Lynne Wong's PhD thesis

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ange of 0.4 to 0.6, the Halsey model up to 0.4, the Caurie I, Caurie II and Oswin models up to 0.6, and the modified GAB model up to 0.95; whereas the GAB, Hailwood-Horrobin and Henderson models fit for the whole range of water activity data. In addition to the above criteria for deciding whether a model is a good fit to the experimental data, Chen and Morey (1989) and Soysal and Öztekin (1999) showed that the residuals (i.e. measured EMC – predicted EMC) could be plotted against the predicted EMC as abscissa. If the residuals were uniformly scattered about the x-axis (independent variable) and showed no systematic distribution or clear pattern in the positive or negative directions of the y-axis (dependent variable residuals), the model showed a good fit to the experimental values. The residual plots for the ten candidate isotherm models were plotted for the experimental EMC data obtained for the nine cane components aged 52 and 36 weeks. A typical plot for stalk fibre aged 52 weeks is shown in Fig 5.11. The whole series of 18 plots is on the CD (file: Fig 5.11.1–5.11.18 Residuals.xls). In this study, the model residual plots have the EMC residuals (measured EMC – predicted EMC) plotted on the y-axis and the predicted EMC on the x-axis; other workers have used measured EMC (Arslan and Toğrul, 2005) on the x-axis, and equilibrium relative humidity (Igathinathane et al., 2005) on the y-axis. The use of either the predicted or the measured EMC on the x-axis has been checked, and it was established that either practice did not affect the eventual randomness or pattern of the residual plot. All the residual plots are examined for randomness (R) or systematic pattern (S), and the results are compiled in Table 5.28. In general, the Halsey and the two Caurie models give the poorest fit to the experimental data; while the residuals of the Bradley, Smith and Oswin models exhibit two distinct regions: at low water activity up to 0.97, a pattern is evident, at high water activity from 0.97 to 0.98, the residual distribution does not have a pattern, but the differences between the predicted EMC and the measured EMC are large, particularly in the case of stalk pith, rind fibre aged 52 weeks, top fibre, dry fibre, green leaf fibre aged 36 weeks and green leaf fines. However, these large differences are no worse than those predicted by the GAB, Hailwood-Horrobin, modified GAB and Henderson models. The residual patterns of these last four models for all the cane components, except dry and green leaf fibre aged 36 weeks at 60 °C, showed a random distribution for the whole range of water activity studied. 211
Table 5.19. Parameters of the sorption isotherm models, coefficient of determination R 2 , mean relative deviation modulus P, and standard errors of the estimate E s for isotherms of stalk fibre aged 52 and 36 weeks at 30, 45, 55 and 60 o C. Stalk fibre Model Parameter 52 weeks 36 weeks 30 o C 45 o C 55 o C 60 o C 30 o C 45 o C 55 o C 60 o C GAB mo 5.43 5.18 3.68 3.22 4.17 3.99 3.54 4.00 b 15.350 6.519 8.583 12.42 27.85 10.40 12.66 5.146 c 0.7817 0.8193 0.8892 0.9140 0.8462 0.8733 0.8886 0.8660 R 2 0.9601 0.9846 0.9949 0.9920 0.9981 0.9899 0.9909 0.9798 P 9.579 6.705 6.099 8.681 2.359 9.083 7.773 5.550 Es 1.874 1.367 0.9519 1.337 0.4523 3.371 1.208 1.663 Hailwood Horrobin b 0.021 0.022 0.014 -0.001 0.006 0.019 0.002 0.041 c 0.143 0.172 0.266 0.336 0.234 0.225 0.301 0.192 d -0.123 -0.158 -0.250 -0.308 -0.204 -0.212 -0.272 -0.199 R 2 0.960 0.985 0.995 0.992 0.998 0.990 0.992 0.980 P 10.37 7.759 5.923 7.857 2.986 5.137 8.152 5.460 Es 1.866 1.330 0.8654 1.257 0.6292 1.213 1.112 1.656 Henderson b 0.01600 0.03501 0.05738 0.06064 0.02252 0.04735 0.04559 0.07212 c 1.761 1.456 1.292 1.262 1.649 1.358 1.386 1.240 R 2 0.9590 0.9893 0.9904 0.9779 0.9830 0.9859 0.9843 0.9939 P 11.01 5.444 7.283 11.16 7.458 7.790 8.294 5.156 Es 1.610 0.7998 1.545 3.004 1.239 1.548 1.923 1.656 Bradley b 4.975 3.285 2.164 1.890 3.539 2.448 2.362 2.244 c 0.7909 0.8209 0.8444 0.8571 0.8085 0.8376 0.8355 0.8309 R 2 0.9590 0.9943 0.9878 0.9732 0.9948 0.9852 0.9815 0.9737 P 10.61 5.577 11.86 17.83 5.588 10.36 12.15 9.862 Es 1.695 0.731 1.252 2.053 0.6541 1.318 1.458 1.693 Caurie I b 0.1401 0.1592 0.1812 0.1839 0.1511 0.1737 0.1720 0.1923 mo 0.9180 0.8833 0.8865 0.8752 0.9139 0.8843 0.8984 0.9204 R 2 0.9378 0.9532 0.9876 0.9958 0.9892 0.9807 0.9915 0.9665 P 11.98 13.90 7.526 4.801 5.425 8.631 5.840 13.05 Es 2.479 2.290 1.644 0.8024 1.339 2.165 1.273 2.997 Smith b -4.900 -5.816 -6.815 -7.494 -5.457 -6.517 -6.422 -6.187 c 4.642 3.436 1.531 0.7796 3.430 2.119 1.918 1.674 R 2 0.9432 0.9863 0.9972 0.9903 0.9965 0.9899 