October 1955
-
INDUSTRIAL AND ENGINEERING CHEMISTRY
available results of the temperature-reaction test on the polymer containing 12.4% acrylic acid, it appears that both butadieneacrylic acid copolymers will crystallize more readily than either GR-S 1000 or the Perbunans. The difference between TR-10 and TR-70 is a measure of crystallization; the higher the value, the greater is the tendency to crystallize. For GR-S 1000 the difference was 17, while for the 12.4% acrylic acid copolymer the difference was 37. Past experience has shown that the slope of the Gehman curve will almost coincide with the TR test data. The greater the difference between Tz and Tloo, the greater the difference between TR-10 and TR-70, and consequently the more a polymer will crystallize. EXPERIMENTAL
Polymerization Techniques. Most of the polymerizations were carried out in emulsion using 190.0 parts of oxygen-free water, 5 parts of Triton X-301 (Rohm & Haas Co.), 0.15 to 0.30 part of azobisisobutyronitrile, 0.10 to 0.50 part of modifier, and 100 parts (20 grams) of monomer mixture. The polymerizations, isolations of products, and determinations of solubility and viscosity were carried out by the standard procedures (6). I n the polymerizations with acrylic acid ratios above 85/15 it was found advantageous to include 0.5 part of Daxad 11 (Dewey and Almy Chemical Co.) in this recipe. The experiments with the Marvel-Meinhardt recipe were carried out essentially as was done with the lesser amounts of acrylic acid (6). I n some cases delayed injection of acrylic acid was tried, but this did not improve reproducibility. The emulsion polymerizations using MP-635-S and azobisisobutyronitrile were carried out in the same recipe as those with Triton X-301, but 0.2 ml. of the emulsifier solution was used to prepare the reaction mixture.
2223
Evaluation Samples. Evaluation sample 324 was prepared from a charge ratio of 85/15 butadiene-acrylic acid in the recipe described above and sample 333 was prepared from a 75/25 charge ratio. A number of standard 20-gram charges were polymerized, the latices were mixed, and the polymer was precipitated in one lot. The samples are described in Table 111. The essential information concerning the properties of the vulcanized polymers is summarized in Tables IV to VI. The recipe used in compounding consisted of 100 parts of polymer, 40 parts of E P C black, 5 parts of zinc oxide, 2 parts of sulfur, and 1.75 parts of benzothiazyl disulfide. Brown and Gibbs (5) reported a t the Gordon Conference on Elastomers in August 1954 and a t CHEMICAL SOCIETY on superior the fall meeting of the AMERICAN results obtained with similar types of polymers compounded in special recipes using metal oxides or amines as cross-linking agents rather than sulfur. The authors, however, have limited their work to the above-mentioned conventional type of recipe. LITERATURE CITED
(1) Am. SOC.Testing hlaterials, Philadelphia, Method D 471-51T. (2) Ihid., D 1053-51T.
(3) Brown, H. P., and Gibbs, C. F., IND.ENG.CHEM.,in press. Frank, C. E., Kraus, G., and Haefner, 4.J., J . Polvmer Sci., 10,
(4)
441 (1953). (5) Garvey, B. S.,Jr., IXD. Eh'a. CHEX, 34, 1320 (1942). (6) Marvel, C. S.,Fukuto, T. R., Berry, J. W., Taft, W. K., and Labbe, B. G., J. Polymer Sci., 8, 599 (1952). (7) Rlarvel, C. S., and Meinhardt, N. A , , Ihid., 6 , 733 (1951). RECEIVED for review February 9 , 1955. ACCEPTED July 7, 1955. Work performed as a part of the research project sponsored by the Federal Facilities Corp., Office of Synthetic Rubber, in connection with the government synthetic rubber program.
Solubility of Air in Brine at High Pressures At 1000 to 3500 Pounds per Square Inch Gage and at 25" to 65" C. WILLIAM C. EICHELBERGER Research Laboratory, Sohay Process Division, Allied Chemical & Dye Corp., Syracuse, N . Y .
