Shortness ratios, viscosities

The rheological data and printability results for the six inks are shown in Table IV and the emulsification curves in Figure 5. To facilitate comparisons, viscosity, yield and shortness ratio (yield stress divided by viscosity) are also shown in bar chart form, Figures 6 through 8. 

The data shows that the second member of each of the three pairs is better in dot resolution and print-ability than the first member. For example, ink A-3 with a rating of 8 was improved over ink A-l with a rating of 7. The dry inks were of roughly equal tack and shortness ratio but the A-3 emulsion was much shorter than the A-l emulsion. This factor plus the higher viscosity of A-3 is the probable reason for the improvement in dot resolution. In series "B", a similar trend was observed with emulsified ink B-5 being shorter than B-l and also of better dot resolution. 

The anion used to prepare the metal soap determines to a large extent whether it will meet fundamental requirements, which can be summed up as follows solubihty and stabiUty ia various kiads of vehicles (this excludes the use of short-chain acids) good storage stabiUty low viscosity, making handling the material easier optimal catalytic effect and best cost/performance ratio. 

To achieve the desired cast density for Octol of 1.8g/cc it is necessary that the ratio of HMX TNT be 3 1. However, at this ratio the apparent viscosity, or efflux, is strongly dependent on the polymorphic variety of HMX used and on its particle size distribution. In the initial pilot production of Octol (Ref 3) it was found that for the desired efflux of < 15 sec, 60—70% of the solid HMX must consist of the beta-polymorph having particle diameters in the range of 500—800 microns. Such precise control of particle size was not possible at that time and early Octol casts were made at approximately 50 secs efflux. The economical production of Octol with a satisfactorily short efflux time continues to present a problem in loading shells with this expl (Refs 4, 11 29)... 

DMSO and water form a solution with nonideal behavior, meaning that the properties of the solution are not predicted from the properties of the individual components adjusted for the molar ratios of the components. The strong H-bonding interaction between water and DMSO is nonideal and is the primary driver for the very hygroscopic behavior of DMSO. Even short exposure of DMSO to humid air results in significant water uptake. Water and DMSO nonideal behavior results in an increase in viscosity on mixing due to the extensive H-bond network. 

An attempt has been made to answer the following questions. What is the relation between r)s(t) and (r) at short times Does the ratio between the two retain a Stokes-like value at all times And how does the relation behave as a function of frequency The analysis seems to suggest that if one includes only the binary interaction in the calculation of the time scale of the short-time dynamics, both viscosity and friction exhibits nearly the same time scale. When the triplet dynamics is included, both the responses become slower with the viscosity being affected more than the friction. The time scale of both the responses axe of the order of 100 fs. It is shown that both the frequency-dependent viscosity and the friction exhibit a clear bimodal dynamics. 

Comminution also may be used to examine the stability of dispersed phases such as oil droplets. Depending on the viscosity of the product one simply mixes it or breaks it up in a solvent (usually water but, for example, use fresh soybean oil for chocolate), a buffer or the appropriate dyes (below). For instance, we mix easily dispersible foods (cream cheese, ice cream mix or tablespreads) with dyes on slides in a ratio of about 1 1 before examination. Where the dye is a diachrome (that is, highly colored) or is fluorescent in the absence of the substrate (for example, Acridine Orange) some attempt must be made to remove excess, uncomplexed dye molecules which might confound the interpretation. This can be done by reduction of the dye concentration or by making the preparation thinner. The advantage of these simple techniques is that a battery of microchemical tests to identify protein, lipid and carbohydrate can be completed on multiple samples in a very short time period. 

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