4.1 This test system has advantages in certain respects over the use of static loading systems in the measurement of glass and glass-ceramics:4.1.1 Only minute stresses are applied to the specimen, thus minimizing the possibility of fracture.4.1.2 The period of time during which stress is applied and removed is of the order of hundreds of microseconds, making it feasible to perform measurements at temperatures where delayed elastic and creep effects proceed on a much-shortened time scale, as in the transformation range of glass, for instance.4.2 The test is suitable for detecting whether a material meets specifications, if cognizance is given to one important fact: glass and glass-ceramic materials are sensitive to thermal history. Therefore the thermal history of a test specimen must be known before the moduli can be considered in terms of specified values. Material specifications should include a specific thermal treatment for all test specimens.1.1 This test method covers the determination of the elastic properties of glass and glass-ceramic materials. Specimens of these materials possess specific mechanical resonance frequencies which are defined by the elastic moduli, density, and geometry of the test specimen. Therefore the elastic properties of a material can be computed if the geometry, density, and mechanical resonance frequencies of a suitable test specimen of that material can be measured. Young's modulus is determined using the resonance frequency in the flexural mode of vibration. The shear modulus, or modulus of rigidity, is found using torsional resonance vibrations. Young's modulus and shear modulus are used to compute Poisson's ratio, the factor of lateral contraction.1.2 All glass and glass-ceramic materials that are elastic, homogeneous, and isotropic may be tested by this test method.2 The test method is not satisfactory for specimens that have cracks or voids that represent inhomogeneities in the material; neither is it satisfactory when these materials cannot be prepared in a suitable geometry. Non-glass and glass-ceramic materials should reference Test Method E1875  for non-material specific methodology to determine resonance frequencies and elastic properties by sonic resonance.NOTE 1: Elastic here means that an application of stress within the elastic limit of that material making up the body being stressed will cause an instantaneous and uniform deformation, which will cease upon removal of the stress, with the body returning instantly to its original size and shape without an energy loss. Glass and glass-ceramic materials conform to this definition well enough that this test is meaningful.NOTE 2: Isotropic means that the elastic properties are the same in all directions in the material. Glass is isotropic and glass-ceramics are usually so on a macroscopic scale, because of random distribution and orientation of crystallites.1.3 A cryogenic cabinet and high-temperature furnace are described for measuring the elastic moduli as a function of temperature from –195 to 1200 °C.1.4 Modification of the test for use in quality control is possible. A range of acceptable resonance frequencies is determined for a piece with a particular geometry and density. Any specimen with a frequency response falling outside this frequency range is rejected. The actual modulus of each piece need not be determined as long as the limits of the selected frequency range are known to include the resonance frequency that the piece must possess if its geometry and density are within specified tolerances.1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this 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.

