定价： 345元 / 折扣价： 294 元 加购物车

5.1 It is important to recognize that the results obtained by this test method or any other method for particle size determination utilizing different physical principles may disagree. The results are strongly influenced by physical principles employed by each method of particle size analysis. The results of any particle sizing method should be used only in a relative sense and should not be regarded as absolute when comparing results obtained by other methods. Particularly for fine materials (that is, average particle size < 20 μm), significant differences are often observed for laser light scattering instruments of different manufacturers. These differences include lasers of different wavelengths, detector configuration, and the algorithms used to convert scattering to particle size distribution. Therefore, comparison of results from different instruments may be misleading.35.2 Light scattering theories (Fraunhofer Diffraction4 and Mie Scattering5) that are used for determination of particle size have been available for many years. Several manufacturers of testing equipment now have units based on these principles. Although each type of testing equipment utilizes the same basic principles for light scattering as a function of particle size, different assumptions pertinent to application of the theory and different models for converting light measurements to particle size, may lead to different results for each instrument. Furthermore, any particles which are outside the size measurement range of the instrument will be ignored, causing an increase in the reported percentages within the detectable range. A particle size distribution which ends abruptly at the detection limit of the instrument may indicate that particles outside the range are present. Therefore, use of this test method cannot guarantee directly comparable results from different types of instruments.5.3 This test method can be used to determine particle size distributions of catalysts, supports, and catalytic raw materials for specifications, manufacturing control, and research and development work.5.4 For fine materials (that is, average particle size < 20 μm), it is critical that Mie Scattering Theory be applied. This involves entering an “optical model” consisting of the “real” and “imaginary” refractive indices of the solid at the wavelength of the laser. The “imaginary” refractive index is also referred to as the “absorbance,” as it has a value of zero for transparent materials such as glass beads. For common materials and naturally occurring minerals (for example, kaolin), these values are known and published, and usually included in the manufacturer’s instrument manual (for example, as an appendix). For example, kaolinite measured at 589.3 nm has a “real” refractive index of 1.55. The absorbance (imaginary component) for minerals and metal oxides is normally taken as 0.001, 0.01 or 0.1. Many of the published values were measured at 589.3 nm (sodium light) but often values at other wavelengths are also given. Extrapolation, interpolation, or estimation to the wavelength of the laser being used can therefore be made.61.1 This test method covers the determination of the particle size distribution of catalyst, catalyst carrier, and catalytic raw material particles and is one of several found valuable for the measurement of particle size. The range of average particle sizes investigated was from 1 to 300 μm equivalent spherical diameter. The technique is capable of measuring particles above and below this range. The angle and intensity of laser light scattered by the particles are selectively measured to permit calculation of a volume distribution using light-scattering techniques.1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

定价： 590元 / 折扣价： 502 元 加购物车

5.1 The determination of the boiling range distribution of gasoline by gas chromatographic simulated distillation provides an insight into the composition of the components from which the gasoline has been blended. Knowledge of the boiling range distribution of gasoline blending components is useful for the control of refinery processes and for the blending of finished gasoline.5.2 The determination of the boiling range distribution of light hydrocarbon mixtures by gas chromatographic simulated distillation has better precision than the conventional distillation by Test Method D86. Additionally, this test method provides more accurate and detailed information about the composition of the light ends. The distillation data produced by this test method are similar to that which would be obtained from a cryogenic, true boiling point (15 theoretical plates) distillation.1.1 This test method covers the determination of the boiling range distribution of gasoline and liquid gasoline blending components. It is applicable to petroleum products and fractions with a final boiling point of 280 °C (536 °F) or lower, as measured by this test method.1.2 This test method is designed to measure the entire boiling range of gasoline and gasoline components with either high or low vapor pressure and is commonly referred to as Simulated Distillation (SimDis) by gas chromatographers.1.3 This test method has been validated for gasoline containing ethanol. Gasolines containing other oxygenates are not specifically excluded, but they were not used in the development of this test method.1.4 This test method can estimate the concentration of n-pentane and lighter saturated hydrocarbons in gasoline.1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.5.1 Results in degrees Fahrenheit can be obtained by simply substituting Fahrenheit boiling points in the calculation of the boiling point-retention time correlation.1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.7 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

