QUANTITATIVE TESTS 



Four quantitative tests are discussed in this section: water 

 test, abrasion test, cleanliness test, and density test. 



Water Test 



The following water properties of sponges were quantitatively 

 determined: 



l a K^ - water-holding power 



2 . K_ - squeezed wetness 



©It 



3. K - cleanability 

 km Kg - stiffness 



5. K - elasticity 



6. K sr - shape recovery 



These properties are express- 

 ed by mathematical symbols — K^Kg^. 

 and so on — because all are calcu- 

 lated values that are computed from 

 measurements made on the sponge • 

 These measurements were as follows: 



V - Bulk volume of sponge. 



Wfr - Volume of water absorbed. 



THht- Volume of water absorbed 

 after sponge has been 

 tipped. 



Figure 10. — Wet test equipment. 



W r - Volume of water remaining 



after sponge has been pressed. 



Hg - Height of uncompressed sponge. 



H c - Height of compressed sponge, 



H r - Height immediately after pressure is released. 

 Hp - Height 2 minutes after pressure is released. 



The device used for obtaining these measurements is shown in 



figure 10. This device consists of three concentric cans supported, 

 one above the other, by a framework of three pipes welded together in 

 such a manner as to form a triangular tower U-l/2 feet high. A pulley 

 device is attached to the top of the tower for raising and lowering 

 the top can. 



37 



