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5.1 The water content of a soil is used throughout geotechnical engineering practice both in the laboratory and in the field. The use of Test Method D2216 for water content determination can be time consuming and there are occasions when a more expedient method is desirable. The use of a microwave oven is one such method.5.2 The principal objection to the use of the microwave oven for water-content determination has been the possibility of overheating the soil, thereby yielding a water content higher than would be determined by Test Method D2216. While not eliminating this possibility, the incremental drying procedure described in this test method will minimize its effects. Some microwave ovens have settings at less than full power, which can also be used to reduce overheating.5.3 The behavior of a soil, when subjected to microwave energy, is dependent on its mineralogical compositions, and as a result no one procedure is applicable for all types of soil. Therefore, the procedure recommended in this test method is meant to serve as a guide when using the microwave oven.5.4 This test method is best suited for minus 4.75-mm (No. 4) sieve sized material. Larger size particles can be tested; however, care must be taken because of the increased chance of particle shattering.5.5 The use of this method may not be appropriate when highly accurate results are required, or the test using the data is extremely sensitive to moisture variations.5.6 Due to the localized high temperatures that the specimen is exposed to in microwave heating, the physical characteristics of the soil may be altered. Degregation of individual particles may occur, along with vaporization or chemical transition. It is therefore recommended that samples used in this test method not be used for other tests subsequent to drying.NOTE 1: The quality of the results produced by this test method is dependent on the competence of the personnel performing it and the suitability of the equipment and facilities used. Agencies that meet the criteria of Practice D3740 are generally considered capable of competent and objective testing. Users of this test method are cautioned that compliance with Practice D3740 does not in itself ensure reliable results. Reliable results depend on many factors; Practice D3740 provides a means of evaluating some of those factors.1.1 This test method outlines procedures for determining the water content of soils by incrementally drying soil in a microwave oven.1.2 This test method can be used as a substitute for Test Method D2216 when more rapid results are desired to expedite other phases of testing and slightly less accurate results are acceptable.1.3 When questions of accuracy between this test method and Test Method D2216 arise, Test Method D2216 shall be the referee method.1.4 This test method is applicable for most soil types. For some soils, such as those containing significant amounts of halloysite, mica, montmorillonite, gypsum or other hydrated materials, highly organic soils, or soils in which the pore water contains significant amounts of dissolved solids (such as salt in the case of marine deposits), this test method may not yield reliable water content values due to the potential for heating above 110°C or lack of means to account for the presence of precipitated solids that were previously dissolved.1.5 The values stated in SI units are to be regarded as the standard. Performance of the test method utilizing another system of units shall not be considered non-conformance. The sieve designations are identified using the “standard” system in accordance with Specification E11, such as 2.0-mm and 19-mm, followed by the “alternative” system of No. 10 and 3/4-in., respectively, in parentheses.1.6 All observed and calculated values shall conform to the guidelines for significant digits and rounding established in Practice D6026, unless otherwise superseded by this standard.1.6.1 The procedures used to specify how data are collected/recorded or calculated in this standard are regarded as the industry standard. In addition, they are representative of the significant digits that generally should be retained. The procedures used do not consider material variation, purpose for obtaining the data, special purpose studies, or any considerations for the user’s objectives; and it is common practice to increase or reduce significant digits of reported data to be commensurate with these considerations. It is beyond the scope of this standard to consider significant digits used in analysis methods for engineering design.1.6.2 Significant digits are especially important if the water content will be used to calculate other relationships such as moist mass to dry mass or vice versa, wet unit weight to dry unit weight or vice versa, and total density to dry density or vice versa. For example, if four significant digits are required in any of the above calculations, then the water content has to be recorded to the nearest 0.1 %, for water contents below 100 %. This occurs since 1 plus the water content (not in percent) will have four significant digits regardless of what the value of the water content is (below 100 %); that is, 1 plus 0.1/100 = 1.001, a value with four significant digits. While, if three significant digits are acceptable, then the water content can be recorded to the nearest 1 %.1.7 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. See Section 7.

