定价： 333元 / 折扣价： 284 元 加购物车

4.1 This test method may be used as a substitute for, or in conjunction with, coring to determine the thickness of slabs, pavements, decks, walls, or other plate structures. There is a certain level of systematic error in the calculated thickness due to the discrete nature of the digital records that are used. The absolute systematic error depends on the plate thickness, the sampling interval, and the sampling period.4.2 Because the wave speed can vary from point-to-point in the structure due to differences in concrete age or batch-to-batch variability, the wave speed is measured (Procedure A) at each point where a thickness determination (Procedure B) is required.4.3 This test method is a pplicable to plate-like structures with lateral dimensions at least six times the thickness. These minimum lateral dimensions are necessary to prevent other modes3 of vibration from interfering with the identification of the thickness mode frequency in the amplitude spectrum. As explained in Note 12, the minimum lateral dimensions and acceptable sampling period are related.4.4 The maximum and minimum thickness that can be measured is limited by the details of the testing apparatus (transducer response characteristics and the specific impactor). The limits shall be specified by manufacturer of the apparatus, and the apparatus shall not be used beyond these limits. If test equipment is assembled by the user, thickness limitations shall be established and documented.4.5 This test method is not applicable to plate structures with overlays, such as a concrete bridge deck with an asphalt or portland cement concrete overlay. The method is based on the assumption that the concrete plate has the same P-wave speed throughout its depth.4.6 Procedure A is performed on concrete that is air dry as high surface moisture content may affect the results.4.7 Procedure B is applicable to a concrete plate resting on a subgrade of soil, gravel, permeable asphalt concrete, or lean portland cement concrete provided there is sufficient difference in acoustic impedance3 between the concrete and subgrade or there are enough air voids at the interface to produce measurable reflections. If these conditions are not satisfied, the waveform will be of low amplitude and the amplitude spectrum will not include a dominant peak at the thickness frequency. If the interface between the concrete and subgrade is rough, the amplitude spectrum will have a rounded peak instead of a sharp peak associated with a flat surface.4.8 The procedures described are not influenced by traffic noise or low frequency structural vibrations set up by normal movement of traffic across a structure.4.9 The procedures are not applicable in the presence of mechanical noise created by equipment impacting (jack hammers, sounding with a hammer, mechanical sweepers, and so forth) on the structure.4.10 Procedure A is not applicable in the presence of high amplitude electrical noise, such as may produced by a generator or some other source, that is transmitted to the data-acquisition system.1.1 This test method covers procedures for determining the thickness of concrete slabs, pavements, bridge decks, walls, or other plate-like structures using the impact-echo method.1.2 The following two procedures are covered in this test method:1.2.1 Procedure A: P-Wave Speed Measurement—This procedure measures the time it takes for the P-wave generated by a short-duration, point impact to travel between two transducers positioned a known distance apart along the surface of a structure. The P-wave speed is calculated by dividing the distance between the two transducers by the travel time.1.2.2 Procedure B: Impact-Echo Test—This procedure measures the frequency at which the P-wave generated by a short-duration, point impact is reflected between the parallel (opposite) surfaces of a plate. The thickness is calculated from this measured frequency and the P-wave speed obtained from Procedure A.1.2.3 Unless specified otherwise, both Procedure A and Procedure B must be performed at each point where a thickness determination is made.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 The text of this standard refers to notes and footnotes that provide explanatory material. These notes and footnotes (excluding those in tables and figures) shall not be considered as requirements of the standard.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

1.1 This practice applies to the classification, design, manufacture, construction, operation, maintenance, and inspection of stationary waves.1.2 Stationary wave systems shall be defined as a system that delivers a constantly flowing sheet of water nominally up to 24 in. thick travelling over a form allowing for patron interaction with a perpetual wave.1.3 Significance and Use: 1.3.1 For the purposes of this practice, a wave system could include:1.3.1.1 The ride surface,1.3.1.2 The ride feature pump(s),1.3.1.3 The water filtration and disinfection system,1.3.1.4 The runout areas,1.3.1.5 The structural supports,1.3.1.6 Vehicles or other aquatic accessories that are part of the water ride as defined by the designer/engineer, and1.3.1.7 Control systems.1.3.2 This practice shall not apply to:1.3.2.1 Amusement rides and devices whose design criterion is specifically addressed in other ASTM standards;1.3.2.2 Preexisting designs manufactured before the effective date of publication of this practice if the design is service proven as defined in Practice F2291; and1.3.2.3 Deep water wave pools, Action Rivers, lazy rivers or waterslides.1.3.3 The terms stationary wave systems, standing wave systems, sheet wave systems, and wave systems shall be considered equivalent when used in this practice.1.4 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.1.5 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： 590元 / 折扣价： 502 元 加购物车