D
ATA on the solubility of air in saturated rock salt solutions under high pressures were desirable in certain process work. Such data were not found in the literature; yet an appreciable amount of air is known t o dissolve in brine a t pressures of 1000 pounds per square inch gage or more. Hence, solubilities in the requisite regions were determined. Three major factors affect this solubility-pressure, temperature, and salt concentration. Each of these variables was studied between definite limits and the results are recorded here. APPARATUS
The literature contains several references (4-8) t o types of apparatus suitable for determining the solubility of gases in liquids under pressure. Wiebe, Gaddy, and Heins (5-7) and Saddington and Krase ( 4 ) used a flow method for saturating the liquid with gas. Wiebe and Tremearne (8) charged a vessel with liquid and gas up t o pressure and rocked the vessel on a trunnion support in B thermostat. An adaptation of the latter was used in the present work. The solubility apparatus is shown diagrammatically in Figure 1 (not drawn t o scale).
The vessel was constructed from 21/2-inch extra heavy 18-8 stainless steel pipe, 2.875 inches in outside diameter and 2.323 inches in inside diameter, with caps 1 inch thick, welded into each end. I t s over-all length was 14 inches and it contained 794 ml. Into each end was welded standard 3/8-inch high pressure tubing, '/8 inch in inside diameter, bent approximately as shown in Figure 1. The ends of the tubing were threaded to take standard high pressure fittings. T o one tube was attached a calibrated 0- to 5000-pound pressure gage with 50-pound subdivisions. T o the other tube was attached a t A a high pressure needle valve for admitting to and removing from the vessel all components of the solution. This pressure vessel with attached gage and valve was mounted on a trunnion assembly in a water thermostat and was rocked back and forth through an arc of about 90" by a motor-driven cam a t about 20 cycles per minute. The temperature of the thermostat was held constant t o better than =t=0.loC. by the usual automatic controls. The apparatus for analyzing the samples was of the buret type and was a simplified adaptation of that of Wiebe, Gaddy, and Heins (5, Figure 2). It was fitted with compensator tube and manometer and surrounded with a water jacket. The solution
INDUSTRIAL AND ENGINEERING CHEMISTRY
2224
AIR DISSOLVED IN BRINE may affect efficient operating conditions
.. .in forcing or pumping brine from wells . . . in process work using brine sample was admitted to the top of the buret, through a three-way stopcock, displacing mercury from the buret into a leveling bulb. MATERIALS
Compressed air was obtained in standard 200-cu.-foot cylinders a t a pressure of 2000 pounds per square inch gage, and was used directly therefrom. Raw brine from the Syracuse plant of Solvay Process Division was used as it came into the plant, and was diluted to the desired concentration wit’h distilled water. Nitrogen for a few experiments was obtained directly from standard cylinders. TECHNIQUE
The pressure vessel was charged in two different ways, depending upon whether the experiment was to be run below or above 2000 pounds per square inch gage. For Pressures to 2000 Pounds per Square Inch Gage. The vessel was evacuated a-ith water suction connected a t A , Figure 1. Then the requisite volume of brine (usually 300 ml.) was sucked into the vessel by connecting a t A a nipple and rubber tubing which led into the measured volume of brine. Bfterwards the nipple a t A was removed and the compressed air cylinder was connected there through suitable fittings and a/,,-inch high pressure tubing. Finally, air was admitted to the vessel up to the desired pressure. For Pressures above 2000 Pounds per Square Inch Gage. Air was admitted to the pressure vessel first, through A , up t o a predetermined value or to cylinder pressure. Then a WatsonStillman hand-operated hydraulic pressure pump was connected at A , through fittings and a/,,-inch high pressure stainless steel tubing, and the brine solution was pumped from a reservoir into the vessel. Xot only did this force the brine into the vessel but it also compressed the air therein to the desired pressure. A rough calculation of the initial air pressure was made, so that the proper amount of brine would be pumped into the vessel. The time of agitation of the solution vias varied from 1.5hours to overnight. Little difference could be noticed in the precision
Vol. 47,No. 10
of the results over this wide time range, except possibly a t the highest pressure. Hence, 2 to 3 hours of agitation were considered adequate for the present work, except for the mixtures a t 3500 pounds per square inch gage, which were run for about 5 hours. At the end of this period the agitation was stopped and the pressure vessel was left stationary in the thermostat for a t least, 30 minutes t o allow any emulsion in the solution to “break.” Then the solution was ready t o be sampled. ANALYSES
Samples of the solution were taken as follows: The pressure vessel was tilted a t an angle, as shown in Figure 1, such that only solution could be withdrawn. A I-mm. capillary glass tube was connected to a fitting a t valve A and t o the stopcock on top of the gas buret. When A was opened, solution ran out of the vessel, through the capillary tube, and to the buret. Meanwhile, pressure on the solution sample was reduced to atmospheric on the outlet side of A and dissolved gas started to come out of solution. This caused alternate slugs of gas and brine to flow in discrete portions through the small capillary tube from A to the gas buret. After all lines had been purged, the solution was run into the buret and the requisite sample was collected. The pressure in the vessel was read before and after each sample was taken. The size of sample taken was so chosen that the over-all pressure drop on the vessel was normally less than 4% of its absolute value. When samples were removed, the pressure in the vessel dropped as expected, owing to the volume removed. Then it rose slightly during the next minute or two, owing to a combination of effects, the main one being the release of air from solution to establish a new but slightly lower solubility a t the somewhat lower pressure. Once the sample was in the gas buret and all stopcocks were closed, the mercury leveling bulb on the buret was lowered and raised t o aid in disengaging the gas from solution. ilfter tem-
1-
I
I
I
I
I
I
I
1
2.4
W2p-
/
I
-
m
)&2.0 D
a
1.0
0
K
0
r
1.6
c?