定价： 590元 / 折扣价： 502 元 加购物车

4.1 The composition and sequential structure of alginate determines the functionality of alginate in an application. For instance, the gelling properties of an alginate are highly dependent upon the monomer composition and sequential structure of the polymer. Gel strength will depend upon the guluronic acid content (FG) and also the average number of consecutive guluronate moieties in G-block structures (NG>1).4.2 Chemical composition and sequential structure of alginate can be determined by 1H- and 13C-nuclear magnetic resonance spectroscopy (NMR). A general description of NMR can be found in <761> of the USP 35-NF30. The NMR methodology and assignments are based on data published by Grasdalen et al. (1979, 1981, 1983).4, 5, 6 The NMR technique has made it possible to determine the monad frequencies FM (fraction of mannuronate units) and FG (fraction of guluronate units), the four nearest neighboring (diad) frequencies FGG, FMG, FGM, FMM, and the eight next nearest neighboring (triad) frequencies FGGG, FGGM, FMGG, FMGM, FMMM, FMMG, FGMM, FGMG. Knowledge of these frequencies enables number averages of block lengths to be calculated. NG is the number average length of G-blocks, and NG>1 is the number average length of G-blocks from which singlets (-MGM-) have been excluded. Similarly, NM is the number average length of M-blocks, and NM>1 is the number average length of M-blocks from which singlets (-GMG-) have been excluded. 13C NMR must be used to determine the M-centered triads and NM>1. This test method describes only the 1H NMR analysis of alginate. Alginate can be well characterized by determining FG and NG>1.4.3 In order to obtain well-resolved NMR spectra, it is necessary to reduce the viscosity and increase the mobility of the molecules by depolymerization of alginate to a degree of polymerization of about 20 to 50. Acid hydrolysis is used to depolymerize the alginate samples. Freeze-drying, followed by dissolution in 99 % D2O, and another freeze-drying before dissolution in 99.9 % D2O yields samples with low 1H2O content. TTHA is used as a chelator to prevent traces of divalent cations to interact with alginate. While TTHA is a more effective chelator, other agents such as EDTA and citrate may be used. Such interactions may lead to line broadening and selective loss of signal intensity.4.4 Samples are analyzed at a temperature of 80 ± 1°C. Elevated sample temperature contributes to reducing sample viscosity and repositions the proton signal of residual water to an area outside that of interest.1.1 This test method covers the determination of the composition and monomer sequence of alginate intended for use in biomedical and pharmaceutical applications as well as in Tissue Engineered Medical Products (TEMPs) by high-resolution proton NMR (1H NMR). A guide for the characterization of alginate has been published as Guide F2064.1.2 Alginate, a linear polymer composed of β-D-mannuronate (M) and its C-5 epimer α-L-guluronate (G) linked by β-(1—>4) glycosidic bonds, is characterized by calculating parameters such as mannuronate/guluronate (M/G) ratio, guluronic acid content (G-content), and average length of blocks of consecutive G monomers (that is, NG>1 ). Knowledge of these parameters is important for an understanding of the functionality of alginate in TEMP formulations and applications. This test method will assist end users in choosing the correct alginate for their particular application. Alginate may have utility as a scaffold or matrix material for TEMPs, in cell and tissue encapsulation applications, and in drug delivery formulations.1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.4 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 and health practices and determine the applicability of regulatory limitations prior to use.

定价： 0元 / 折扣价： 0 元

4.1 The degree of deacetylation of chitosan salts is an important characterization parameter since the charge density of the chitosan molecule is responsible for potential biological and functional effects.4.2 The degree of deacetylation (% DDA) of water-soluble chitosan salts can be determined by 1H nuclear magnetic resonance spectroscopy (1H NMR). Several workers have reported on the NMR determination of chemical composition and sequential arrangement of monomer units in chitin and chitosan. The test method described is primarily based on the work of Vårum et al. (1991),5 which represents the first publication on routine determination of chemical composition in chitosans by solution state 1H NMR spectroscopy. This test method is applicable for determining the % DDA of chitosan chloride and chitosan glutamate salts. It is a simple, rapid, and suitable method for routine use. Quantitative 1H NMR spectroscopy reports directly on the relative concentration of chemically distinct protons in the sample, consequently, no assumptions, calibration curves or calculations other than determination of relative signal intensity ratios are necessary.4.3 In order to obtain well-resolved NMR spectra, depolymerization of chitosans to a number average degree of polymerization (DPn) of ~15 to 30 is required. This reduces the viscosity and increases the mobility of the molecules. Although there are several options for depolymerization of chitosans, the most convenient procedure is that of nitrous acid degradation in deuterated water. The reaction is selective, stoichiometric with respect to GlcN, rapid, and easily controlled (Allan & Peyron, 1995).6 The reaction selectively cleaves after a GlcN-residue, transforming it into 2,5-anhydro-D-mannose (chitose), consequently, depletion of GlcN after depolymerization is expected. On the other hand, the chitose unit displays characteristic 1H NMR signals the intensity of which may be estimated and utilized in the calculation of % DDA, eliminating the need for correction factors. Using the intensity of the chitose signals, the number average degree of polymerization can easily be calculated as a control of the depolymerization.4.4 Samples are equilibrated and analyzed at a temperature of 90 ± 1°C. Elevated sample temperature contributes to reducing sample viscosity and repositions the proton signal of residual water to an area outside that of interest. While samples are not stored at 90°C but only analyzed at this elevated temperature, the NMR tubes should be sealed with a stopper to avoid any evaporation. At a sample pH* of 3.8-4.3 (see 6.1.5 below), artifactual deacetylation of the sample does not occur during the short equilibration and analysis time.4.5 A general description of NMR can be found in <761> of the USP 35-NF30.1.1 This test method covers the determination of the degree of deacetylation in chitosan and chitosan salts intended for use in biomedical and pharmaceutical applications as well as in Tissue Engineered Medical Products (TEMPs) by high-resolution proton NMR (1H NMR). A guide for the characterization of chitosan salts has been published as Guide F2103.1.2 The test method is applicable for determining the degree of deacetylation (% DDA) of chitosan chloride and chitosan glutamate salts and is valid for % DDA values from 50 up to and including 99. It is simple, rapid, and suitable for routine use. Knowledge of the degree of deacetylation is important for an understanding of the functionality of chitosan salts in TEMP formulations and applications. This test method will assist end users in choosing the correct chitosan for their particular application. Chitosan salts may have utility in drug delivery applications, as scaffold or matrix material, and in cell and tissue encapsulation applications.1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.4 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.1.5 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.

