Ramp rate

Colgan E G 1995 Activation energy for Pt2Si and PtSi formation measured over a wide range of ramp rates J. Mater. Res. 10 1953... 

Higher-speed machines may be designed to operate between the first and second, or second and third, critical speeds of the rotor assembly. As these machines accelerate through the resonant zones or critical speeds, their natural frequency is momentarily excited. As long as the ramp rate limits the duration of excitation, this mode of operation is acceptable. However, care must be taken to ensure that the transient time through the resonant zone is as short as possible. 

The operating envelope defines the physical requirements, dimensions, and type of coupling needed in a specific application. The envelope information should include shaft sizes, orientation of shafts, required horsepower, full-range of operating torque, speed ramp rates, and any other data that would directly or indirectly affect the coupling. 

H2TPR results (Flow rate of 5% H2 = 20cc/min, Ramp rate= lOtl/min) show that Sb modifies the catalyst surface reducibility. The hydrogen consumption on WO3 takes place above 500 °C. It is evident from TPR results that new surface species were formed by Sb addition. The population of such species, that is represented as the area under the new peak, increases with increasing Sb content with the maximum at Sb=0.4 and then decreases with further increasing Sb content. 

Oven program Initial temperature Initial hold time Ramp rate Final temperature Final hold time Detector Temperature Auxiliary gas Hydrogen Air... 

The catalysts were characterized by inductively coupled plasma emission spectroscopy (ICP-ES Perkin Elmer Optima 3300RL) to determine cobalt content, x-ray diffraction (XRD Bruker A-500) with crystallite size determination using the Rietveld method, and temperature-programmed reduction (Zeton Altamira AMI-200) using 30 ml/min 10% H2/Ar and a ramp rate of 10°C/min. Surface area... 

Figure 2.9. Approximate temperature ranges for densification processes contributing to structural evolution (non-isothermal processing with moderate ramp rate).

Figure 2.10. Variations in refractive indices of zirconia thin films prepared with the drying control agent, diethanolamine (DEA), and using three different heating ramp rates.

Figure 3.14. TGA of N4FI9CU7S4 (5°C/min ramp rate nitrogen atmosphere). Weight loss at 270 °C is shown. [Reproduced with permission from [Ref. 38]. Copyright 2007 American Chemical Society.]...

Performing a Redhead analysis of the TPD. an estimation of the activation energy (Ea) of hydrogen desorption from npSi can be derived from the following equation [7], where v is the evolution rate, and p is the linear temperature ramp rate. 

A load ramp rate of 10 kW/second when connected to the utility grid... 

A load ramp rate of 80 kW/second when operated independently of the utility grid and following the initial ramp up to full power... 

Jhung, S.H., Lee, J.H., and Chang, J. (2008) Crystal size control of transition metal ion-incorporated aluminophos-phate molecular sieves effect of ramping rate in the syntheses. Micropor. Mesopor. Mater., 112, 178-185. 

Fig. 5.5 FE-SEM cross-sectional views of tapered nanotubes obtained (a) using the ramp rate 0.43 V/min. to raise the voltage from lOV to 23V within 30 minutes and then holding the voltage at 23 V for 10 minutes and (b) by initially anodizing the sample at lOV for 20 minutes and then increased the voltage linearly at the rate of 1.0 V/min to 23V, and finally kept at 23V for 2 minutes, (c) shows a view of straight nanotubes obtained by applying a constant 23V for 45 minutes. Here, d denotes diameter of apex, and D diameter of cone base.

The thermal behavior of the hyperbranched polymer 7, as well as that of the related tetra- and octanuclear dendrimers 1 and 2, was examined by thermal gravimetric analysis (TGA) and derivative thermogravimetry (DTG). The samples were heated at a ramp rate of 10 °Cymin under nitrogen atmosphere in the tenqierature range 25-8(K) °C. The major decompositions occur between 340 and 540 °C for the tetranuclear 1, and between 370 and 520 °C for the octanuclear 2, whereas for polymer 7 a faster rate of weight loss is observed at a higher (480 and 560 C) temperature range. The thermal stability of the network dendrimeric material 7 is... 

Complementary techniques in catalytic chemistry involve temperature programmed (TP) methods where a reaction is investigated by subjecting the catalyst immersed in a reactant, to a temperature ramp. Rates of both reduction and oxidation can be studied. The extent of the catalytic reaction is then plotted as a function of temperature. In TP-desorption (TPD), the desorbed material is detected and plotted against temperature. 

Generally, high space velocities of ammonia and low temperature ramp rates are required for maximisation of surface area. The former has the effect of reduction in the partial pressure of water vapour generated on reaction, whilst the latter minimises sintering by solid-solid reaction. In a factorial study, Choi... 

Determination of CholesteroL For meat extraction, the procedures for determining the cholesterol of extracted lipid samples were described Chao et al. (2i). For edible beef tallow extraction, the preparation of samples for cholesterol content was based on the AOAC (22) method Section 28.110. The prepared sample was then injected into a Supelco SPB-1 fused silica capillary column of 30 meters x 032 mm i.d. in a Varian Model 3700 gas chromatograph equipped with dual flame ionization detectors. The initial holdup time was 4 min at 270°C and then programmed to a temperature of 300°C at a ramp rate of 10°C/min. Helium flow rate and split ratio were 13 ml and 50 1, respectively, while the injector/detector temperature was 310°C. 

Whereas intelligent control comprises the aforementioned computer technology, control methods, and sensors, the control methods and advances in them are the focus of this chapter. Sensors parallel control methods in their importance to intelligent control of product quality, but a discussion of them is left to other works [1-8]. The control methods discussed in this chapter are on-line supervisory control methods, as opposed to regulatory control methods. The latter are commonly used, for example, to keep the operation of an autoclave in control When a ramp in temperature is called for, regulatory control methods govern the autoclave in achieving that ramp however, the supervisory control determines the ramp rate in order to influence product quality. 

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