5.1 This test method produces a measure of retroreflective efficiency (coefficient of retroreflected luminance, RL-2) for a pavement marking system under conditions of continuous wetting. The test result depends on factors such as the pavement marking binder and optic materials, their application, wear from traffic and plowing, wetting rate, and road grade and cross slope.5.2 The measured retroreflective efficiency under conditions of continuous wetting may be used to characterize the properties of a pavement marking on the road as water is continuously falling on it. The retroreflective efficiency of the marking under conditions of continuous wetting is almost always different than under dry conditions.5.3 The wetting rate of 2 in./h represents the upper limit of what is meteorologically classified as heavy rainfall. Rainfall rates above 2 in./h are classified as extreme or violent, and are sometimes associated with weather such as tropical storms.5.4 The retroreflectivity of pavement markings degrades with traffic wear and requires periodic measurement to ensure that the coefficient of retroreflected luminance under continuous wetting meets requirements and provides adequate visibility for nighttime drivers.5.5 The continuous wetting rate as well as the roadway grade and cross slope impact the results of this test method. The user shall measure and report the rate used for testing.5.6 The roadway grade and cross slope adjacent to the measurement area impact the results of this test method. A digital level (inclinometer) can be used to quickly measure grade and cross slope.5.7 Results obtained using this test method should not be the sole basis for specifying and assessing the wet retroreflective effectiveness of pavement marking systems. Users should complement the results of this test method with other evaluation results, such as nighttime visual inspections.1.1 This test method covers a measurement of the wet retroreflective (RL-2) properties of horizontal pavement marking materials, such as traffic stripes and road surface symbols. A standardized method utilizing a standardized continuous wetting device and a portable retroreflectometer is described to obtain measurements of the wet retroreflective properties of horizontal pavement markings.1.2 Retroreflective performance obtained with this test in a standardized condition of continuous wetting does not necessarily relate to how markings perform in all conditions of natural rain.NOTE 1: Test Method E2177 may be used to describe the retroreflective properties of pavement markings in conditions of wetness, such as after a period of rain.1.3 This test method is suitable for measurements made in the laboratory and in the field when the necessary controls and precautions are followed.1.4 This test method specifies the use of external beam retroreflectometers conforming to Test Method E1710.2 The entrance and observation angles required of the retroreflectometer in this test method are commonly referred to as “30 meter geometry.”21.5 The test method excludes the effects of rain between the vehicle and the marking.1.6 Results obtained using this test method should not be the sole basis for specifying and assessing the wet retroreflective effectiveness of pavement marking systems. Users should complement the results of this test method with other evaluation results, such as nighttime visual inspections.1.7 The values stated in SI units are to be regarded as standard. The values given in parentheses are for information only.1.8 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.1.9 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 1 The ball dynamic stiffness is a measure of a ball’s hardness. Its measurement is conducted to represent bat-ball impact forces. It is normalized by the ball weight and speed to minimize the influence of manufacturing and test variations from the measure.5.2 The cylindrical coefficient of restitution is a ball property of relative velocity change caused by impact with a cylindrical surface.5.3 This test method compares the performance of baseballs and softballs after impact with a cylindrical test surface.5.4 Sports associations can use DS and CCOR measurements in specifications for official baseballs and softballs.1.1 This procedure describes a method of measuring the dynamic stiffness (DS) and cylindrical coefficient of restitution (CCOR) of baseballs and softballs providing similar impact forces and ball deformation as are observed in a bat-ball collision.1.2 This procedure is for a ball that is intended for the game of baseball or softball.1.3 The test method is based on ball speed measurements before and after impact with a cylindrical test surface and the impact force between the ball and impacted surface.1.4 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.1.5 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 test method can be used to determine the coefficient of friction of lubricating fluids under the prescribed test conditions. The user of this test method should determine to his own satisfaction whether results of this test method correlate with field performance or other bench test machines.1.1 This test method covers a procedure for determining the coefficient of friction by means of the Four-Ball Wear Test Machine.21.2 The values stated in either SI units or in the former cm-kgf metric units are to be regarded separately as the standard. Within the text the cm-kgf units are shown in parentheses. The values stated in each system are not exact equivalents, therefore each system must be used independently of the other. Combining values from the two systems can result in nonconformance to specification.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. Specific warning statements are given in 7.3 and 7.4.1.4 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

3.1 The reliability of any of the practices using panels prepared by these procedures may be dependent upon the manner and care in which the test panels are prepared. Having these practices in a single procedure eliminates the necessity for covering these details in all of the practices wherein the panels are used.1.1 This practice covers procedures for the preparation of OVCT (Official Vinyl Composition Tile) and wood panels for subsequent use in tests to measure the coefficient of friction.1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.1.3 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

