Cold stabilization procedures

Care must be taken when fining a sparkling wine with bentonite in order to preserve its foaming properties. Excessive use of bentonite for the fining of sparkling wine cuv es can produce a finished product that has a large bubble size and a poor bubble stability as a result of a reduction in both protein and peptide contents. Cold stabilization procedures cause both a precipitation of potassium bitartrate crystals as well as proteins because of the downward shift in pH. This precipitation of proteins... 

Refrigeration. At least one major winery minimizes the amount of wine movement necessary by cold stabilizing the wine at 28° F (-2.22° C) in a jacketed tank until laboratory evaluation shows the wine to be cold stable. The wine is allowed to warm to 30°-32° F (-1. ll°-0° C), then a slurry of bentonite, which has been soaked at least overnight in hot water, is added to the wine at the level prescribed by the previously described laboratory procedure. When the bentonite has settled to the bottom of the tank, the wine is racked off the bentonite lees and filtered to a holding tank. The wine is now ready for polish filtration and bottling. 

STABILIZER DR-9 may be used to stabilize peroxide bleach baths for cellulosic fibers alone or in blends, in soft or hard water, in hot or cold bleach procedures, and on yarns or white or yarn-dyed fabrics. 

The spontaneous crystallization temperature of each sample of treated wine (Table 1.16) was also determined using the same procedure. Examination of the results shows that a wine filtered on a 10 Da Millipore membrane, i.e. a wine from which all the colloids have been removed, has the lowest value for the supersaturation field (Tsat - Tcso), closest to that of the model dilute alcohol solution. Therefore, the difference between the results for this sample and the higher values of the supersaturation fields of fined samples define the effect of the protective colloids. It is interesting to note that the sample treated with metatartaric acid had the widest supersaturation field, and cold stabilization was completely ineffective in this case. This clearly demonstrates the inhibiting effect this polymer has on crystallization and, therefore, its stabilizing effect on wine (Section 1.7.6). Stabilization by this method, however, is not permanent. 

It can be seen from the previous description that the design of both a cold-feed stabilizer and a stabilizer with reflux is a rather complex and involved procedure. Distillation computer simulations are available that can be used to optimize the design of any stabilizer if the properties of the feed stream and desired vapor pressure of the bottoms product are known. Cases should be run of both a cold-feed stabilizer and one with reflux before a selection is made. Because of the large number of calculations required, it is not advisable to use hand calculation techniques to design a distillation process. There is too much opportunity for computational eiToi. 

Collection of air samples in stainless steel canisters whose surfaces have been passivated is another common collection technique for VOCs. (Aluminum has also been used but the stability of polar organics in them is poor Gholson et al., 1990.) Indeed, this method is used not only for sampling air but in medical applications as well, where they have been used to sample organics in a single breath (Pleil and Lindstrom, 1995). Passivation of the canisters is often carried out using a process called SUMMA and hence referred to as SUMMA canisters. The canisters also have to be thoroughly cleaned before use an example of one such procedure is described by Blake et al. (1994). The sample is then typically preconcentrated by transfer to a cold trap prior to injection onto the GC column (e.g., see Blake et al., 1994). 

Other New Methods. Because the values obtained are dependent on the conditions of measurement, standard test procedures are under review by ISO for determination of cold-water solubility of water-soluble dyes determination of the solubility and solution stability of waler-soluhle dyes and determination of the electrolyte stability of reactive dyes. 

In order to try to stabilize the properties of the support, a calcination was carried out. Two different procedures were followed. In the first one, the cold solid was placed in a fiimace at 100°C and immediately heated up to 200°C (50°C/h). The temperature was kept constant at this level for 2 hours and was then risen at 350°C (100°C/h) and stabilised for 3 hours. The furnace was then switched off and allowed to cool down to ambient temperature overnight. The second procedure consisted in putting the cold solid in the furnace directly at 200°C and then in following the same thermal treatment as above. 

The stability of BaPbOs and its effect on the performance of a battery over its useful life have also been investigated for automotive applications [12-14]. A conventional automotive cell with 1 wt.% BaPbOs in the positive paste and a control cell were formed by means of a standard high-rate formation procedure. Cell performance was then evaluated by means of a standard Battery Council International (BCI) sequence of reserve capacity and cold-cranking tests. The cell containing BaPbOs formed three times faster with 12% less input capacity. The BCI test results of the two cells were comparable. 

Vinyl trifluoroacetate (VTFA) monomer was readily prepared by the vinyl-ation of trifluoroacetic acid. Purification was difficult because of the very similar boiling points of the monomer (39 °C) and trifluoroacetic anhydride (38-39 °C). An effective procedure involved the titration of the anhydride with water to form the more readily separable carboxylic acid (b.p. is 72 °C). By using this approach, VTFA monomer of very high purity (>99.8%) has been routinely prepared. Monomer stability was excellent if cold, dark, dry conditions were maintained. 

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