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定价： 605元 / 折扣价： 515 元 加购物车

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5.1 Eddy current methods are used for nondestructively locating and characterizing discontinuities and geometric property variations in magnetic or nonmagnetic electrically conducting materials. Conformable eddy current sensor arrays permit examination of planar and non-planar materials but usually require suitable fixtures to hold the sensor array near the surface of the material of interest, such as a layer of foam behind the sensor array along with a rigid support structure.5.2 In operation, the sensor arrays are standardized with measurements in air or a reference part, or both. Responses measured from the sensor array may be converted into physical property values, such as lift-off, electrical conductivity, or magnetic permeability, or a combination thereof. Proper instrument operation is verified by ensuring that these measurement responses or property values are within a prescribed range. Performance verification is performed periodically. Performance verification on a discontinuity-free reference standard or regions of the material being examined that do not contain discontinuities ensures that the electrical and geometric properties, such as electrical conductivity, layer thickness, or lift-off, or a combination thereof, are appropriate for the sensor array. Performance verification on a discontinuity-containing reference standard ensures that the sensor array response to the discontinuity is appropriate.5.3 The sensor array dimensions, including the size and number of sense elements, and the operating frequency are selected based on the type of examination being performed. The depth of penetration of eddy currents into the material under examination depends upon the frequency of the signal, the electrical conductivity and magnetic permeability of the material, and some dimensions of the sensor array. The depth of penetration is equal to the conventional skin depth at high frequencies but is also related to the sensor array dimensions at low frequencies, such as the size of the drive winding and the gap distance between the drive winding and sense element array. For surface-breaking discontinuities on the surface adjacent to the sensor array, high frequencies should be used where the penetration depth is less than the thickness of the material under examination. For subsurface discontinuities or wall thickness measurements, lower frequencies and larger sensor dimensions should be used so that the depth of penetration is comparable to the material thickness.5.4 Insulating layers or coatings may be present between the sensor array and the surface of the electrically conducting material under examination. The sensitivity of a measurement to a discontinuity generally decreases as the coating thickness or lift-off, or both, increases. For eddy current sensor arrays having a linear drive conductor and a linear array of sense elements, the spacing between the drive conductor and the array of sense elements should be smaller than or comparable to the thickness of the insulating coating. For other array formats the depth of sensitivity should be verified empirically.5.5 Models for the sensor response may be used to convert responses measured from the sensor array into physical property values, such as lift-off, electrical conductivity, magnetic permeability, coating thickness, or substrate thickness, or a combination thereof. For determining two property values, one operational frequency can be used. For nonmagnetic materials and examination for crack-like discontinuities, the lift-off and electrical conductivity should be determined. For magnetic materials, when the electrical conductivity can be measured or assumed constant, then the lift-off and magnetic permeability should be determined. The thickness can only be determined if a sufficiently low excitation frequency is used where the depth of sensitivity is greater than the material thickness of interest. For determining more than two property values, measurements at operating conditions having at least two depths of penetration should be used; these different depths of penetration can be achieved by using multiple operational frequencies or multiple spatial wavelengths.5.6 Processing of the measurement response or property value data may be performed to highlight the presence of discontinuities, to reduce background noise, and to characterize detected discontinuities. As an example, a correlation filter can be applied in which a reference signature response for a discontinuity is compared to the measured responses for each sensor array element to highlight discontinuity-like defects. Care must be taken to properly account for the effect of interferences such as edges and coatings on such signatures.5.7 The measurement and analysis methods described in this guide can also be applied to applications where the sensor array is mounted against a surface or embedded within the material being examined. In that situation the sensor array response is monitored over a period of time instead of the scanning the sensor array over a specific location. This leads to the horizontal axes for the B-scans and C-scans to correspond to time or some other input associated with the test such as the number of loading cycles.1.1 This guide covers the use of conformable eddy current sensor arrays for nondestructive examination of electrically conducting materials for discontinuities and material quality. The discontinuities include surface breaking and subsurface cracks and pitting as well as near-surface and hidden-surface material loss. The material quality includes coating or layer thickness, electrical conductivity, magnetic permeability, surface roughness, and other properties that vary with the electrical conductivity or magnetic permeability.1.2 This guide is intended for use on nonmagnetic and magnetic metals as well as composite materials with an electrically conducting component, such as reinforced carbon-carbon composite or polymer matrix composites with carbon fibers.1.3 This guide applies to planar as well as non-planar materials with and without insulating coating layers.1.4 Units—The values stated in SI units are to be regarded as standard. The values given in parentheses are mathematical conversions to inch-pound 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.

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定价： 515元 / 折扣价： 438 元 加购物车

1. Scope 1.1 This Standard specifies the methods to be used for measuring the energy consumption and drum volume, and for te sting the performance characteristics, of automatic household electric tumble-type clothes dryers. 1.2 This Standard descri

定价： 455元 / 折扣价： 387 元

1. Scope 1.1 This standard applies to electrically heated flexible appliances designed for the application of heat to a bed, or to the human body, such as blankets, pads and mattresses for household purposes, and to control units delivered with them.