定价： 515元 / 折扣价： 438 元 加购物车

5.1 Assumptions: 5.1.1 Well discharges at a constant rate, Q.5.1.2 Well is of infinitesimal diameter and fully penetrates the aquifer, that is, the well is open to the full thickness of the aquifer.5.1.3 The nonleaky aquifer is homogeneous, isotropic, and areally extensive. A nonleaky aquifer receives insignificant contribution of water from confining beds.5.1.4 Discharge from the well is derived exclusively from storage in the aquifer.5.1.5 The geometry of the assumed aquifer and well conditions are shown in Fig. 1.5.2.3 Application of Theis Nonequilibrium Method to Unconfined Aquifers: 5.2.3.1 Although the assumptions are applicable to confined conditions, the Theis solution may be applied to unconfined aquifers if drawdown is small compared with the saturated thickness of the aquifer or if the drawdown is corrected for reduction in thickness of the aquifer and the effects of delayed gravity yield are small.5.2.3.2 Reduction in Aquifer Thickness—In an unconfined aquifer, dewatering occurs when the water levels decline in the vicinity of a pumping well. Corrections in drawdown need to be made when the drawdown is a significant fraction of the aquifer thickness as shown by Jacob (8). The drawdown, s, needs to be replaced by s′, the drawdown that would occur in an equivalent confined aquifer, where:5.2.3.3 Gravity Yield Effects—In unconfined aquifers, delayed gravity yield effects may invalidate measurements of drawdown during the early part of the test for application to the Theis method. Effects of delayed gravity yield are negligible in partially penetrating observation wells at a distance, r, from the control well, where:after the time, t, as given in the following equation from Neuman (9):where:Sy   =   the specific yield.For fully penetrating observation wells, the effects of delayed yield are negligible at the distance, r, in Eq 11 after one tenth of the time given in the Eq 12.NOTE 2: 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.NOTE 3: The injection of water into an aquifer may be regulated or require regulatory approvals. Withdrawal of contaminated waters may require that the removed water be properly treated prior to discharge.1.1 This practice covers an analytical procedure for determining transmissivity and storage coefficient of a nonleaky confined aquifer under conditions of radial flow to a fully penetrating well of constant flux. This practice is a shortcut procedure used to apply the Theis nonequilibrium method. The Theis method is described in Practice D4106.1.2 This practice, along with others, is used in conjunction with the field procedure given in Test Method D4050.1.3 Limitations—The limitations of this practice are primarily related to the correspondence between the field situation and the simplifying assumptions of this practice (see 5.1). Furthermore, application is valid only for values of u less than 0.01 (u is defined in Eq 2, in 8.6).1.4 All observed and calculated values shall conform to the guidelines for significant digits and rounding established in Practice D6026.1.4.1 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 analytical methods for engineering design.1.5 Units—The values stated in either SI Units or inch-pound units are to be regarded separately as standard. The values 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. Reporting of results in units other than SI shall not be regarded as nonconformance with this practice.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 the 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 the consideration of a project’s many unique aspects. The word “Standard” in the title of this document 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

5.1 Assumptions:  5.1.1 Well discharges at a constant rate, Q. 5.1.2 Well is of infinitesimal diameter and fully penetrates the aquifer. 5.1.3 The nonleaky aquifer is homogeneous, isotropic, and aerially extensive. A nonleaky aquifer receives insignificant contribution of water from confining beds. 5.1.4 Discharge from the well is derived exclusively from storage in the aquifer. 5.1.5 The geometry of the assumed aquifer and well conditions are shown in Fig. 1. 5.2.3 Application of Theis Method to Unconfined Aquifers:  5.2.3.1 Although the assumptions are applicable to artesian or confined conditions, the Theis solution may be applied to unconfined aquifers if drawdown is small compared with the saturated thickness of the aquifer or if the drawdown is corrected for reduction in thickness of the aquifer, and the effects of delayed gravity yield are small. 5.2.3.2 Reduction in Aquifer Thickness—In an unconfined aquifer dewatering occurs when the water levels decline in the vicinity of a pumping well. Corrections in drawdown need to be made when the drawdown is a significant fraction of the aquifer thickness as shown by Jacob (5). The drawdown, s, needs to be replaced by s′, the drawdown that would occur in an equivalent confined aquifer, where: 5.2.3.3 Gravity Yield Effects—In unconfined aquifers, delayed gravity yield effects may invalidate measurements of drawdown during the early part of the test for application to the Theis method. Effects of delayed gravity yield are negligible in partially penetrating observation wells at and beyond a distance, r, from the control well, where: After the time, t, as given in Eq 9 from Neuman (6). where: Sy   =   the specific yield. For fully penetrating observation wells, the effects of delayed yield are negligible at the distance, r, in Eq 8 after one tenth of the time given in the Eq 9. Note 1: 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 ensure reliable results. Reliable results depend on many factors; Practice D3740 provides a means of evaluating some of those factors. 1.1 This practice covers an analytical procedure for determining the transmissivity and storage coefficient of a nonleaky confined aquifer. It is used to analyze data on water-level response collected during radial flow to or from a well of constant discharge or injection. 1.2 This analytical procedure, along with others, is used in conjunction with the field procedure given in Test Method D4050. 1.3 Limitations—The limitations of this practice for determination of hydraulic properties of aquifers are primarily related to the correspondence between the field situation and the simplifying assumptions of this practice (see 5.1). 1.4 All observed and calculated values shall conform to the guidelines for significant digits and rounding established in Practice D6026. 1.4.1 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 analytical methods for engineering design. 1.5 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 the 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 the consideration of a project’s many unique aspects. The word “Standard” in the title of this document means only that the document has been approved through the ASTM consensus process. 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

