Time-temperature superposition software

Data Analysis. PeakFit version 2.0 from AISN software, Jandel Scientific (Corte Madera, California) was used to separate overlapping transitions in tan(S) and e" versus temperature plots. TA Instruments model 2000 thermal analyzer was used with version 4.1 time-temperature superposition software to analyze the stress data. 

Time-temperature superposition software generally has many user-friendly features such as toolbars, icons, and point-and-click mouse interactions. In addition, the automatic shifting capability enables even an inexperienced operator to rapidly generate master curves and evaluate the alternative equations for correlating the data. Plots of the shift factors calculated for the respective equations can be compared to the actual shift factors obtained from both the automatic or the manual curve-fitting routine in the software. Also, TTS can be coupled with the instrument control software to allow completely unattended experimental evaluation and master curve generation once a sample is loaded. 

To obtain as much information as possible on a material, an empirical technique known as time-temperature superposition (TTS) is sometimes performed. This technique is applicable to polymeric (primarily amorphous) materials and is achieved by performing frequency sweeps at temperatures that differ by a few degrees. Each frequency sweep can then be shifted using software routines to form a single curve called a master curve. The usual method involves horizontal shifting, but a vertical shift may be employed as well. This method will not... 

The utility of empirically determined WLF equations was investigated using DMA data obtained on the PVC acoustical damping material. Using a separate software package (available from DuPont Intruments), E, E" and tan 8 were empirically fit using the time-temperature superposition procedure. A reference temperature is first determined by the computer software. The data are then shifted manually and the WLF equation is fit to the resulting temperature shift factors. Values for and calcu-... 

Depending on the nature of the class, the instructor may wish to spend more time with the basics, such as the mass balance concept, chemical equilibria, and simple transport scenarios more advanced material, such as transient well dynamics, superposition, temperature dependencies, activity coefficients, redox energetics, and Monod kinetics, can be skipped. Similarly, by omitting Chapter 4, an instructor can use the text for a water-only course. In the case of a more advanced class, the instructor is encouraged to expand on the material suggested additions include more rigorous derivation of the transport equations, discussions of chemical reaction mechanisms, introduction of quantitative models for atmospheric chemical transformations, use of computer software for more complex groundwater transport simulations, and inclusion of case studies and additional exercises. References are provided... 

---