water droplet sizes in butter and margarine using pulsed field gradient-NMR and confocal scanning laser microscopy : this thesis was presented in partial fulfillment of the requirements for [the] degree of Master of Science in Chemistry at Massey University

PFG-NMR has been used to determine the distribution of water droplets in emulsions. Especially, it has been used to measure the samples with high optical dense systems and highly viscous systems Butters and Margarines). To refine the method, the optimum measuring condition was investigated. It included delay time (Δ) between the field gradient pulses, τ null (τ0), gradient strength (G), water self-diffusion coefficients (D) and sampling techniques. Under the optimum conditions the water droplet size distributions of commercial butters, experimental butters and margarines were measured. Experimental results showed that PFG-NMR is an accurate, fast method to determine the water droplet size distributions of the butters and margarines. Also, it is can be used to investigate the properties of dispersed phase in emulsions. Especially, the method is suitable not only in the laboratory but also in the factory environment. The method was able to distinguish different distributions in butters of the same water content but with different manufacturing techniques. Differences in the distributions of water droplets were also obtained when comparing butters made by the same manufacturing technique but with different water contents. To confirm the results from PFG-NMR, confocal scanning laser microscopy (CSLM) was chosen to determine the droplet size distributions and the moisture contents of samples. Comparison between PFG-NMR and CSLM shows limitations in the latter techniques and its uses are limited

Sonic Gradient Index Lens for Aqueous Applications

We study the acoustic scattering properties of a phononic crystal designed to behave as a gradient index lens in water, both experimentally and theoretically. The gradient index lens is designed using a square lattice of stainless-steel cylinders based on a multiple scattering approach in the homogenization limit. We experimentally demonstrate that the lens follows the graded index equations derived for optics by mapping the pressure intensity generated from a spherical source at 20 kHz. We find good agreement between the experimental result and theoretical modeling based on multiple scattering theory.Comment: 10 pages, 4 figure