定价： 590元 / 折扣价： 502 元 加购物车

定价： 646元 / 折扣价： 550 元 加购物车

定价： 590元 / 折扣价： 502 元 加购物车

定价： 590元 / 折扣价： 502 元 加购物车

定价： 590元 / 折扣价： 502 元 加购物车

定价： 515元 / 折扣价： 438 元 加购物车

定价： 646元 / 折扣价： 550 元 加购物车

5.1 PCRT Applications and Capabilities—PCRT PTI examination has been applied successfully to a wide range of parts in manufacturing and maintenance environments. Examples of manufacturing processes, repair processes, and in-service damage mechanisms evaluated with PTI are discussed in 1.1. PCRT has been shown to provide cost effective and accurate PTI-based NDT, process monitoring, and life monitoring in many industries including automotive, aerospace, and power generation. Examples of successful applications currently employed in commercial use include, but are not limited to:(1) Heat treatment operations:(a) Aerospace gas turbine engine components (blades, vanes, disks)(b) Additively manufactured components(c) Steel mechanical components(d) Industrial gas turbine blades(2) Induction hardening and carburization (both case-hardened and through-hardened parts):(a) Gears(b) Ballnuts(3) Hot Isostatic Pressing (HIP):(a) Gas turbine engine components (blades, vanes, disks)(b) Additively manufactured components(4) Shot peening:(a) Steel mechanical components(5) In-service thermal history, aging, creep damage, fatigue:(a) Gas turbine engine components (blades, vanes, disks)(b) Industrial gas turbine blades(c) Aircraft landing gear wheels(6) Maintenance repair/rejuvenation processes:(a) Gas turbine engine components (blades, vanes, disks)(b) Industrial gas turbine blades(c) Aircraft landing gear wheels.5.2 General Approach and Equipment Requirements for PCRT via Swept Sine Input: 5.2.1 PCRT systems comprise hardware and software capable of inducing vibrations, recording the component response to the induced vibrations, and analyzing the data collected. Inputting a swept sine wave into the part has proven to be an effective means of introducing mechanical vibration and can be achieved with a high-quality signal generator coupled with an appropriate active transducer in physical contact with the part. Collection of the part’s resonance response is achieved by recording the signal received by an appropriate passive vibration transducer. The software required to analyze the available data may include a variety of suitable statistical analysis and pattern recognition tools. Measurement accuracy and repeatability are extremely important to the application of PCRT.5.2.2 Hardware Requirements—A swept sine wave signal generator and response measurement system operating over the desired frequency range of the test part are required with accuracy better than 0.002 %. The signal generator should be calibrated to applicable industry standards. Transducers must be operable over same frequency range. Three transducers are typically used; one Drive transducer and two Receive transducers. Transducers typically operate in a dry environment, providing direct contact coupling to the part under examination. However, noncontacting response methods can operate suitably when parts are wet or oil-coated. Other than fixturing and transducer contact, no other contact with the part is allowed as these mechanical forces dampen certain vibrations. For optimal examination, parts should be placed precisely on the transducers (generally, ±0.062 in. (1.6 mm) in each axis provides acceptable results). The examination nest and cabling shall isolate the Drive from Receive signals and ground returns, so as to not produce (mechanical or electrical) cross talk between channels. Excessive external vibration or audible noise, or both, will compromise the measurements.5.3 Constraints and Limitations: 5.3.1 PCRT cannot separate parts based on visually detectable anomalies that do not affect the structural integrity of the part. It may be necessary to provide additional visual inspection of parts to identify these indications.5.3.2 Excessive variation in part geometry or base material properties may limit the sensitivity of PCRT PTI examination.5.3.3 A direct measurement of a single geometric dimension of a region undergoing a material state change, such as the case depth (in centimeters or inches) of an induction hardened region, is generally not possible with PCRT PTI. The frequency changes are dependent on the total volumetric effect of the process that causes the material state change. With accurately trained acceptability