Puncture defects

Plasticized polymer films are known to possess an unusual property of self-healing. Their sealing capacity is not impaired noticeably even by 100 pm diameter punctures. The data presented in Fig. 2.59a prove that the electrolyte (0.1 N solution of HCl) cannot penetrate through the PE film plasticized by the mineral oil even in the presence of puncture defects and the effect of mechanical vibration. Testing of a plasticized PE film has shown... 

Figure 16.27. A classical lamellar arrangement of bilayers (a) containing (b) a puncture defect and (c) a channel defect...

FML placed on a bed of sand, geotextiles, or other highly permeable materials would allow liquid to move through the defect in the FML, spread over the whole area of the clay liner, and percolate down as if the FML was not there. With clay liner soils that contain some rock, it is sometimes proposed that a woven geotextile be placed on top of the soil liner under the FML to prevent the puncture of rocks through the FML. A woven geotextile between the FML and the clay, however, creates a highly transmissive zone between the FML and the clay. The surface of the soil liner instead should be compacted and the stones removed so that the FML can be placed directly on top of the clay. 

Permeability of an FML is evaluated using the Water Vapor Transmission test.28 A sample of the membrane is placed on top of a small aluminum cup containing a small amount of water. The cup is then placed in a controlled humidity and temperature chamber. The humidity in the chamber is typically 20% relative humidity, while the humidity in the cup is 100%. Thus, a concentration gradient is set up across the membrane. Moisture diffuses through the membrane, and with time the liquid level in the cup is reduced. The rate at which moisture is moving through the membrane is measured. From that rate, the permeability of the membrane is calculated with the simple diffusion equation (Fick s first law). It is important to remember that even if a liner is installed correctly with no holes, penetrations, punctures, or defects, liquid will still diffuse through the membrane. 

Catastrophic rupture of a tank. It may be the result of a manufacturing defect, abusive handling or stress fracture, puncture by a sharp object, or external fire combined with failure of pressure relief device to open. 

A membrane-puncturing theory has been proposed by Davis (Dravnieks 1967). According to this theory, the odorous substance molecules are adsorbed across the interface of the thin lipid membrane, which forms part of the cylindrical wall of the neuron in the chemoreceptor and the aqueous phase that surrounds the neuron. Adsorbed molecules orient themselves with the hydrophilic end toward the aqueous phase. When the adsorbed molecules are desorbed, they move into the aqueous phase, leaving a defect. Ions... 

To investigate the coating adhesion stability one can use a method during which the coating delamination rate is recorded around a handmade point defect (puncture) reaching the substrate [19]. 

Blood samples were collected by venous puncture, centrifuged and the resulting plasma or serum was stored at -20°C until analysis. Samples were collected from patients (n = 103) either suspected of a defect in fatty acid oxidation or an organic acidemia, or from patients known to suffer from any of these defects. All diagnoses were confirmed either enzymatically or using molecular analysis. Reference samples (n = 250) were obtained from hospitalized children in the age from 1 month to 10 years not suspected or suffering from one of the above mentioned disorders. 

Fig. 23 Plan view SEM image of photo-etchpits initiated at the van der Waals surface of WS2, after creating defects by microscopic puncture at selected places and upon PEC etching (adapted from Ref 41).

GEST 90/159B also analyzes a number of other accidents and assesses their causes. Table 9.12 summarizes the incidents that resulted in releases of chlorine. Rail accidents involved 90 wagons in 28 derailments and 17 collisions. None resulted in punctures there were two incidents, attributed to NCI3 decomposition, in which harrels were distorted. Causes of derailment were shunting errors, defective switches, broken axles, and... 

Inspected for damage or defect, such as holes, tears, punctures, cuts, embedded objects, swelling, softening, or hardening ... 

If the material enclosing the lead-painted surface is punctured or not sealed well, lead dust can escape. This system of hazard control must be monitored, and if any defect appears it must be repaired. 

Insulating equipment with any of the following defects may not be used o A hole, tear, puncture, or cut ... 

Personal protective equipment (PPE) must be consistent with workplace hazard assessment. PPE can protect the employee against burns, absorption, abrasions, airborne hazards, punctures, or other hazards. In most cases, such equipment involves the use of gloves, goggles, laboratory coats, and protective shoes (Table 19.1). In each case, workers need to be trained regarding both the need for PPE as well as proper use. Damaged or defective PPE should never be used. 

---