Bell telephone test

Bell telephone test ASTM D1693-59T uses Igepal 630 at 50°C as a stress test. Results are given in hours to stress crack on a notched bent strip. 

ASTM D1693 [209] is a test specifically for polyethylene and is generally known as the Bell Telephone Test. It consists of bending a strip of plastic into which has been cut a... 

Figure 38 Stress cracking —Bell telephone test.

ESC resistance. In the Bell Telephone test, a razor cut is made parallel to the length of rectangular 38 x 13 x 3 mm specimen. It is bent into a U shape, with maximum surface tensile strain of about 12% and placed in concentrated surface active agent at 50 °C. The time until cracks appear, at the corner between the cut and the tensile surface, is measured. The cut does not create a stress concentration, because it is parallel to the bending stresses, but the two free surfaces may assist the crack opening process. 

Table 4.25 Time to fracture by means of the Bent Strip Method (using notched samples incl. Bell Telephone Test).

A laboratory programme on ESC was formulated to back up the site work. This ensured that data was available on the effect of likely organics to be encountered and possibly to define the life of HDPE under gross spillage conditions. HDPE samples (Bell telephone test, U-bend specimens. 

Physical Properties. Tensile test pieces were cut with an ASTM T50 die, modified by putting a radius as specified in Bell Telephone Laboratories, Inc., drawing B604844, on the junction between the tongues and the reduced section. Dumbbells of this small size were used to facilitate simultaneous irradiation in the water-cooled cell under nitrogen. These dumbbells were pulled at 2 inches a minute for both tensile strength and elongation at rupture measurements at ambient temperature. 

The brittle point test developed by the Bell Telephone Laboratories is simple and sensitive. It is believed that this test may be used to study all cold-resistance problems where damage to the rubber itself and not increase in stiffness is the first consideration. 

First, there was the call from Washington. Although the line was not busy, there was a cacophony of excited voices as if tests were being made on Bell s first telephone. Too bad, I thought, that Farben s technical men hadn t gotten into this field I hung up to wait for a better connection. 

Oxidative induction time (OIT) provides an index useful in comparing the relative resistance to oxidation of a variety of hydrocarbon materials. The OIT procedure was first developed in 1975 by Gilroy and coworkers at Bell Laboratory as a test procedure to screen polyethylene insulation used in telephone wire and cable for its oxidation resistance. The method first became available as a Western Electric Specification and later as ASTM Test Method for Copper-Induced Oxidative Induction Time of Polyolefins. Polyolefin manufacturers quickly embraced the procedure and began to apply it to other applications including raw resins, finished pipes, wire and cable insulation, and, most recently, geosynthetic waste pit liners (ASTM D3895 2009). 

The telephone was invented by people from several countries. In the United States, papers from Alexander Graham Bell and F.lisha Gray were filed on the same day in 1876. BeU received the patent, and this patent has withstood the test of time. 

Figure 1. The air conditioning room of the Laboratory of Ventilation and Illumination at the Harvard School of Public Health in 1924. In this sealed cement room, insulated with two inches of cork, temperature, humidity, and airflow were mechanically controlled. Next door in the temperature control room, the scientists cahbrated and controlled the chmate conditions and communicated to subjects with wires, bell, and a telephone. The physiological reactions of test subjects were recorded at various levels of exertion, such as riding a stationary bicycle or hfting weights, to simulate labor. From Drinker, Laboratories of Ventilation. ...

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