Magnetic heating rate

Fig. 3.7 DSC trace of as-received, undoped NaAlH (purity 90%) and (b) the same hydride after milling for 5 h in the magneto miU Uni-Ball-Mill 5 under HES57 mode (two magnets at 5 and 7 o clock positions). Heating rate 10°C/min at argon flow 50 ml/min...

Solutions were mixed with a magnetic stirrer and heated up to 300°C to evaporate the solvents and to obtain a crisp powder. These organo-metallic precursors were ground and calcined in pure alumina crucibles at 700°C, 800°C, 900°C, 1,000°C, 1,050°C, 1,100°C, 1,150°C, or 1,200°C in a box furnace (in air) with 10°C/min heating rate. After reaching the final temperature the furnace was turned of immediately and the powders were allowed to cool in the furnace. 

Fig. 2.32 DSC curves for the as-received MgH2 (Tego Magnan) and ball-milled MgH2 powders (IMP2 single magnet), (a) As-received commercial MgH2. Milled for (b) 15 min, (c) 1 h, (d) 10 h, (e) 25 h, (f) 50 h, (g) 75 h, and (h) 100 h in hydrogen (heating rate 4°C/min) [6]...

The total amount of moisture lost in TGA experiments is not affected by the heating rate, however, the temperature at which it occurs may vary (Figure 3.23). In addition, the dehydration mechanism and activation of the reaction maybe dependent on the particle size and sample weight (Agbada and York 1994). The TGA is calibrated using magnetic standards. 

Figure 3.12. Magnetic transition effective mass-loss curves al heating rates of 20 and 100°C/ min 1 (II).

One of the methods of studying the composition of macromolecular sedimentary organic matter in more detail is the molecular analysis of pyrolysis products. For this purpose, the pyrolysis products are transferred to a gas chromatographic column and analyzed as described for extractable organic matter in Sect. 4.5.5, with or without the combination with a mass spectrometer. Both flash pyrolysis (Curie-point pyrolysis samples are heated on a magnetic wire by electrical induction almost instantaneously, e.g., to 610°C) or off-line pyrolysis at various heating rates have been applied to geological samples (see Larter and Horsfield 1993 for an overview of various pyrolysis techniques). 

General procedure The zeolite sample (0.220 g) was calcinated in situ at 550 C (heating rate l°C.min-l) under a stream of dried N2-O2 mixture in a pyrex reactor equipped with a magnetic stirrer, a controlled heating and a sample tube with a frit to draw samples under controlled atmosphere. After temperature equilibration at 80°C, 50 ml of a solution of CH2(CN)C(0)0C2H5 (1.86 g) in dried DMSO was introduced through a septum in the reactor. After temperature adjustment, 5 ml solution of C6H5C(0)H (1.74 g) was added. Thus, the molarity of each reactant was 0.3 M. 

Conductive samples, for example metal powders and carbide samples, can be heated much more efficiently in the magnetic field. In contrast, for pure ceramic samples, which are insulators with little conductivity, much higher heating rates were obtained in the pure electric field. It was concluded that it is not possible to... 

Catalysts were reduced previously in controlled hydrogen atmosphere at 923 K for 2 hours in a quartz cell joined to a system of continuous flow. The heating rate was 7K/min. The magnetization was carried out at 300K. The Ni° content and the dispersion degree were determined from experimental data. 

Table VII. Effect of Heating Rate on Magnetic Properties of Catalysts...

The effect of heating rate during carburization (H2/CO = 3/1) on the magnetic properties of the catalysts were studied at 1 atm in the magnetic susceptibility apparatus and in the tubular reactor (Table VII). The mass gain of the samples carburized at 1 atm in the susceptibility... 

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