limits, however, PCRT PTI is very effective at screening populations of components for acceptable and unacceptable processing.5.3.4 PCRT will only work with stiff objects that provide resonances whose peak quality factor (Q) values are greater than 500. Non-rigid materials or very thin-walled parts will not yield useful Q values.5.3.5 While PCRT can be applied to painted and coated parts in many cases, the presence of some surface coatings such as vibration absorbing materials and heavy oil layers may limit or preclude the application of PCRT.5.3.6 While PCRT PTI examination can be applied to parts over a wide range of temperatures, it cannot be applied to parts that are rapidly changing temperature. The part temperature should be stabilized before collecting resonance data.5.3.7 Misclassified parts in the teaching set, along with the presence of unknown anomalies in the teaching set, can significantly reduce the accuracy and sensitivity of PCRT.1.1 This practice covers a general procedure for using the Process Compensated Resonance Testing (PCRT) via swept sine input method to perform Part-to-Itself (PTI) examination on populations of newly manufactured and in-service parts. PCRT detects resonance pattern differences in metallic and non-metallic parts. Practice E2534 for Defect Detection with PCRT and Practice E3081 for Outlier Screening with PCRT cover the development and application of PCRT sorting modules that inspect a part at a single point in time. These methods use the resonance frequency spectra recorded from test parts and perform different statistical analyses to compare test parts to reference populations. These comparisons include, and must compensate for, the normal geometric, material, and processing variations present in any population of parts. In many applications, however, the user may need to evaluate the effects of a single processing step or in-service load in isolation from other sources of variation. For example, a manufacturer may want to perform process monitoring and control on a heat treatment or hardening process. A maintainer may want to evaluate the effect of service cycles in an engine. A PCRT PTI examination measures the resonance frequency spectrum of a part at two points in time, such as before and after a manufacturing process step, and calculates the change in resonance frequencies to evaluate the effect of the intervening process. Control limits can be set on the frequency change to field a PTI PASS/FAIL inspection capability. The limits may be based on training populations of parts with acceptable and unacceptable levels of change, model predictions of the effects of part changes, or criteria derived from process control practices. Manufacturing processes and in-service loads that can be evaluated with a PCRT PTI inspection include, but are not limited to heat treatment, hot isostatic pressing (HIP), shot peening, induction hardening, carburization, coating, thermal history changes, residual stress changes, creep, plastic deformation, corrosion, and fatigue. This practice is intended for use with instruments capable of exciting, measuring, recording, and analyzing multiple, whole body, mechanical vibration resonance frequencies in acoustic or ultrasonic frequency ranges, or both.1.2 Units—The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered 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.

定价： 590元 / 折扣价： 502 元 加购物车

5.1 Performance properties are dependent on the number and type of short chain branches. This test method permits measurement of these branches for ethylene copolymers with propylene, butene-1, hexene-1, octene-1, and 4-methylpentene-1.1.1 This test method determines the molar composition of copolymers prepared from ethylene (ethene) and a second alkene-1 monomer. This second monomer can include propene, butene-1, hexene-1, octene-1, and 4-methylpentene-1.1.2 Calculations of this test method are valid for products containing units EEXEE, EXEXE, EXXE, EXXXE, and of course EEE where E equals ethene and X equals alkene-1. Copolymers containing a considerable number of alkene-1 blocks (such as, longer blocks than XXX) are outside the scope of this test method.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 and health practices and determine the applicability of regulatory limitations prior to use. See Section 8 for a specific hazard statement.NOTE 1: There is no known ISO equivalent to this standard.

