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

5.1  Hydrogen is delivered to fuel cell powered automotive vehicles and stationary appliances at pressures up to 87.5 MPa. The quality of hydrogen delivered is a significant factor in maximizing fuel cell efficiency and life span. Contamination can occur during the production of fuel cell feed gases, contaminating storage containers, station tubing, and fuel lines used for fuel delivery. Collection of a representative fuel sample without the introduction of contaminants even as low as parts-per-billion (ppb) per contaminant during collection is crucial for assessing the quality of fuel in real world applications.5.2 This practice is intended for application to high pressure, high purity hydrogen; however, the apparatus design and sampling techniques may be applicable to collection of other fuel cell feed gases. Many of the techniques used in this practice can be applied to lower pressure/lower purity gas streams.1.1 This standard practice describes a sampling procedure of high pressure hydrogen at fueling stations operating at 35 or 70 megapascals (MPa) using a hydrogen quality sampling apparatus (HQSA).1.2 This practice does not include the analysis of the acquired sample. Applicable ASTM standards include but are not limited to test methods referenced in Section 2 of this practice.1.3 This practice is not intended for sampling and measuring particulate matter in high pressure hydrogen. For procedures on sampling and measuring particulate matter see ASTM D7650 and D7651.1.4 The values stated in SI units are standard. The values stated in inch-pounds are for information only.1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.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 Several physical properties of rigid cellular plastics are dependent on cell size and cell orientation. Measuring water absorption and open-cell content in accordance with Test Method D2842 and Test Method D6226 requires knowledge of surface cell volume, which uses cell size values in the calculations.5.2 This test method provides an apparent cell size because it assumes that there is no measurable edge to edge or top to bottom variation in average cell size and that the cell size distribution about the average cell size is normal. If the analyst is concerned there may be significant variation in either the average cell size or the cell size distribution more detailed analysis may be required.5.3 Before proceeding with this test method, reference should be made to the specification of the material being tested. Any test specimen preparation, conditioning, dimensions, or testing parameters, or a combination thereof, covered in the materials specification shall take precedence over those mentioned in this test method. If there are no material specifications, then the default conditions apply.FIG. 1 Razor Blade Cell Size Specimen SlicerFIG. 2 Cell Size Scale Slide Assembly1.1 This test method covers the determination of the apparent cell size of rigid cellular plastics by counting the number of cell-wall intersections in a specified distance.1.2 Procedure A requires the preparation of a thin slice, not more than one half the average cell diameter in thickness, that is mechanically stable. For most rigid cellular plastics this limits the test method to materials with an average cell size of at least 0.2 mm.1.3 Procedure B is intended for use with materials whose friable nature makes it difficult to obtain a thin slice for viewing.1.4 The values stated in SI units are to be regarded as standard. The values given in parentheses are for information only.1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.NOTE 1: The annex to ISO 2896 is technically equivalent to this test method.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

This practice covers the procedures used for detection of mycoplasma contamination of cell cultures by growth on agarose medium. This practice does not cover identification of mycoplasma and indirect methods for detection of mycoplasma. This practice will not detect cultivar strains of Mycoplasma hyorhinis nor intended for use in detection of mycoplasma contamination in sera, culture media, vaccines, or other systems. The practice involves DM-1 solid medium preparation, quality control, and mycoplasma isolation.1.1 This practice covers the procedures used for detection of mycoplasma contamination by direct microbiological culture.1.2 This practice does not cover indirect methods for detection of mycoplasma such as DNA staining, biochemical detection, or genetic probes.1.3 This practice does not cover methods for identification of mycoplasma organisms.1.4 This practice will not detect cultivar strains (1) of Mycoplasma hyorhinis.1.5 This practice is not intended for use in detection of mycoplasma contamination in sera, culture media, vaccines, or other systems.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

Mycoplasma hyorhinis, cultivar α strains (1)3 do not grow on any of the standard media used for mycoplasma cultivation. These strains, which are found as contaminants in cell cultures, are detected by indirect methods.A specialized medium has been described but it is not yet in wide use (2).This practice should be used in conjunction with Practice E 1531.All cell cultures to be examined for mycoplasma should undergo a minimum of two passages in antibiototic-free tissue culture medium before testing.1.1 This practice covers the use of cell cultures and DNA-binding flurorochrome techniques to detect mycoplasma contamination of cell cultures.1.2 This practice does not cover axenic cultivation or identification of mycoplasmas.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.