0.9926 0.9745 P 13.14 11.06 2.799 9.100 3.434 4.745 4.769 6.834 Es 1.996 1.135 0.6048 1.231 0.5348 1.088 0.9196 1.667 Oswin b 8.662 8.177 6.951 6.559 7.783 7.375 6.943 6.821 c 0.260 0.301 0.364 0.398 0.300 0.343 0.354 0.344 R 2 0.936 0.978 0.992 0.999 0.987 0.978 0.992 0.955 P 16.35 16.08 10.18 5.247 8.611 13.67 6.616 19.10 Es 2.122 1.430 1.000 0.4352 1.029 1.611 0.9704 2.224 Halsey b 2.816 2.412 2.121 2.057 2.584 2.196 2.260 2.090 c 200.2 71.92 30.65 27.16 102.7 38.40 43.06 23.92 R 2 0.9046 0.9119 0.9613 0.9785 0.9653 0.9534 0.9688 0.9314 P 16.42 19.08 13.25 10.54 10.37 13.99 10.90 18.35 Es 2.997 2.944 2.462 1.758 2.026 2.914 1.963 3.626 Caurie II b 1.067 0.7904 0.5304 0.5116 0.9534 0.6279 0.6674 0.3633 c 2.043 2.423 2.703 2.751 2.154 2.594 2.509 2.824 R 2 0.9733 0.9811 0.9695 0.9492 0.9718 0.9749 0.9556 0.9822 P 9.357 8.451 12.60 15.83 10.31 10.64 14.20 8.790 Es 1.779 1.951 3.169 4.391 2.120 2.725 3.387 2.507 Modified GAB b 5.705 4.784 3.440 3.007 4.080 3.864 3.282 3.798 c 0.771 0.832 0.897 0.920 0.850 0.877 0.897 0.872 d 322.894 503.164 1296.622 200000000 1364.002 694.361 1047.207 443.567 R 2 0.960 0.985 0.995 0.992 0.998 0.990 0.992 0.980 P 10.3181 7.6235 5.9209 7.7407 2.7014 5.071 8.349 5.437 Es 1.8652 1.3230 0.8616 1.2204 0.4367 1.215 1.203 1.650 Kuhn b -0.3184 -0.3773 -0.4441 -0.4953 -0.3627 -0.4264 -0.4204 -0.3849 c 8.700 8.312 7.140 6.813 7.826 7.495 7.174 7.039 R 2 0.7719 0.8408 0.8986 0.9396 0.8533 0.8587 0.9027 0.8194 P 33.75 41.20 37.63 32.25 31.00 40.19 32.20 47.78 Es 4.000 3.869 3.611 3.080 3.475 4.077 3.341 4.434 Iglesias - Chirife b 0.319 0.378 0.444 0.496 0.363 0.427 0.421 0.385 c 8.842 8.481 7.339 7.033 7.987 7.685 7.361 7.212 R 2 0.770 0.840 0.898 0.939 0.852 0.858 0.902 0.818 P 33.89 41.39 37.85 32.49 31.15 40.40 32.41 48.00 Es 4.012 3.885 3.627 3.099 3.489 4.092 3.357 4.447 Mizrahi b -8.842 -8.481 -7.339 -7.033 -7.987 -7.685 -7.361 -7.212 c -8.523 -8.103 -6.894 -6.538 -7.624 -7.258 -6.941 -6.827 R 2 0.770 0.840 0.898 0.939 0.852 0.858 0.902 0.818 P 33.89 41.39 37.85 32.50 31.15 40.42 32.41 48.00 Es 4.012 3.885 3.627 3.099 3.489 4.093 3.357 4.447 Modified BET mo 2.164 2.336 2.453 2.608 2.234 2.433 2.366 2.220 Note: m o, b, c and d are constants. b 30000000 70000000 50000000 70000000 60000000 40000000 50000000 40000000 R 2 0.354 0.607 0.819 0.893 0.619 0.749 0.799 0.718 P 43.43 36.75 30.12 26.05 39.39 33.36 33.33 33.08 Es 6.730 6.082 4.830 4.091 5.597 5.429 4.799 5.535 212
Page 1 and 2:
THE BRIX-FREE WATER CAPACITY AND SO
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dissolved and hydrated waters, and
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ACKNOWLEDGEMENTS I am particularly
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Page 1.5 THE DELETERIOUS EFFECTS OF
Page 9 and 10:
Page 2.2 THE PHENOMENON OF BRIX-FRE
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Page 3.4.3.3 Cane tops 83 3.4.4 Cha
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4.3.3 Temperature at which Brix-fre
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4.6.1 Materials 143 4.6.1.1 Samples
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CHAPTER 6. PROPERTIES OF THE SORBED
Page 19 and 20:
APPENDIX 3. CALCULATIONS LEADING TO
Page 21 and 22:
LIST OF FIGURES Page Figure 1.1. Fi
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Figure 3.1. Glucose and fructose an
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Figure 5.11. Residual plots for the
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total adsorbed water (m) and the pr
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Table 2.18. Moisture content in sug
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Page Table 4.4. Results of the dete
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Page Table 4.24. Analysis of varian
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Page Table 5.13. Table 5.14. Equili
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Table 6.3. Heat of sorption of the
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GLOSSARY OF TERMS Absorption is the
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Filterability of a raw sugar is mea
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Sorption is the generic term used w
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LIST OF MAIN SYMBOLS Symbol Descrip
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s c s Slope of Caurie I isotherm pl
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number of 255, and cane land covere
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Nouvelle Mon In Trésor ustrie and
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Figure 1.3. Cane sampling by core s
