Homogenisation methods

For other models of flow of electrolytes through porous media the reader is referred to [2], [5], [6]. To take into account FCD (fixed charge density) one has to impose additional condition on the interface T (w) and the electroneutrality condition. A challenging problem is to use homogenisation methods for the case of finitely deformable skeleton, even hyperelastic. The permeability would then necessarily depend on strains. Such a dependence (nonlinear) is important even for small strain, cf. [7]. It is also important to include ion channels [8]. 

Homogenisation method none mechanical or ultrasonic none... 

There are clearly opportunities for further research in this area, particularly in relating the homogenisation methods to the upscaling and multiscale methods. The results of [23] that show the need for dual permeability models as effective media for 2-phase flow are particularly interesting. Dual permeability behaviour has been observed in the field, [35], in apparently unfractured reservoirs. 

Ladle metallurgy, the treatment of Hquid steel in the ladle, is a field in which several new processes, or new combinations of old processes, continue to be developed (19,20). The objectives often include one or more of the following on a given heat more efficient methods for alloy additions and control of final chemistry improved temperature and composition homogenisation inclusion flotation desulfurization and dephosphorization sulfide and oxide shape control and vacuum degassing, especially for hydrogen and carbon monoxide to make interstitial-free (IF) steels. Electric arcs are normally used to raise the temperature of the Hquid metal (ladle arc furnace). 

Protein concentration can be determined using a method introduced by Bradford,4 which utilises Pierce reagent 23200 (Piece Chemical Company, Rockford, IL, USA) in combination with an acidic Coomassie Brilliant Blue G-250 solution to absorb at 595 nm when the reagent binds to the protein. A 20 mg/1 bovine serum albumin (Piece Chemical Company, Rockford, IL, USA) solution will be used to prepare a standard calibration curve for determination of protein concentration. The sample for analysis of SCP is initially homogenised or vibrated in a sonic system to break down the cell walls. 

Flotation is another method to remove solid (cells) from fermentation broth, using air bubbles to float protein. We may use different kinds of high shear-force devices to make homogeneous solutions for liberating intracellular enzymes. Figure 7.8 shows several types of impeller for homogenisation. 

Preparation of AIR and extraction of pectic fractions For the preparation of the alcohol-insoluble residue (AIR) the apples were peeled, cut into small pieces and boiled in 96% ethanol for lOmin. After this enzyme inactivation step, the sample material was blended, homogenised and filtered through a G3 sintered glass niter funnel. The residue was washed with 96% ethanol, followed by acetone and diethyl-ether, dried overnight at 40°C under vacuum and stored at -20°C in the dark. Portions of about lOg of AIR were fractionated according to the method of Selvendran et al. [10] as shown in figure 1. 

Pretreatment of biological samples for surfactant analysis is usually straightforward and includes either homogenising with anhydrous sodium sulphate or freeze-drying. Below, the sample treatment methods for extraction and clean-up of non-ionic and anionic surfactants in biota that have been encountered in the literature are reviewed. 

Adsorption was performed using the batch method by placing a constant mass (200 mg) of the powdered adsorbent in Erlenmeyer flasks. The solid was sonicated with an appropriate amount of water (30 cm3) in order to homogenise and decrease the particle size. Surfactant solution (20 cm3) was then added to produce a final concentration ranging from one order of magnitude below the respective critical micelle concentration (CMC) to a concentration about three times higher than the CMC. 

During shrinkage, the materials involved remain with elastic deformation. The method is well suited for high-strength brittle materials (e.g., Fig. 4.1-44c corrosion-resistant high-strength titanium alloys up to 1500 bar for homogenisation pumps). 

Samples can be dried and moisture content determined by special methods [19] and soil samples can be homogenised with a blender or a similar device. 

Kovatcheva [12] has described a method using an automated amino acid analyser for the determination of S-methylmethionine in cabbage, kohlrabi, celery and sweetcorn. The plant sample is first homogenised with 0.1N hy-... 

Semi- or non-volatile chlorinated organic compounds, hexachlorobutadiene, hexachlorocyclopentadiene, octa, chlorocyclopentadiene, hexachlorobenzene Extractions performed on homogeniser using hexane, hexane -benzene or hexane -toluene Purge and trap method, recoveries 88-125% 0.1 PPb [189]... 

Dufour, E., Riaublanc, A. 1997a. Potentiality of spectroscopic methods for the characterisation of dairy products. I. Front-face fluorescence study of raw, heated and homogenised milks. Lait 77, 657-670. 

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