Protecting Gas

In general, the carbides of metals of Groups 4—6 (IVB—VIB) are prepared by reaction of elementary carbon or hydrocarbons and metals and metal compounds at high temperatures. The process may be carried out ia the presence of a protective gas, under vacuum, or ia the presence of an auxiUary metal (menstmum). 

Carburization by Thermal Diffusion. Carburization of chemically processed metal or metal-compound powders is carried out through sohd-state, thermal diffusion processes, either in protective gas or vacuum. Carbide soHd solutions are prepared by the same methods. Most carbides are made by these processes, using loose or compacted mixtures of carbon and metal or metal-oxide powders. HaUdes of Group 5 (VB) metals recovered from ores by chlorination are similarly carburized. 

In iadustrial production of titanium carbide, pure (99.8%, with minor impurities of Si, Fe, S, P, and alkahes) titanium oxide [13463-67-7] Ti02, iu the dry or wet state is mixed iu 68.5 31.5 ratio with carbon black or finely milled low ash graphite. The dry mixture is pressed iato blocks that are heated iu a horizontal or vertical carbon-tube furnace at 1900—2300°C hydrogen that is free of oxygen and nitrogen serves as protective gas. In the vertical push-type furnaces, the Hberated CO itself provides protection. 

RTD protection Over-current protection Ground fault protection Gas protection Differential protection Restricted ground fault protection... 

Gaseous CO2 is extensively used to carbonate soft drinks and this use alone accounts for 20% of production. Other quasi-chemical applications are its use as a gas purge, as an inert protective gas for welding, and for the neutralization of caustic and alkaline waste waters. Small amounts are also used in the manufacture of sodium salicylate, basic lead carbonate ( white lead ), and various carbonates such as M2CO3 and M HC03 (M = Na, K, NH4, etc.). One of the most important uses of CO2 is to manufacture urea via ammonium carbamate ... 

Craven, D., The Protected Gas Service , Institution of Gas Engineers, Cardiff, March (1969)... 

Underground and underwater Underground fuel/oil tanks and pipelines water, fire protection, gas and compressed underground air distribution schemes underground metallic sewers and culverts underground communication and power cables deep wells other buried tanks and tanks in... 

Succinimide is readily silylated by HMDS 2 to the N-silylated product 201, which seems, however, to be in equilibrium with the O-silylated derivative 202 a (cf the closely related reactive center in persilylated uridine 3) and reacts after 6-10 days at 24 °C with one equivalent of primary or secondary amines such as morpholine to give the crystalline colorless cyclic acylamidine 203 and HMDSO 7, even in the absence of any protective gas [33] (Scheme 4.12). The reaction is much faster on heating to 120 °C under argon. At these temperatures 201 and 202 a, and possibly also the acylamidine 203, are apparently partially O-silylated by HMDS 2 to the very sensitive 2,5-bis(trimethylsilyloxy)pyrrole 202b or to 2-tri-... 

For a protected development of light-sensitive substances, a specially designed cover, the Baron Protective Cover against Light for Development Chambo-s, provides auxiliaries. For various chamber sizes of different manufacturers, adjusted models are available. As a special option, a connection for protective gas can also be installed. 

Eye protection Gas-tight safety goggles or full-face respirator. 

It accumulates during the liquefaction of air, and is a common and popular protective gas in chemistry and metal- A. Argon lasers have many versatile lurgy, for example, in electrowelding. in, eseaKh and... 

Evacuate danger area immediately Consult an expert Ventilation. Absorb remaining liquid in sand or inert absorbent and remove to safe place. Do NOT wash away into sewer. NEVER direct water jet on liquid. Prevent from entering confined spaces. Do NOT let this chemical enter the environment (extra personal protection gas-tight chemical protection suit including self-contained breathing apparatus). 

Milling atmosphere, which is a neutral protective gas (helium or argon) during mechanical milling or hydrogen under pressure up to 0.9 MPa under reactive mechanical alloying processes. 

Other kinds of electrical equipment may also be used in hazardous locations. One kind is purged and pressurized electrical equipment. This equipment works by using air or nonflammable protective gas flow or pressure to prevent hazardous materials from entering the enclosure NFPA 496 defines three types of purged and pressurized equipment as identified in Table 7-5. 

In the case of dust filters which are used to protect gas ballast pumps and roots pumps, the percentage restriction value for the various pressure levels are listed in the catalog. Other components, namely the condensate separators and condensers, are designed so that they will not reduce pumping speed to any appreciable extent. 

The oxygen activity of various Co—N4 complexes in sulfuric acid can be considerably improved by subjecting the carbon/chelate sample to thermal pretreatment in an atmosphere of a protective gas 7>. Such an effect is also reported by other authors for CoTMPP 22>. Figure 21 shows the influence of pretreatment on CoTMPP, pCoPc, and CoTAA. The given loadings (in mA/g catalyst) are all related to chelate plus carbon. The activity of CoTPP and CoTPAP is so low that,... 

Ref 25a). Here i is used as a fuel in proplnt compns which are used to generate a gas for inflation of impact-protective gas bags in automobiles during a collision... 

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