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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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5.1 Extraction of organic pollutants from wastes can provide information on the susceptibility of compounds to leeching, water quality changes, or other site conditions.5.2 Rapid heating, in combination with temperatures in excess of the atmospheric boiling point of organic solvents, reduces sample extraction times.5.3 Small amounts of solvents (30 mL) are used resulting in reduced sample preparation cost and time.1.1 This practice describes the closed vessel microwave extraction of soils, sediments, sludges, and wastes for subsequent determination of solvent extractable semivolatile and nonvolatile organic compounds by such techniques as gas chromatography and gas chromatography-mass spectrometry.1.1.1 Compounds listed in Tables 1–5 can be extracted from the preceding materials.1.2 This test method is applicable to samples that will pass through a 10-mesh (approximately 2-mm opening) screen.1.3 The detection limit and linear concentration range for each compound is dependent on the gas chromatograph or gas chromatograph-mass spectrometer technique employed and may be found in the manual accompanying the instrument used.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 establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

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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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This test method establishes the apparatuses required, the standard procedures, and associated calculations involved in the determination of relatively polar nonvolatile ultraviolet (UV) absorbing extractable components that may migrate from microwave susceptor packaging into food simulants, such as corn oil and Miglyol 812. This test method has been collaboratively studied using bilaminate susceptors constructed of paperboard, adhesive, and a layer of polyethylene terephthalate polymer (PETE) susceptor.1.1 This test method covers the determination of nonpolar and relatively polar ultraviolet (UV) absorbing components that may migrate from microwave susceptor packaging into food simulants, such as corn oil and Miglyol 812.1.2 This test method has been collaboratively studied using bilaminate susceptors constructed of paperboard, adhesive, and a layer of polyethylene terephthalate polymer (PETE) susceptor. Adhesive and PETE related compounds were quantitated using this test method.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 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 4.3.2.3.1.5 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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ASTM F1360-17(2023) Standard Specification for Ovens, Microwave, Electric Active 发布日期 :  1970-01-01 实施日期 : 

This specification covers commercial microwave ovens. These ovens use ultrahigh frequency electromagnetic radiation in the approved industrial, scientific, and medical bands to defrost, heat, and cook food. The microwave ovens are classified by types, sizes, groups, styles, and classes. In terms of types, there are two kinds: Type I is commercial microwave oven and Type II is combination of commercial microwave and convection/radiant heat oven. They can be classified into Size 600, Size 1200, and Size 1800 according to microwave output power. In terms of cavity volume, these ovens can be divided into Group 1, Group 2, Group 3, and Group 4. As for the size of cooking cavity, these microwave ovens may be grouped into Class 1, Class 2, Class 3, and Class 4. They may have two styles: Style 1 which has a dial type timer and Style 2 which has a digital timer and touchpad controls(computer controlled). The material, design, construction, and physical requirements of microwave ovens shall be discussed. The performance requirements of these ovens shall be discussed after evaluating the following: cooking cavity light, interchangeability, microwave rated power output, and operation. The following tests shall be performed: cavity weight load test, microwave rated power output test, commercial microwave oven reliability test, production unit test, operational test, and microwave energy distribution test.1.1 This specification covers commercial microwave ovens. These ovens use ultrahigh frequency electromagnetic radiation in the approved industrial, scientific, and medical bands to defrost, heat, and cook food.1.2 Limitations—This specification does not include all types, sizes, groups, styles, and classes of the commodities indicated by the titles of the specification, or that are commercially available, but is intended to cover the types, sizes, groups, styles, and classes that are suitable for general requirements.1.3 Oven Selection And Application—Prior to the use of the classifications given in 4.1, the user agency should ensure they are not restricted by some aspect of the microwave oven design such as a weight or external dimension limitation that would prevent the unrestricted use of the classifications given in 4.1.1.4 Microwave Oven Availability—Although 4.1 lists a wide range of sizes, classes, groups, and styles for commercial types of ovens, not all combinations are available.1.5 The values stated in inch-pound units are to be regarded as the standard. The SI units given in parentheses are for information only.1.6 The following precautionary caveat pertains to the test method portion only, Section 11, 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.1.7 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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5.1 Solvent extraction of soils and sediments can provide information on the availability of petroleum hydrocarbons to leaching, water quality changes, or other site conditions.5.2 Rapid heating, in combination with temperatures in excess of the atmospheric boiling point of acetone/hexane, reduces sample preparation or extraction times.5.3 Reduced amounts of solvents are required and solvent loss due to boiling and evaporation are eliminated by use of closed extraction vessels.1.1 This practice covers the solvent extraction of total petroleum hydrocarbon (TPH) from soils and sediments, using closed vessel microwave heating, for subsequent determination by gravimetric or gas chromatographic techniques.1.2 This practice is recommended only for solid samples that can pass through a ten mesh screen (approximately 2 mm openings).1.3 The solvent extract obtained by this practice may be analyzed for total or specific nonvolatile and semivolatile petroleum hydrocarbons but may require sample clean-up procedures prior to specific compound analysis.1.4 This practice is limited to solvents that are recommended for use in microwave solvent extraction systems.1.5 The values stated in SI units are to be regarded as standard.1.5.1 Exception—The inch-pound values given for units of pressure are to be regarded as standard; SI unit conversions are shown in parentheses.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. Specific hazard statements are given in Section 9.

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4.1 Design calculations for such components as transmission lines, antennas, radomes, resonators, phase shifters, etc., require knowledge of values of complex permittivity at operating frequencies. The related microwave measurements substitute distributed field techniques for low-frequency lumped-circuit impedance techniques.4.2 Further information on the significance of permittivity is contained in Test Methods D150.4.3 These test methods are useful for specification acceptance, service evaluation, manufacturing control, and research and development of ceramics, glasses, and organic dielectric materials.1.1 These test methods cover the determination of relative (Note 1) complex permittivity (dielectric constant and dissipation factor) of nonmagnetic solid dielectric materials.NOTE 1: The word “relative” is often omitted.1.1.1 Test Method A is for specimens precisely formed to the inside dimension of a waveguide.1.1.2 Test Method B is for specimens of specified geometry that occupy a very small portion of the space inside a resonant cavity.1.1.3 Test Method C uses a resonant cavity with fewer restrictions on specimen size, geometry, and placement than Test Methods A and B.1.2 Although these test methods are used over the microwave frequency spectrum from around 0.5 to 50.0 GHz, each octave increase usually requires a different generator and a smaller test waveguide or resonant cavity.1.3 Tests at elevated temperatures are made using special high-temperature waveguide and resonant cavities.1.4 The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are inch-pound units that are provided for information only and are not considered 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 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.

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