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In Mauritius, most of the sugar fac
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are: cane tops, dry and green leave
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1.4 TRENDS IN CANE QUALITY RECEIVED
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campaign was launched to encourage
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The level of extraneous matter in c
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In Australia (Cargill, 1976), cane
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The effect of soil on factory perfo
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leaves increased the level of impur
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• From 1976 to 1980, when the pro
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Clerget purity of molasses 40 Clerg
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CHAPTER 2. IMPACT OF EXTRANEOUS MAT
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Since the extrapolated purity of mo
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Figure 2.1. Jeffco cutter grinder.
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2.1.4 Results The analytical result
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Table 2.3. Analytical results of re
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Table 2.5. Composition of dry trash
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Table 2.7. Predicted factory perfor
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Boiling house recovery 91.0 89.8 89
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0 5 10 15 20 % EM in cane y = 0.572
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% EM in cane 0 5 10 15 20 0 -2 -4 -
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1 y = 0.020 (% D) R 2 = 1.00 = 0.03
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% EM in cane 0 5 10 15 20 0 -2 y =
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esulting in 0.015 unit sucrose loss
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2.2.1 Experimental procedure Cane m
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filter paper, rejecting the first f
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Table 2.9. Effect of increased addi
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Table 2.11. Effect of increased add
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Table 2.13. Effect of increased add
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various components such as stalk fi
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in the presence of dry leaves, if c
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Table 2.17. Moisture content in sug
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CHAPTER 3. SEPARATION OF THE SUGAR
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Table 3.1. It can be seen that the
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Table 3.2. Fibrous physical composi
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R 579 R 570 M 1557/70 M 1400/86 74
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loosen the fibre. The woody core is
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agitate the mixture in the pot, and
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Figure 3.7. Custom-built fibre-pith
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The extraction of fibres starting f
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pre-treatment in a Jeffco cutter-gr
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Figure 3.19. Stalk cake washed free
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not have many dry leaves attached t
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Table 3.5. Masses of cane samples a
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Table 3.7. Masses of cane samples a
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Table 3.9. Masses of cane component
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3 57.6 126.3 23.7 97.2 31.1 53.8 11
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Table 3.12. Material loss (%) from
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3.5.3 Fibre/pith ratios in cane com
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Table 3.15. Effect of extraneous ma
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Snow (1974) investigated the season
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from Figure 2.9 that the change in
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Table 3.18. Fibre % cane results by
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110
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(a). Dry leaf (b). Green leaf (c).