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At this time, none of these tests has been demonstrated to correlate with field service. It is essential that consideration be given to the appropriate pairing of metal and fluid since these procedures do not restrict the selection of either the containment material or the fluid for testing. Likewise, knowledge of the corrosion protection mechanism and the probable mode of failure of a particular metal is helpful in the selection of test conditions and the observation, interpretation, and reporting of test results. The design of solar heating and cooling systems strongly affects the applicability of the results of the laboratory screening tests. Therefore, the results of these laboratory procedures should be confirmed by component and systems testing under actual or simulated service conditions. Table 1 is provided to assist in an orderly consideration of the important factors in testing. It is expected that the user of the test procedure will investigate a range of test times and temperatures for the containment material in a metal/fluid pair, and adjust the time and temperature of testing as necessary. Note 1—Corrosion, whether general or localized, is a time-dependent phenomenon. This time dependence can show substantial nonlinearity. For example, formation of a protective oxide will diminish corrosion with time, while certain forms of localized attack accelerate with time. The minimum time required for a test to provide a corrosion rate that can be extrapolated for the prediction of long-term performance varies widely, depending on the selection of metal and fluid, and on the form of corrosion attack. Therefore, it is not possible to establish a single minimum length of test applicable to all materials and conditions. However, it is recommended that for the tests described in this practice, a test period of no less than 30 days be used. Furthermore, it is recommended that the effect of time of testing be evaluated to detect any significant time dependence of corrosion attack. It is essential for the meaningful application of these procedures that the length of the test be adequate to detect changes in the nature of the fluid that might significantly alter the corrosivity of the fluid. For example, exhaustion of chemical inhibitor or chemical breakdown of the fluid may occur after periods of months in selected cycles of operation. Note 2—Many fluids that may be considered for solar applications contain additives to minimize the corrosivity of the fluid. Many such additives are useful only within a specific concentration range, and some additives may actually accelerate corrosion if the concentration falls below a critical level. Depletion kinetics can be a strong function of the exposed metal surface area. Therefore, for tests involving fluids with such additives, consideration must be given to the ratio of metal surface area to fluid volume as it may relate to an operating system. TABLE 1 Significant Variables in Evaluation of Containment Material/Heat Transfer Fluid PairsA Test AspectVariable TemperatureFlow Rate I.Operating Conditions of System: A. Operating, full flow B. Stagnant, fullnormal operating fluid boiling point without pressurization or no-flow temperature with pressurization normal operating convection C. Stagnant, partial fill D. Stagnant, emptysame as stagnant, full no-flow temperature convection not applicable II.Test Specimen Design A. flat metal couple B. metal couple with crevice C. dissimilar metal couple D. dissimilar metal couple with crevice III.Fluid TypeA. fluid intended for use in system B. fluid pretreated by thermal exposure or chemical contamination IV.Test CycleA. long time, constant temperature B. cycles of heating, holding, and cooling C. cycles of operating full flow, and stagnation D. cycles of wetting and drying A In this table, the subdivisions are not necessarily related in correspondence to their lettering.1.1 This practice covers several laboratory test procedures for evaluating corrosion performance of metallic containment materials under conditions similar to those that may occur in solar heating and cooling systems. All test results relate to the performance of the metallic containment material only as a part of a metal/fluid pair. Performance in these laboratory test procedures, taken by itself, does not necessarily constitute an adequate basis for acceptance or rejection of a particular metal/fluid pair in solar heating and cooling systems, either in general or in a particular design. This practice is not intended to preclude the use of other screening tests, particularly when those tests are designed to more closely simulate field service conditions. 1.2 This practice describes apparatus and procedures for several tests, any one or more of which may be used to evaluate the deterioration of the metallic containment material in a metal/fluid pair. The procedures are designed to permit simulation, heating, and cooling systems including (1) operating full flow, (2) stagnant full, (3) stagnant partial fill, and (4) stagnant empty. Particular attention should be directed to properly reflecting whether the system is open or closed to atmosphere. 1.3 This practice covers the following six tests: Practice ABasic Immersion Test at Atmospheric Pressure Practice BHeat-Rejecting Surface Test at Atmospheric Pressure Practice CHigh-Pressure Test Practice DRepeated Dip Dry Test at Atmospheric Pressure Practice ECrevice Test at Atmospheric Pressure Practice FTube Loop Test at Atmospheric Pressure 1.4 Practice A is concerned with the interaction of metal and fluid when both are at the same temperature with no heat transfer from one to the other. It is regarded as useful for plumbing, pumps, tanking, etc., but of less significance, taken by itself, for collector panels. Practices B and F are concerned with the deterioration of the metal when there is transfer of heat from the metal into the heat transfer fluid. These practices are especially applicable to the collector panel. Practice C permits a variety of tests but is especially useful in relation to systems that experience high temperatures, or are closed to the atmosphere. Practices D and E evaluate specific corrosion problems that may be associated with particular metal/fluid pairs and particular designs of systems and components. 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 and health practices and determine the applicability of regulatory limitations prior to use.

