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定价： 689元 / 折扣价： 586 元 加购物车

定价： 590元 / 折扣价： 502 元 加购物车

Moisture has an adverse effect on the dielectric strength, dielectric loss, dc resistivity, and aging characteristics of oil-impregnated cellulosic insulating materials.When cellulosic insulation such as paper and pressboard are impregnated with and immersed in oil, there is an interchange of moisture between the cellulose and oil until they attain equilibrium with respect to their relative saturations with moisture.Considerable care should be taken in using these test methods to measure the water content of dry (<0.5 %) paper and board. Contamination of material by water from the surroundings during sampling and handling may be both rapid and significant in the case of dry test specimens. This is an even greater concern with cellulose insulation prior to oil impregnation.1.1 These test methods cover the determination of the weight percent of water in new or aged, oil-impregnated electrical insulation. These test methods depend on solvent extraction of the water at room temperature. The range from 0.1 to 7.0% water has been explored.1.2 There are four test methods, A, B, C, and D. Methods A and B for thin paper and dense materials, respectively, are manual methods for solvent extraction of water from the specimens. Titration is used to determine the amount of water. Method C uses automatic titration to determine the amount of water. Method D is a direct automated method for extraction and detection of the water.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 and health practices and determine the applicability of regulatory limitations prior to use.

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4.1 This practice defines a procedure that ensures reasonably consistent preparation of specimens for product testing and evaluation.4.2 This practice can be used in the laboratories of producers, users, and general interest parties for research and development or quality control work. It is particularly useful for interlaboratory comparisons on products, for repetitive evaluations or comparisons of products or product quality, and in specifying a uniform preparation practice for specimens for acceptance testing.4.3 If pitch-impregnated samples are prepared by wet cutting or drilling, care should be taken in drying them. If the samples are heated to facilitate drying, the temperature to which they are heated should not be so high that it causes drainage of pitch from the samples.4.4 Porosities of metal-containing brick must be measured using kerosene or mineral spirits, because using water will result in an artificially low result.1.1 This practice covers a procedure for preparing test specimens from magnesia-carbon and impregnated burned basic brick. This practice generally concerns preparation of test specimens from brick greater than 13 in. (33 cm) in length. These brick are mainly manufactured for use in electric arc furnaces and basic oxygen furnaces.1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered 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

5.1 This test method differentiates between web materials on the basis of their ability to cause wear on surfaces with which they come in contact. This test method can also be used to evaluate the wear resistance of different materials against such web materials.1.1 This test method covers the determination of the abrasiveness of ink-impregnated fabric printer ribbons and other web materials by means of a sliding wear test.1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered 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.

