Physical Pre-treatment

Monostreams that are not suitable for grinding or pulverisation before being fed into the burners should be pre-treated thermally indirect co-combustion, Figure 2 summarises the possible types of thermal pre-treatment, including the necessary physical pre-treatment, taking into account all possible types of indirect cocombustion. 

Physical pre-treatments are essentially processes that reduce the size or disrupt the structure of the biomass substrate in order to increase the surface area. For instance, the milling process is one such example which is also used in the production of bioethanol from sugarcane and corn. 

Ionizing irradiation is another type of physical pre-treatment process that disrupts the structure of lignocellulosic biomass to form free fermentable sugars. The efficiency of irradiation pre-treatment depends on the... 

Physical pre-treatment processes are employed without chemical agent and microorganisms (Zheng et al, 2014). The common methods are mechanical machines, irradiation and extrusion (Karimi et al., 2013) with the objectives to open up lignocelluloses, reducing crystallinity, and increasing surface area and porosity, for more attacking availability of post-treatment (Behera etal., 2014). 

Xu, X., Cortie, M.B. and Stevens, M. (2005) Effect of glass pre-treatment on the nucleation of semi-transparent gold coatings. Materials Chemistry and Physics, 94, 266-274. 

Feng, H., Tang, J., Mattinson, D.S., and Fellman, J.K. 1999. Microwave and spouted bed drying of frozen blueberries The effect of drying and pre-treatment methods on physical properties and retention of flavor volatiles. J. Food Process. Preserv. 23, 463-479. 

Torreggiani, D. and Bertolo, G. 2001. Osmotic pre-treatments in fruit processing Chemical, physical and structural effects. J. Food Engineer. 49, 247-253. 

In general the preparation of a polymer monolithic rod is performed as a multi-step procedure (Figure 11). Generally, the stages involved are pre-treatment and preparation of the monolithic matrix by polymerization and derivatization or functionalization. Pre-treatment of the bare capillary is sometimes needed in order to obtain good physical stability. Most columns are therefore polymerized in silanized columns. The capillary column is first washed with a strong alkaline solution such as 1.0 M sodium hydroxide so that the siloxane groups at... 

To understand these results, we must look at the band structure of the MgO surface (Fig. 5). In the band gap a number of lattice defects and surface states can be observed. The various transitions are shown by arrows. Vacuum pre-treatment at 300 °C will cause oxygen chemisorbed as O2 or 0 79) to be removed from the surface or to migrate into the lattice, thereby annihilating an oxygen vacancy. Physically and chemically adsorbed water will be removed, thus occupying another O2 vacancy in the surface ... 

An analyst is measuring the concentration of americium-241 (alpha emitter) in a soil sample. Most of the components in the soil will act as interferents as they physically block the alpha particles reaching the detector. The measured concentration of americium-241 in soil will be low due to the interference caused by the solid material in the sample. Therefore, the sample will require pre-treatment to remove the interferents before the americium-241 concentration can be measured. 

A more rigorous technique involves the use of internal standards. An internal standard is a compound that is similar in chemical structure and physical properties to the sample being analysed. The internal standard should be added to the sample in question before extraction or assay commences and is then present in the sample matrix throughout the subsequent assay In the assay of complex samples, some sample pre-treatment is usually required and the recovery of the sample from the extraction process may not be 100%. If an internal standard is used, losses in sample will be mirrored by similar losses in the standard and the ratio of sample to standard should remain constant. Internal standards are particularly used in chromatographic analysis (especially gas chromatography and high-performance liquid chromatography), where fluctuations in instrumental parameters (e.g. flow rate of mobile phase) affect accuracy... 

It is thus necessary to optimise the effects of various pre-treatment chemicals, focusing on fabric physical properties such as tensile strength, weight loss, fuzzing, hand, copper number, moisture regain and colour change (in the case of dyed fabrics). 

Wool fibre during its various pre-treatment stages also undergoes some kind of damage, the extent of which may be assessed by both physical and chemical methods. The very multiplicity of tests available is in itself evidence of the lack of a universal method for assessment of damage [19],... 

When the wastewater arrives at the treatment plant, it moves through a series of processes which remove the waste from the water and reduce its threat to public health. Treatment at the plant consists of p re-treatment, primary treatment, and secondary treatment. Pre-treatment physically screens out large debris, and removes sand, gravel, and oil. Primary treatment removes settled and floating materials. Secondary treatment involves biological, chemical, and physical processes which remove suspended and dissolved solids secondary treatment also kills pathogenic organisms. 

As the Halex reaction using alkaline fluorides is carried out in an heterogeneous system, the influence of the physical state of the solids must be taken into account. Several pre-treatments of potassium fluoride have been proposed to improve its performances which are evidently linked to the area of the solid surface. Spray-drying (refs. 68, 69) and freeze-drying (ref. 70) are now considered as more activating treatments of KF than calcination. Very recently, however, slow recrystallisation in methanol has been claimed to deliver a potassium fluoride which is even more effective than the spray-dried one (ref. 41). Some comparisons are given on Figure 8, Table 24 and Pictures 1 and 2. 

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