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At this time none of these practices have been demonstrated to correlate with field service. Because these procedures do not restrict the selection of either the containment material or the fluid for testing, it is essential that consideration be given to the appropriate pairing of metal and fluid. Likewise, knowledge of the corrosion protection mechanism and the probable mode of failure of a particular metal is helpful in the selection of test conditions and the observation, interpretation, and reporting of test results. It is important that consideration be given to each of the permitted variables in test procedure so that the results will be meaningfully related to field performance. It is especially important that the time of testing selected be adequate to correctly measure the rate of corrosion of the containment material. Note 1—Corrosion, whether general or localized, is a time-dependent phenomenon. This time dependence can show substantial nonlinearity. For example, formation of a protective oxide will diminish corrosion with time, while certain forms of localized attack accelerate corrosion with time. The minimum time required for a test to provide a corrosion rate that can be extrapolated for the prediction of long-term performance varies widely, depending on the selection of metal and fluid, and on the form of corrosion attack. Therefore, it is not possible to establish a single minimum length of test applicable to all materials and conditions. However, it is recommended that for the tests described in these practices, a test period of no less than 6 months be used. Furthermore, it is recommended that the effect of time of testing be evaluated to detect any significant time dependence of corrosion attack. It is essential for the meaningful application of these procedures that the length of test be adequate to detect changes in the nature of the fluid that might significantly alter the corrosivity of the fluid. For example, exhaustion of chemical inhibitor or chemical breakdown of the fluid may occur after periods of months in selected cycles of operation. Note 2—Many fluids that may be considered for solar applications contain additives to minimize the corrosivity of the fluid. Many such additives are useful only within a specific concentration range, and some additives may actually accelerate corrosion if the concentration falls below a critical level. Depletion kinetics can be a strong function of the exposed metal surface area. Therefore, for tests involving fluids with such additives, consideration must be given to the ratio of metal surface area to fluid volume as it may relate to an operating system.1.1 These practices cover test procedures simulating field service for evaluating the performance under corrosive conditions of metallic containment materials in solar heating and cooling systems. All test results relate to the performance of the metallic containment material only as a part of a metal/fluid pair. Performance in these test procedures, taken by itself, does not necessarily constitute an adequate basis for acceptance or rejection of a particular metal/fluid pair in solar heating and cooling systems, either in general or in a particular design. 1.2 These practices describe test procedures used to evaluate the resistance to deterioration of metallic containment materials in the several conditions that may occur in operation of solar heating and cooling systems. These conditions include: (1) operating full flow; (2) stagnant empty vented; (3) stagnant, closed to atmosphere, non-draindown; and (4) stagnant, closed to atmosphere, draindown. 1.3 The recommended practices cover the following three tests: 1.3.1 Practice A—Laboratory Exposure Test for Coupon Specimens. 1.3.2 Practice B—Laboratory Exposure Test of Components or Subcomponents. 1.3.3 Practice C—Field Exposure Test of Components or Subcomponents. 1.4 Practice A provides a laboratory simulation of various operating conditions of solar heating and cooling systems. It utilizes coupon test specimens and does not provide for heating of the fluid by the containment material. Practice B provides a laboratory simulation of various operating conditions of a solar heating and cooling system utilizing a component or a simulated subcomponent construction, and does provide for heating of the fluid by the containment material. Practice C provides a field simulation of various operating conditions of solar heating and cooling systems utilizing a component or a simulated subcomponent construction. It utilizes controlled schedules of operation in a field test. 1.5 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. 1.6 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 and health practices and determine the applicability of regulatory limitations prior to use. For a specific safety precaution statement see Section 6.

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5.1 On-line, at-line, in-line, and other near-real time monitoring systems that measure fuel gas characteristics, such as heating value, are prevalent in various gaseous fuel industries and in industries either producing or using gaseous fuel in their industrial processes. The installation and operation of particular systems vary depending on process type, regulatory requirements, and the user’s objectives and performance requirements. This practice is intended to provide guidance for standardized start-up procedures, operating procedures, and quality assurance practices for calorimeter based on-line, at-line, in-line, and other near-real time heating value monitoring systems. Users employing gas chromatographic based instrumentation for measurement of gaseous fuel heating value are referred to Practice D7164.1.1 This practice is for the determination of the heating value measurement of gaseous fuels using a calorimeter. Heating value determination of sample gasses containing water vapor will require vapor phase moisture measurements of the pre-combustion sample gas as well as the non-condensed gasses exiting the calorimeter. Instruments equipped with appropriate conditioners and algorithms may provide heating value results on a net or gross and dry or wet basis.1.2 This practice is applicable to at-line and in-line instruments that are operated from time to time on a continuous basis.1.3 Units—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 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.

