定价： 1756元 / 折扣价： 1493 元 加购物车

定价： 1333元 / 折扣价： 1134 元

定价： 345元 / 折扣价： 294 元

定价： 345元 / 折扣价： 294 元 加购物车

定价： 260元 / 折扣价： 221 元 加购物车

4.1 This practice is intended to assist the user, in particular the power-plant operations and maintenance departments, to maintain effective lubrication of all parts of the turbine and guard against the onset of problems associated with oil degradation and contamination. The values of the various test parameters mentioned in this practice are purely indicative. In fact, for proper interpretation of the results, many factors, such as type of equipment, operation workload, design of the lubricating oil circuit, and top-up level, should be taken into account.1.1 This practice covers the requirements for the effective monitoring of mineral turbine oils in service in steam and gas turbines, as individual or combined cycle turbines, used for power generation. This practice includes sampling and testing schedules to validate the condition of the lubricant through its life cycle and by ensuring required improvements to bring the present condition of the lubricant within the acceptable targets. This practice is not intended for condition monitoring of lubricants for auxiliary equipment; it is recommended that the appropriate practice be consulted (see Practice D6224).1.2 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.1.3 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 With the common occurrence in water of organic compounds, some of which are toxic, it is often necessary to identify the specific compounds present and to determine the concentration.1.1 This guide covers the identification and quantitation of organic compounds by gas chromatography/mass spectrometry (GC-MS) (electron impact) that are present or extracted from water and are capable of passing through a gas chromatograph without alteration. This guide can be used to provide tentative identifications of volatile and semi-volatile organics, but is restricted to (a) compounds for which reference spectra can be obtained and (b) compounds that can be separated by gas chromatography (GC). These restrictions are imposed on the guide, but are not a limitation of the technique. The guide is written for analysis using automated data acquisition and handling.1.2 Guidelines have been included for quantitation using ASTM Test Methods D3871, D3973, and other GC-MS volatile/semivolatile procedures used for environmental analysis2. The actual detection limits for each component must be determined in each laboratory. Actual detection amounts will vary with the complexity of the matrix, the kind and condition of the GC-MS system, the sample preparation technique chosen, and the application of cleanup techniques to the sample extract, if any. Lower levels of detection can be achieved using modern sensitive instruments or with selected ion monitoring (SIM). To determine the interlaboratory detection estimate (IDE) and the interlaboratory quantitation estimate (IQE), follow Practices D6091 and D6512.1.3 The guide is applicable to the identification of many organic constituents of natural and treated waters. It includes all modes of sample introduction, including injection of organic extracts, direct aqueous injection, and purge and trap techniques.1.4 The guide is applicable to capillary column gas chromatography.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

3.1 These test methods are used to determine the basicity of leather when used in accordance with Test Method D4654.1.1 These test methods are intended for use in determining the total, neutral, and combined acid sulfate in mineral-tanned leather.1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this 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： 515元 / 折扣价： 438 元 加购物车

3.1 This practice may be used to determine non-protein or non-nitrogen containing organic matter in leather which is not extractable with water or hexane. Examples would be vegetable tannins and acrylic lubricants.1.1 This practice covers the determination of the combined tannin and nonextractable organic resins and the degree of tannage of all types of vegetable-tanned leather and leather with organic retannages. This practice does not apply to wet blue.1.2 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 Both NO2 and NO play an important role in photochemical-smog-forming reactions. In sufficient concentrations NO2 is deleterious to health, agriculture, materials, and visibility.5.2 In combustion processes, significant amounts of NO may be produced by combination of atmospheric nitrogen and oxygen; at ambient temperatures, NO can be converted to NO2 by oxygen and other atmospheric oxidants. Nitrogen dioxide also may be generated from processes involving nitric acid, nitrates, the use of explosives, and welding.1.1 This test method covers the manual determination of the combined nitrogen dioxide (NO2) and nitric oxide (NO) content, total NOx; in the atmosphere in the range from 4 to 10 000 μg/m3 (0.002 to 5 ppm (v)).1.2 The maximum sampling period is 60 min at a flow rate of 0.4 L/min.1.3 The values stated in SI units are to be regarded as standard. The values given in parentheses are for information only.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： 956元 / 折扣价： 813 元

4.1 Relative density (specific gravity) is the characteristic generally used for calculation of the volume occupied by the aggregate in various mixtures containing aggregate, including portland cement concrete, bituminous concrete, and other mixtures that are proportioned or analyzed on an absolute volume basis. Relative density (specific gravity) is also used in the computation of voids in aggregate in Test Method C29/C29M. Relative density (specific gravity) saturated surface dry (SSD) is used if the aggregate is at SSD, that is, if its absorption has been satisfied. Conversely, the relative density (specific gravity) oven dry (OD) is used for computations when the aggregate is dry or assumed to be dry.4.2 Apparent density and apparent relative density (apparent specific gravity) pertain to the solid material making up the constituent particles not including the pore space within the particles which is accessible to water.4.3 Absorption values are used to calculate the change in the mass of an aggregate due to water absorbed in the pore spaces within the constituent particles, when it is deemed that the aggregate has been in contact with water long enough to satisfy the absorption potential. The laboratory standard for absorption is that obtained after submerging dry aggregate for a prescribed period of time.NOTE 1: There are other test methods that have been used and continue to be used to determine these aggregate properties: Test Methods C127 and C128. This test method may result in values for these properties that are close to or divergent from values from other test methods.NOTE 2: The quality of the results produced by this standard are dependent upon the competence of the personnel performing the procedure and the capability, calibration, and the maintenance of the equipment used. Agencies that meet the criteria of Specification D3666 are generally considered capable of competent and objective testing, sampling, inspection, etc. Users of this standard are cautioned that compliance with Specification D3666 alone does not completely ensure reliable results. Reliable results depend on many factors; following the suggestions of Specification D3666 or similar acceptable guideline provides a means of evaluating and controlling some of those factors.1.1 This test method covers the determination of relative density and absorption of fine aggregates by Method A and coarse and blended aggregates by Method B.1.2 A multi-laboratory precision and bias statement for coarse and combined aggregate tests in this standard has not been developed at this time. Therefore, this standard should not be used for acceptance or rejection of coarse and combined aggregate materials for purchasing purposes.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. Some values have only SI units because inch-pound equivalents are not used in practice.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