1.4
-
t’ L e o UI
-w
1.0
-
2
K
L cd E BOA a m
io.8 I E
0.8
z
do.2
PRESSURE. PSI0
Figure 2.
Solubility of air in brine a t high pressures at 65” C. Pure water Brine, g./ 1 . B. 30 C. 97 D. 197 E. 250 F. 309 A.
Figure 1.
Solubility apparatus
*
October 1955
INDUSTRIAL AND ENGINEERING CHEMISTRY Table I.
Expt. NO.
Brine Concn., G./L. SaCl 29.5 29.5 30.7 30.8
39 40 41 42 Av.
-4T.
5 6
7 37 38 .IT.
Pressure, Lb./Sq. Inch
Agitation, Hours
M1. Air MI. Brine
Expt.
.4t 65' C. 3460 2480 1645 1010
2.75 2.0 2.5 2.5
1.94 1.50 1.07 0.69
59 60 61 62
1430 1020 3530 2960 2530 1990
2.2 1.83 2.0 2.1 2.0 2.5
0.70 0.51 1.44 1.28 1.15 0.91
67 68 69 70 71 72 73
0.43 0.32 0.45 0.32 0.55 0.46 0.91 0.70
74 75 76 77 78 79
16.0
4.0
16.0 4.8 16.0 5.1 2.0 2.0
Agitation, Hours
1\11. Air 1\11. Brine
At 450 C. 1900 1000 3500 2760
2.4 2.5 2.5 2.0
1.36 0.77 2.24 1.85
1890 1010 3500 2750 3560 3410 3000
2.75 2.5 2.0 3.0 6.0 1.75 1.5
0.94 0.55 1.58 1.28 1.49 1.48 1.37
3530 2730 1750 1025 3480 2940
3.0 2.5 1.75 2.5 2.5 2.5
0.94 0.82 0.55 0.33 0.95 0.84
1740 1025 3430 2830 3530 2430
2.5 2.5 2.7 2.0 2.5 2.5
0.31 0.21 0.55 0.47 0.55 0.42
30.1 30.1 30.1 29.7 30 98.0 97.4 98.7 98.5 99.9 98.1 98.8 Av.
1420 970 1450 1050 1990 1570 3460 2490
Pressure Lb./Sq. Inhh
98 204.5 203,9 203.0 201.3 192.7 193.3
Av.
203 best value
197 4.0 15.5 5.0 15.3 6.5 15.3 5.0 6.5 15.4 18.5 5.0
8 9 IO
11 12 18 19 20 21 22 23 .kv.
Brine Concn.,
G./L. NaCl
No.
Av.
97 192.3 189.4 192.6 191.9 198.9 203.2 202.9 202.4
2 3 4
Solubility of Air in Brine a t High Pressures
30 96.2 96.4 100.0 99.5 96.7 95.3
31 32 13 34 35 36
2225
0135 0.41 0.34 0.63 0.55 0.71 0.62 0.56 0.45
Av.
