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5.1 Mean particle diameters defined according to the Moment-Ratio (M-R) system are derived from ratios between two moments of a particle size distribution.1.1 The purpose of this practice is to present procedures for calculating mean sizes and standard deviations of size distributions given as histogram data (see Practice E1617). The particle size is assumed to be the diameter of an equivalent sphere, for example, equivalent (area/surface/volume/perimeter) diameter.1.2 The mean sizes/diameters are defined according to the Moment-Ratio (M-R) definition system.2,3,41.3 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.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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5.1 The greater a carbon black resists compression by having substantial aggregate irregularity and non-sphericity, the greater the compressed volume and void volume. Also, the more that a carbon black resists compression, the greater the energy required to compress the sample per unit void volume.5.2 Structure is a property that strongly influences the physical properties developed in carbon black-elastomer compounds for use in tires, mechanical rubber goods, and other manufactured rubber products. Structure by void volume is based on compression while structure measurements by OAN (Test Method D2414) and COAN (Test Method D3493) are based on oil absorption.1.1 This test method covers a procedure to measure a carbon black structure property by Void Volume at mean pressure. Compressed void volumes are obtained by measuring the compressed volume of a weighed sample in a cylindrical chamber as a function of pressure exerted by a movable piston. A profile of void volume as a function of pressure provides a means to assess carbon black structure at varying levels of density and aggregate reduction. For the purposes of standardized testing a single value of void volume is reported at 50 MPa mean pressure.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.

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Environmental decisions often require the comparison of a statistic to a decision point or the comparison of a confidence limit to a regulatory limit to determine which of two alternate actions is the proper one to take.This practice provides a logical basis for statistically deriving a decision point, or a confidence limit as an alternative, for different underlying presumptions.This practice is useful to users of a planning process generally known as the data quality objectives (DQO) process (see Practice D5792), in which calculation of a decision point is needed for the decision rule.1.1 This practice covers a logical basis for the derivation of a decision point and confidence limit when mean concentration is used for making environmental waste management decisions. The determination of a decision point or confidence limit should be made in the context of the defined problem. The main focus of this practice is on the determination of a decision point.1.2 In environmental management decisions, the derivation of a decision point allows a direct comparison of a sample mean against this decision point, where similar decisions can be made by comparing a confidence limit against a concentration limit (for example, a regulatory limit, which will be used as a surrogate term for any concentration limit throughout this practice). This practice focuses on making environmental decisions using this kind of statistical comparison. Other factors, such as any qualitative information that may be important to decision-making, are not considered here.1.3 A decision point is a concentration level statistically derived based on a specified decision error and is used in a decision rule for the purpose of choosing between alternative actions.1.4 This practice derives the decision point and confidence limit in the framework of a statistical test of hypothesis under three different presumptions. The relationship between decision point and confidence limit is also described.1.5 Determination of decision points and confidence limits for statistics other than mean concentration is not covered in this practice. This practice also assumes that the data are normally distributed. When this assumption does not apply, a transformation to normalize the data may be needed. If other statistical tests such as nonparametric methods are used in the decision rule, this practice may not apply. When there are many data points below the detection limit, the methods in this practice may not apply.

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5.1 This test method may be used to:5.1.1 Determine the maximum pore size of a filter,5.1.2 Compare the maximum pore sizes of several filters, and5.1.3 Determine the effect of various processes such as filtration, coating, or autoclaving on the maximum pore size of a membrane.5.2 Membrane filters have discrete pores from one side to the other of the membrane, similar to capillary, tubes. The bubble point test is based on the principle that a wetting liquid is held in these capillary pores by capillary attraction and surface tension, and the minimum pressure required to force liquid from these pores is a function of pore diameter. The pressure at which a steady stream of bubbles appears in this test is the bubble point pressure. The bubble point test is significant not only for indicating maximum pore size, but may also indicate a damaged membrane, ineffective seals, or a system leak.5.3 The results of this test method should not be used as the sole factor to describe the limiting size for retention of particulate contaminants from fluids. The effective pore size calculated from this test method is based on the premise of capillary pores having circular cross sections, and does not refer to actual particle size retention. See Test Method E128 for additional information.1.1 These test methods cover the determination of two of the pore size properties of membrane filters with maximum pore sizes from 0.1 to 15.0 μm.1.2 Test Method A presents a test method for measuring the maximum limiting pore diameter of nonfibrous membranes. The limiting diameter is the diameter of a circle having the same area as the smallest section of a given pore (Fig. 1).FIG. 1 Examples of Limiting Diameters1.3 Test Method B measures the relative abundance of a specified pore size in a membrane, defined in terms of the limiting diameter.1.4 The analyst should be aware that adequate collaborative data for bias statements as required by Practice D2777 is not provided. See the precision and bias section for details.1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.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： 590元 / 折扣价： 502 元 加购物车

