Spongy

Raney nickel A special form of nickel prepared by treating an Al-Ni alloy with NaOH solution. The nickel is left in a spongy mass which is pyrophoric when dry. This form of nickel is a most powerful catalyst, especially for hydrogenations. 

As the reaction beings to subside, run in from the dropping-funnel without delay a mixture of 25 ml. of acetone and 20 ml. of benzene, in order to maintain a brisk and continuous reaction. When the reaction finally subsides, heat the mixture on a boiling water-bath for 45 minutes with occasional shaking. If the shaking does not break up the spongy mass of magnesium pinacolate,... 

A 0.3619-g sample of tetrachloropicolinic acid, C6HNO2CI4, is dissolved in distilled water, transferred to a 1000-mL volumetric flask, and diluted to volume. An exhaustive controlled-potential electrolysis of a 10.00-mL portion of this solution at a spongy silver cathode requires 5.374 C of charge. What is the value of n for this reduction reaction ... 

Metal—Water Processes. The steam-iron process, one of the oldest methods to produce hydrogen, iavolves the reaction of steam and spongy iron at 870°C. Hydrogen and iron oxide are formed. These then react further with water gas to recover iron. Water gas is produced by reaction of coal with steam and air. 

DRI can be produced in pellet, lump, or briquette form. When produced in pellets or lumps, DRI retains the shape and form of the iron oxide material fed to the DR process. The removal of oxygen from the iron oxide during direct reduction leaves voids, giving the DRI a spongy appearance when viewed through a microscope. Thus, DRI in these forms tends to have lower apparent density, greater porosity, and more specific surface area than iron ore. In the hot briquetted form it is known as hot briquetted iron (HBI). Typical physical properties of DRI forms are shown in Table 1. 

Cavitation produces spongy, porous-appearing surfaces, strongly resembling acid attack. However, cavitation usually causes highly localized areas of metal loss, unlike acid, which attacks over a much wider area. 

In contrast to external protection, the anodes in internal protection are usually more heavily covered with corrosion products and oil residues because the electrolyte is stagnant and contaminated. The impression can be given that the anodes are no longer functional. Usually the surface films are porous and spongy and can be removed easily. This is achieved by spraying during tank cleaning. In their unaltered state they have in practice little effect on the current output in ballast seawater. In water low in salt, the anodes can passivate and are then inactive. 

Air pollutants may enter plant systems by either a primary or a secondary pathway. The primary pathway is analogous to human inhalation. Figure 8-2 shows the cross section of a leaf. Both of the outer surfaces are covered by a layer of epidermal cells, which help in moisture retention. Between the epidermal layers are the mesophyll cells—the spongy and palisade parenchyma. The leaf has a vascular bundle which carries water, minerals, and carbohydrates throughout the plant. Two important features shown in Fig. 8-2 are the openings in the epidermal layers called stomates, which are controlled by guard cells which can open and close, and air spaces in the interior of the leaf. 

Ozone Flecking, stippling, bleached spotting, pigmentation conifer needle tips become brown and necrotic Oldest leaves most sensitive youngest least sensitive Palisade or spongy parenchyma in leaves with no palisade 0.03 59 4 hr... 

Peroxyacefyl- nitrafe (PAN) Glazing, silvering, or bronzing on lower surface of leaves Youngest leaves most sensitive Spongy cells 0.01 50 6 hr... 

In suspension processes the fate of the continuous liquid phase and the associated control of the stabilisation and destabilisation of the system are the most important considerations. Many polymers occur in latex form, i.e. as polymer particles of diameter of the order of 1 p.m suspended in a liquid, usually aqueous, medium. Such latices are widely used to produce latex foams, elastic thread, dipped latex rubber goods, emulsion paints and paper additives. In the manufacture and use of such products it is important that premature destabilisation of the latex does not occur but that such destabilisation occurs in a controlled and appropriate manner at the relevant stage in processing. Such control of stability is based on the general precepts of colloid science. As with products from solvent processes diffusion distances for the liquid phase must be kept short furthermore, care has to be taken that the drying rates are not such that a skin of very low permeability is formed whilst there remains undesirable liquid in the mass of the polymer. For most applications it is desirable that destabilisation leads to a coherent film (or spongy mass in the case of foams) of polymers. To achieve this the of the latex compound should not be above ambient temperature so that at such temperatures intermolecular diffusion of the polymer molecules can occur. 

Frenchman P. F. Chabeneau, and subsequently in London by W. H. Wollaston/ who in the years 1800-21 produced well over 1 tonne of malleable platinum. These techniques were developed because the chemical methods used to isolate the metal produced an easily powdered spongy precipitate. Not until the availability, half a century later, of furnaces capable of sustaining sufficiently high temperatures was easily workable, fused platinum commercially available. 

Pellets of the dry powder, when ignited in air, form snakelike tubes of spongy ash of unknown composition — the so-called Pharaoh s serpents . 

When reduced by spongy platinum it yields dihydro-/3-gurjunene,... 

By reducing natural cedrene with hydrogen in the presence of spongy platinum, a dihydrocedrene is obtained which has the following characters —... 

It forms an acetate, which boils at 165° to 170° at 11 mm. By re- duction with hydrogen and spongy platinum, it yields dihydroeudesmol, an alcohol melting at 82°. On dehydration it yields a sesquiterpene, eudesmene. Eudesmol appears to have a tendency to liquefy by keeping. Whether the liquid body is an isomer or not is unsettled. 

---