15.4 5.0 15.5 5.2 17.9 6.2 5.5 16.0 4.5 2.2 2.5
304 At 250 30.3 30.5 30.3 30.6 30.4
95 96 97 98 99
250
13 14 15 16 24 25 26 27 28 29 30
304.1 305.3 303.4 302.2 303.4 303.4
80 81 82 83 84 85
0.43
0.33 0.27 0.26 0.19 0.54 0.50 0.54 0.51 0.43 0.34 0.27
Av.
Av.
.Lv. 309
Av.
perature equilibrium was established, pressure was equalized to atmospheric, and the volumes of the liquid and gas in the buret were read. Usually three samples were taken on a given solution and averaged. Most samples had a combined gas and liquid volume of 12 t o 20 ml. Among the corrections which had to be applied to these gas and liquid volumes as read in the buret were the meniscus corrections. The mercury was convex a t the solution-mercury interface and the solution was concave st the solution-gas interface. When large volumes are involved, these meniscus corrections are relatively insignificant; but they are important in the present case of small volumes, The correction a t the mercury-water meniscus was computed (S, Table I ) to be 0.10 ml., to be added to the volume of liquid as read. The volume of the liquid meniscus a t the liquid-gas interface v a s computed (3,Table 111) t o be 0.18 ml. This value agrees closely with general tables of menisci corrections in physical chemical textbooks. Therefore, the meniscue corrections are 0.18 ml. to be subtracted from the gas volume as read (because of the liquid-gas interface) and 0.18 0.10 = 0.28 ml. to be added to the liquid volume as read (because of the two interfaces involved). Each experiment was run at a chosen brine concentration and a t a pressure attained by one of the two methods described above. After one experiment had been run and sampled, the pressure was usually reduced to a selected value by releasing vapor and/or liquid phase; then another experiment was run on the same charge in the pressure vessel.
Av.
Table 11. Expt. NO.
2.3 2.5 5.0 3.75 2.0
3530 2570 1820 1010
3.0 2.0 3.0 2.0
0.99 0.78 0.59 0.36
1560
2.5 2.0 2.5 2.0 4.5
0.29 0.21 0.48 0.39 0.55
0.95 0.66
1.77 1.53 1.23
201 305.4 304.4 304.1 304.4 305.6
105 106 107 108 109
1600 1030 3500 2950 2245
'
99 200.5 199.8 203.2 201.4
110 111 112 113
2.65 1.42 0.94 2.34 1.78
4.0 2.5 2.5 3.0 2.0
30 98 2 98.3 99.8 99.8 99.9
100 101 102 103 104
c.
3530 1650 1015 2970 2195
1010
2930 2235 3490
305
Solubility of Air in Water at High Pressures Pressure. Lb./Sq. Inch
Agitation, Hours
M1.Water .4ir M1.
At 65' C. 2.75 2.5 3.0 2.5 2.25 2.5
3430 2430 1645 970 1935 1475
2.27 1.73 1.27 0.78 1.42 1.14
At 45' C. 2.0 1.75 2.0 2.0 3.0 2 5 3.0 2.0
+
At 2 5 O C. 114 115 116 117
2.75 2.0 3.5 4.25
1.83 1.15 2.98 2.58
2226
INDUSTRIAL AND ENGINEERING CHEMISTRY
i
o
.
Vol. 47, No. 10
o PRESSURE,
Figure 4. 0.0
Figure 3.
I SO0
I IO00
I
I
I
1500 2000 2500 PRESSURE, PSI0
I
SO00
Pure water Brine, u./l.
B.
30
D. E.
203 304
C.
98
EXPERIMENTAL DATA
i
'
Solubility of air in brine at high pressures a t 25" C.
I
5500
Solubility of air i n brine at high pressures a t 45' C. A.
i PSI0
A.
Pure water Brine, g./l.