4.1 This test method provides a means of calculating the mean relative molecular mass of petroleum oils from another physical measurement.4.2 Mean relative molecular mass is a fundamental physical constant that can be used in conjunction with other physical properties to characterize hydrocarbon mixtures.1.1 This test method covers the estimation of the mean relative molecular mass of petroleum oils from kinematic viscosity measurements at 100 °F and 210 °F (37.78 °C and 98.89 °C).2 It is applicable to samples with mean relative molecular masses in the range from 250 to 700 and is intended for use with average petroleum fractions. It should not be applied indiscriminately to oils that represent extremes of composition or possess an exceptionally narrow mean relative molecular mass range.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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1.1 This practice is applicable to the processing of road surface profiles for the purpose of computing a single numerical index related to the roughness of a profile.1.2 A data record of the surface profile, measured according to an applicable test method, is assumed. The data record may be a representation of either elevation, slope, or acceleration.1.3 Procedures are defined for computing the index over the length of the profile record, or over specified sub-sections of the record.1.4 This practice covers only the computation procedures and does not specify or define the form of the profile index weighting function except in the requirement that the index be expressed in the form of either a "mean square" or "root mean square" measure of the surface profile. The numerical value of the computed index will depend on the weighting and window functions used. The weighting function used can incorporate any linear mathematical operation, such as multiplication by a constant, differentiation, or integration. Measures obtained using nonlinear operations, such as rectification, are not covered.

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Mean specific heat is an essential property of a thermal insulating material when the latter is used under conditions of unsteady or transient heat flow. It is a part of the parameter, thermal diffusivity, which governs the rate of temperature diffusion through insulation. It is a basic thermodynamic property of all substances, the value of which depends upon chemical composition and temperature.Note 1—Specific heat of insulations, as measured by this test method, using small specimens of a multi-component composite or of a low-density product that has to be highly compressed, may not be directly applicable for use in calculations involving transient thermal response. The applicability of the results will depend upon a system being analyzed, the desired accuracy, and the relative amounts, and specific heats of the various solid or fluid components, or both, of the thermal insulation.1.1 This test method covers the determination of mean specific heat of thermal insulating materials. The materials must be essentially homogeneous and composed of matter in the solid state.1.2 This test method employs the classical method of mixtures. This provides procedures and apparatus simpler than those generally used in scientific calorimetry, an accuracy that is adequate for most thermal insulating purposes, and a degree of precision that is reproducible by laboratory technicians of average skill. While this test method was developed for testing thermal insulations, it is easily adaptable to measuring the specific heat of other materials.1.3 The test procedure provides for a mean temperature of approximately 60°C (100 to 20°C temperature range), using water as the calorimetric fluid. By substituting other calorimetric fluids the temperature range may be changed as desired.1.4 The values stated in SI units are to be regarded as the standard.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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Ranked set sampling is cost-effective, unbiased, more precise and more representative of the population than simple random sampling under a variety of conditions (1).3Ranked set sampling (RSS) can be used when:4.2.1 The population is likely to have stratification in concentrations of contaminant.4.2.2 There is an auxiliary variable.4.2.3 The auxiliary variable has strong correlation with the primary variable.4.2.4 The auxiliary variable is either quick or inexpensive to measure, relative to the primary variable.This guide provides a ranked set sampling method only under the rule of equal allocation. This guide is intended for those who manage, design, and implement sampling and analysis plans for management of wastes and contaminated media. This guide can be used in conjunction with the DQO process (see Practice D 5792).1.1 This guide describes ranked set sampling, discusses its relative advantages over simple random sampling, and provides examples of potential applications in environmental sampling.1.2 Ranked set sampling is useful and cost-effective when there is an auxiliary variable, which can be inexpensively measured relative to the primary variable, and when the auxiliary variable has correlation with the primary variable. The resultant estimation of the mean concentration is unbiased, more precise than simple random sampling, and more representative of the population under a wide variety of conditions.This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