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定价： 646元 / 折扣价： 550 元 加购物车

Mycoplasma contamination of cell cultures is a common problem that can affect the growth, metabolism, and function of cultured animal cells. The ability to detect mycoplasma in cell cultures provides an opportunity to ensure that cells are free of contamination, and to replace those that are not. For additional information, see Practices E 1531, E 1532, and E 1536. Strict adherence to established, well-tested procedures is necessary. This practice was developed by Task Group E48.01.02 to assist in developing and maintaining an established regimen for mycoplasma detection by indirect 4′-6-Diamidino-2-Phenylindole (DAPI) fluorochrome staining.This practice is intended for use in examining cultured animal cells for the presence of mycoplasma contamination.This practice is not intended for use in the detection of mycoplasma contamination in serum, culture media, or systems other than cultures of animal cells.All cell cultures to be examined for mycoplasma should undergo a minimum of two passages in antibiotic-free tissue culture medium before testing.1.1 This practice covers procedures used for the detection of mycoplasma contamination by indirect DNA staining.1.2 This practice does not cover direct methods for the detection of mycoplasma or other indirect methods such as enzymatical detection or DNA probes.1.3 This practice does not cover methods for the identification of mycoplasma organisms.1.4 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.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

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： 590元 / 折扣价： 502 元 加购物车

定价： 0元 / 折扣价： 0 元 加购物车

定价： 0元 / 折扣价： 0 元 加购物车

4.1  Zeolites Y and X, particularly for catalyst and adsorbent applications, are a major article of manufacture and commerce. Catalysts and adsorbents comprising these zeolites in various forms plus binder and other components have likewise become important. Y-based catalysts are used for fluid catalytic cracking (FCC) and hydrocracking of petroleum, while X-based adsorbents are used for desiccation, sulfur compound removal, and air separation.4.2 The unit cell dimension of a freshly synthesized faujasite-type zeolite is a sensitive measure of composition which, among other uses, distinguishes between the two synthetic faujasite-type zeolites, X and Y. The presence of a matrix in a Y-containing catalyst precludes determination of the zeolite framework composition by direct elemental analysis.4.3 Users of the test method should be aware that the correlation between framework composition and unit cell dimension is specific to a given cation form of the zeolite. Steam or thermal treatments, for example, may alter both composition and cation form. The user must therefore determine the correlation that pertains to his zeolite containing samples.3 In addition, one may use the test method solely to determine the unit cell dimension, in which case no correlation is needed.4.4 Other crystalline components may be present in the sample whose diffraction pattern may cause interference with the selected faujasite-structure diffraction peaks. If there is reason to suspect the presence of such components, then a full diffractometer scan should be obtained and analyzed to select faujasite-structure peaks free of interference.1.1 This test method covers the determination of the unit cell dimension of zeolites having the faujasite crystal structure, including synthetic Y and X zeolites, their modifications such as the various cation exchange forms, and the dealuminized, decationated, and ultra stable forms of Y. These zeolites have cubic symmetry with a unit cell parameter usually within the limits of 24.2 and 25.0 Å (2.42 and 2.50 nm).1.2 The samples include zeolite preparation in the various forms, and catalysts and adsorbents containing these zeolites. The zeolite may be present in amounts as low as 5 %, such as in a cracking catalyst.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： 515元 / 折扣价： 438 元 加购物车