定价： 646元 / 折扣价： 550 元 加购物车

5.1 Manufacturers and users of alumina powders will find this test method useful to determine the particle size distribution of these materials for product specification, quality control, and research and development testing.1.1 This test method covers the determination of the particle size distribution of alumina in the range from 0.1 to 20 μm having a median particle diameter from 0.5 to 5.0 μm.1.2 The procedure described in this test method may be successfully applied to other ceramic powders in this general size range. It is the responsibility of the user to determine the applicability of this test method to other material.1.3 The values stated in SI units are to regarded as the standard. The values given in parentheses are for information only.1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

定价： 515元 / 折扣价： 438 元 加购物车

4.1 The distribution coefficient, Kd, is an experimentally determined ratio quantifying the distribution of a chemical species between a given fluid and solid material sample under certain conditions, including the attainment of constant aqueous concentrations of the species of interest. The Kd concept is used in mass transport modeling, for example, to assess the degree to which the movement of a species will be delayed by interactions with the local geomedium as the solution migrates through the geosphere under a given set of underground geochemical conditions (pH, temperature, ionic strength, etc.). The retardation factor (Rf) is the ratio of the velocity of the groundwater divided by the velocity of the contaminant, which can be expressed as: where: ρb   =   bulk density of the porous medium (mass/length3), and ηe   =   effective porosity of the medium (unitless) expressed as a decimal. 4.2 Because of the sensitivity of Kd to site specific conditions and materials, the use of literature derived Kd values is strongly discouraged. For applications other than transport modeling, batch Kd measurements also may be used, for example, for parametric studies of the effects of changing chemical conditions and of mechanisms related to the interactions of fluids with solid material. 1.1 This test method covers the determination of distribution coefficients, Kd, of chemical species to quantify uptake onto solid materials by a batch sorption technique. It is a laboratory method primarily intended to assess sorption of dissolved ionic species subject to migration through pores and interstices of site specific geomedia, or other solid material. It may also be applied to other materials such as manufactured adsorption media and construction materials. Application of the results to long-term field behavior is not addressed in this method. Kd for radionuclides in selected geomedia or other solid materials are commonly determined for the purpose of assessing potential migratory behavior of contaminants in the subsurface of contaminated sites and out of a waste form and in the surface of waste disposal facilities. This test method is also applicable to studies for parametric studies of the variables and mechanisms which contribute to the measured Kd. 1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

定价： 590元 / 折扣价： 502 元 加购物车

5.1 High quality physical product standards for color or appearance are the keystone of a successful color control program. Standards are often grouped into three major categories: product standards, intermediate production control standards, and instrument standards. This guide deals only with physical product standards. Some instrument-based color control programs use “numerical standards,” derived from instrumental measurements of a physical product standard.AbstractThis guide covers three levels of physical product standards (preparation, maintenance, and distribution) for color or geometric appearance, or both, of coatings commonly used in the coatings industry. Described here is terminology to describe each level, and techniques for generating and caring for standards. Product standards are the only standards by which products should be accepted or rejected for color or appearance. A master standard is generated from the concept color submitted by the customer. Duplicate master standards, when needed, are generated from the master standard. Working standards are generated from a duplicate master standard. They are used in the laboratory or on the production line to accept or reject the color or appearance of coatings. After initial generation, product standards must be maintained to ensure they remain valid. This guide considers the characteristics of product standards, factors to be considered in their creation, and factors to be considered in their replacement.1.1 This guide covers three levels of physical product standards for color or appearance, or both, commonly used in the coatings industry, provides terminology to describe each level, and describes techniques for generating and caring for standards.1.2 The values stated in SI units are to be regarded as the standard. The values given 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, 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 The MW averages and the MWD are important characteristics of a resin. They may be used for a variety of correlations for fundamental studies, processing, or product applications. The MW and MWD values may also be used for production quality control of resins.5.2 Limitations—Comparison of SEC molecular weight values should be made only if the data were obtained under identical chromatographic conditions.1.1 This practice covers the determination of apparent molecular weight (MW) averages and molecular weight distributions (MWD) for THF-soluble hydrocarbon, rosin and terpene resins by size-exclusion chromatography (SEC). This technique is not absolute; it requires calibration with standards of known molecular weight. This practice is applicable to resins containing molecular-weight components that have elution volumes falling within the elution volume range defined by polystyrene standards.NOTE 1: SEC is also known as gel permeation chromatography (GPC).1.2 SEC systems employ low-volume liquid chromatography components and columns packed with relatively small (generally 3 to 20 μm) microporous particles. High-performance liquid chromatography instrumentation and automated data handling systems for data acquisition and processing are also required.1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

