Initial weights

Polyquinolines have also been obtained by a post-polymerization thermal treatment of poly(enamino nitriles) (93). The resulting polymers show excellent thermal stabiUty, with initial weight losses occurring between 500 and 600°C in air (tga) under nitrogen, initial weight loss occurs at about 600°C and there is a 20% weight loss up to 800°C. 

Cancel initial weight alarm and remain at controls... 

Check tanker while filling Check omitted (Cl) Tanker not monitored while filling On initial weight alarm Alarm will alert operator if correctly set. Equipment fault, e g.,leaks not detected early and remedial action delayed... 

Cancel final weight alarm Operation omitted (08) Final weight alarm taken as initial weight alarm No recovery Tanker overfills... 

Step 1 Initialize weights Wi(t = 0) to be small random values and choose the threshold r. 

Compound Initial mixture, mol Final temperature of process, °C Product weight at end of process, % initial weight... 

Thermogravimetry may be used to determine the composition of binary mixtures. If each component possesses a characteristic unique pyrolysis curve, then a resultant curve for the mixture will afford a basis for the determination of its composition. In such an automatic gravimetric determination the initial weight of the sample need not be known. A simple example is given by the automatic determination of a mixture of calcium and strontium as their carbonates. 

Figure 8. Overall conversion vs. time, and polymer composition, styrene concentration in the particles, and MMA concentration in the particles vs. overall conversion for the data of Nomura and Fujita (12.). Initial weight ratio (MMA/Total monomer) = 0.5.

Copolymerizations were performed at 70 C using an ampoule technique similar to that used for MMA. Monomers were purified by distillation. Most of the runs had an initial weight fraction styrene of 0.767 and 1.45 mole % AIBN initiator. Also utilized is one run using 0.235 wt. fraction styrene (0.350 mole % AIBN) and one at 0.557 (1.45 mole % AIBN). Gruber and Knell (10) used both the former compositions. The latter one is the calculated azeotropic composition using their values of the reactivity ratios. 

Results. Various solvent mixtures were tested for extraction efficiency. The test sample was a bone-dry sediment reference material containing 24.6 ppm of Arochlor 1242. This reference material is a real sediment from New Bedford Harbor which was homogenized and carefully assayed for PCB s by the Cincinnati EPA facility. Figure 3 shows recovery of 1242 using (1) hexane alone, (2) hexane and water (1 1), (3) hexane, water, and ethyl ether, (4) ethyl ether and water, (5) ethyl ether, water, and methanol, (6) methanol and hexane (1 1), and (7) water, methanol, and hexane (1 4 5). This last combination appears to give the best recovery. When added in this order to a dry sample, the effect of the water is to wet the sample, thus permitting extraction by methanol. The extracted PCB is partitioned almost exclusively into the hexane from the aqueous methanol. Final recovery is calculated from initial weight and hexane volume. 

The curve consists or two parts, a fast initial weight increase followed by a slow weight increase. The interpretation is as follows. First a fast surface oxidation takes place. From these data the dispersion should be calculated. As the rate becomes lower, oxidation of the atoms below the surface occurs. This does not give direct information on the di.spersion but rather on the kinetics of the bulk oxidation of the Cu particles. 

Initialize the weights of all units (in a (pxc) matrix W) with a fixed value. The parameter p is the length of the weight vector and c is the total number of units. Usually the fixed value is used for the initial weights, such that the length of the weight vector is scaled to unity. 

All copolymers were prepared by solution polymerization, under adiabatic conditions, giving at least 99.9% conversions. The polymer gels were granulated and then dried at 90 °C to a residual water content of 10 to 12%. The active polymer content of each sample was calculated from the initial weight of the comonomers and the weight of the dried gel. Hydrolysis of the polymers was determined by conductometric titration to be less than 0.2% of the acrylamide charge. The molecular weight of the polymers was 8-10 million as determined by intrinsic viscosity measurements. 

The result of training a two-dimensional SOM with a set of angles in t e range to data used for Figure 3.14 and Figure 3.15 are identical. The same geometry was use on occasion, but with two different sets of random initial weights. 

Each node is drawn at a position defined by its two weights, interpreted as an x- and a y-coordinate, respectively. Connecting lines are then drawn to join nodes that are next to each other in the SOM lattice. Thus, if the first and second SOM nodes, with lattice positions [0,0] and [0,1], have initial weights (0.71,0.06) and (0.98,0.88), points are drawn at (x = 0.71, y = 0.06) and (x = 0.98, y = 0.88) and connected with a line. The points occupy the available space defined by the range of x and y coordinates. Because the data points are positioned at random within a 1 x 1 square, the network nodes are initially spread randomly across that same space. 

A SOM trained on the same dataset as the SOM shown in Figure 3.25 and Figure 3.26, but starting from a different random set of initial weights. 

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