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This specification establishes the physical and performance requirements, and the corresponding test methods, for the evaluation of reflective insulation systems that are applied externally to rigid ducts in heating, ventilation, and air conditioning (HVAC) systems operating at specified temperatures. The products covered here are classified into five types according to the substrate material used, namely: Type A, product with polyethylene foam substrate; Type B, product with polyethylene bubble pack substrate; Type C, product with fiberglass substrate; Type D, product with polyester fiber substrate; and Type E, product with kraft paper substrate. Properly sampled specimens shall undergo test procedure to examine their conformance with the following requirements: emittance; water vapor permeance; surface burning characteristics; aging resistance; adhesive performance (bleeding and delamination); pliability; fungi resistance; thermal resistance; and hot-surface performance.1.1 This specification covers the requirements and physical properties of reflective insulation systems applied externally to Rigid Heating, Ventilation, and Air Conditioning (HVAC) duct systems operating at or below 250°F (121.1°C). These insulation systems consist of one or more low-emittance surfaces, such as metallic foil or metallic deposits, mounted on substrates to produce reflective air spaces. Reflective insulation systems derive thermal performance from surfaces with an emittance of no greater than 0.1 facing enclosed air spaces.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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The spontaneous heating value of a substance is a measure of the ability of that substance to undergo self-heating reactions while supported by cellulosic or other fibrous material in air. It is an index of the autoignition tendency of the substance under such conditions.1.1 This test method covers the non-adiabatic determination of the spontaneous heating values (SHV) of liquids and solids. It is applicable to substances that are not completely volatile at the test temperature. Spontaneous heating values obtained by this test method are qualitative indications of the degree of self-heating that may be expected to occur upon exposure of the sample to air at the test temperature.1.2 Values obtained by this method are applicable to liquids and solids supported on cellulosic surfaces. They are not applicable to liquids on metal surfaces, on contaminated surfaces, or at pressures above atmospheric.1.3 Spontaneous heating values determined by the present test method are regarded only as qualitative measurements of self-heating which occurs under the conditions of the test. The test method does not purport to produce a quantitative measure of the enthalpy of reaction of the sample with air at a given test temperature. Such data can be obtained by the use of an adiabatic calorimeter. The existence, under the test conditions, of a positive temperature difference between the sample and the reference is evidence of a thermochemical reaction in the sample.1.4 The magnitude of the measured temperature difference is a semiquantitative indication of the enthalpy and rate of that reaction. Since factors such as heat loss from the sample to the bath and quenching of the reaction due to too rapid consumption of oxygen affect the amount and duration of the measured heat effect, care must be taken not to attribute too much quantitative significance to the test results. It is sufficient, for the purpose of this test, to determine whether or not the sample is capable of undergoing a self-heating reaction of sufficient magnitude and rapidity to produce a detectable thermal effect. The spontaneous heating value (SHV) can be lower than the test temperature. A negative result does not preclude spontaneous heating initiating at a temperature higher than the test temperature.1.5 This standard should be used to measure and describe the response of materials, products, or assemblies to heat and flame under controlled conditions and should not be used to describe or appraise the fire-hazard or fire-risk of materials, products, or assemblies under actual fire conditions. However, results of this test may be used as elements of a fire-hazard assessment or a fire-risk assessment which takes into account all of the factors which are pertinent to an assessment of the fire hazard or fire risk of a particular end use.1.6 The values stated in SI units are to be regarded as the standard. In cases where materials, products or equipment are available in inch-pound units only, SI units are omitted.1.7 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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This specification covers annealed, drawn or rolled iron-chromium-aluminum alloy shapes used for electrical heating and resistance purposes. This specification contains the requirements for chemical composition, electrical resistance, mechanical properties and temperature-dependent changes in resistance