定价： 590元 / 折扣价： 502 元 加购物车

5.1 This test method may be used for material development, characterization, design data generation, and quality control purposes. It is specifically appropriate for determining the modulus of advanced ceramics that are elastic, homogeneous, and isotropic.5.1.1 This test method is nondestructive in nature. Only minute stresses are applied to the specimen, thus minimizing the possibility of fracture.5.1.2 The period of time during which measurement stress is applied and removed is of the order of hundreds of microseconds. With this test method it is feasible to perform measurements at high temperatures, where delayed elastic and creep effects would invalidate modulus measurements calculated from static loading.5.2 This test method has advantages in certain respects over the use of static loading systems for measuring moduli in advanced ceramics. It is nondestructive in nature and can be used for specimens prepared for other tests. Specimens are subjected to minute strains; hence, the moduli are measured at or near the origin of the stress-strain curve with the minimum possibility of fracture. The period of time during which measurement stress is applied and removed is of the order of hundreds of microseconds. With this test method it is feasible to perform measurements at high temperatures, where delayed elastic and creep effects would invalidate modulus measurements calculated from static loading.5.3 The sonic resonant frequency technique can also be used as a nondestructive evaluation tool for detecting and screening defects (cracks, voids, porosity, density variations) in ceramic parts. These defects may change the elastic response and the observed resonant frequency of the test specimen. Guide E2001 describes a procedure for detecting such defects in metallic and nonmetallic parts using the resonant frequency method.5.4 Modification of this test method for use in quality control is possible. A range of acceptable resonant frequencies is determined for a specimen with a particular geometry and mass. Any specimen with a frequency response falling outside this frequency range is rejected. The actual modulus of each specimen need not be determined as long as the limits of the selected frequency range are known to include the resonant frequency that the specimen must possess if its geometry and mass are within specified tolerances.1.1 This test method covers the determination of the dynamic elastic properties of advanced ceramics. Specimens of these materials possess specific mechanical resonant frequencies that are determined by the elastic modulus, mass, and geometry of the test specimen. Therefore, the dynamic elastic properties of a material can be computed if the geometry, mass, and mechanical resonant frequencies of a suitable rectangular or cylindrical test specimen of that material can be measured. The resonant frequencies in flexure and torsion are measured by mechanical excitation of vibrations of the test specimen in a suspended mode (Section 4 and Figs. 1 and 4). Dynamic Young’s modulus is determined using the resonant frequency in the flexural mode of vibration. The dynamic shear modulus, or modulus of rigidity, is found using torsional resonant vibrations. Dynamic Young’s modulus and dynamic shear modulus are used to compute Poisson’s ratio.1.2 This test method is specifically appropriate for advanced ceramics that are elastic, homogeneous, and isotropic (1).2 Advanced ceramics of a composite character (particulate, whisker, or fiber reinforced) may be tested by this test method with the understanding that the character (volume fraction, size, morphology, distribution, orientation, elastic properties, and interfacial bonding) of the reinforcement in the test specimen will have a direct effect on the elastic properties. These reinforcement effects must be considered in interpreting the test results for composites. This test method is not satisfactory for specimens that have cracks or voids that are major discontinuities in the specimen. Neither is the test method satisfactory when these materials cannot be fabricated in a uniform rectangular or circular cross-section.1.3 A high-temperature furnace and cryogenic cabinet are described for measuring the dynamic elastic moduli as a function of temperature from −195 to 1200 °C.1.4 There are material-specific ASTM standards that cover the determination of resonance frequencies and elastic properties of specific materials by sonic resonance or by impulse excitation of vibration. Test Methods C215, C623, C747, C848, C1259, E1875, and E1876 may differ from this test method in several areas (for example: sample size, dimensional tolerances, sample preparation, calculation details, etc.). The testing of those materials should be done in compliance with the appropriate material-specific standards. Where possible, the procedures, sample specifications, and calculations in this standard are consistent with the other test methods.1.5 The values stated in SI units are to be regarded as the standard. The non-SI values given in parentheses are for information only and are not considered 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.