5.1 This test method is a procedure for determining the peak-to-valley depth and the wavelength of roll wave in flat glass and then calculating the optical distortion resulting from that roll wave. Peak-to-valley measurements provide a means of monitoring the roll wave distortion in a heat processed glass product.5.2 Measured peak-to-valley depth provides information required by some specifiers of heat-treated glass products.5.3 Roll wave is inherent in flat glass which has been heat treated in a furnace in which rollers are used to convey the glass.5.4 Consult Specifications C1036 and C1048 for additional glass characteristics and quality information.1.1 This test method is applicable to the determination of the peak-to-valley depth and peak-to-peak distances of the out-of-plane deformation referred to as roll wave which occurs in flat, heat-treated architectural glass substrates processed in a heat processing continuous or oscillating conveyance oven.1.2 This test method does not address other flatness issues like edge kink, ream, pocket distortion, bow, or other distortions outside of roll wave as defined in this test method.1.3 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.1.4 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

5.1 This guide is intended to illustrate the fabrication of ultrasonic reference blocks that are representative of the production material to be examined. Care in material selection and fabrication can result in the manufacture of reference blocks that are ultrasonically similar to the production material thus eliminating the reference block as an examination variable.1.1 This guide covers general procedures for the material selection and fabrication of reference blocks made of metal or metal alloys and intended to be used for the examination of the same or similar production materials by pulsed longitudinal ultrasonic waves applied perpendicular to the beam entry surface. Primary emphasis is on solid materials but some of the techniques described may be used for midwall examination of pipes and tubes of heavy wall thickness. Near-surface resolution in any material depends upon the characteristics of the instrument and search unit employed.1.2 This guide covers the fabrication of reference blocks for use with either the immersion or the contact method of ultrasonic examination.1.3 Reference blocks fabricated in accordance with this guide can be used to determine proper ultrasonic system operation. Area-amplitude and distance-amplitude curves can also be determined with these reference blocks.1.4 This guide does not specify reference reflector sizes or product rejection limits. It does describe typical industry fabrication practices and commonly applied tolerances where they lend clarity to the guide. In all cases of conflict between this guide and customer specifications, the customer specification shall prevail.1.5 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.1.6 This standard does not purport to address 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 to determine the applicability of regulatory limitations prior to use.