定价： 590元 / 折扣价： 502 元 加购物车

This test method details the standard procedures for the determination of the particle size distribution of alumina or quartz powders using X-ray monitoring of gravity sedimentation. This test procedure shall make use of an X-ray sedimentation apparatus, and ultrasonic probe or bath. An aqueous homogeneous dispersion of the specimen is permitted to settle in a cell. The decrease in particle concentration over a programmed settling distance is monitored by an X-ray beam passing through the sedimenting dispersion to a detector. The specimen concentration at any given sedimentation distance is inversely proportional to the X-ray flux and the equivalent diameter (spherical) is calculated from Stokes' law.1.1 This test method covers the determination of the particle size distribution of alumina or quartz powders in the range from 0.5 μm to 50 μm and having a median particle diameter from 2.5 μm to 10 μm using a sedimentation method. This test method is one of several found valuable for the measurement of particle size. Instruments used for this test method employ a constant intensity X-ray beam that is passed through a sedimenting dispersion of particles.1.2 The values stated in SI units are to be regarded as the standard. The values given 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use. For specific hazard statements, see Section 7.1.4 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

This specification covers requirements, test methods, and methods of marking for polybutylene plastic system components. These components comprise pipe and tubing, socket-fusion fittings, compression fittings, mechanical fittings, and plastic-to-metal transition fittings. The components covered by this specification are intended for use in hot- and cold-water potable water service and distribution systems and such non-potable water applications. The components are classified as follows: pipe, tubing, and socket-fusion fittings; plastic-to-metal transition fittings; and compression and mechanical plastic fittings. The following tests shall be performed: sustained hydrostatic pressure; thermocycling; hydrostatic burst strength; assembly; excessive temperature and pressure capability of tubing and pipe; and elongation value at break.1.1 This specification covers requirements, test methods, and methods of marking for polybutylene plastic system components made in one standard dimension ratio and intended for 0.69 MPa (100 psi) water service up to and including 82°C (180°F). These components comprise pipe and tubing, socket-fusion fittings, compression fittings, mechanical fittings, and plastic-to-metal transition fittings. Requirements and test methods are included for sustained, hydrostatic pressure strength, thermocycling resistance, joint strength, and dimensions and tolerances for pipe and socket fusion fittings. The components covered by this specification are intended for use in hot- and cold-water potable water service and distribution systems and such non-potable water applications as building services piping, water heating and cooling systems, fire sprinkler applications, and other miscellaneous applications involving the transport of water, ethylene glycol solutions, or other aqueous liquids shown not to adversely affect PB performance.1.2 The text of this specification references notes, footnotes, and appendixes which provide explanatory material. These notes and footnotes (excluding those in tables and figures) shall not be considered as requirements of the specification.1.3 The values in SI units are the standard. The values stated in parentheses are for information only.Note 1—Suggested hydrostatic design stresses and hydrostatic pressure ratings for pipe, tubing, and fittings are listed in Appendix X1. Design, assembly, and installation considerations are discussed in . An optional performance qualification and an in-plant quality control program are recommended in Appendix X3.1.4 The following precautionary caveat pertains only to the test method portion, Section 7, 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 and health practices and determine the applicability of regulatory limitations prior to use.