of the alloys.1.1 This specification covers annealed, drawn, or rolled shapes for electrical heating and resistance purposes of alloys consisting mainly of iron, chromium, and aluminum as detailed in Table 1.1.2 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 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.1.4 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 In the United States, high sulfur content (defined by the United States Environmental Protection Agency (USEPA)) middle distillate products and diesel fuel used for off-road purposes, other than aviation turbine fuel, are required by government agencies to contain red dye. The dye concentration required to be present in high-sulfur and off-road diesel products is regulated by the United States Environmental Protection Agency and the United States Internal Revenue Service, respectively.5.2 Some fuels that are readily exchanged in the market have a color specification. The color of the base fuel is masked by the presence of the red dye. This test method provides a means of estimating the base color of Number 1 and Number 2 diesel fuel and heating oil in the presence of red dye.5.3 The test method provides a means to indicate conformance to contractual and legal requirements.1.1 This test method covers the determination of the red dye concentration of diesel fuel and heating oil and the estimation of the ASTM color of undyed and red-dyed diesel fuel and heating oil. The test method is appropriate for use with diesel fuel and heating oil of Grades 1 and 2 described in Specifications D396, D975, D2880, and D3699. Red dye concentrations are determined at levels equivalent to 0.1 mg/L to 20 mg/L of Solvent Red 26 in samples with ASTM colors ranging from 0.5 to 5. The ASTM color of the base fuel of red-dyed samples with concentration levels equivalent to 0.1 mg/L to 20 mg/L of Solvent Red 26 is estimated for the ASTM color range from 0.5 to 5. The ASTM color of undyed samples is estimated over the ASTM color range of 0.5 to 5.1.2 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 and health 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： 590元 / 折扣价： 502 元 加购物车

5.1 This test method is intended for the determination of the radiant heat resistance value of a material, a combination of materials, or a comparison of different materials used in flame-resistant clothing for workers exposed to radiant thermal hazards.5.2 This test method evaluates a material's heat transfer properties when exposed to a continuous and constant radiant heat source. Air movement at the face of the specimen and around the calorimeter can affect the measured heat transferred due to forced convective heat losses. Minimizing the air movement around the specimen and test apparatus will aid in the repeatability of the results.5.3 This test method maintains the specimen in a static, vertical position and does not involve movement, except that resulting from the exposure.5.4 This test method specifies two standard sets of exposure conditions: 21 kW/m2 (0.5 cal/cm2s) and 84 kW/m2 (2.0 cal/cm2s). Either can be used.5.4.1 If a different set of exposure conditions is used, it is likely that different results will be obtained.5.4.2 The optional use of other conditions representative of the expected hazard, in addition to the standard set of exposure conditions, is permitted. However, the exposure conditions used must be reported with the results along with a determination of the exposure energy level stability.5.5 This test method does not predict skin burn injury from the standardized radiant heat exposure.NOTE 4: See Appendix X4 for additional information regarding this test method and predicted skin burn injury.1.1 This test method rates the non-steady state thermal resistance or insulating characteristics of flame resistant clothing materials subjected to a continuous, standardized radiant heat exposure.1.1.1 This test method is not applicable to clothing materials that are not flame resistant.NOTE 1: The determination of a clothing material's flame resistance shall be made prior to testing and done in accordance with the applicable performance standard, specification standard, or both, for the clothing material's end use.1.1.2 This test method does not predict skin burn injury from the standardized radiant heat exposure, as it does not account for the thermal energy contained in the test specimen after the exposure has ceased.NOTE 2: See Appendix X4 for additional information regarding this test method and predicted skin burn injury.1.2 This test method is used to measure and describe the response of materials, products, or assemblies to heat under controlled conditions, but does not by itself incorporate all factors required for fire hazard or fire risk assessment of the materials, products, or assemblies under actual fire conditions.1.3 The values stated in SI units are to be regarded as standard. The values given in parentheses are mathematical conversions to inch-pound or other units that are commonly used for thermal testing.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.