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4.1 This document describes the basic principles that need to be followed to obtain a mean value of the Darcy permeability coefficient for structures that consist of a series of interconnected voids or pores. The coefficient is a measure of the permeability of the structure to fluid flowing through it that is driven by a pressure gradient created across it.4.2 The technique is not sensitive to the presence of closed or blind-end pores (Fig. 1).FIG. 1 Schematic of the Different Pores Types Found in Tissue Scaffolds. Fluid Flow Through the Structure is via the Open Pores4.3 Values of the permeability coefficient can be used to compare the consistency of manufactured samples or to determine what the effect of changing one or more manufacturing settings has on permeability. They can also be used to assess the homogeneity and anisotropy of tissue scaffolds. Variability in the permeability coefficient can be also be indicative of:4.3.1 Internal damage within the sample, for example, cracking or permanent deformation.4.3.2 The presence of large voids, including trapped air bubbles, within the structure.4.3.3 Surface effects such as a skin formed during manufacture.4.3.4 Variable sample geometry.4.4 This test method is based on the assumption that the flow rate through a given sample subjected to an applied pressure gradient is constant with time.NOTE 1: If a steady-state flow condition isn’t reached, then this could be due to structural damage (that is, crack formation or the porous structure deformed as a result of the force being placed upon it by the fluid flowing through it). Sample deformation in the form of stretching (bowing) can also occur for less resilient structures as a result of high fluid flow rates. This topic is discussed in more detail in Section 7.4.5 Care should be taken to ensure that hydrophobic materials are fully wetted out when using water or other aqueous-based liquids as permeants.4.6 Conventionally, the pressure differential created across a sample is measured as a function of both increasing and decreasing flow rates. An alternative approach, which may be practically easier to create, is to apply a range of different pressure differentials across the sample and measure the resultant flow of fluid through it. The hysteresis that occurs during a complete cycle of increasing flow rate followed by a progressive decrease in flow rate can provide an excellent measure of the behavioural consistency of the matrix. Significant hysteresis in the measured pressure differential during increasing and decreasing flow rates can indicate the existence of induced damage in the structure, the fact that the material is behaving viscoelastically, or is suffering from permanent plastic deformation. Some guidance on how to identify which of these factors is responsible for hysteresis is provided in Section 7.4.7 It is assumed that Darcy’s law is valid. This can be established by plotting the volume flow through the specimen against the differential pressure drop across the specimen. This plot should be linear for Darcy’s law to apply and a least-squares fit to the data should pass through the origin. It is not uncommon for such plots to be nonlinear which may indicate that the structure does not obey Darcy’s law or that the range of pressures applied is too broad. This topic is further discussed in Section 7.1.1 This guide describes test methods suitable for determining the mean Darcy permeability coefficient for a porous tissue scaffold, which is a measure of the rate at which a fluid, typically air or water, flows through it in response to an applied pressure gradient. This information can be used to optimize the structure of tissue scaffolds, to develop a consistent manufacturing process, and for quality assurance purposes.1.2 The method is generally nondestructive and non-contaminating.1.3 The method is not suitable for structures that are easily deformed or damaged. Some experimentation is usually required to assess the suitability of permeability testing for a particular material/structure and to optimize the experimental conditions.1.4 Measures of permeability should not be considered as definitive metrics of the structure of porous tissue scaffolds and should complement measures obtained by other investigative techniques, for example, scanning electron microscopy, gas flow porometry, and micro-computer X-ray tomography (Guides F2450, F2603, and F3259).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.

定价： 590元 / 折扣价： 502 元 加购物车

5.1 This practice is suitable for the calculation of the average macrotexture depth from profile data. The results of this calculation (MPD) have proven to be useful in the prediction of the speed dependence of wet pavement friction.5.2 The MPD can be used to estimate the result of a measurement of macrotexture depth using a volumetric technique according to Test Method E965. The values of MPD and MTD differ due to the finite size of the glass spheres used in the volumetric technique and because the MPD is derived from a two-dimensional profile rather than a three-dimensional surface. Therefore, a transformation equation must be used.NOTE 2: The two concepts are closely related and have strong correlations; these correlations can differ depending on the pavement types used to establish the correlation. Although they are not the same physical characteristic, the MPD measurement technique is intended to replace the manual MTD measurements.5.3 This practice may be used with pavement macrotexture profiles taken on actual road surfaces or from cores or laboratory-prepared samples.5.4 Aggregate size, shape, and distribution are features which are not addressed in this practice. This practice is not meant to provide a complete assessment of texture characteristics. In particular, care should be used when interpreting the result for porous or grooved surfaces.5.5 This practice does not address the problems associated with obtaining a measured profile. Laser or other optical noncontact methods of measuring profiles are usually preferred. However, contact methods using a stylus also can provide accurate profiles if properly performed.1.1 This practice covers the calculation of mean profile depth from a profile of pavement macrotexture.1.2 The mean profile depth has been shown to be useful in predicting the speed constant (gradient) of wet pavement friction.1.3 A linear transformation of the mean profile depth can provide an estimate of the mean texture depth measured according to Test Method E965.NOTE 1: A similar method for measurement and calculation of MPD is presented in ISO 13473-1. The only technical differences are the way spike removal and extreme MSD removal are calculated. Despite these differences, the ASTM and ISO methods will arrive at the same results, with only insignificant differences in normal cases. The ASTM method for spike removal applies calculations which are much more complicated but will result in less correct samples which are adjacent to spikes being removed. The extreme MSD removal in the ASTM method will also be more precise than the ISO method, but at the expense of more complicated calculations. Significant differences will potentially appear only on some uncommon or special textures, such as tined or grooved cement concrete pavements. In the next few years, attempts will be made to coordinate the calculations with a view to make them identical in both standards. The ISO standard includes eight annexes with additional information, for example about uncertainty calculations and how users can check their software against standard texture profiles. A note corresponding to this one will be included in the ISO 13473-1 standard.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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

定价： 590元 / 折扣价： 502 元 加购物车