定价： 0元 / 折扣价： 0 元

5.1 The purpose of this practice is to outline a procedure for using GWT to locate areas in metal pipes in which wall loss has occurred due to corrosion or erosion.5.2 GWT does not provide a direct measurement of wall thickness, but is sensitive to a combination of the CSC (or reflection coefficient) and circumferential extent and axial extent of any metal loss. Based on this information, a classification of the severity can be assigned.5.3 The GWT method provides a screening tool to quickly identify any discontinuity along the pipe. Where a possible defect is found, a follow-up inspection of suspected areas with ultrasonic testing or other NDT methods is normally required to obtain detailed thickness information, nature, and extent of damage.5.4 GWT also provides some information on the axial length of a discontinuity, provided that the axial length is longer than roughly a quarter of the wavelength.5.5 The identification and severity assessment of any possible defects is qualitative only. An interpretation process to differentiate between relevant and non-relevant signals is necessary.5.6 This practice only covers the application specified in the scope. The GWT method has the capability and can be used for applications where the pipe is insulated, buried, in road crossings, and where access is limited.5.7 GWT shall be performed by qualified and certified personnel, as specified in the contract or purchase order. Qualifications shall include training specific to the use of the equipment employed, interpretation of the test results, and guided wave technology.5.8 A documented program which includes training, examination, and experience for the GWT personnel certification shall be maintained by the supplying party.1.1 This practice provides a guide for the use of waves generated using magnetostrictive transduction for guided wave testing (GWT) welded tubulars. Magnetostrictive materials transduce or convert time varying magnetic fields into mechanical energy. As a magnetostrictive material is magnetized, it strains. Conversely, if an external force produces a strain in a magnetostrictive material, the material’s magnetic state will change. This bi-directional coupling between the magnetic and mechanical states of a magnetostrictive material provides a transduction capability that can be used for both actuation and sensing devices.1.2 GWT utilizes ultrasonic guided waves in the 10 to approximately 250 kHz range, sent in the axial direction of the pipe, to non-destructively test pipes for discontinuities or other features by detecting changes in the cross-section or stiffness of the pipe, or both.1.3 GWT is a screening tool. The method does not provide a direct measurement of wall thickness or the exact dimensions of discontinuities. However, an estimate of the severity of the discontinuity can be obtained.1.4 This practice is intended for use with tubular carbon steel products having nominal pipe size (NPS) 2 to 48 corresponding to 60.3 to 1219.2 mm (2.375 to 48 in.) outer diameter, and wall thickness between 3.81 and 25.4 mm (0.15 and 1 in.).1.5 This practice only applies to GWT of basic pipe configuration. This includes pipes that are straight, constructed of a single pipe size and schedules, fully accessible at the test location, jointed by girth welds, supported by simple contact supports and free of internal, or external coatings, or both; the pipe may be insulated or painted.1.6 This practice provides a general practice for performing the examination. The interpretation of the guided wave data obtained is complex and training is required to properly perform data interpretation.1.7 This practice does not establish an acceptance criterion. Specific acceptance criteria shall be specified in the contractual agreement by the cognizant engineer.1.8 Units—The values stated in SI 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.1.9 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.1.10 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

5.1 Proton exchange membranes (PEM) used in fuel cells are susceptible to contamination from a number of species that can be found in hydrogen. It is critical that these contaminants be measured and verified to be present at or below the amounts stated in SAE J2719 and ISO 14687 to ensure both fuel cell longevity and optimum efficiency. Contaminant concentrations as low as single-figure ppb(v) for some species can seriously compromise the life span and efficiency of PEM fuel cells. The presence of contaminants in fuel-cell-grade hydrogen can, in some cases, have a permanent adverse impact on fuel cell efficiency and usability. It is critical to monitor the concentration of key contaminants in hydrogen during the production phase through to delivery of the fuel to a fuel cell vehicle or other PEM fuel cell application. In ISO 14687, the upper limits for the contaminants are specified. Refer to SAE J2719 (see 2.3) for specific national and regional requirements. For hydrogen fuel that is transported and delivered as a cryogenic liquid, there is additional risk of introducing impurities during transport and delivery operations. For instance, moisture can build up over time in liquid transfer lines, critical control components, and long-term storage facilities, which can lead to ice buildup within the system and subsequent blockages that pose a safety risk or the introduction of contaminants into the gas stream upon evaporation of the liquid. Users are reminded to consult Practice D7265 for critical thermophysical properties such as the ortho/para hydrogen spin isomer inversion that can lead to additional hazards in liquid hydrogen usage.1.1 This test method describes contaminant determination in fuel cell grade hydrogen as specified in relevant ASTM and ISO standards using cavity ring-down spectroscopy (CRDS). This standard test method is for the measurement of one or multiple contaminants including, but not limited to, water (H2O), oxygen (O2), methane (CH4), carbon dioxide (CO2), carbon monoxide (CO), ammonia (NH3), and formaldehyde (H2CO), henceforth referred to as “analyte.”1.2 This test method applies to CRDS analyzers with one or multiple sensor modules (see 6.2 for definition). This test method describes sampling apparatus design, operating procedures, and quality control procedures required to obtain the stated levels of precision and accuracy.1.3 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used independently of the other, and values from the two systems shall not be combined.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