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4.1 This test method is useful in characterizing certain petroleum products by the determination of their loss of mass upon heating under standardized conditions.1.1 This test method covers the determination of the loss in mass (exclusive of water) of oil and asphaltic compounds when heated as hereinafter prescribed.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.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 and 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 Often it is necessary to dissolve the sample, particularly if it is a solid, before atomic spectroscopic measurements. It is advantageous to use a microwave oven for dissolution of such samples since it is a far more rapid way of dissolving the samples instead of using the traditional procedures of dissolving the samples in acid solutions using a pressure decomposition vessel, or other means.5.2 The advantage of microwave dissolution includes faster digestion that results from the high temperature and pressure attained inside the sealed containers. The use of closed vessels also makes it possible to eliminate uncontrolled trace element losses of volatile species that are present in a sample or that are formed during sample dissolution. Volatile elements arsenic, boron, chromium, mercury, antimony, selenium, and tin may be lost with some open vessel acid dissolution procedures. Another advantage of microwave aided dissolution is to have better control of potential contamination in blank as compared to open vessel procedures. This is due to less contamination from laboratory environment, unclean containers, and smaller quantity of reagents used (9).5.3 Because of the differences among various makes and models of satisfactory devices, no detailed operating instructions can be provided. Instead, the analyst should follow the instructions provided by the manufacturer of the particular device.5.4 Mechanism of Microwave Heating—Microwaves have the capability to heat one material much more rapidly than another since materials vary greatly in their ability to absorb microwaves depending upon their polarities. Microwave oven is acting as a source of intense energy to rapidly heat the sample. However, a chemical reaction is still necessary to complete the dissolution of the sample into acid mixtures. Microwave heating is internal as well as external as opposed to the conventional heating which is only external. Better contact between the sample particles and the acids is the key to rapid dissolution. Thus, heavy nonporous materials such as fuel oils or coke are not as efficiently dissolved by microwave heating. Local internal heating taking place on individual particles can result in the rupture of the particles, thus exposing a fresh surface to the reagent contact. Heated dielectric liquids (water/acid) in contact with the dielectric particles generate heat orders of magnitude above the surface of a particle. This can create large thermal convection currents which can agitate and sweep away the stagnant surface layers of dissolved solution and thus, expose fresh surface to fresh solution. Simple microwave heating alone, however, will not break the chemical bonds, since the proton energy is less than the strength of the chemical bond (5).5.4.1 In the electromagnetic irradiation zone, the combination of the acid solution and the electromagnetic radiation results in near complete dissolution of the inorganic constituents in the carbonaceous solids. Evidently, the electromagnetic energy promotes the reaction of the acid with the inorganic constituents thereby facilitating the dissolution of these constituents without destroying any of the carbonaceous material. It is believed that the electromagnetic radiation serves as a source of intense energy which rapidly heats the acid solution and the internal as well as the external portions of the individual particles in the slurry. This rapid and intense internal heating either facilitates the diffusion processes of the inorganic constituents in solution or ruptures the individual particles thereby exposing additional inorganic constituents to the reactive acid. The heat generated in the aqueous liquid itself will vary at different points around the liquid-solid interface and this may create large thermal convection currents which can agitate and sweep away the spent acid solution containing dissolved inorganic constituents from the surface layers of the carbonaceous particles thus exposing the particle surfaces to fresh acid (16).5.4.2 Unlike other heating mechanisms, true control of microwave heating is possible because stopping of the application of energy instantly halts the heating (except the exotherms which can be rapid when pure compounds are digested). The direction of heat flow is reversed from conventional heating, as microwave energy is absorbed by the contents of the container, energy is converted to heat, and the bulk temperature of the contents rises. Heat is transferred from the reagent and sample mixture to the container and dissipated through conduction to the surrounding atmosphere. Newer synthesized containers made up of light yet strong polymers can withstand over 240 °C temperatures and over 800 psi pressure. During the digestion process of samples containing organic compounds, largely insoluble gases such as CO2 are formed. These gases combine with the vapor pressure from the reagents, at any temperature, to produce the total pressure inside the vessel. Since the heat flow from a microwave digestion vessel is reversed from that of resistive devices, the total pressures generated for microwave dissolutions are significantly lower at the same temperature than other comparably heated devices or systems. This means larger samples can be digested at higher temperatures and lower pressures than would normally be expected from such pressurized vessels. Sample size should be controlled to prevent rapid exotherm rupture, exacerbated by excess CO2 generation. However, the pressure limitations of the vessel still restrict both the sample size that can be used and the maximum temperature that can be achieved due to the vapor pressure resulting from the reagents (17).5.4.3 Organic