Semi-dry pressing

For casting with a fluid slip, a considerable proportion of water must be added to the clay which itself contains some moisture for plastic mixes that have to be moulded, less water is added finally for semi-dry pressing the moisture already in the clay may be sufficient. 

For example, many mudrocks have a natural moisture content in excess of 15% and therefore are unsuitable for the semi-dry pressed or even the stiff plastic methods of production unless they are dried before moulding. 

Hydraulic Mining. The method used to win china clay a high-pressure (2 MPa) jet of water is aimed at the exposed vertical clay face and the clay is washed down. The suspension is then pumped to settling tanks where the impurities (chiefly mica) settle out. The purified suspension of china clay is then concentrated, filtered, and dried. Hydraulic Press. A machine used for dry pressing, or semi-dry pressing the pressure (up to 100 MPa) is applied hydraulically to the top, and sometimes also to the bottom, mould-plate. Such presses are used, for example, in dry pressing basic refractories. 

Semi-dry Mortar, mortar (q.v.) which is mixed using just sufficient water to make a mix which coheres in the hand (much less than in a conventional mix). This leads to lower shrinkage, an advantage in tile-fixing, (q.v.). Semi-dry Pressing. See dry pressing. Semi-muffle. See under muffle. Semi-porcelain. A trade term sometimes applied, both in the UK and the USA, to semi-vitreous tableware. The term is... 

Stock Brick. Originally a term localized to S.E. England and meaning a clay building brick made by hand on a stock , i.e. the block of wood that defined the position of the mould on the moulding table. Stock bricks are now machine-made. The London Stock Brick is a yellow brick of rough texture. The term stock in the sense of usual , is sometimes applied to bricks of other areas, however, e.g. a Lincoln Stock is a semi-dry-pressed brick from the Lias. A Belfast Stock is a pink wire-cut brick from the Keuper Marl. 

The oil is extracted from the seed by expelling and solvent extraction. Cold pressed oil, light yellow in colour, is used for edible purposes without refining. The oil is a semi-drying oil and is also used in artists paints, in white paint in conjunction with boiled poppy seed oil and in soap after hydrogenation. Poppy seeds are used for decorating baked goods and as bird seed. 

Pressure Cracking. Cracking of the compacted semi-dry powder immediately after it has been shaped in a dry-press the cause is sudden expansion of air that has been trapped and compressed in the pores of the compact. The fault has been largely eliminated by designing presses so that the plunger descends twice to its lowest level, the trapped air having time to escape between the first and second pressings. 

One and seven-tenths liters of nitric acid (sp. gr. 1.42) is heated to boiling in a flask equipped with an efficient reflux condenser. To the boiling acid is added 500 g. (4.4 moles) of 4-methylcyclohexanol over a period of 5 hours. [Hood.) The mixture is heated for 20 minutes after completion of the addition. An equal volume of water is added, and the mixture is saturated with ammonium sulfate and extracted with two portions of ether. The ethereal solution is dried over anhydrous sodium sulfate, and the ether is removed by distillation. The residue is heated in two separate portions under a water pump vacuum until slight decomposition sets in at approximately 160-180°. The two residues are dissolved in warm benzene, and petrolemn ether (b.p. 40-60°) is added to precipitate an oil which partially solidifies on standing overnight. The semi-solid product is collected by filtration on a large Buchner funnel, and suction is applied for 12 hours, during which time the product is pressed to... 

For an extended review of experimental work on mini and microchannels, the reader is refered to the Thome (2004) and Kandlikar (2002) papers. This brief review covers a representative selection of heat transfer studies in minichannels and its aim is to illustrate the tendencies observed in the presented data. Recently Kandlikar (2004) developed a new general correlation adapted to minichannels which gives very good results for low qualities but fails to take dry-out into account, as noted by the author in question. Lately Thome et al. (2004) and Dupont et al. (2004) proposed a semi-empirical three zone model which is the only published work to predict the unique trends observed in minichannels. In this model the dominant boiling mechanism is the evaporation of the liquid film pressed under confined bubbles. 

In recent years, fully automated dry bag presses for the production of small ceramic components were developed, while semi-automatic wet bag equipment has been used to manufacture large and sometimes complex components that require only minor trimming to produce the final form with acceptable accuracy. For this, the size of the pressure vessels has been increased considerably. 

Chips For the manufacture of chips, sweet potatoes are peeled, boiled, or steamed for 30 min, mashed, mixed with pea or cornstarch, salt, and monosodium glutamate mixture is pressed into paste and transformed into rectangular shape. The strips are boiled or steamed to gelatinize the starch, cooled, and cut into slices of 1-2 mm thick. The slices are then dried and packed as semi-finished product. The semifinished dried chips are fried before consumption. 

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