Experimental heating rates

DATA FROM THE INSULATED EXOTHERM TEST lET results can be illustrated using a 3 g sample of rert-butyl peroxybenzoate The reference material is an equal mass of silicone oil and an experimental heating rate of 0.5 K min" is chosen. 

Now, considering any one of the experimental heating rate P , relationship of the type... 

In Fig. 9 we show the evolution of the experimental (left panels) and calculated (right panels) LEED intensities during desorption for initial coverages 1/3, 1/2, and 2/3ML but for a smaller heating rate (IKs ) than in Fig. 8(a). Also shown are the corresponding experimental and... 

FIG. 9 (a-c) Experimental LEED intensities for (1 x 3) (solid line) and (1x2) (long-short dashed) structures and corresponding TPD rates (dotted lines) as a function of desorption temperature for approximate initial coverages 1 /3, 1 /2, 2/3 ML. Arbitrary units, (d-f) Theoretical LEED intensities, calculated with Eq. (40), and theoretical TPD rates for these initial coverages. Heating rate 1 K/s. (Reprinted from Ref. 39 with permission from Elsevier Science.)... 

Concerning the nature of electronic traps for this class of ladder polymers, we would like to recall the experimental facts. On comparing the results of LPPP to those of poly(para-phenylene vinylene) (PPV) [38] it must be noted that the appearance of the maximum current at 167 K, for heating rates between 0.06 K/s and 0.25 K/s, can be attributed to monomolecular kinetics with non-retrapping traps [26]. In PPV the density of trap states is evaluated on the basis of a multiple trapping model [38], leading to a trap density which is comparable to the density of monomer units and very low mobilities of 10-8 cm2 V-1 s l. These values for PPV have to be compared to trap densities of 0.0002 and 0.00003 traps per monomer unit in the LPPP. As a consequence of the low trap densities, high mobility values of 0.1 cm2 V-1 s-1 for the LPPPs are obtained [39]. 

Fig. 1. Effect of pumping speed on a desorption peak at a fixed heating rate. Experimental parameters given in the text. Reproduced from Ehrlich (27), with permission.

Subscripts w and a are introduced to distinguish between the constant temperature of the spots where the pressure is monitored and the system is pumped out, and the changing temperature of the heated adsorbent, respectively. If the experimental conditions are such that the term with dP/dt can be neglected, Eq. (13) gives directly the dependence of the pressure in the system on the adsorbent temperature and even on the time t elapsed from the beginning of the experiment, if an analytical expression for the heating rate is available. The time derivative of Eq. (13) gives for... 

Figure 5.21. Experimental setup (inset) showing the location of the working (WE), counter (CE) and reference (RE) electrodes and of the heating element (HE) thermal desorption spectra after gaseous oxygen dosing at 673 K and an 02 pressure of 4x1 O 6 Torr on Pt deposited on YSZ for various exposure times. Oxygen exposure is expressed in kilo-langmuirs (1 kL=l0 3 Torrs). Desorption was performed with linear heating rate, ()=1 K/s.4 S Reprinted with permission from Academic Press.

The calculations for the experimental reaction rates are based on an unsteady state heat transfer analysis. We computed the overall heat transfer coefficient of the system and estimated the experimental rates as follows dT... 

This paper reviews recycling technologies of PMMA waste, its applications and its markets. It relates in detail experimentation on thermal and oxidative depolymerisation of PMMA scrap, under nitrogen and oxygen atmospheres, at different heating rates by thermogravimetry and differential scanning calorimetry techniques. 15 refs. 

The plastic samples used in this study were palletized to a form of 2.8 3.2min in diameter. The molecular weights of LDPE and HDPE were 196,000 and 416,000, respectively. The waste catalysts used as a fine powder form. The ZSM-5 was used a petroleum refinement process and the RFCC was used in a naphtha cracking process. The BET surface area of ZSM-5 was 239.6 m /g, whose micropore and mesopore areas were 226.2 m /g and 13.4 m /g, respectively. For the RFCC, the BET surface area was 124.5 m /g, and micropore and mesopore areas were 85.6 m /g and 38.89 m /g, respectively. The experimental conditions applied are as follows the amount of reactant and catalyst are 125 g and 1.25-6.25 g, respectively. The flow rate of nitrogen stream is 40 cc/min, and the reaction temperature and heating rate are 300-500 C and 5 C/ min, respectively. Gas products were vented after cooling by condenser to -5 °C. Liquid products were collected in a reservoir over a period of... 

Accessibility to Cu sites was determined by temperature programmed desorption of NO (NO TPD), using an experimental setup similar to that used for TPR, except the detector was a quadrupole mass spectrometer (Balzers QMS421) calibrated on standard mixtures. The samples were first activated in air at 673 K, cooled to room temperature in air, and saturated with NO (NO/He 1/99, vol/vol). They were then flushed with He until no NO could be detected in the effluent, and TPD was started up to 873 K at a heating rate of 10 K/min with an helium flow of 50 cm min. The amount of NO held on the surface was determined from the peak area of the TPD curves. 

Figure 2. Experimental reaction rates vs. the conversion degree for the CTMAB decomposition in SBA-3 at different heating rates (from bottom to top 3, 6, 9, 12 and...

The microwave power could be adjusted in order to allow constant pressure within the vessel. A incorporated pressure release valve permits to use this experimental device routinely and safely. Furthermore, an inert gas as argon could be introduced within the reactor to avoid sparking risk with flammable solvents. This experimental device is able to raise temperature from ambient to 200 °C in less than 20 s (pressure is close to 1.2 Mpa and heating rate is close to 7° s 1). The RAMO system has been designed for nanoparticles growing and elaboration [59-62]. The RAMO system is a batch system. It could be easily transpose to continuous process with industrial scale (several hundred kilograms by seconds). 

Experimental data with biomass show that devolatilization time increases with particle size.4 The feedstock particle size affects the heating rate. Both heat flux and heating rates are lower in the larger particles than in the smaller ones.5... 

The subscript "s" refers to experimental values. The plot of the self-heat rate as a function of the reciprocal temperature (at the start of the reaction) may result in a straight line with a slope of Ea/R which is the zero-order line. 

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