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dry fibre, or a factor, is used in
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Steuerwald (1912) applied sucrose s
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solution/fibre ratio was lowered fr
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leave some residual moisture on the
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instead of 150 g of 10° Brix sucro
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Table 4.2. Determination of Brix-fr
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Table 4.3. Comparison of Brix-free
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Table 4.4. Results of the determina
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In order to test for homogeneity of
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Table 4.7. Results of the repeat de
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The experiment was repeated with th
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e any residual moisture in the samp
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By means of the same technique, Won
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was still hot. Since the filter was
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value determined could be corrected
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Qin and White’s finding was confi
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A sample size of 3.5 g with 75 g co
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Figure 4.4. Fibre samples drying in
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- One large fibre sample (rind) of
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Table 4.18. Brix-free water values/
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Table 4.20. Brix-free water values/
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4.7.3 Statistical analysis It is es
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Table 4.23. Analysis of variance (B
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pointing out that at 52 weeks old,
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The crop of R 570 sampled in 2001 w
Page 213 and 214: 4.7.4. Estimated Brix-free water co
Page 215 and 216: The main difference in the two sets
Page 217 and 218: Table 4.27. Predicted Brix-free wat
Page 219 and 220: 4.8 SUMMARY AND CONCLUSIONS An anal
Page 221 and 222: component parts, and verify the Bri
Page 223 and 224: 3) Thermodynamic, water in equilibr
Page 225 and 226: Langmuir (1916, 1917, 1918) propose
Page 227 and 228: to determine the moisture sorption
Page 229 and 230: Table 5.1. Some commonly used isoth
Page 231 and 232: Lomauro et al. (1985) found that wi
Page 233 and 234: and on agricultural products such a
Page 235 and 236: Bruijn (1963) studied the mass incr
Page 237 and 238: After measuring the EMC of dry corn
Page 239 and 240: approached, that is, either by adso
Page 241 and 242: Table 5.4. Water activity (a w ) of
Page 243 and 244: 5.6.3 Procedure to determine equili
Page 245 and 246: 5.6.4 Results and discussion An exa
Page 247 and 248: Table 5.8. Equilibrium moisture con
Page 249 and 250: Table 5.10. Equilibrium moisture co
Page 251 and 252: Table 5.12. Equilibrium moisture co
Page 253 and 254: 30 o C 45 o C 55 o C 60 o C Water w
Page 255 and 256: m/m of 96% activity, a w (g/100g dr
Page 257 and 258: vaporisation generally decreases fr
Page 259 and 260: 30 o C isotherm 45 o C isotherm 55
Page 261 and 262: 4 0 Stalk fibre 5 0 Stalk pith 5 0
Page 263: 5.6.4.4 Fitting of sorption models
Page 267 and 268: Table 5.21. Parameters of the sorpt
Page 275 and 276: Modified GAB Kuhn Iglesias - Chirif
Page 277 and 278: Table 5.28. Classification of resid
Page 279 and 280: Stalk fibre Stalk pith Rind fibre 4
Page 281 and 282: 5.6.4.5 Calculated EMC values of re
Page 283 and 284: Table 5.30. Calculated equilibrium
Page 285 and 286: m/m of 96% Table 5.32. Calculated e
Page 287 and 288: Table 5.33. Parameters of the Hailw
Page 289 and 290: CHAPTER 6. PROPERTIES OF THE SORBED
Page 291 and 292: where m is the equilibrium moisture
Page 297 and 298: 6.2 THE NUMBER OF ADSORBED MONOLAYE
Page 299 and 300: 6.3 TOTAL SOLID SURFACE AREA AVAILA
Page 301 and 302: Thus, for each cane component of ea
Page 303 and 304: abscissa. For each moisture level (
Page 307 and 308: A similar procedure was followed to
Page 309 and 310: 10 0 Stalk fibre Stalk pith Rind fi
Page 311 and 312: Moreover, if T β > T hm the proces
Page 313 and 314: Table 6.5. Characteristic parameter
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Binding energy/kJ (kg mol) -1 2 0 0
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6.8 CALCULATION OF BOUND WATER AND
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The values of K 1 , K 2 and W were
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Table 6.7. Separation of the total
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Table 6.7. (Contd.) Sample 30 o C 4
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3 0 S talk fibre 4 0 Stalk pith 3 0
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3 0 Reconstituted cane at 30 o C 3
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when water is added to dry wood, wh
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It is evident that in some cases ma
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The number of adsorbed monolayers,
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Data in Tables 2.9 and 2.11 show th
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particular fibre is systematically
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Anon. (1985b). Laboratory manual fo
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Blanchi R.H. and A.G. Keller (1952)
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Day D.L. and G.L. Nelson (1965). De
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Heyrovsky J. (1970). Determination
Page 347 and 348:
Kuhn I.J. (1964). A new theoretical
Page 349 and 350:
Madamba P.S., R.H. Driscoll and K.A
Page 351 and 352:
Prinsen Geerligs, H.C. (1897). Stud
Page 353 and 354:
Sing K.S.W., D.H. Everett, R.A.W. H
Page 355 and 356:
Van der Pol C., C.M. Young and K. D
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Lynne Wong's PhD thesis

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