5.1 The dynamic modulus of elasticity provided by these test methods is a fundamental property for the configuration tested.5.1.1 The rapidity and ease of application of these test methods facilitate their use as a substitute for static measurements.5.1.2 Dynamic modulus of elasticity is often used for surveys, for segregation of lumber for test purposes, for quality assessment of engineered wood products, and to provide indication of environmental or processing effect.5.2 The modulus of elasticity, whether measured statically or dynamically, is often a useful predictor variable to suggest or explain property relationships.5.3 Results from these test methods can be related to other measurements of modulus of elasticity, such as static methods (see Annex A1 and Appendix X4).5.4 These methods use calculations that assume specimens are prismatic in cross-section and are uniform in modulus of elasticity and density.5.4.1 As a result of the above assumptions, the obtained values of modulus of elasticity are dependent on how the specimen is stressed (see Commentary).5.4.2 Transverse vibration and longitudinal stress wave modulus of elasticity are correlated but not necessarily equal.5.4.3 These methods provide a means to establish a model to predict one dynamic modulus of elasticity from another dynamic method or a static method (that is, D198, D4761, etc.).5.4.4 The methods can also be used to estimate the Class I or Class II modulus of elasticity from the Class III method, or the Class I from the Class II method.5.5 Testing specified to be undertaken in accordance with this Method shall include any requirements regarding the following for each Class:5.5.1 Grades and species permitted to be combined to form the training and validation test sample.5.5.2 Selection and positioning of manufacturing or growth characteristics to be included or permitted in the test sample.5.5.3 Moisture content conditioning undertaken prior to testing.5.5.4 Acceptable moisture content adjustment models.5.5.5 Any other sampling and data adjustment requirements to obtain a representative sample of the population under consideration.NOTE 5: Guidance or requirements from applicable product standards or specifications for representative sampling should be considered. See Annex A2.NOTE 6: See Commentary Appendix X4 for additional information (for example, blocking parameter and blocking limits) that may need to be provided for generating a test sample suitable for developing the test method conversion model.1.1 These test methods cover the non-destructive determination of the following dynamic properties of wood and wood-based materials from measuring the fundamental frequency of vibration:1.1.1 Flexural (see Refs (1-3))2 stiffness and apparent modulus of elasticity (Etv) properties using simply or freely supported beam transverse vibration in the vertical direction, and1.1.2 Axial stiffness and apparent longitudinal modulus of elasticity (Esw) using stress wave propagation time in the longitudinal direction.1.2 The test methods can be used for a broad range of wood-based materials and products ranging from logs, timbers, lumber, and engineered wood products.1.2.1 The two flexural methods can be applied to flexural products such as glulam beams and I-joists.1.2.2 The longitudinal stress wave methods are limited to solid wood and homogeneous grade glulam (for example, columns but not products with distinct subcomponents such as wood I-joists).1.3 The standard recognizes three implementation classes for each of these test methods.1.3.1 Class I—Defines the fundamental method to achieve the highest degree of repeatability and reproducibility that can be achieved under laboratory conditions.NOTE 1: Testing should follow Class I methods to develop training and validation data sets for method conversion models (see Annex A2).1.3.2 Class II—Method with permitted modifications to the Class I method that can be used to address practical issues found in the field, and where practical deviations from the Class I protocol are known and their effects can be accounted.NOTE 2: Practical deviations include, for example, environmental and test boundary conditions. Class II methods allow for corrections to test results to account for quantifiable effect such as machine frame deflections.1.3.3 Class III—Method permitting the broadest range of application, with permitted modifications to suit a wider range of practical needs with an emphasis on repeatability.NOTE 3: Online testing machines implemented to grade/sort lumber may be treated as Class III.1.4 The standard provides guidance for developing a model for estimating a non-destructive test method result (for example, static modulus of elasticity obtained in accordance with Test Methods D198) from another non-destructive test method result (for example, dynamic longitudinal modulus of elasticity from measurement of longitudinal stress wave propagation time).1.4.1 The standard covers only models developed from test data obtained directly from non-destructively testing a representative sample using one test method, and retesting the same sample following a second test method.1.4.2 Results used for model development shall not be estimated from a model.1.5 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.1.6 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： 843元 / 折扣价： 717 元 加购物车