B. C.
30 99 201 305
D. E.
may be expected to show a minimum solubility. The flattening of the solubility curves around 65" would indicate that they are approaching such a minimum. Nine experiments were run a t 55' a t a total of only three brine concentrations between 2800 and 3500 pounds per square inch gage. The results are given in Table IV and are incorporated in the temperature plots in Figures 5, 6, and 8. They are seen $0 fall closely in line with the other dsta,
A summary of solubility data in terms of milliliters of air (STP'I, Der . milliliter of brine for each exoeriment is given in Tables I and I1 for the three temperatures, These solubility data were plotted against pressure for each brine concentration a t a given Table 111. Solubility of Air in Brine a t High Pressures temperature in Figures 2 t o 4. Most data lie (Data read from solubility u s . pressure curves of Figures 2 t o 4) Solubility within 2% of the curves drawn. Temperature, C. values were read from these curves a t selected 25 65 45 pressures and at the given concentrations for Brine Brine Brine each temperature and were compiled in Table 111. Pressure, concn., concn., g./l, MI. air c ~ j ~ r lMI. . ~air g,/j, MI. air Lb./Sq. Substantially straight lines were obtained for Inch Gage NaCl ml. brine NaCl ml. brine NaCl ml. brine each temperature when log solubility (Table 111) 1000 0 0.83 0 0.91 0 1.10 was plotted against concentration. 30 0.67 30 0.77 30 0.93 97 0.50 98 0.54 99 0.65 Solubility was plotted against temperature a t 197 0.31 203 0.34 201 0 . 355 ... ... .. ... 250 two brine concentrations and five pressures in 309 0.19 304 0.206 305 0.21 Figures 5 and 6, and a t two pressures and five 1500 0 1.15 0 1.29 0 1.54 brine concentrations in Figures 7 and 8. The 30 1.315 30 0.97 30 0.89 99 98 ::E5 97 curves in these four figures portray the general 203 0.486 201 0.50 E 5 197 250 0.34 ... ... effect of temperature, pressure, and brine con309 0.275 304 0.28 305 0.285 centration on the solubility of air. The general 0 1.64 0 1.96 2000 0 shape of the curves for the more dilute brines 30 1.41 30 1.69 :E 5 30 98 1.00 99 1.13 97 0.94 agrees with those of Wiebe, Gaddy, and Heins (6, 197 0.58 203 0.62 203 0.64 p. 950) for nitrogen in water a t various pressures , . ... .. ... 250 0.45 309 0.36 304 0.355 305 0.36 over this same temperature range, 25' to 65". 2500 0 1.76 0 1.985 0 2 36 These curves of Wiebe and others ( 7 ) , 25" to 30 1.51 30 1.71 30 2.04 IOO", show a minimum around 70". Saddington 98 1.20 99 1.36 97 203 0.75 203 0.77 197 and Krase ( 4 ) plotted curves for the solubility 250 0,55' ... ... 309 0.43 304 0.425 305 0.425 of nitrogen in water from about 50' to 240' C. at several pressures. These solubility curves 3500 0 2.30 0 2.55 0 3.05 2.63 30 1.96 30 2.24 30 show a minimum a t about 75". Bykov ( 1 ) also 97 1.43 98 1.50 99 1.77 203 0.945 203 0.98 0.92 197 found minima in the solubility of gases in dilute ... 250 0.72 ... 304 0.55 3'05 0 55 309 0.545 p o t a s s i u m c h l o r i d e solutions under pressure. Hence, the system studied in the present work
.
:: ;
INDUSTRIAL AND ENGINEERING CHEMISTRY
October 1955
1 '
I
I
I
I
I
2227
I
I
w 111
E
$: :t'
iF O4
-
8- -
-"-
.
c
V
" "
0 E
-
1
O*t
A.
TEMPERATURE ' 0 .
Figure 5.
B.
c.
Solubility of air in brine at high pressures
D. E.
3500 2500 2000 1500 1000
30 grams per liter of brine
Lb./Sq. Inch Gage A. 3500 B. 2500 c. 2000 D. 1500 E. 1000
MATHEMATICAL EQUATIONS FOR SOLUBILITY
-1
E
Figure 7.
Solubility of air in brine at 1000 pounds per square inch gage A.
Table IV.
93 94
P u r e water Brine, G./L.
Solubility of Air i n Brine at High Pressures a t 55" c.
Brine Concn. G./L. NaCl
Expt. NO.
1
Pressure, Lb./Sq. Inch Gage 3490 2700
Agitation, Hours 2.75 2.0
M1. Air ___ MI. Brine
2.07 1.63
Av.
30.6 30.6 30
2930 2280 3480 2640
2.5 2.5 3.0 2.0
1.28 1.05 1.46 1.18
Av.
98.9 98.9 99.6 99.7 99
3480 2855 3530
2.5
0.56 0.47 0.55
Av.