定价： 0元 / 折扣价： 0 元

5.1 Particle-size distribution (gradation) is a descriptive term referring to the proportions by dry mass of a soil distributed over specified particle-size ranges. The gradation curve generated using this method yields the distribution of silt and clay size fractions present in the soil based on size definitions, not mineralogy or Atterberg limit classification.5.2 Unless the sedimentation sample is representative of the entire sample, the sedimentation results must be combined with a sieve analysis to obtain the complete particle size distribution.5.3 The clay size fraction is material finer than 2 µm. The clay size fraction is used in combination with the Plasticity Index (Test Methods D4318) to compute the activity, which provides an indication of the mineralogy of the clay fraction.5.4 The gradation of the silt and clay size fractions is an important factor in determining the susceptibility of fine-grained soils to frost action.5.5 The gradation of a soil is an indicator of engineering properties such as hydraulic conductivity, compressibility, and shear strength. However, soil behavior for engineering and other purposes is dependent upon many factors, such as effective stress, mineral type, structure, plasticity, and geological origin, and cannot be based solely upon gradation.5.6 Some types of soil require special treatment in order to correctly determine the particle sizes. For example, chemical cementing agents can bond clay particles together and should be treated in an effort to remove the cementing agents when possible. Hydrogen peroxide and moderate heat can digest organics. Hydrochloric acid can remove carbonates by washing and Dithionite-Citrate-Bicarbonate extraction can be used to remove iron oxides. Leaching with test water can be used to reduce salt concentration. All of these treatments, however, add significant time and effort when performing the sedimentation test and are allowable but outside the scope of this test method.5.7 The size limits of the sedimentation test are from about 100 µm to about 0.1 µm. The length of time required to obtain a stable initial reading on the hydrometer controls the upper range of results, and the test duration controls the lower range.5.8 The shape and density of the grains are important to the results. Stokes’ Law is assumed to be valid for spherical particles even though fine silt- and clay-sized particles are more likely to be plate-shaped and have greater mineral densities than larger particles.5.9 High plasticity clays develop structured water layers on their surfaces. According to Zhang and Lu3 this near surface water can be as dense as 1.4 g/L. This high-density structured water causes an error in this test method and shifts the particle size distribution curve upwards. Correction for the structured water is beyond the scope of this standard but values of percent passing above 100 % are possible and should not be excluded from the report.NOTE 5: The quality of the result produced by this standard 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/etc. Users of this standard are cautioned that compliance with Practice D3740 does not in itself assure 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 the quantitative determination of the distribution of particle sizes of the fine-grained portion of soils. The sedimentation by hydrometer method is used to determine the particle-size distribution (gradation) of the material that is finer than the No. 200 (75-µm) sieve and larger than about 0.2-µm. The test is performed on material passing the No. 10 (2.0-mm) or finer sieve and the results are presented as the mass percent finer of this fraction versus the log of the particle diameter.1.2 This method can be used to evaluate the fine-grained fraction of a soil with a wide range of particle sizes by combining the sedimentation results with results from a sieve analysis using D6913 to obtain the complete gradation curve. The method can also be used when there are no coarse-grained particles or when the gradation of the coarse-grained material is not required or not needed.NOTE 1: The significant digits recorded in this test method preclude obtaining the grain size distribution of materials that do not contain a significant amount of fines. For example, clean sands will not yield detectable amounts of silt and clay sized particles, and therefore should not be tested with this method. The minimum amount of fines in the sedimentation specimen is 15 g.1.3 When combining the results of the sedimentation and sieve tests, the procedure for obtaining the material for the sedimentation analysis and calculations for combining the results will be provided by the more general test method, such as Test Methods D6913 (Note 2).NOTE 2: Subcommittee D18.03 is currently developing a new test method “Test Method for Particle-Size Analysis of Soils Combining the Sieve and Sedimentation