定价： 646元 / 折扣价： 550 元 加购物车

4.1 IEM Applications and Capabilities—IEM has been successfully applied to a wide range of NDT applications in the manufacture, maintenance, and repair of metallic and non-metallic parts. Examples of anomalies detected are discussed in 1.1 and 6.2. IEM has been proven to provide fast, cost-effective, and accurate NDT solutions in nearly all manufacturing, maintenance, or repair modalities. Examples of the successful application focuses include, but are not limited to: sintered powder metals, castings, forgings, stampings, ceramics, glass, wood, weldments, heat treatment, composites, additive manufacturing, machined products, and brazed products.4.2 General Approach and Equipment Requirements for IEM: 4.2.1 IEM systems are comprised of hardware and software capable of inducing vibrations, recording the component response to the induced vibrations, and executing analysis of the data collected.4.2.2 Hardware Requirements—Examples of a tabletop impact excitation system and a production-grade drop excitation system are shown in Fig. 1 and Fig. 2, respectively. IEM systems include: an excitation device (for example, modal hammer / impact device / dropping system) providing an impulse excitation to the object, a vibration detector (for example., microphone), a signal amplifier, an Analog-to-Digital Converter (ADC), an embedded logic, and a data User Interface (UI). Tested parts can typically be on any surface type, but they can also be supported (for example, foam support, held with an elastic) in consideration of possible damping influences. The following schematics show the basic parts for an impact excitation approach (Fig. 3) and a drop excitation approach (Fig. 4).FIG. 1 IEM Tabletop Testing System Using a Non-Instrumented ImpactorFIG. 2 Production-Grade Drop Excitation SystemFIG. 3 Schematic of Impact Excitation ApproachFIG. 4 Schematic of Drop Excitation Approach4.3 Constraints and Limitations: 4.3.1 IEM needs a change in structural integrity to properly sort different parts. This means that parts with only cosmetic issues, such as a visual surface anomaly would still need be inspected with a focused visual inspection.4.3.2 The location of a flaw or specific flaw type characterization is challenging. As IEM measures the whole-body response of a part, location and categorization of defects usually requires additional data (such as additional nondestructive and destructive evaluation) and analysis.4.3.3 Large raw material or process variation, or both, may limit the sensitivity of IEM without some method for compensating for those variations.4.3.4 Groups of parts with a wide range of physical temperatures are not good subjects for IEM without some method for compensating for those variations. Temperature affects the natural frequencies, so stabilization of temperature is desired for parts testing. Data can be taken over a large range of temperatures, as long as the parts are stable during the testing.4.3.5 IEM is a volumetric inspection method. Sensitivity to defects will be driven by the size of the defect relative to the size and mass of the part. For example, a small hairline crack of a certain length that may be detectable in a 0.5 lb part may not be detectable in a 100 lb part.4.3.6 The expected useful frequency range of the part to be tested must be considered when selecting and configuring an IEM examination. Many IEM systems are limited to detecting frequencies up to 50 kHz, but more modern systems have demonstrated detection of frequencies up to 150 kHz on some parts. Parts with small dimensions or parts made from certain materials, or both, may have resonance spectra that fall partially or entirely outside of the frequency range of some IEM systems. The physics of energy distribution from the impulse and attenuation from interfering harmonic modes can also cause a reduction in signal-to-noise ratio at the higher end of IEM frequency ranges.4.3.7 Materials that resonate poorly or dampen vibrations are typically not good candidates for IEM examination.1.1 This practice covers a general procedure for using the Impulse Excitation Method (IEM) to facilitate natural frequency measurement and detection of defects and material variations in metallic and non-metallic parts. This test method is also known as Impulse Excitation Technique (IET), Acoustic Resonance Testing (ART), ping testing, tap testing, and other names. IEM is listed as a Resonance Ultrasound Spectroscopy (RUS) method. The method applies an impulse load to excite and then record resonance frequencies of a part. These recorded resonance frequencies are compared to a reference population or within subgroups/families of examples of the same part, or modeled frequencies, or both.1.2 Absolute frequency shifting, resonance damping, and resonance pattern differences can be used to distinguish acceptable parts from parts with material differences and defects. These defects and material differences include, cracks, voids, porosity, material elastic property differences, and residual stress. IEM can be applied to parts made with manufacturing processes including, but not limited to, powdered metal sintering, casting, forging, machining, composite layup, and additive manufacturing (AM).1.3 This practice is intended for use with instruments capable of exciting, measuring, recording, and analyzing multiple whole body, mechanical vibration resonance frequencies in acoustic or ultrasonic frequency ranges, or both. This practice does not provide inspection acceptance criteria for parts. However, it does discuss the processes for establishing acceptance criteria specific to impulse testing. These criteria include frequency acceptability windows for absolute frequency shifting, scoring criteria for statistical analysis methods (Z-score), Gage Repeatability & Reproducibility (R&R) for diagnostic resonance modes, and inspection criteria adjustment (compensation) for manufacturing process and environmental variations.1.4 This practice uses inch pound units as primary units. SI units are included in parentheses for reference only and are mathematical conversions of the primary units.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.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.