定价： 2184元 / 折扣价： 1857 元

1 Scope This part of ISO 10079 specifies minimum safety and performance requirements for medical and surgical suction equipment (see Figure 1) for health care facilities such as hospitals, for domiciliary care of patients and for field and transport us

定价： 1001元 / 折扣价： 851 元

1. Scope 1.1 This Standard applies to cord-connected and permanently connected electrically heated pottery kilns for use on nominal system voltages of 600 V or less, designed to be used in accordance with the Rules of the Canadian Electrical Code, Par

定价： 455元 / 折扣价： 387 元

1 Scope and object This clause of the General Standard applies except as follows: 1.1 Scope Addition: This Particular Standard specifies the particuar requirements for the safety of DOSEMETERS used in medical practice in the PATIENT ENVIRONMEN

定价： 410元 / 折扣价： 349 元

1 Scope and object This clause of the General Standard applies, except as follows: 1.1 Scope Addition: This Particular Standard specifies requirements for safety of ELECTRICALLY OPERATED HOSPITAL BEDS, hereinafter referred to as BED, as defined in 2.

定价： 1365元 / 折扣价： 1161 元

This practice covers the procedure for sorting electrically conductive materials using the thermoelectric method, which is based on the seebeck effect. The procedure relates to the use of direct- and comparator-type thermoelectric instruments for distinguishing variations in materials which affect the thermoelectric properties of those materials. The two techniques that are primarily used in thermoelectric sorting are direct and comparative instrumentation. In the direct instruments, equipment is standardized by placing materials with known chemistry and metallurgical structure in the test system. In the comparative instruments, the thermoelectric response of the test piece is compared with that of a known standard(s) and the response indicates whether the piece is within the acceptance limits. The electronic apparatus shall be capable of maintaining a sufficient temperature differential across the electrodes to produce a suitable thermoelectric voltage. The different procedures for sorting electrically conductive materials are presented in details.1.1 This practice covers the procedure for sorting materials using the thermoelectric method, which is based on the Seebeck effect. The procedure relates to the use of direct- and comparator-type thermoelectric instruments for distinguishing variations in materials which affect the thermoelectric properties of those materials.1.2 While the practice is most commonly applied to the sorting of metals, it may be applied to other electrically conductive materials.1.3 Thermoelectric sorting may also be applied to the sorting of materials on the basis of plating thickness, case depth, and hardness.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： 515元 / 折扣价： 438 元 加购物车

5.1 With the increased use of geomembranes as a barrier material to restrict liquid migration from one location to another, a need has been created for standardized tests by which the continuity of the installed geomembrane, including the seams, can be evaluated. This practice is intended to meet such a need whenever the subgrade soil is nonconductive, or a geomembrane is installed on a nonconductive material.5.2 The use of a suitably conductive geotextile installed between a nonconductive soil or material and the geomembrane will permit electrical leak location survey to be conducted.5.3 The compatibility of a conductive geotextile and leak location equipment shall be assessed for each leak location technique considered (covered or exposed, when applicable). A realistic small-scale test shall have been conducted by the supplier of geotextile and/or leak detection equipment to demonstrate their mutual compatibility for a given leak detection technique.1.1 This standard practice describes standard procedures for using a conductive geotextile with electrical methods to locate leaks in exposed geomembranes and geomembranes covered with water or earth materials containing moisture.1.2 This standard practice provides guidance for the use of appropriate conductive geotextile used in leak location surveys on geomembranes. This guide includes all types of conductive geotextiles with sufficient conductivity for the particular electrical leak location method. A conductive geotextile is applicable to all types of geoelectric surveys when there is otherwise not a conductive layer under the geomembrane.1.3 This standard practice is intended to ensure that leak location surveys can always be performed with a reasonable level of certainty. This standard practice provides guidance for the use of appropriate conductive geotextiles used in leak location surveys on geomembranes.1.4 Leak location surveys can be used on nonconductive geomembranes installed in basins, ponds, tanks, ore and waste pads, landfill cells, landfill caps, other containment facilities, and building applications such as in parking garages, decks, and green roofs. The procedures are applicable for geomembranes made of nonconductive materials such as polyethylene, polypropylene, polyvinyl chloride, chlorosulfonated polyethylene, bituminous material, and other electrically insulating materials. Leak location surveys involving conductive or partially conductive geomembranes are not within the scope of this document.1.5 Warning—The electrical methods used for geomembrane leak location could use high voltages, resulting in the potential for electrical shock or electrocution. This hazard might be increased because operations might be conducted in or near water. In particular, a high voltage could exist between the water or earth material and earth ground, or any grounded conductor. These procedures are potentially VERY DANGEROUS, and can result in personal injury or death. Because of the high voltage that could be involved, and the shock or electrocution hazard, do not come in electrical contact with any leak unless the excitation power supply is turned off. The electrical methods used for geomembrane leak location should be attempted only by qualified and experienced personnel. Appropriate safety measures must be taken to protect the leak location operators as well as other people at the site.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： 515元 / 折扣价： 438 元 加购物车

This PDF includes GI #2 and Amd #1. 1. Scope 1.1 This Standard applies to portable hand-held electrically heated tools for voltages of 250 V and less, designed to be used in ordinary (ie, nonhazardous) locations in domestic, commercial, or industr

定价： 455元 / 折扣价： 387 元