Techniques.”1.4 The terms “soil” and “material” are used interchangeably throughout the standard.1.5 The sedimentation analysis is based on the concept that larger particles will fall through a fluid faster than smaller particles. Stokes’ Law gives a governing equation used to determine the terminal velocity of a spherical particle falling through a stationary liquid. The terminal velocity is proportional to the square of the particle diameter. Therefore, particles are sorted by size in both time and position when settling in a container of liquid.1.5.1 Stokes’ Law has several assumptions which are: the particles are spherical and smooth; there is no interference between the particles; there is no difference between the current in the middle of the container and the sides; flow is laminar; and the particles have the same density. These assumptions are applied to soil particles of various shapes and sizes.1.6 A hydrometer is used to measure the fluid density and determine the quantity of particles in suspension at a specific time and position. The density of the soil-water suspension depends upon the concentration and specific gravity of the soil particles and the amount of dispersant added. Each hydrometer measurement at an elapsed time is used to calculate the percentage of particles finer than the diameter given by Stokes’ Law. The series of readings provide the distribution of material mass as a function of particle size.1.7 This test method does not cover procurement of the sample or processing of the sample prior to obtaining the reduced sample in any detail. It is assumed that the sample is obtained using appropriate methods and is representative of site materials or conditions. It is also assumed that the sample has been processed such that the reduced sample accurately reflects the particle-size distribution (gradation) of this finer fraction of the material.1.8 Material Processing—Material is tested in the moist or as-received state unless the material is received in an air-dried state. The moist preparation method shall be used to obtain a sedimentation test specimen from the reduced sample. Air-dried preparation is only allowed when the material is received in the air-dried state. The method to be used may be specified by the requesting authority; however, the moist preparation method shall be used for referee testing.1.9 This test method is not applicable for the following soils:1.9.1 Soils containing fibrous peat.1.9.2 Soils containing less than approximately 5 % of fine-grained material (Note 1).1.9.3 Soils containing extraneous matter, such as organic solvents, oil, asphalt, wood fragments, or similar items (Note 3).NOTE 3: If extraneous matter, such as wood, can be easily removed by hand, it is permissible to do so. However, there may be cases where the extraneous matter is being evaluated as part of the material and it should not be removed from the material.1.9.4 Materials that contain cementitious components, such as cement, fly ash, lime, or other stabilization admixtures.1.10 This test method may not produce consistent test results within and between laboratories for the following soils. To test these soils, this test method must be adapted and these adaptations documented.1.10.1 Soils that flocculate during sedimentation. Such materials may need to be treated to reduce salinity or alter the pH of the suspension.1.10.2 Friable soils in which processing changes the gradation of the soil. Typical examples of these soils are some residual soils, most weathered shales, decomposed granites, and some weakly cemented soils.1.10.3 Soils that will not readily disperse, such as glauconitic clays or some dried plastic clays.1.11 Samples that are not soils, but are made up of particles may be tested using this method. The applicable sections above should be used in applying this standard.1.12 Units—The values stated in SI units are to be regarded as standard. Except the sieve designations, they are identified using the “alternative” system in accordance with Practice E11, such as 3-in. and No. 200, instead of the “standard” designation of 75-mm and 75-µm, respectively. Reporting of test results in units other than SI shall not be regarded as non-conformance with this test method. The use of balances or scales recording pounds of mass (lbm) shall not be regarded as nonconformance with this standard.1.13 All observed and calculated values shall conform to the guidelines for significant digits and rounding established in Practice D6026, unless superseded by this test method.1.13.1 The procedures used to specify how data are collected/recorded and calculated in the 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 test method to consider significant digits used in analysis methods for engineering or other data.1.14 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.1.15 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： 843元 / 折扣价： 717 元 加购物车

