WEBVTT NOTE Sentence cues use the original English narration. Timing derives from exact PCM samples. 01-01 00:00:00.180 --> 00:00:14.199 In this demonstration, we will move a vapor-liquid equilibrium dataset from Excel into Lab Eight, check one calculation, compare two activity models, and save results that we can reopen. 01-02 00:00:14.379 --> 00:00:20.395 All nineteen observations are synthetic teaching data, not experimental measurements. 01-03 00:00:20.575 --> 00:00:25.589 Download the demonstration workbook and keep the walkthrough available beside it. 01-04 00:00:25.769 --> 00:00:34.459 You will need Excel, or another spreadsheet application that can export a worksheet as CSV, and a browser for the Lab. 01-05 00:00:34.639 --> 00:00:39.801 Watch each step, then pause and repeat it with your own copy of the files. 02-01 00:00:40.331 --> 00:00:43.425 Open the workbook and select the Demo tab. 02-02 00:00:43.605 --> 00:00:49.173 This sheet shows a worked calculation linked to one observation in the data sheet. 02-03 00:00:49.353 --> 00:00:58.185 The observation appears near the top, followed by saturation pressures, activity coefficients, and their natural logarithms. 02-04 00:00:58.365 --> 00:01:05.703 An activity coefficient, called gamma, adjusts the ideal-liquid prediction for nonideal behavior. 02-05 00:01:05.883 --> 00:01:09.126 We will check these values against the Lab later. 02-06 00:01:09.306 --> 00:01:14.853 For now, notice the formulas and the separate Antoine input block below. 02-07 00:01:15.033 --> 00:01:21.411 Keep this workbook intact so you can return to the calculation after importing the data. 03-01 00:01:21.941 --> 00:01:24.821 Now select the VLE data tab. 03-02 00:01:25.001 --> 00:01:29.247 The import table occupies cells A one through D twenty. 03-03 00:01:29.427 --> 00:01:34.775 Its first row contains four headers: T, P, x one, and y one. 03-04 00:01:34.955 --> 00:01:43.077 The remaining nineteen rows contain temperature, total pressure, and component one's liquid and vapor mole fractions. 03-05 00:01:43.257 --> 00:01:47.567 Temperatures are in kelvin, and pressures are in kilopascals. 03-06 00:01:47.747 --> 00:01:52.717 Locate spreadsheet row eleven, where x one is zero point five. 03-07 00:01:52.897 --> 00:01:56.865 This is the observation linked to the Demo calculation. 03-08 00:01:57.045 --> 00:02:01.952 Keep the header row and all nineteen observations together when exporting. 04-01 00:02:02.482 --> 00:02:10.466 With VLE data still active, choose Save As and select CSV UTF-eight, comma delimited. 04-02 00:02:10.646 --> 00:02:16.641 Give the export a recognizable name and keep the original Excel workbook separately. 04-03 00:02:16.821 --> 00:02:25.632 If Excel warns that only the active sheet will be saved, confirm that the active sheet is VLE data before proceeding. 04-04 00:02:25.812 --> 00:02:34.729 The CSV contains the observation table; it does not preserve the Demo sheet, workbook formatting, or property settings. 04-05 00:02:34.909 --> 00:02:37.960 After saving, note the file's location. 04-06 00:02:38.140 --> 00:02:44.518 We will select this actual exported file in the browser, rather than stop at loading a preset. 05-01 00:02:45.048 --> 00:02:46.563 Open Lab Eight. 05-02 00:02:46.743 --> 00:02:49.516 First select Load synthetic example. 05-03 00:02:49.696 --> 00:02:59.830 For this particular teaching dataset, that button initializes the matching component names, units, and both Antoine property definitions. 05-04 00:03:00.010 --> 00:03:02.612 It also loads an example table. 05-05 00:03:02.792 --> 00:03:09.648 Next, use Load CSV or tab-separated text to select the CSV you just saved. 