and polymer samples can be especially problematic because they are highly volatile and produce large amounts of gaseous by-products such as CO2 and NOx. As a result larger sample sizes will produce higher pressures inside the digestion vessel. Generally, no more than 1 g of these sample types can be digested in a closed vessel (18).5.4.3.1 While in open digestion vessel systems the operating temperatures are limited by the acid solutions’ boiling points, temperatures in the 200 °C to 260 °C range can be typically achieved in sealed digestion vessels. This results in a dramatic acceleration of the reaction kinetics, allowing the digestion reactions to be carried out in a shorter time period. The higher temperatures, however, result in a pressure increase in the vessel and thus in a potential safety hazard. Rapid heating of the sample solution can induce exothermic reactions during the digestion process. Therefore in modern microwave digestion systems, sensors and interlocks for temperature and pressure control are introduced. Since different types of sample behave differently in microwave field, heating control is necessary in this operation (19).5.4.4 Microwave heating occurs because microwave reactors generate an electromagnetic field that interacts with polarizable molecules or ions in the materials. As the polarized species compete to align their dipoles with the oscillating field, they rotate, migrate, and rub against each other, causing them to heat up. This microwave effect differs from indirect heating by conduction achieved by using a hot plate (20).1.1 This practice covers the procedure for use of microwave radiation for sample decomposition prior to elemental determination by atomic spectroscopy.1.1.1 Although this practice is based on the use of inductively coupled plasma atomic emission spectrometry (ICP-AES) and atomic absorption spectrometry (AAS) as the primary measurement techniques, other atomic spectrometric techniques may be used if lower detection limits are required and the analytical performance criteria are achieved.1.2 This practice is applicable to both petroleum products and lubricants such as greases, additives, lubricating oils, gasolines, and diesels.1.3 Although not a part of Committee D02’s jurisdiction, this practice is also applicable to other fossil fuel products such as coal, fly ash, coal ash, coke, and oil shale.1.3.1 Some examples of actual use of microwave heating for elemental analysis of fossil fuel products and other materials are given in Table 1.(A) The boldface numbers in parentheses refer to the list of references at the end of this standard.1.3.2 Some additional examples of ASTM methods for microwave assisted analysis in the non-fossil fuels area are included in Appendix X1.1.4 During the sample dissolution, the samples may be decomposed with a variety of acid mixture(s). It is beyond the scope of this practice to specify appropriate acid mixtures for all possible combinations of elements present in all types of samples. But if the dissolution results in any visible insoluble material, this practice may not be applicable for the type of sample being analyzed, assuming the insoluble material contains some of the analytes of interest.1.5 It is possible that this microwave-assisted decomposition procedure may lead to a loss of “volatile” elements such as arsenic, boron, chromium, mercury, antimony, selenium, and/or tin from the samples. Chemical species of the elements is also a concern in such dissolutions since some species may not be digested and have a different sample introduction efficiency.1.6 A reference material or suitable NIST Standard Reference Material should be used to confirm the recovery of analytes. If these are not available, the sample should be spiked with a known concentration of analyte prior to microwave digestion.1.7 Additional information on sample preparation procedures for elemental analysis of petroleum products and lubricants can be found in Practice D7455.1.8 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.9 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. Specific warning statements are given in Sections 6 and 7.1.10 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 The water content of a soil is used throughout geotechnical engineering practice both in the laboratory and in the field. The use of Test Methods D2216 for water content determination can be time consuming and there are occasions when a more expedient method is desirable. Drying by direct heating is one such method. Results of this test method have been demonstrated to be of satisfactory accuracy for use in field control work, such as in the determination of water content, and in the determination of in-place dry unit weight of soils.5.2 The principal objection to the use of the direct heating for water content determination is the possibility of overheating the soil, thereby yielding a water content higher than would be determined by Test Methods D2216. While not eliminating this possibility, the incremental drying procedure in this test method will minimize its effects. Some heat sources have settings or controls that can also be used to reduce overheating. Loose fitting covers or enclosures can also be used to reduce overheating while assisting in uniform heat distribution.5.3 The behavior of a soil when subjected to direct heating is dependent on its mineralogical composition, and as a result, no one procedure is applicable for all types of soils or heat sources. The general procedure of this test method applies to all soils, but test details may need to be tailored to the soil being tested.5.4 When this test method is to be used repeatedly on the same or similar soil from a given site, a correction factor can usually be determined by making several comparisons between the results of this test method and Test Methods D2216. A correction factor is valid when the difference is consistent for several comparisons, and is reconfirmed on a regular specified basis.5.5 This test method may not be appropriate when precise results are required, or when minor variations in water content will affect the results of other test methods, such as borderline situations where small variations in the measured