定价： 646元 / 折扣价： 550 元 加购物车

定价： 646元 / 折扣价： 550 元 加购物车

5.1 This test method describes a test procedure for evaluating the ∆T associated with RF power deposition during an MR procedure, involving a specific frequency of RF irradiation of a passive implant. The method allows characterization of the heating propensity of an implant rather than the prediction of heating during a specific MR procedure in a patient. The results may be used as an input to a computational model for estimating ∆T due to the presence of that implant in a patient. The combination of the test results and the computational model results may then be used to help assess the safety of a patient with the implant during an MR examination.1.1 This test method covers measurement of radio frequency (RF)-induced heating on or near a passive medical implant within a phantom during magnetic resonance imaging (MRI). The test method does not specify levels of heating considered to be safe to the patient and relies on users to define their own acceptance criteria.1.2 This test method does not address other possible safety issues which include, but are not limited to: issues of magnetically-induced displacement, magnetically-induced torque, image artifact, acoustic noise, tissue heating, interaction among devices, and the functionality of the device and the MR system.1.3 The amount of RF-induced temperature rise (∆T) for a given incident electric field will depend on the RF frequency, which is dependent on the static magnetic field strength of the MR system. While the focus in this test method is on 1.5 tesla (T) or 3 T MR systems, the ∆T for an implant in MR systems of other static magnetic field strengths or magnet designs can be evaluated by suitable modification of the method described herein.1.4 This test method assumes that testing is done on devices that will be entirely inside the body. Testing for devices with other implantation conditions (e.g., external fixation devices, percutaneous needles, catheters or tethered devices such as ablation probes) is beyond the scope of this standard; for such devices, modifications of this test method may be necessary.NOTE 1: RF-heating induced by any electrically conductive implanted device may be impacted by the presence of other metallic or otherwise electrically conductive devices present nearby.1.5 This test method is written for several possible RF exposure systems, including Volume RF transmit coils. The exposure system needs to be properly characterized, within the stated uncertainties, in term of local background RF exposure for the implants which are tested.1.6 The values stated in SI units are to be regarded as standard.1.7 A device with deployed dimensions of less than 2 cm in all directions may not need to be tested with respect to RF-induced heating, as it is expected to generate ∆T of less than 2°C over 1 h of exposure at 1.5 T/64-MHz or 3 T/128-MHz frequencies (1, 2)2 and ANSI/AAMI/ISO 14708-3:2017). This condition is not valid when multiple replicas of the device (e.g., multiple anchors) are implanted within 3 cm of the device.NOTE 2: The above values were derived from existing data and literature. The 3 cm distance is recommended to avoid any RF coupling with other neighboring devices.1.8 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.1.9 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.

定价： 646元 / 折扣价： 550 元 加购物车