05-06 00:03:09.828 --> 00:03:13.796 Check the selected filename and the table in the text box. 05-07 00:03:13.976 --> 00:03:19.608 These are two separate actions: initialize the properties, then import your file. 05-08 00:03:19.788 --> 00:03:27.830 Do not press Load synthetic example again afterward, because that would replace your imported table with the preset. 06-01 00:03:28.360 --> 00:03:35.848 Check that the path is isothermal, measured temperature uses kelvin, and measured pressure uses kilopascals. 06-02 00:03:36.028 --> 00:03:45.330 Both Antoine definitions use log base ten of saturation pressure equal to A minus B divided by the quantity T plus C. 06-03 00:03:45.510 --> 00:03:55.404 Their equation temperature uses kelvin, their pressure uses kilopascals, and their valid range is three hundred to three hundred ninety kelvin. 06-04 00:03:55.584 --> 00:04:05.291 Three hundred fifty kelvin is seventy-six point eight five degrees Celsius; do not change the selector to Celsius for these numbers. 06-05 00:04:05.471 --> 00:04:08.138 Select Validate and inspect data. 06-06 00:04:08.318 --> 00:04:13.032 Expect nineteen observations and nineteen interior points used. 06-07 00:04:13.212 --> 00:04:15.772 Keep No extrapolation selected. 07-01 00:04:16.302 --> 00:04:23.214 In Imported observations, find x one equal to zero point five, input row eleven. 07-02 00:04:23.394 --> 00:04:28.813 Here, x is the liquid mole fraction and y is the vapor mole fraction. 07-03 00:04:28.993 --> 00:04:39.596 Under the ideal-vapor assumption, with negligible Poynting correction, y times total pressure equals x times gamma times saturation pressure. 07-04 00:04:39.776 --> 00:04:45.642 Rearranging gives gamma from the observed compositions and our property inputs. 07-05 00:04:45.822 --> 00:04:50.217 Notice that the table displays the natural logarithm of gamma. 07-06 00:04:50.397 --> 00:04:55.410 To compare with gamma itself, take the exponential of that table value. 07-07 00:04:55.590 --> 00:04:57.830 We will check this in Excel next. 08-01 00:04:58.360 --> 00:05:00.686 Switch to the workbook's Demo tab. 08-02 00:05:00.866 --> 00:05:08.994 Cells B twelve and B thirteen calculate saturation pressures of one hundred fifty and sixty kilopascals. 08-03 00:05:09.174 --> 00:05:22.321 B fourteen and B fifteen calculate gamma one and gamma two: approximately one point four nine one five four five, and one point five six one three seven seven. 08-04 00:05:22.501 --> 00:05:28.901 For component two, the formulas use one minus x one and one minus y one. 08-05 00:05:29.081 --> 00:05:33.668 B sixteen and B seventeen take the natural logarithms. 08-06 00:05:33.848 --> 00:05:39.288 Compare those with the Lab's log gamma values, allowing for displayed rounding. 08-07 00:05:39.468 --> 00:05:44.630 Agreement checks these calculations, not the property source independently. 09-01 00:05:45.160 --> 00:05:52.286 Return to Lab zero eight and save a baseline using Export complete study JSON. 09-02 00:05:52.466 --> 00:05:56.156 Give it a clear name, such as week zero two baseline. 09-03 00:05:56.336 --> 00:06:06.022 This file preserves the setup as well as recorded results; the observation CSV alone does not preserve the property settings. 09-04 00:06:06.202 --> 00:06:12.111 Keep Unmeasured endpoint intervals set to No extrapolation, no full-area verdict. 09-05 00:06:12.291 --> 00:06:16.472 Our observations do not cover the pure-component endpoints. 09-06 00:06:16.652 --> 00:06:22.796 Do not turn an incomplete composition interval into a full-area consistency claim. 09-07 00:06:22.976 --> 00:06:27.478 Keep that limitation with the baseline before fitting either model. 10-01 00:06:28.008 --> 00:06:32.402 Select Margules, one parameter, and then Fit selected model. 10-02 00:06:32.582 --> 00:06:36.993 Once fitting finishes, choose View: Pressure and vapor residuals. 10-03 00:06:37.173 --> 00:06:43.061 Here, the mean absolute pressure error is about one point one four one percent. 