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定价： 646元 / 折扣价： 550 元 加购物车

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5.1 Activated carbons used in containment systems for nuclear reactors must be capable of functioning under both normal operating conditions and those conditions which may exist following a design basis accident (DBA). Adsorbent beds that are part of recirculatory systems inside containment may be exposed to the peak pressure, temperature, and steam content of a post-DBA condition.5.2 Carbon beds outside containment will be protected by fast-acting shutoff valves from the sudden rise in pressure, temperature, and humidity of the containment atmosphere which would exist following a DBA. However, some rise in temperature and humidity will be experienced even by beds outside containment if they are reconnected to containment after the initial pressure rise (due to escape of steam into the containment volume) has been reduced by containment coolers. The amount of radioactivity that can reach either type of adsorption system is conceivably quite high; hence, there is a possibility of a bed temperature rise due to decay heating. The gaseous radioactive contaminants of most interest are organic iodides. In this test, CH3I is used to typify the performance of the carbon on organic iodine compounds in general. The test described here provide a reasonable picture of the effectiveness of an activated carbon for organic iodides under normal and post-DBA conditions. The equipment and methods described can be used, with discretion, for similar tests at different gas flow conditions and, to some extent, on different gaseous radioactive contaminants and other adsorbents.AbstractThis standard covers the specifications for physical properties and performance requirements of virgin impregnated activated carbon to be used for the removal of gaseous radioiodine species from gas streams. The activated carbon furnished under this specification shall be virgin material. Each batch of impregnated activated carbon shall conform to the requirements for physical properties prescribed. The following test methods shall used to determine the physical properties and performance capability of the sample: apparent density; particle size distribution; ash content; moisture content; ignition temperature; ball-pan hardness; and pH.1.1 This standard covers the specifications for physical properties and performance requirements of virgin impregnated activated carbon to be used for the removal of gaseous radioiodine species from gas streams.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 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 Dissipation Factor and Relative Permittivity—Knowledge of these properties is important in the design of electrical equipment such as cables, transformers, insulators, and so forth. The numerical product of these two properties of a dielectric system is proportional to the energy loss converted to heat, and is called its loss index (see Terminology D1711). The energy loss reduces the efficiency of electrical equipment. The heat produced tends to chemically degrade the dielectric material and may even lead to thermal runaway. Test results of impregnated specimens can disclose significant differences between combinations of papers and oils that appear similar when the papers and the oils are tested separately. Dissipation factor, particularly at elevated temperatures, is often changed significantly by the presence of a small quantity of impurities in either the liquid or the paper. This practice is useful in the comparison of materials and in evaluating the effects of different papers on a given liquid. Judicious analysis of results with respect to time, temperature, and field strength are useful in predicting the performance and capabilities of systems using the paper and the liquid. For additional information on the significance of dissipation factor and relative permittivity, see Test Methods D150.5.2 Test Method for Dielectric Breakdown Voltage and Dielectric Strength of Solid Electrical Insulating Materials at Commercial Power Frequencies: 5.2.1 A comprehensive discussion of the significance of the dielectric strength test as applied to solid, semi-solid, and liquid materials is given in Appendix X1 of Test Method D149. Other factors peculiar to high-quality composite insulations, such as oil-impregnated papers, are considered in the following:5.2.2 In tests involving high electrical stresses, immersion of critical parts of a test circuit in oil is a widely used technique for inhibiting corona. However, it has limitations that must be recognized when using the submerged electrode option of this practice (Note 1). Attack on the paper by corona generated in the surrounding fluid at electrode edges can occur whether the fluid is air or oil. Corona occurs at considerably higher voltages in oil than in air. Thick and dense papers are more likely to cause discharge-initiated breakdowns. For interpretation of breakdown measurements consider the number of edge breakdowns, implying discharge-initiated breakdowns.NOTE 1: Two techniques are in use in the industry for testing specimens for dielectric breakdown voltage. In one, the test is made with the electrodes and test specimen submerged in the impregnating liquid while in the other the electrodes are not submerged, that is, the specimen is tested in air. Much data has been accumulated using the latter technique. These techniques yield different values of breakdown voltage. Test Method D149 states preference for testing materials in the medium in which they are used. The use of submerged electrodes follows this preference. When testing thick insulating boards, the use of submerged electrodes is greatly preferred.5.2.3 The results of power frequency tests on oil impregnated papers are useful for screening, research, and quality control, provided that considerable judgment is exercised in interpreting the results. The application of the test results to equipment design and service requires particular caution and skill (see Appendix X1 of Test Method D149).5.3 Dielectric Breakdown Voltage and Dielectric Strength Under Impulse Conditions—Testing impregnated paper or board under impulse conditions can yield useful data for the designer of electrical equipment. The test results are useful in the comparison of materials and for research studies. For a more general treatise on the significance of impulse testing see Test Method D3426.1.1 This practice covers the preparation of insulating paper and board impregnated with a liquid dielectric. Where this practice states only “paper,” the same procedure shall apply to board.1.2 This practice has been found practicable for papers having nominal thickness of 0.05 mm (2 mil) and above. It has been used successfully for insulating board as thick as 6 mm (1/4 in.) when care is taken to ensure the specimen geometry necessary for valid measurement of dielectric properties. Suitable geometry depends on the electrode system used. Rigid solid opposing electrodes require flat specimens that have essentially parallel surfaces.1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.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.

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1.1 This specification covers iron-copper-tin-graphite sintered metal powder oil-impregnated bearings of one composition commonly known as diluted bronze.1.2 The following safety hazards caveat pertains only to the test method described in 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 and health practices and determine the applicability of regulatory limitations prior to use.

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The volume of an arbitrary P/M shape cannot be accurately measured by standard techniques such as by micrometers or calipers. Since density is mass/volume, a precise method to measure the volume is needed. For nonporous objects, the volume of water displaced by the immersed object is determined by Archimedes principle. For porous P/M parts, a method is required to seal surface connected pores. If the pores are not sealed or the part is not oil impregnated, the part will absorb some of the water and decrease its buoyancy and exhibit an erroneously high density.Density and oil content values are generally contained in the specifications for oil-impregnated bearings and other self-lubricating P/M parts. Desired lubrication requires sufficient interconnected porosity and satisfactory oil impregnation of the porosity.For a particular P/M material, the mechanical properties of P/M structural parts are directly related to their density. Density values are therefore generally contained in the specifications for P/M parts.1.1 This test method covers determination of the density, oil content, and interconnected porosity of sintered bearings and structural parts with or without oil impregnation.1.2 The values stated in SI units are to be regarded as the standard. The values in parentheses are for information only.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 and health practices and determine the applicability of regulatory limitations prior to use.

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