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5.1 This test method is applicable to the measurement of airborne asbestos in a wide range of ambient air situations and for detailed evaluation of any atmosphere for asbestos structures. Most fibers in ambient atmospheres are not asbestos, and therefore, there is a requirement for fibers to be identified. Most of the airborne asbestos fibers in ambient atmospheres have diameters below the resolution limit of the light microscope. This test method is based on transmission electron microscopy, which has adequate resolution to allow detection of small thin fibers and is currently the only technique capable of unequivocal identification of the majority of individual fibers of asbestos. Asbestos is often found, not as single fibers, but as very complex, aggregated structures, which may or may not also be aggregated with other particles. The fibers found suspended in an ambient atmosphere can often be identified unequivocally if sufficient measurement effort is expended. However, if each fiber were to be identified in this way, the analysis would become prohibitively expensive. Because of instrumental deficiencies or because of the nature of the particulate matter, some fibers cannot be positively identified as asbestos even though the measurements all indicate that they could be asbestos. Therefore, subjective factors contribute to this measurement, and consequently, a very precise definition of the procedure for identification and enumeration of asbestos fibers is required. The method defined in this test method is designed to provide a description of the nature, numerical concentration, and sizes of asbestos-containing particles found in an air sample. The test method is necessarily complex because the structures observed are frequently very complex. The method of data recording specified in the test method is designed to allow reevaluation of the structure-counting data as new applications for measurements are developed. All of the feasible specimen preparation techniques result in some modification of the airborne particulate matter. Even the collection of particles from a three-dimensional airborne dispersion on to a two-dimensional filter surface can be considered a modification of the particulate matter, and some of the particles, in most samples, are modified by the specimen preparation procedures. However, the procedures specified in this test method are designed to minimize the disturbance of the collected particulate material.5.2 This test method applies to analysis of a single filter and describes the precision attributable to measurements for a single filter (see 13.1). Multiple air samples are usually necessary to characterize airborne asbestos concentrations across time and space. The number of samples necessary for this purpose is proportional to the variation in measurement across samples, which may be greater than the variation in a measurement for a single sample.1.1 This test method2 is an analytical procedure using transmission electron microscopy (TEM) for the determination of the concentration of asbestos structures in ambient atmospheres and includes measurement of the dimension of structures and of the asbestos fibers found in the structures from which aspect ratios are calculated.1.1.1 This test method allows determination of the type(s) of asbestos fibers present.1.1.2 This test method cannot always discriminate between individual fibers of the asbestos and non-asbestos analogues of the same amphibole mineral.1.2 This test method is suitable for determination of asbestos in both ambient (outdoor) and building atmospheres.1.2.1 This test method is defined for polycarbonate capillary-pore filters or cellulose ester (either mixed esters of cellulose or cellulose nitrate) filters through which a known volume of air has been drawn and for blank filters.1.3 The upper range of concentrations that can be determined by this test method is 7000 s/mm2. The air concentration represented by this value is a function of the volume of air sampled.1.3.1 There is no lower limit to the dimensions of asbestos fibers that can be detected. In practice, microscopists vary in their ability to detect very small asbestos fibers. Therefore, a minimum length of 0.5 μm has been defined as the shortest fiber to be incorporated in the reported results.1.4 The direct analytical method cannot be used if the general particulate matter loading of the sample collection filter as analyzed exceeds approximately 10 % coverage of the collection filter by particulate matter.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： 843元 / 折扣价： 717 元 加购物车

5.1 This test method is applicable to the measurement of airborne carbon nanotubes in a wide range of ambient air situations and for evaluation of any atmosphere for carbon nanotube structures. Single carbon nanotube structures in ambient atmospheres have diameters below the resolution limit of the light microscope. This test method is based on transmission electron microscopy, which has adequate resolution to allow detection of small thin single carbon nanotubes and is currently a reliable technique capable of unequivocal identification of the majority of nanotube structures. Carbon nanotubes are often found, not as single carbon nanotubes, but as very complex, aggregated structures, which may or may not be aggregated with other particles.5.2 This test method applies to the analysis of a single filter and describes the precision attributable to measurements for a single filter. Multiple air samples are usually necessary to characterize airborne nanotube structure concentrations across time and space. The number of samples necessary for this purpose is proportional to the variation in measurement across samples, which may be greater than the variation in measurement for a single sample.1.1 This test method is an analytical procedure using transmission electron microscopy (TEM) for the determination of the concentration of carbon nanotubes and carbon nanotube-containing particles in ambient atmospheres.1.1.1 This test method is suitable for determination of carbon nanotubes in both ambient (outdoor) and building atmospheres.1.2 This test method is defined for polycarbonate capillary pore filters through which a known volume of air has been drawn and for blank filters.1.3 The direct analytical method cannot be used if the general particulate matter loading of the sample collection filter as analyzed exceeds approximately 25 % coverage of the collection filter by particulate matter.1.4 Units—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.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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1. Scope This part of IEC 79 prescribes the specific requirements for construction and testing of electrical apparatus, parts of electrical apparatus and Ex components which have rated voltages not exceeding 11 kV with the type of protection encapsulat

定价： 1092元 / 折扣价： 929 元

5.1 Data on the composition and characteristics of environmental atmospheres, such as ambient or work space air, are frequently used to evaluate the health and safety of humans. Data on the composition of atmospheric deposition samples are often used for environmental impact assessment.5.2 These data are frequently used to ascertain compliance with regulatory statutes that place limits on acceptable compositions and characteristics of these atmospheres.5.3 Laboratories that produce environmental sampling and analysis data and those who have the responsibility of selecting a laboratory to perform air quality studies need to know what criteria, practices, and recommendations have been accepted by consensus within this field of endeavor.5.4 Demonstration and documentation by a laboratory that there is judicious selection and control of organizational factors, facilities, resources, and operations enhance the reliability of the data produced and promote the acceptance of these data.1.1 This guide covers criteria to be used by those responsible for the selection, evaluation, operation, and control of laboratory organizations engaged in sampling and analysis of environmental atmospheres, including ambient, work space, and source emissions, as well as atmospheric deposition samples. For details specific to stack gases, see Practice D7036, which covers administrative issues in full; several specifics in this guide regarding laboratory operations may yet be helpful and do not overlap with Practice D7036.1.2 This guide presents features of organizations, facilities, resources, and operations which by their selection and control affect the reliability and credibility of the data generated.1.3 This guide presents the criteria for the selection and control of the features listed in 1.2 so that acceptable performance may be attained and sustained. Also, this guide presents recommendations for the correction of unacceptable performance.1.4 The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units 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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5.1 This test method will allow comparisons of the burning characteristics of various metallic materials. The burning characteristics that can be evaluated include (1) burn and no-burn pressure, (2) burn and no-burn temperature, (3) regression rate of the melting interface, and (4) visual evaluation of the burning process of the test sample.1.1 This test method covers test apparatus and techniques to determine the minimum test gas pressure and sample temperature that supports self-sustained burning and the regression rate of the melting surface of a standardized sample of a metallic material that has been ignited using a promoter.1.2 The data obtained from this test method are dependent on the precise test sample configuration and provide a basis for comparing the burning characteristics of metallic materials. No criteria are implied for relating these data for the suitability of a material's use in any actual system.1.3 Requirements for apparatus suitable for this test method are given, as well as an example. The example is not required to be used.1.4 This test method is for gaseous oxygen or any mixture of oxygen with inert diluents that will support burning, at any pressure or temperature within the capabilities of the apparatus used.1.5 The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units 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： 590元 / 折扣价： 502 元 加购物车