Primary drying

Dry primary-standard-grade potassium hydrogen phthalate for 1 h at 110°C and store it in a desiccator. 

Process condition Product loading Cooling rate Freezing Ramp to primary drying Primary drying Ramp to secondary drying Secondary drying... 

Curve C in Figure 16 indicates that after standing for 24 hr at 65% relative humidity the lead azide reabsorbed moisture and the sensitivity to impact decreased. Current practice is to vacuum dry primary explosives at 60°C for 24 hr prior to impact testing with the Picatinny Arsenal apparatus. 

Samples of 1 gram of dried primary and dried wasted sludge were extracted in a Soxhlet extraction apparatus with 150 ml methanol for 4 hours. An aliquot of the methanol extract (20 ml out of a total volume of 200 ml) was passed over a small anion exchange column. The column was washed with 10 ml methanol before elution of the LAS with 3 ml of acidic methanol. The effluent was diluted to about 70 ml with water and the pH was adjusted to a value of 7. The solution was then brought to a value of 100 ml and an aliquot of 25 ml was passed over an octadecyl reversed phase SPE column. The sample was further treated as described above. The samples were kept in a dry state until analysis by HPLC. Prior to HPLC, the residues were dissolved in an acetonitrile/water 70/30 solvent mixture. 

Figure 2. Room temperature sorption-desorption isotherms of acid Nafion. Key , room temperature dried absorption , 220° C dried primary absorption , 220° C dried desorption Q, 220° C dried secondary absorption.

An approximate 0.1 M hydrochloric acid solution is prepared by 120-fold dilution of concentrated hydrochloric acid. It is standardized by titrating 0.1876 g of dried primary standard sodium carbonate ... 

Excessive amounts of water in the sample interfere by destruction of the esterification reagent and contribution to a high unreal hydroxyl number value. If the water content of the sample exceeds 0-2%, it is recommended that the sample be dried. Primary and secondary amines and higher fatty acids also interfere since they react with the reagent to form stable compounds and would be included in the analysis. 

Freeze-drying is a thermal separation process during which the frozen product is dried carefully under vacuum. At the beginning, the product is frozen at atmospheric pressure. After this, in the first phase of drying (primary drying), the water in the product is sublimated. In the second phase (secondary drying), the water still bound in the capillaries is removed through desorption. 

The purpose of repulping or slushing is to break down the dried primary fiber pulp or recovered paper into individual fibers or, at least, to form a suspension which can be pumped. In the latter case the remaining flakes have to be broken down in subsequent deflaking machinery. Repulping is needed not only at the beginning of the stock preparation system but also for the wet or dry broke from the paper machine. 

Fig. 3.10 Simulation of suspension drying primary particles stick at first touch...

The importance of the nickel cadmium cells lies in the fact that, by a special design, they can be made dry giving the portability and freedom of dry primary batteries and the economy of a storage battery. Toward the end of the charging process, both hydrogen and oxygen are liberated at the electrodes, the electrode reactions being... 

The standard carbon-zinc Leclanche battery is expected to remain one of the most widely used dry primary batteries in the future beeause of its low cost and reliable performance. This type of battery is manufaetured in many styles by many companies-one company alone manufaetures over 100 versions with voltages varying from 1.5 V to approximately 500 V and with various shapes, sizes and terminal arrangements. 

Primary batteries applies to dry primary cell batteries with the object of enumerating the types coiresponding to the most current needs, defining their characteristics, ensuring their interchangeability and limiting their number. 

Modern knowledge of cell wall structure comes from detailed chemical analyses, X-ray diffraction studies and work with the electron microscope. The dry primary cell wall contains hemicelluloses (up to 50%), cellulose (up to 25%) and smaller amounts of pectic substances, fats and protein. Hemicelluloses, cellulose and pectins are all polysaccharides with molecules built up from the linking together in chains of sugars or uronic acid residues. The morphology of cell walls is, however, not destroyed by extracting the hemicelluloses and pectins, indicating that the structural framework of the wall is... 

---