Attacks precautions

Siace dimer acids, monomer acids, and trimer acids are unsaturated, they are susceptible to oxidative and thermal attack, and under certain conditions they are slightly corrosive to metals. Special precautions are necessary, therefore, to prevent product color development and equipment deterioration. Type 304 stainless steel is recommended for storage tanks for dimer acids. Eor heating coils and for agitators 316 stainless steel is preferred (heating coils with about 4s m (50 ft ) of heat transfer surface ia the form of a 5.1 cm schedule-10 U-bend scroU are recommended for a 37. 9-m (10,000-gal) tank. Dimer acid storage tanks should have an iaert gas blanket. 

Ferrous-aUoy-clad tube sheets are generally prepared by a weld overlay process in which the alloy material is deposited by welding upon the face of the tube sheet. Precautions are required to produce a weld deposit free of defects, since these may permit the process fluid to attack the base metal below the alloy. Copper-aUoy-clad tube sheets are prepared by brazing the alloy to the carbon steel backing material. 

Good Good 7.5 Widely used for sulfuric acid pickling equipment also for propeller shafts in motor boats precautions needed to avoid sulfur attack during fabrication... 

In addition many other chemicals used can attack the body, both externally and internally, in many ways. It is necessary that the effects of any material used should be known and appropriate precautions taken if trouble is to be... 

Lead is a toxic metal and rigid precautions against lead poisoning are essential. Sprayed lead is, like other sprayed metals, porous, and the sprayed layers will not as a rule withstand attack by strong acids. On the other hand, lead from 0-13 to 0-25 mm (0-005 to 0-01 in) in thickness has proved extremely useful in atmospheres containing sulphuric acid. In this case the pores in the lead become blocked with lead sulphate, with the result that complete protection is assured. In the event of mechanical breakdown, lead does not exhibit any sacrificial action and therefore corrosion may lift the lead layer. 

Diethyl sulphate, b.p. 210° (decomp.), does not ordinarUy react so vigorously as dimethyl sulphate, but is nevertheless of great value for ethylations. It is somewhat less poisonous than the methyl analogue, but the same precautions should be taken. Both sulphates should be stored in glass-stoppered bottles sealed with paraffin wax, for they attack cork. 

High-temperature/low-pressure inorganic digestions are an area of application that has benefited from recent advances in vessel and sensor design. The inert properties of Teflon and its resistance to acid attack make it the material of choice for microwave pressure-vessel construction. Improved commercial systems offer additional safety precautions and improved facilities for pressure and/or temperature control. Also, the distribution of microwave radiation inside the oven cavity is fairly homogeneous. Low-pressure systems allow decomposition temperatures of about 180 °C. However, for many matrices, such temperatures are not sufficient to guarantee the complete ashing of thermoresistant sample components. 

Clinically, the drug has been studied (for the most part) in poorly controlled trials with few precautions against subjective bias [272- ]. Two careful doubleblind assessments have however been reported, one [275] measuring reduction of weekly consumption of glyceryl trinitrate. The other [276], by far the most informative published to date, demonstrates the drug s ability to increase the amount of exercise necessary to provoke anginal attacks,as well as its effectiveness in reducing the need for nitrate consumption. Qinically, this study failed to show any difference between propranolol and verapamil (in appropriate doses) and, in... 

Since dimer acids, monomer acids, and trimer acids are unsaturated, they are susceptible to oxidative and thermal attack, and under certain conditions they are slightly corrosive to metals, Special precautions arc necessary, therefore, to prevent product color development and equipment deterioration. 

Precautions should be taken to prevent oxidation during lipid analysis. Polyunsaturated fatty acids in lipid samples are easily attacked by active oxygen species (e.g., free radicals), exacerbated by the presence of strong light and metal ions. Therefore, it is arule of thumb while working with lipids that samples should be handled in a way that minimizes contact with air, light, and metals. To accomplish this, handle samples in glass vessels, use Teflon-lined or coated materials, and maintain the samples... 

---