Gelling test

Before jams or jellies in which gelling aids (excepting agar agar) have been used are put into the jars, it is advisable to carry out a gelling test. This makes sure that the mixture really does gel when it goes cold. 

The pot is usually taken off the hot-plate and a few drops of the still-hoiling hot mixture are dripped on to a plate. If the mixture sets after cooling, the filling of jars is started. In order to speed up cooling, the plate can be cooled in a refrigerator beforehand. 

If the drops do not set, boiling must be continued. The maximum boiling time of about 15 min should not be exceeded, otherwise the added pectin loses its gelling power. 

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As soon as manufacture is completed and a successful gelling test has been performed, the jars that have been prepared must be filled with the hot mixture. Any foam produced during boiling is removed with a skimmer before the jars are filled. 

Uses, (see also under Perchlorate Propellants and Explosives). It is used in pyrotechnics to impart a bright red color to flames (Ref 3). A gel was made from 50g of Sr perchlorate, lOOg of me ale, and 4.6g of Carbopol 940 gelling agent. Five g of this gel burned for 10 mins with an intense red flame (Ref 11). A 66/34 mixt of Sr perchlorate/powd Al was tested as a photo-flash compn for both sea level and high altitude use (Ref 8). Another mixt of 50ml of me... 

This test is based on a preselected amplitude for the applied strain (y) at a constant frequency (f) and a constant temperature (T). The method can be applied to test the stability of substances with temporary physical changes of structure or the course of chemical reactions like gelling at a given temperature. Again the pectin sols are filled into the measuring system... 

Certainly the optimal techniques depend on the type of reservoir. Reports that compare the techniques in a related environment are available. In the Kansas Hugoton field (Mesa Limited Partnership), several hydraulic fracturing methods were tested [403]. A method in which a complexed gelled water fracture was applied was the most successful when compared with a foam technique and with older and simpler techniques. The study covers some 56 wells where such techniques were applied. 

Typically, a binary system was selected as the base component of the recipe and the addition of polyelectrolytes to either side (core or receiving bath) was tested to evaluate the change in the capsule properties. The 33 successful multicomponent membrane systems are presented in Table 1. The components of the core material side (21 different chemical compositions) are listed in the first column, while the receiving bath components (20 different chemical compositions) are listed in the second column. With the exception of xanthan and CMC, the first polymer listed on the core side are gelling polymers which form beads with the appropriate ionotropic cation (salt). CMC can also be gelled by ions (alum), although they are considered to be non-compatible for cellular applications. The cations were tested both sequentially, usually with ionotropic cation first, and simultaneously. Walled capsules with adequate mechanical properties were often obtained through the simultaneous application of two polycations. Such a... 

Preparative Photolysis. The preparative photolysis of an aqueous solution (pH=8.5) of AETSAPPE (2.5 M) was conducted in a 1-inch diameter quartz test tube in a Rayonet Reactor (Southern New England Radiation Co.) fitted with 254 nm lamps. Within two hours the solution gelled and the reaction was terminated. Upon acidification the solution cleared, and the product could be re-precipitated by addition of base. This indicates loss of the thiosulfate functionality. The product was dissolved in dilute HC1, precipitated with acetone, and filtered. This process was repeated three times, and the final precipitate was washed with water. The product (20 to 30 mg) was dried in vacuo for 24 hours and stored in a dessicator until use. Comparison of the13 C NMR spectrum of the product with the starting AETSAPPE 13C NMR spectrum clearly shows that the thiosulfate methylene peak shifted upfield, from 39 ppm to 35 ppm. The complete 13 C NMR and IR analysis of the product were consistent with the disulfide product. Further, elemental analysis of the product confirmed that the product was the desired disulfide product 2-amino (2-hydroxy 3-(phenyl ether) propyl) ethyl disulfide (AHPEPED) Expected C 58.39, H 7.08, N 6.20, S 14.18 actual C 58.26, H 7.22, N 6.06, S 14.28. 

The efficacy of high-pressure jet washout of agent and gelled agent from M55 sheared pieces must be tested. 

Membranes cast from THF-formamide, dried for 200 seconds in room temperature air, and gelled for one hour, were tested for desalination performance. The results are listed in Table VIII. The best results were obtained with membranes cast from AO 60 and 70 30 THF-formamide and gelled in isopropyl alcohol (IPA)-see discussion below concerning gelation media. Of these two systems the AO 60 is superior. This... 

Failure of sensitive filtration tests such as ASTM D-2276, Particulate Contamination in Aviation Fuel by Line Sampling, can be due to caustic neutralized corrosion inhibitor salts. Sodium or calcium salts of dimer-trimer fatty acid corrosion inhibitors are gel-like in character. Filtration of jet fuel containing gelled corrosion inhibitor will be impeded due to plugging of fuel filter media by the inhibitor gel. This slowdown of filtration can result in failure of jet fuel to pass this critical performance test. 

If shearing has destroyed the loosely formed wax lattice network of gelled crude oil so that the oil flows below its natural pour point, heating can restore the oil to its original pour point. By heating the crude oil to temperatures 20°F to 30°F (11.1 °C to 16.7°C) above the cloud point, waxes can be melted, solubilized and redistributed into the oil. When the pour point is then determined for this heated oil, the result obtained may be higher than the result obtained for the same oil which was not heated prior to pour point testing. All wax must be melted and solubilized into... 

Microscopy). Different conditions of gelling and drying the precursor were tested, and the corresponding pore size distributions of the materials so obtained were evaluated. 

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