Preparation of Seeds

The seed has to be introduced as well-dispersed particles. One should consider that storage of dry seeds, for example, in bags that are typically piled up in a storage room may in the long term lead to severe agglomeration inside these bags and if the user does not take care of this time consolidation, there may be a gradual loss of process control over time. 

The best and safest way to prepare the seeds is to disperse them in the same solvent as used in the crystallizer. This dispersion can be achieved by sonication or high-shear mixing. Dispersing seeds has some more advantages very fine material from the milling may be dissolved, distorted lattices may heal, amorph-ized surfaces may recrystallize, and desolvated solvates (during drying of the seed 

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The Penniman-Zoph process involves the preparation of seeds or nucleating particles by the alkaU precipitation of ferrous sulfate. The reaction is carried out at alow temperature using an excess of ferrous ions. The hydroxide is then oxidized to the seeds of hydrated ferric oxide ... 

A seed culture of S. cerevisiae ATCC 24860 (American Type Culture Collection, Manassas, VA, USA) was grown in a media of 5g glucose, and 0.5 g yeast extract, respectively, 1.5 g KH2P04 and 2.25 g Na2P04 phosphate buffer up to a total volume of distilled water, 500 ml. The media was sterilised at 121 °C for 15 min. The stock culture of the microorganisms was transferred to the broth media for preparation of seed culture. 

Singh, U. P., Singh, A., Singh, M., and Maurya, K. P. S. (2008). Estimation of phenolic acids in different preparations of seeds of finger millet (Eleusine coracana) Their possible implications in human health. Internet. Alternative Med. 6(1). 

For obtaining low defect densities larger bulk crystals by HVPE seeded with high-pressure needles, careful selection and preparation of seeds is necessary to avoid parasitic 3D nucleation on seed imperfections. It is shown that the HVPE growth on the needle-shaped seeds is a very stable process. Therefore, it seems that there are no physical obstacles for growing much larger crystals by this method. 

Wet preparation of red iron oxides can involve either a hydrothermal process (see Hydrothermal processing) or a direct precipitation and growth of iron oxide particles on specially prepared nucleating seeds of Fe202- In the hydrothermal process, iron(II) salt is chemically oxidized to iron(III) salt, which is further treated by alkahes to precipitate a hydrated iron(III) oxide gel. The gel can be dehydrated to anhydrous hematite under pressure at a temperature around 150°C. 

Tire usual commercial method of preparation of gibbsite is by cry staUization from a supersaturated caustic aluminate, Na A102, solution. Seed gibbsite crystals are used. 

Extra-Fine Precipitated Hydroxide. Very fine (< 1 /im-diameter) particle size hydroxide is produced by precipitation under carefully controlled conditions using specially prepared hydroxide seed. Precipitation is usually carried out at low (30 —40°C) temperatures causing massive nucleation of fine, uniform hydroxide particles (Fig. 5). Tray or tumiel Ape dry ers are used to dry the thorouglily washed filter cake to a granular product wliich is easily pulverized to obtain the fine hydroxide. Alternatively, the washed product is spray dried. Precipitation from an organic-free aluniinate Hquor, such as that obtained from the soda—sinter process, fields a very wliite product. Tlie fine precipitated hydroxide is used by the paper and plastic industries as fillers. 

Precipitation of a hydrated titanium oxide by mixing aqueous solutions of titanium chloride with alkaU forms the precipitation seeds, which are used to initiate precipitation in the Mecklenburg (50) variant of the sulfate process for the production of pigmentary titanium dioxide. Hydrolysis of aqueous solutions of titanium chloride is also used for the preparation of high purity (>99.999%) titanium dioxide for electroceramic appHcations (see Ceramics). In addition, hydrated titanium dioxide is used as a pure starting material for the manufacture of other titanium compounds. 

Herbal drugs are available in coarsely to finely chopped forms, as cut or concis" drugs leaves often appear on the market cut into four-sided fragments woods, roots, and barks as chips most fruits and seeds usually unbroken, in the whole or toto " condition, and they are sometimes crushed before being used. The extent of comminution plays an important part in the preparation of herbal infusions (see below Making the Tea). 

Sabadilla Seeds. Processes for the isolation of the total alkaloids and separation of the components have been published by Wright and Luff, by Bosetti and by G. Merck. The more modem methods used by Poethke, Saito, Seiferle et al., Jacobs and Craig, and others for the alkaloids of white and green hellebores (see below) could no doubt also be used to advantage for sabadilla seed. A test for galenical preparations of sabadilla has been devised by Ramstad depending on the presence of chelidonie acid in the seed. ... 

This alcohol is almost invariably present in those essential oils which contain aliphatic terpene alcohols, but in most of these it is present in very small amount, and it is only from ambrette seed oil that any quantity has been prepared. Ambrette seeds contain about 0-1 per cent, of this alcohol, which, when freed from decylic alcohol which is also present, has the following characters —... 

Preparation of 5a,17a-Dihydroxy-6 -Methylallopregnane-3,20-dione A solution was prepared containing 38.9 g of 5a,17a-dihydroxy-6/3-methylallopregnane-3,20-dione 3,20-bis-(ethylane ketal) in 389 ml of boiling acetone. Thereto was added 39 ml of 1 N sulfuric acid in portions under swirling and seeding with product. 8oiling was continued for a pariod of 2 minutes and the mixture was allowed to stand at room temperature. Thereafter the mixture was diluted with 1,500 ml of water, chilled and filtered. 

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