5.1 The ability to correlate results of analyzers to sieve sets enables the use of non-sieve methods to be employed that give comparable results to each other.5.2 The use of analyzers for proppant measurement has the benefit of providing particle shape characteristics which are important in the performance of these materials. Shape analysis is currently done by operator’s determination based on a visual observation of a small number of particles per API 19C. Available information from imaging analysis of many particles can be used to assess the proppant shape characteristics as opposed to just a small number.1.1 This practice describes procedural steps to create a correlation that can be used to compare results of proppant size distributions between dynamic imaging analyzers (analyzers) and prescribed sieve sets.1.2 The proppant size and distribution specifications that are included in this practice are listed in API Standard 19C (API 19C) and shown in Table 1, however as industry evolves additional specifications may come into use and this practice can be used with those as well.1.3 This practice may not be applicable to all proppant types and designations. The acceptability of the correlations determined are judged by the operator.1.4 The values stated in SI units are to be regarded as the standard, except sieve designations are typically identified using the ‘alternative’ system in accordance with Practice E11, such as 3 in. and No. 200 instead of the ‘standard’ system of 75 mm and 75 µm, respectively.1.5 Observed and calculated values shall conform to the guidelines for significant digits and rounding established in Practice D6026, unless superseded by this standard.1.5.1 The procedures used to specify how data are collected/recorded and calculated in Practice D6026 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 these test methods to consider significant digits used in analysis methods for engineering data.1.6 This practice offers a set of instructions for performing one or more specific operations. This document cannot replace education or experience and should be used in conjunction with professional judgment. Not all aspects of this practice may be applicable in all circumstances. This ASTM standard is not intended to represent or replace the standard of care by which the adequacy of a given professional service must be judged, nor should this document be applied without consideration of a project’s many unique aspects. The word “Standard” in the title means only that the document has been approved through the ASTM consensus process.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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.8 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

The apparent size and distribution of tungsten carbide grains in cemented carbides affects the material’wear resistance and fracture. For a given chemical composition, an increase in the average grain size will result in increased toughness and decreased wear resistance. This practice illustrates representative micro-structures for a wide range of tungsten carbide-cobalt grades. This is not intended to be used as a specification for carbide grades; producers and users may use the micrographs and the grain size chart as a guide in developing their own specifications.1.1 This practice for the visual comparison and classification of the apparent grain size and distribution of cemented tungsten carbides is limited to cemented tungsten carbides that contain approximately 6, 10, and 18 % cobalt.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.

