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5.1 The primary advantage of RUS is its ability of making numerous measurements in a single test. In addition, it can examine rough ground parts. It requires little sample preparation, no couplants, and generally will work with soiled items; however, it has limited capability with soft materials. Soft metals, polymers, rubbers, and wood parts must be considered on a case by case basis.1.1 This guide describes a procedure for detecting defects in metallic and non-metallic parts using the resonant ultrasound spectroscopy method. The procedure is intended for use with instruments capable of exciting and recording whole body resonant states within parts which exhibit acoustical or ultrasonic ringing. It is used to distinguish acceptable parts from those containing defects, such as cracks, voids, chips, density defects, tempering changes, and dimensional variations that are closely correlated with the parts' mechanical system dynamic response.1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

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5.1 Since the beginning of human history, currency has existed in the form of metal coins and bullion. Thieves learned that shaving some precious metal provided a method to change its value. Substitution of common metals for precious metals of higher value was commonplace until weighing methods became so accurate, that it became easily detected. Alloys were also used as substitutes until inexpensive spectrometers became available which ended the counterfeiting practice. The rapid rise in the value of gold inspired the unscrupulous to find a new method. Tungsten was widely used for light bulb filaments until regulations changed that market. The great abundance of tungsten now available, coupled with the almost identical density of gold, presented a new opportunity.5.2 RUS provides a method to create an unique electronic signature for each piece tested which is operator independent.1.1 This practice is intended for use with resonant ultrasound spectrometers capable of exciting, measuring, recording, and analyzing multiple whole body mechanical vibration resonant frequencies within parts exhibiting acoustical ringing in the acoustic or ultrasonic, or both, resonant frequency ranges.1.2 This practice uses Resonant Ultrasound Spectroscopy (RUS) to distinguish conforming parts, as determined from qualified training sets, from those containing significant anomalies in their elastic properties.1.3 The basic functions of a RUS monitoring system are to detect and classify resonance phenomena. Solid structure resonances are governed by the part’s dimensions, density, and elastic properties. When a material substitution occurs in a precious metal, the chosen metals have almost identical densities and unchanged dimensions, leaving only the elastic properties to affect the resonances.1.4 This practice can be used to replace destructive methods, which damage the test object through drilling or melting, or both.1.5 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard.1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.7 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

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5.1 This method allows for the evaluation of seal quality by passing an ultrasound signal through the sealed area of a package or item. Poorly sealed areas will not transmit as much ultrasonic energy as properly sealed areas.5.2 This method relies on quantitative analysis of ultrasound signal strength, providing a non-subjective approach to assessing package seal quality and detecting defects.5.3 This technique has been used for inspecting a variety of materials including flexible pouch seals, rigid tray seals and other packaging components such as affixed valves. The precision and bias for any specific package and seal configuration needs to be individually determined and validated.5.4 The C-Scan approach is useful for laboratory applications or off-line seal inspection. The L-Scan approach can be used for on-line, real time inspection of seal quality. The sensitivity of either approach to detect a given defect size and level of severity needs to be individually determined.5.5 Sound waves propagate at different speeds through different materials generally moving faster through more dense materials. The acoustic impedance (expressed as g/cm2·μs) is the product of density (g/cm3) and velocity (cm/μs). Of particular importance is the extreme difference between the impedance of air and that of any solid material. Any gap or poorly bonded area can be readily detected.Material Velocity(cm/μsec) Density(g/cm3) AcousticImpedance(g/cm2-μsec)Air (20°C, 1 bar) 0.0344 0.00119 0.000041Water (20°C) 0.148 1.0 0.148Polyethylene 0.267 1.1 0.294Aluminum 0.632 2.7 1.7101.1 This standard method describes the technology and testing procedures that can be used to detect seal defects in the size range of 1 mm and characterize seal quality in a variety of packaging styles using airborne ultrasound technology.1.2 This test method does not purport to be the only method for measurement of seal quality.1.3 Heat seals and other package components can be tested in flexible, semi-rigid and rigid packages. Only the precision and bias for flexible package seals were evaluated in a recent ILS included in the method. The precision and bias for any specific package needs to be individually determined.1.4 On-line, real time inspection of seals can be considered particularly in the L-Scan mode.1.5 This method provides a non-destructive, quantitative, non-subjective approach to flexible package seal inspection.1.6 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.8 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

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4.1 The density of polyethylene is a conveniently measurable property which is frequently useful as a means of following physical changes in a sample, as an indication of uniformity among samples, and as a means of identification.4.2 This test method is designed to yield results with a precision of ±0.08 % or better.1.1 This test method covers the determination of the density of polyethylene through the utilization of ultrasound equipment.1.2 This test method is based on the distinct behaviors of the amorphous and crystalline phases of polyethylene in response to ultrasound. Polyethylene shall be viewed as a composite structure where high-density crystalline regions are connected by lower-density amorphous material. The ratio of crystalline to amorphous material determines the final density of the material. The amorphous and crystalline phases exhibit very distinct behaviors with regard to the propagation of sound waves. The propagation characteristics in the composite will depend on the relative amount of the two phases (the degree of crystallinity).1.3 Inorganic materials increase density as measured by Test Methods D792 and D1505, but they have little or no effect on ultrasonic density. The ultrasonic measurement is basically a base resin density.1.4 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.NOTE 1: There is no known ISO equivalent to this standard.1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

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