This practice describes the standard procedures for providing exposure of thermal control materials to a simulated space environment comprising of the major features of vacuum, electromagnetic radiation, charged particle radiation, and temperature control. Broad recommendations relating to spectral reflectance measurements, as well as test parameters and other information that should be reported as an aid in interpreting test results are delineated. Specifications are provided for the vacuum system, solar simulator, charged particle sources, safety precautions, and data interpretation.1.1 This practice describes procedures for providing exposure of thermal control materials to a simulated space environment comprising the major features of vacuum, electromagnetic radiation, charged particle radiation, and temperature control.1.2 Broad recommendations relating to spectral reflectance measurements are made.1.3 Test parameters and other information that should be reported as an aid in interpreting test results are delineated.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： 646元 / 折扣价： 550 元 加购物车

This specification covers the production, properties, packaging, and testing of packaged, dry, combined materials for concrete and mortars. Concrete mixtures covered by this specification includes high-early strength concrete, normal strength concrete, normal weight concrete, high-strength mortar, and mortars for unit masonry. The purchaser shall specify the material desired as concrete, high strength mortar, or mortar for use with unit masonry, and the respective physical requirements. Materials used as ingredients in packaged, dry, combined materials for mortar and concrete shall be composed of aggregates, air-entraining admixtures, blended cement, chemical admixtures, fly ash, ground granulated blast-furnace slag, hydrated lime, latex and powder polymer modifiers, masonry cement, mortar cement, Portland cement, and silica fume. All aggregates shall be dried, without disintegration, to specific moisture content The proportions of cementitious material and aggregate shall be such that the strength requirements will be met. Packaged, dry, combined materials for concrete, high strength mortar and mortar for use with unit masonry shall conform to the respective compressive strength requirements. Scales conforming to the standards will be used for sampling concretes from a single batch using a sufficient quantity. A slump test will be performed to check if additional water is required. In sampling mortar, the contents of an entire package of dry, combined material for mortar for unit masonry or for concrete mortar shall be used. Mortar mixing equipment, which must be provided with a bowl positioning adapter, shall be used to ensure clearance for the largest size aggregate in the mix being tested. The specification includes the following testing methods for mortar: compressive strength, density and yield, air content, and water retention.1.1 This specification covers the production, properties, packaging, and testing of packaged, dry, combined materials for concrete and high strength mortar. The classifications of concrete and mortar covered are defined in Section 3.NOTE 1: The scope of this standard does not cover mortars for unit masonry. Dry preblended mortars for unit masonry are covered by Specification C1714/C1714M.1.2 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard. Some values have only SI units because the inch-pound equivalents are not used in practice.1.3 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 this standard.1.4 The following safety hazards caveat pertains only to the test method portion of this specification. 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 Hydrogen peroxide (formed photochemically in the atmosphere) is a primary oxidizer of dissolved sulfur dioxide in atmospheric water. Detection of H2O2 in atmospheric water is useful for inferring gas-phase H2O2 concentrations and for assessing the relative importance of various acidifying mechanisms under specific atmospheric conditions.5.2 Hydroperoxides in samples to be analyzed are unstable in water and can decay rapidly due to bacterial action or chemical reaction with other constituents. The test method includes procedures for sample derivatization and methods for estimating and correcting for hydroperoxide decay.1.1 This test method covers the determination of hydroperoxides, which include hydrogen peroxide (H2O2) and combined organic peroxides, in samples of atmospheric water by the method of horseradish peroxidase derivatization and fluorescence analysis of the derived dimer.2,31.2 The range of applicable hydrogen peroxide concentrations was determined to be 0.6–176.0 × 10−6 M from independent laboratory tests of the test method.1.3 The primary use of the test method is for hydrogen peroxide, but it may also be used to quantitate organic hydroperoxides. Determinations of organic hydroperoxide concentration levels up to 30 × 10−6 M may be adequately obtained by calibration with hydrogen peroxide.2,3 While organic hydroperoxides have not been detected at significant concentration levels in rain or cloud water, their presence may be tested by operation of the test method with the addition of catalase for destruction of H2O2.31.4 Because of the instability of hydroperoxides in atmospheric water samples, proper sample collection, at-collection derivatization, and stringent quality control are essential aspects of the analytical process.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