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定价： 646元 加购物车

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定价： 646元 加购物车

定价： 571元 加购物车

4.1 The structural carbohydrate content is used in conjunction with other assays to determine the total composition of biomass samples.1.1 This test method describes the determination of structural carbohydrates present in a biomass sample, expressed as the percent mass of an oven-dried sample basis of each anhydrosugar.1.2 Sample materials suitable for this procedure include hard and softwoods, herbaceous materials, such as sericea and switchgrass, agricultural residues, such as corn stover, wheat straw, and bagasse, wastepaper, such as boxboard, office waste, and newsprint, acid or alkaline-pretreated biomass, washed free of any residual acid or alkali, and the solid fraction of fermentation residues.1.3 The options for the types of samples to be analyzed in this procedure are:1.3.1 Prepared Biomass Samples: 1.3.1.1 Air Dried Material—Results are reported as the percent by mass, based on the oven-dried mass of the air-dried sample.1.3.1.2 45 °C Dried Material—Results are reported as the percent by mass, based on the oven-dried mass of the 45 °C dried sample.1.3.1.3 Freeze Dried Material—Results are reported as the percent by mass, based on the oven-dried mass of the freeze dried sample.1.3.2 Extractives-Free Sample—Results are reported as the percent by mass, based on the oven-dried mass of the extracted sample.1.4 This standard method is generally not suitable for samples that contain soluble, nonstructural carbohydrates unless they are removed prior to analysis.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. See Section 8 for specific hazards statements.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.

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定价： 712元 加购物车

定价： 646元 加购物车

定价： 712元 加购物车

定价： 646元 加购物车

定价： 646元 加购物车

4.1 Preservation of a conducting surface on electrical contact is vital to the continued functioning of such contacts. Contamination of the surface with insulating layers formed by corrosion processes is one potential hazard. Laboratory testing of contacts in MFG tests is used to assess the effectiveness of design features and materials.4.2 MFG tests are used in development studies of processes and materials for contacts. For example, coupon specimens may be exposed to MFG tests to evaluate new contact materials, layers of new coating materials on a supporting substrate, reduced coating thicknesses, or protective surface treatments.4.3 MFG tests are also employed to test the durability of a finished product with respect to atmospheric corrosion. For example, finished connectors may be exposed to a MFG test and their performances compared against each other or against a set of fixed requirements. Relays or switch contacts may be exposed in the operated and non-operated conditions to compare performance.4.4 MFG tests are useful for determining the effectiveness of connector housings and shrouds as barriers to ingress of atmospheric corrodants to the contact surfaces. These tests can also be used to assess the screening of the metal-to-metal contact areas of mated connectors.4.5 MFG tests are employed as qualification tests to determine connector failure rates in application environments for which correlation between test and application has previously been established.4.6 This guide provides test conditions which are to be applied in conjunction with Practice B827 which defines the required test operation and certification procedures, tolerances, and reporting requirements. Where the test specifier requires certifications or tolerances different than those provided in Practice B827, the required certifications or tolerances shall be part of the test specification. Differences from the specifications in Practice B827 shall be reported in the test report provided by the test operator to the test specifier. Specification of one of the test conditions defined in this document in the form of a statement such as, “Parts shall be tested in accordance with ASTM B845 Method Z,” implicitly requires test condition, Z, applied according to Practice B827.1.1 The techniques described in this guide pertain to mixed flowing gas (MFG) tests containing species that are applied to evaluate devices containing electrical contacts such as slip rings, separable connectors, electromechanical relays or switch contacts. These techniques may be relevant to other devices, but it is the responsibility of the user to determine suitability prior to testing.1.2 The MFG tests described in this guide are designed to accelerate corrosive degradation processes. These accelerations are designed such that the degradation occurs in a much shorter time period than that expected for such processes in the intended application environment of the device being tested. Application environments can vary continuously from benign to aggressively corrosive. Connectors and contacts within closed electronic cabinets may be affected by an environment of different severity than the environment on the outside of such cabinets. In general, indoor environments are different than outdoor environments. The MFG tests described herein, being discrete embodiments of specific corrosive conditions, cannot be representative of all possible application environments. It is the responsibility of the test specifier to assure the pertinence of a given test condition to the specifier's application condition.1.3 The MFG tests described herein are not designed to duplicate the actual intended application environment of the device under test. An extended bibliography that provides information which is useful to test specifiers to assist them in selecting appropriate test methods is included in this guide. The bibliography covers the scope from application condition characterization, single and multiple gas effects, and material and product effects to key application and test variables as well as discussions of atmospheric corrosion processes.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 become familiar with all hazards including those identified in the appropriate Safety Data Sheet (SDS) for this product/material as provided by the manufacturer, 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 加购物车

定价： 712元 加购物车

定价： 590元 加购物车

定价： 646元 加购物车