10-04 00:06:43.241 --> 00:06:50.430 The mean absolute vapor-composition error is about zero point six seven six percentage points. 10-05 00:06:50.610 --> 00:06:56.971 Record both metrics, inspect the residual pattern, and note any parameter-bound warning. 10-06 00:06:57.151 --> 00:07:04.852 Before changing models, export the complete study JSON and the fitted residuals CSV. 10-07 00:07:05.032 --> 00:07:10.878 Give both files Margules names so the next fit cannot be confused with this result. 11-01 00:07:11.408 --> 00:07:17.104 Now choose N R T L, fixed alpha, and set alpha to zero point three. 11-02 00:07:17.284 --> 00:07:21.166 Leave the temperature-dependent parameter option unchecked. 11-03 00:07:21.346 --> 00:07:26.317 Keep the observations and property settings unchanged, then fit again. 11-04 00:07:26.497 --> 00:07:39.852 The pressure error is approximately one point one four times ten to the minus six percent, and the vapor error is about three point eight three times ten to the minus seven percentage points. 11-05 00:07:40.032 --> 00:07:47.370 These very small training errors are expected: N R T L generated the synthetic observations. 11-06 00:07:47.550 --> 00:07:52.734 This is model recovery, not evidence of universal superiority. 12-01 00:07:53.264 --> 00:08:02.800 Export the N R T L complete study JSON and fitted residuals CSV under separate, clearly named files. 12-02 00:08:02.980 --> 00:08:11.087 In the residuals CSV, y underscore error is the calculated minus observed vapor mole fraction. 12-03 00:08:11.267 --> 00:08:16.280 Multiply it by one hundred to express the difference in percentage points. 12-04 00:08:16.460 --> 00:08:21.900 The pressure underscore error underscore percent column is already a percentage. 12-05 00:08:22.080 --> 00:08:25.984 Do not multiply that column by one hundred again. 12-06 00:08:26.164 --> 00:08:35.146 Also distinguish individual signed residuals from the displayed mean absolute error, which averages their absolute values. 12-07 00:08:35.326 --> 00:08:38.995 Keep both model exports for comparison and recovery. 13-01 00:08:39.525 --> 00:08:43.365 Expand Study workspace, reopen and compare cases. 13-02 00:08:43.545 --> 00:08:49.326 Enter a label such as Restored Margules in Label for the next captured case. 13-03 00:08:49.506 --> 00:08:56.098 Use Load studies or a comparison JSON to select the saved Margules study. 13-04 00:08:56.278 --> 00:08:58.582 Then select its Restore button. 13-05 00:08:58.762 --> 00:09:04.679 Check the restored observations, units, property constants, and model controls. 13-06 00:09:04.859 --> 00:09:10.278 Loading first displays recorded results; it does not recalculate them. 13-07 00:09:10.458 --> 00:09:12.506 Restore loads the settings. 13-08 00:09:12.686 --> 00:09:17.848 Now select Validate and inspect data, followed by Fit selected model. 13-09 00:09:18.028 --> 00:09:23.703 Compare the fresh errors with the saved result to check that you recovered the same setup. 14-01 00:09:24.233 --> 00:09:27.838 Finish with a finding, a number, and a limitation. 14-02 00:09:28.018 --> 00:09:38.770 For example, N R T L reproduces these synthetic training data more closely than Margules: compare the two pressure-error values you saved. 14-03 00:09:38.950 --> 00:09:50.385 But the generating model was N R T L, and training error alone does not establish thermodynamic consistency or prediction on new observations. 14-04 00:09:50.565 --> 00:10:01.350 Now allow about twenty minutes to repeat the full workflow yourself: export, import, verify one row, fit both models, save, and restore. 14-05 00:10:01.530 --> 00:10:04.773 Keep your files and corrections with the worksheet. 14-06 00:10:04.953 --> 00:10:07.982 This practice adds no new attendance task.