303.1 302.3 304.8 303
89
90
91 92
86 87 88
2.0
4.5
When log solubility was plotted against concentration, t h e data for each pressure fell on substantially straight lines, parallel t o one another a t each temperature, Starting with this relationship, a study was made of the mathematical correlation between the solubility and some, or all, of the variables-namely, concentration, pressure, and temperature. T h e fundamental form of the equation applicable to the data was found by the method suggested by Davis ( 2 ) . Then the method of least squares was applied to the original data of Tables I and 11. It can be shown that the following empirical equations so derived express the solubility of air in brine over the pressure range of 1000 to 3500 pounds per square inch gage, for concentrations from that of pure water t o saturated brine and within the limits of experimental error: At 25" C. log
826
At 48' C. log
545 =
=
0.8087 log P - 0.00243X
-
2.3708 ( 1 )
0.8241 log P - 0.00215X - 2.5130 (2)
-4t 68' C. log Ses = 0.8453 log P - 0.00202X
- 2.6318
(3)
n-here S = solubilityof air as milliliters of air (STP) per milliliter of brine, or as cubic feet of air (STP) per cubic foot of brine; P = pressure, pounds per square inch gage; and X = brine concentration in grams per liter (at atmospheric pressure). An equation for the solubility a t 53", derived from more limited data and applicable only over the pressure range of 2500 t o 3500 pounds per square inch gage and for brine concentrations from 30 grams per liter to saturation, is: Log S5&= 0,7705 log P
- 0.00208X -
2.3580
(4)
SOLUBILITY O F NITROGEN IN WATER
A few experiments were run at 65' C. t o see how well data for the solubility of nitrogen in water obtained in this apparatus check the more precise determinations of Saddington and Krase (4). These data are given in Table V and plotted in Figure 9. Solubility values read from the curves of Saddington and Krase for comparable conditions are plotted in t h e same figure. The agreement with their data is as good as can be expected. Therefore, the data determined herewith can be said t o yield solubility curves which conform generally in shape with those
2228
I N D U S T R I A L A N D E N G I N E E R I N G CHEMISTRY
tu-w-40.0
Vol. 47, No. 10
TEMPERATURE %.
aoo
Figure 8. Solubility of air in brine at 3500 pounds per square inch gage A . Pure water Brine, g./L B. 30
c.
500
I600 PRESSURE,
ID00
eOOO
PSI0
esoo
3ooo
K)
Figure 9. Solubility of nitrogen in water at high pressures a t 65" C. 0. Author's data 8 . Data of Saddington and Krase (4)
98
D . 200 E . 306
reported in the literature for inert gases in aqueous solutions over the temperature, and pressure ranges studied.
Table V. Expt. SQ.
49 50
51 52 53 54 ~~
Solubility of Nitrogen in Water at High Pressures at 65" C. Pressure, Lb./Sq. Inch Gage 1370
2810 2930 1475
2230 1010
Agitation, Hours 2.0 4.0 2.5 2.5 3.0 2.5
MI. Na M1. water 0.91 1.69 1.76 0.97 1.39
0.68
~
ACKNOWLEDGMENT
The author wishea to thank L. J. Beckham, chief of research, Ammonia Section, Nitrogen Division, Allied Chemical & Dye Corp., Hopewell, Va., and those members of that research labora-
tory and machine shop who so kindly assisted in the design and fabrication of this high pressure solubility apparatus. LITERATURE CITED (1) Bykov, M. JI.,Acta Univ. Voronegiensts, 9,S o . 3, 29-58 (1937) (in German). Davis, D , S., "Empirical Equations and Somography," 1st ed., McGraw-Hill, New York, 1943. "International Critical Tables," 1 s t ed., vol. 1, pp. i2-3, McGraw-Hill, New York, 1926. Saddington, A. W., and Krase, PJ. W., J . Am. Chem. Soc.. 56, 353-61 (1934). (5) Wiebe, R.: Gaddy, V. L., and Heins, Conrad, Jr., IXD, ENG. CHEM.,24,823-5 (1932). (6) Ibid., p. 927. (7) Wiebe, R., Gaddy, V. L., and Heins, Conrad, Jr., J . B ~ RChem. . SOL,55, 947-63 (1933). (8) Wiebe, R., and Tremearne, T. H., Ihid., 55, 975-8 (1933).
RBCEIYBD for review January 8, 1965.
ACCEPTEDApril
29, 1955