water content could affect acceptance or rejection.5.6 This test method is not appropriate for specimens known to contain flammable organics or contaminants, and other test methods should be utilized in these situations.NOTE 1: The quality of the results produced by this test method is dependent on the competence of the personnel performing it and the suitability of the equipment and facilities used. Agencies that meet the criteria of Practice D3740 are generally considered capable of competent and objective testing/sampling/inspection. Users of this test method are cautioned that compliance with Practice D3740 does not in itself ensure reliable results . Reliable results depend on many factors; Practice D3740 provides a means of evaluating some of those factors.1.1 This test method covers procedures for determining the water content of soils by drying with direct heat, such as using a hotplate, stove, blowtorch, and the like.1.2 This test method can be used as a substitute for Test Methods D2216 when more rapid results are desired to expedite other phases of testing and slightly less accurate results are acceptable.1.3 When questions of accuracy between this test method and Test Methods D2216 arise, Test Methods D2216 shall be the referee method.1.4 This test method is applicable for most soil types. For some soils, such as those containing significant amounts of halloysite, mica, montmorillonite, gypsum, or other hydrated materials, highly organic soils or soils that contain dissolved solids, (such as salt in the case of marine deposits), this test method may not yield reliable water content values due to the potential for heating above 110°C or lack of means to account for the presence of precipitated solids that were previously dissolved.1.5 The values stated in SI units are to be regarded as standard. Performance of the test method utilizing another system of units shall not be considered non-conformance. The sieve designations are identified using the “standard” system in accordance with Specification E11, such as 2.0-mm and 19-mm, followed by the “alternative” system of No. 10 and 3/4-in., respectively, in parentheses.1.6 All observed and calculated values shall conform to the guidelines for significant digits and rounding established in D6026, unless otherwise superseded by this standard.1.6.1 The procedures used to specify how data are collected/recorded or calculated, in this standard are regarded as the industry standard. In addition, they are representative of the significant digits that generally should be retained. The procedures used do not consider material variation, purpose for obtaining the data, special purpose studies, or any considerations for the user’s objectives; and it is common practice to increase or reduce significant digits of reported data to be commensurate with these considerations. It is beyond the scope of this standard to consider significant digits used in analysis methods for engineering design.1.6.2 Significant digits are especially important if the water content will be used to calculate other relationships such as moist mass to dry mass or vice versa, wet unit weight to dry unit weight or vice versa, and total density to dry density or vice versa. For example, if four significant digits are required in any of the above calculations, then the water content has to be recorded to the nearest 0.1 %, for water contents below 100 %. This occurs since 1 plus the water content (not in percent) will have four significant digits regardless of what the value of the water content is (below 100 %); that is, 1 plus 0.1/100 = 1.001, a value with four significant digits. While, if three significant digits are acceptable, then the water content can be recorded to the nearest 1 %.1.7 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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5.1 This test method is used to measure the apparent viscosity of thermoplastic pavement marking at elevated temperatures. Elevated temperature viscosities of thermoplastic pavement marking may be related to the properties of coatings, adhesives, and composite thermoplastics. This method is helpful in determining the flow properties which can be used in determining processability when applied to the road surface.5.2 Thermoplastic pavement markings may be applied to the road surface in several different ways. Typical methods of application are screed extrude, ribbon extrude, thin film spray, and standard spray. Proper application depends on the viscosity of the thermoplastic material at application temperatures for the method being used. Thin-line applied thermoplastic pavement marking, for example, requires a relatively lower viscosity. Screed extrude applied thermoplastic requires a higher viscosity.5.3 Materials of the type described in this procedure may be non-Newtonian, and as such, the apparent viscosity will be a function of shear rate under the conditions of test. Although the viscometer described in this test method operates under conditions of relatively low shear rate, differences in shear effect can exist depending upon the spindle and rotational speed conditions selected for the test program. Comparisons between non-Newtonian viscosity values should be made only for measurements made with similar viscometers under conditions of equivalent shear. For this method, “torpedo” spindles are recommended. Spindles considered torpedo spindles are ~1-in. long and come in many diameters with a 45° conical bottom. A diameter that is half the diameter of the thimbles used is recommended. If large glass beads are used in the pavement marking formulation, a smaller diameter spindle may be needed so the beads do not cause an impedance of the spindle due to a jamming between the inside wall of the thimble and the spindle.1.1 This test method covers the sample preparation and testing procedure needed to determine the apparent viscosity of a thermoplastic pavement marking formulation at elevated temperatures to the specimen.1.2 The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are customary units and are provided as a courtesy to the user.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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