定价： 0元 / 折扣价： 0 元

5.1 The use of STM images and data is for purposes of textural quality assessment and calculation of figures of merit, and for high purity gas system clean room components.5.2 This test method defines a standard data presentation format and suggests figures of merit that utilize STM's ability to analyze three-dimensional surface features.1.1 The purpose of this test method is to define a method for analyzing the surface texture of the above-mentioned components using a scanning tunneling microscope (STM). STM is a noncontact method of surface profiling that can measure three-dimensional surface features in the nanometer size range, which can then be used to represent the surface texture or to provide figures of merit. Application of this test method, where surface texture is used as a selection criterion, is expected to yield comparable data among different components tested.1.2 Limitations: 1.2.1 This test method is limited to characterization of stainless steel surfaces that are smoother than Ra = 0.25 μm, as determined by a contact-stylus profilometer and defined by ANSI B46.1. The magnifications and height scales used in this test method were chosen with this smoothness in mind.1.2.2 Intentional etching or conductive coating of the surface are considered modifications of the gas-wetted surface and are not covered by this test method.1.2.3 This test method does not cover steels that have an oxide layer too thick to permit tunneling under the test conditions outlined in 11.3.1.3 This technique is written with the assumption that the STM operator understands the use of the instrument, its governing principles, and any artifacts that can arise. Discussion of these points is beyond the scope of this test method.1.4 The values stated in SI units are to be regarded as the 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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This specification provides a standard means for testing and measuring the performance characteristics of printed, pressure-sensitive adhesive labels for containers, particularly containers to be used in extreme distribution environments (for example, hazardous materials labels, aerospace, military containers). For the purposes of this specification, an extreme distribution environment is one in which it can be reasonably expected to experience direct exposure to deteriorating chemicals, weather, elevated/cold temperatures, and other environmental and physical elements for an extended period of time. This specification includes standard laboratory test methods to simulate exposure to various conditions and measure associated degradation of required performance characteristics. The data from these methods can be used as acceptance criteria between a supplier and customer. This specification covers the physical properties of the labels, as well as workmanship, finish and appearance, acceptance criteria, testing procedures, reporting of all the steps taken, certification, and preparation for delivery.1.1 This specification provides a standard means to test and measure performance characteristics of printed, pressure-sensitive adhesive labels for containers, particularly containers to be used in extreme distribution environments (for example, hazardous materials labels, aerospace, military containers). For the purposes of this specification, an extreme distribution environment is one in which it can be reasonably expected to experience direct exposure to deteriorating chemicals, weather, elevated/cold temperatures, and other environmental and physical elements for an extended period of time.1.2 Units—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 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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5.1 This test method is useful to both suppliers and users of powders, as outlined in 1.1 and 1.2, in determining particle size distribution for product specifications, manufacturing control, development, and research. 5.2 Users should be aware that sample concentrations used in this test method may not be what is considered ideal by some authorities, and that the range of this test method extends into the region where Brownian movement could be a factor in conventional sedimentation. Within the range of this test method, neither the sample concentration nor Brownian movement is believed to be significant. Standard reference materials traceable to national standards, of chemical composition specifically covered by this test method, are available from NIST,3 and perhaps other suppliers. 5.3 Reported particle size measurement is a function of the actual particle dimension and shape factor as well as the particular physical or chemical properties being measured. Caution is required when comparing data from instruments operating on different physical or chemical parameters or with different particle size measurement ranges. Sample acquisition, handling, and preparation can also affect reported particle size results. 5.4 Suppliers and users of data obtained using this test method need to agree upon the suitability of these data to provide specification for and allow performance prediction of the materials analyzed. 1.1 This test method covers the determination of particle size distribution of advanced ceramic powders. Experience has shown that this test method is satisfactory for the analysis of silicon carbide, silicon nitride, and zirconium oxide in the size range of 0.1 up to 50 µm. 1.1.1 However, the relationship between size and sedimentation velocity used in this test method assumes that particles sediment within the laminar flow regime. It is generally accepted that particles sedimenting with a Reynolds number of 0.3 or less will do so under conditions of laminar flow with negligible error. Particle size distribution analysis for particles settling with a larger Reynolds number may be incorrect due to turbulent flow. Some materials covered by this test method may settle in water with a Reynolds number greater than 0.3 if large particles are present. The user of this test method should calculate the Reynolds number of the largest particle expected to be present in order to judge the quality of obtained results. Reynolds number (Re) can be calculated using the following equation: where: D   =   the diameter of the largest particle expected to be present, in cm, ρ   =   the particle density, in g/cm3, ρ0   =   the suspending liquid density, in g/cm3, g   =   the acceleration due to gravity, 981 cm/sec2, and η   =   the suspending liquid viscosity, in poise. 1.1.2 A table of the largest particles that can be analyzed with a suggested maximum Reynolds number of 0.3 or less in water at 35 °C is given for a number of materials in Table 1. A column of the Reynolds number calculated for a 50-µm particle sedimenting in the same liquid system is also given for each material. Larger particles can be analyzed in dispersing media with viscosities greater than that for water. Aqueous solutions of glycerine or sucrose have such higher viscosities. 1.2 The procedure described in this test method may be applied successfully to other ceramic powders in this general size range, provided that appropriate dispersion procedures are developed. It is the responsibility of the user to determine the applicability of this test method to other materials. Note however that some ceramics, such as boron carbide and boron nitride, may not absorb X-rays sufficiently to be characterized by this analysis method. 1.3 The values stated in cgs units are to be regarded as the standard, which is the long-standing industry practice. The values given in parentheses are for information only. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. Specific hazard information is given in Section 8. 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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