Taha Selman Cakir
030070023
10th week


Biocides (in polymer additives):

The biggest customers for biocidesare outside the plastic industry, which actually accounts for only a very small fraction of all the biocides used. According to the Biocide Information Service, the most important single antimocrobial application in plastics is PVC flooring which uses more than a third of all the biocides incorporated in plastics products. The second most important application is the protection of hygienic surfaces such as worktops. Smaller amounts are used in PVC pool liners, floorcoverings, artificial leather, tarpaulins and tents. Other outlets include rubbish sacks, food packaging and footwear. In japan, antimicrobials are used in telephone hand sets (one of the commonest sites of infection) and in pens. There are growing markets for biocides in medical devices and wood plastics composites.

The original purpose of antimicrobial additives in plastics was to protect the materials, not the users. This applied especially to flexible PVC which needs protection in moist atmospheres from mildew, moulds and funghi. The situation has changed considerably in the last five years, with more use being made of antimicrobial products designed to promote a hygienic image for the product, to protect surfaces and to reassure human users of bathroom, medical and food related products.

(Pritchard G., Plastic additives, 2005, p. 85)


Creep feed grinding:

Creep feed grinding is a new form of grinding operation different from the conventional grinding process. In creep feed grinding the entire depth of cut is completed is one pass only using very small in feed rates. As shown in Fig. 9.16, this process is characterized by high depth of cut o the order of 1 to 30 mm with low work speeds of the order of 1 to 0,025 m/min. The actual removal rates calculated from these process parameters are generally in the same range as that of conventional grinding. However, the idle time (stopping and wheel/table reversal) gets reduced since the grinding operation is completed in one pass.











(Rao P. N., Manufacturing technology: metal cutting and machine tools, p. 235)


Diecast alloys:

The four major types of alloys that are die cast are zinc, aluminum, magnesium, and copper-based alloys. The die-casting process was developed in the nineteenth century for the manufacture of lead/tin alloy parts. However, lead and tin are now very rarely die cast because of their poor mechanicalproperties. A tabulation of the specific gravity, mechanical properties, and cost of commonly used examples of the four principal alloy groups is given in Table 10.1.

(Boothroyd G., Dewhurst P., Knight W. A., Product design for manufacture and assembly, Ed. 3rd, p. 423,424)

NED (North–East–Down) frame:

The NED frame can be found if the nearest point Q from the point P is determined on the rotational ellipsoid which will be the origin of the KNED frame. Then the tangential plane at the point Q will be determined in which plane the orthonormal coordinate axes xNED, yNED, and zNED points to local north, east, and down, respectively. Notice that zNED points downwards, inside the rotational ellipsoid.

(Lantos B., Marton L., Nonlinear conrol of vehicles and robots, Ed. 1st, p. 107)