5.1 This test method provides a means for a reliable field determination of fuel dilution that is quick and preparation-free. Results are obtained in approximately 1 min. Such a method is used, for example, at remote railroad depots where it is impractical to carry out a standard laboratory method for determination of fuel dilution, such as described in Test Method D7593, but it is a critical need to determine if fuel has contaminated the lubricant. If fuel has contaminated the lubricant, this is significantly detrimental to the machinery and it is typically serviced immediately. Further, the fuel can ignite at the high temperatures encountered in machinery lubricant paths.1.1 This test method describes a means for determining the amount of fuel dilution present in an in-service lubricant. This is achieved by drawing into a surface acoustic wave (SAW) sensor vapor from the lubricant. Fuel vapor will be absorbed by the SAW sensor’s polymer coating. The amount of absorbance is then related to fuel content in the lubricant.1.2 The range of fuel dilution capable of being measured by the test method is from 0.1 % to 10.0 % by mass fuel dilution.1.3 This test method is specifically tailored to determining the fuel dilution of in-service lubricants, including newly utilized lubricants. The method is applicable to contamination with diesel, gasoline, and jet fuels.1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.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. See Section 9.1.6 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： 590元 / 折扣价： 502 元 加购物车

5.1 The initial shear modulus (Gmax) of a soil specimen under particular stress and time conditions is an important parameter in small-strain dynamic analyses such as those to predict soil behavior or soil-structure interaction during earthquakes, explosions, and machine or traffic vibrations. Gmax can be equally important for small-strain cyclic situations such as those caused by wind or wave loading. Small-strain Gmax is also vital for non-linear analyses of large strain situations, where the larger strain soil stiffness results could come from torsional shear tests, for example. Shear wave velocity and Gmax can be used to compare different soil specimens in a laboratory testing program, and also for comparing laboratory and field measurements of these parameters.5.2 Torsional resonant column tests (Test Method D4015) are often used to determine properties of a soil specimen at small shear strains up to and possibly slightly beyond 0.01%. Resonant column test results can include Gmax versus time, shear modulus versus strain, damping ratio versus time and damping ratio versus strain. Bender element tests can only provide the first of these, Gmax versus time. The strain level in bender element tests is small (constant Gmax strain levels), but the strain magnitude is not known and the strain is not constant along the shear wave travel path due to material and geometric damping. Bender elements can therefore not be used to evaluate shear modulus versus strain and do not provide information about damping ratio. However, bender elements can be incorporated in a variety of different laboratory testing devices, allowing the measurement of small-strain and large-strain stiffness on the same specimen at the particular conditions of the test and possibly eliminating the need for additional resonant column tests.NOTE 1: The quality of the result produced by this standard is dependent on the competence of the personnel performing it, and the suitability of the equipment and facilities used. Agencies that meet the criteria of Practice D3740 are generally considered capable of competent and objective testing/sampling/inspection/etc. Users of this standard are cautioned that compliance with Practice D3740 does not in itself assure reliable results. Reliable results depend on many factors; Practice D3740 provides a means of evaluating some of those factors.1.1 This test method covers the laboratory use of piezo-ceramic bender elements to determine the shear wave velocity in soil specimens. A shear wave is generated at one boundary of a soil specimen and then received at an opposite boundary. The shear wave travel time is measured, which over a known travel distance yields the shear wave velocity. From this shear wave velocity and the density of the soil specimen the initial shear modulus (Gmax) can be determined, which is the result of primary interest from bender element tests.1.2 This shear wave velocity determination involves very small strains and is non-destructive to a test specimen. As such, bender element shear wave velocity determinations can be made at any time and any number of times during a laboratory test.1.3 This test method describes the use of bender elements in a triaxial type test (for example, Test Methods D3999, D4767, D5311, or D7181), but a similar procedure may be used for other laboratory applications, like in Direct Simple Shear (Test Method D6528) or oedometer tests (for example, Test Methods D2435 and D4186). Shear wave velocity can also be determined in unconfined soil specimens held together by matrix suction.1.4 Shear wave velocity can be determined in different directions in a triaxial test, for example vertically and horizontally. Shear waves generated to determine shear wave velocity can also be polarized in different directions, for example a horizontally propagating shear wave with either vertical or horizontal polarization. This test method describes the use of bender elements mounted in the top platen and base pedestal of a triaxial test specimen to measure shear wave velocity in the vertical direction. With additional bender elements mounted on opposite sides of a triaxial specimen, a similar procedure may be used to determine horizontal shear wave velocity.1.5 A variety of different interpretation methods to evaluate the shear wave travel time in a soil specimen have been proposed and used. This test method only describes two of these, Start to Start and Peak to Peak using a single sine wave signal sent to the transmitter bender element. Other interpretation methods producing similar results may also be used.1.6 Bender element measurements may not work very well in some situations, like in extremely stiff soils where the generated shear wave amplitude may be exceedingly small.1.7 This test method does not cover the determination of compressional wave velocity in soil specimens. This measurement requires a different type of piezo-ceramic element configuration, and such determinations are generally not useful in saturated soft soil specimens as the earliest identifiable compressional wave arrival at the receiver end of a saturated specimen will likely have been transmitted through the (relatively incompressible) specimen pore water rather than the (compressible) soil skeleton.1.8 Units—The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.9 All observed and calculated values shall conform to the guidelines for significant digits and rounding established in Practice D6026, unless superseded by this test method.1.9.1 The procedures used to specify how data are collected/recorded and calculated in the standard are regarded as the industry standard. In addition, they are representative of the significant digits that generally should be retained. The procedures used do not consider material variation, purpose for obtaining the data, special purpose studies, or any considerations for the user’s objectives; and it is common practice to increase or reduce significant digits of reported data to be commensurate with these considerations. It is beyond the scope of these test methods to consider significant digits used in analysis methods for engineering data.1.10 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.1.11 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

1 Scope This Particular Standard specifies requirements for the safety of SHORT-WAVE THERAPY EQUIPMENT as defined in Sub-clause 2.1.101, hereinafter referred to as EQUIPMENT, having a RATED OUTPUT POWER not exceeding 500 W. This equipment shall be des

定价： 410元 / 折扣价： 349 元

No Scope Available

定价： 1183元 / 折扣价： 1006 元

5.1 The purpose of this practice is to outline a procedure for using GWT to locate areas in metal pipes in which wall loss has occurred due to corrosion or erosion.5.2 GWT does not provide a direct measurement of wall thickness, but is sensitive to a combination of the CSC and circumferential extent and axial extent of any metal loss. Based on this information, a classification of the severity can be assigned.5.3 The GWT method provides a screening tool to quickly identify any discontinuity along the pipe. Where a possible defect is found, follow-up inspection of suspected areas with ultrasonic testing or other NDT methods is normally required to obtain detailed thickness information, nature, and extent of damage.5.4 GWT also provides some information on the axial length of a discontinuity, provided that the axial length is longer than roughly a quarter of the wavelength of the excitation signal.5.5 The identification and severity assessment of any possible defects is qualitative only. An interpretation process to differentiate between relevant and non-relevant signals is necessary.5.6 This practice only covers the application specified in the scope. The GWT method has the capability and can be used for applications where the pipe is insulated, buried, in road crossings, and where access is limited.5.7 GWT shall be performed by qualified and certified personnel, as specified in the contract or purchase order. Qualifications shall include training specific to the use of the equipment employed, interpretation of the test results and guided wave technology.5.8 A documented program that includes training, examination and experience for the GWT personnel certification shall be maintained by the supplying party.1.1 This practice provides a procedure for the use of guided wave testing (GWT), also previously known as long range ultrasonic testing (LRUT) or guided wave ultrasonic testing (GWUT).1.2 GWT utilizes ultrasonic guided waves, sent in the axial direction of the pipe, to non-destructively test pipes for defects or other features by detecting changes in the cross-section or stiffness of the pipe, or both.1.3 GWT is a screening tool. The method does not provide a direct measurement of wall thickness or the exact dimensions of defects/defected area; an estimate of the defect severity however can be provided.1.4 This practice is intended for use with tubular carbon steel or low-alloy steel products having Nominal Pipe size (NPS) 2 to 48 corresponding to 60.3 mm to 1219.2 mm (2.375 in. to 48 in.) outer diameter, and wall thickness between 3.81 mm and 25.4 mm (0.15 in. and 1 in.).1.5 This practice covers GWT using piezoelectric transduction technology.1.6 This practice only applies to GWT of basic pipe configuration. This includes pipes that are straight, constructed of a single pipe size and schedules, fully accessible at the test location, jointed by girth welds, supported by simple contact supports and free of internal, or external coatings, or both; the pipe may be insulated or painted.1.7 This practice provides a general procedure for performing the examination and identifying various aspects of particular importance to ensure valid results, but actual interpretation of the data is excluded.1.8 This practice does not establish an acceptance criterion. Specific acceptance criteria shall be specified in the contractual agreement by the responsible system user or engineering entity.1.9 Units—The values stated in SI 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.1.10 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.1.11 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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