5.1 The reported values of convective heat transfer coefficients are somewhat dependent upon measurement technique and it is therefore the purpose of this guide to focus on methods to provide accurate measures of heat transfer and precise methods of reporting. The benefit of developing such a guide is to provide a well-understood basis by which heat transfer performance of fluids may be accurately compared and reported.5.2 For comparison of heat transfer performance of heat transfer fluids, measurement methods and test apparatus should be identical, but in reality heat transfer rigs show differences from rig to rig. Therefore, methods discussed in the guide are generally restricted to the use of heated tubes that have wall temperatures higher than the bulk fluid temperature and with turbulent flow conditions.5.3 Similar test methods are found in the technical literature, however it is generally left to the user to report results in a format of their choosing and therefore direct comparisons of results can be challenging.1.1 This guide covers general information, without specific limits, for selecting methods for evaluating the heating and cooling performance of liquids used to transfer heat where forced convection is the primary mode for heat transfer. Further, methods of comparison are presented to effectively and easily distinguish performance characteristics of the heat transfer fluids.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 quality of the stripe for visibility in daylight or under road lighting is determined by the luminance coefficient under diffuse illumination, Qd, and depends on the materials used, age, and wear pattern. These conditions shall be observed and noted by the user.5.2 Under the same conditions of illumination and viewing, higher levels of Qd correspond to higher levels of lightness.5.3 Reflectivity of pavement (road) markings degrade with traffic wear and require periodic measurement to ensure that sufficient line visibility is provided to drivers.5.4 For a given viewing distance, measurements of Qd made with a reflectometer having a geometry corresponding to that distance are a good indicator of the visual ranking of material measured.5.5 specified by CEN, the measurement geometry of the instrument is based on a viewing distance of 30 m and an eye height of 1.2 m.5.6 It shall be the responsibility of the user to employ an instrument having the specified co-viewing angle.1.1 This test method covers measurement of the luminance coefficient under diffuse illumination of horizontal pavement markings, such as traffic stripes and surface symbols, and pavement surfaces, in a particular viewing direction using a portable reflectometer.NOTE 1: The luminance coefficient under diffuse illumination is a measure of the reflection of horizontal pavement markings and pavement surfaces in a particular viewing direction in daylight or under road lighting. Diffuse illumination approximates daylight illumination from the overcast sky, and road lighting as an average of locations on the pavement surface.1.2 The co-viewing angle of the reflectometer affects the readings. As specified by the European Committee for Standardization (CEN), the co-viewing angle shall be 2.29°.1.3 This test method is intended to be used for field measurement of pavement markings and pavement surfaces but may be used to measure the performance of materials on sample panels before placing the marking material in the field.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

5.1 This non-proprietary laboratory test method allows for the reproducible testing of whole footwear and footwear-related soling materials for evaluating relative slip performance. Other ASTM test methods generally employ a standardized test foot primarily for evaluation of flooring materials.1.1 This test method2 determines the dynamic coefficient of friction between footwear and floorings under reproducible laboratory conditions for evaluating relative slip performance. The method is applicable to all types of footwear, outsole units, heel top lifts and sheet soling materials, also to most types of floorings, including matting and stair nosing, and surface contaminants on the flooring surface, including but not limited to liquid water, ice, oil and grease. The method may also be applied to surfaces such as block pavers, turf and gravel.1.2 Special purpose footwear or fittings containing spikes, metal studs or similar may be tested on appropriate surfaces but the method does not fully take account of the risk of tripping due to footwear/ground interlock.1.3 The values stated in the ASTM test method in metrics are to be regarded as the standard. The values in parentheses are for information.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： 646元 / 折扣价： 550 元 加购物车

5.1 Measurements made by this test method are related to visual observations of retroreflective sheeting as seen by the human eye when illuminated by tungsten-filament light sources such as a motor vehicle headlamp.5.2 The values determined relate to the visual effects for a given geometric configuration as specified by the user of the test method. This test method has been found useful for tests at observation angles between 0.1 and 2.0° (observation angles between 0.1° and 0.2° may be achieved by careful design of source and receiver aperture configuration), and at entrance angles up to 60°. It has been used to determine coefficient of retroreflection values as low as 0.1 cd·lx−1 · m−2, but for values less than 1 cd·lx−1 · m−2 special attention must be given to the responsivity of the receiver and to the elimination of very small amounts of stray light.1.1 This test method describes an instrument measurement of the retroreflective performance of retroreflective sheeting.1.2 The user of this test method must specify the entrance and observation angles to be used, and may specify the rotation angles.1.3 This test method is intended as a laboratory test and requires a facility that can be darkened sufficiently so that stray light does not affect the test results. The testing apparatus must be able to achieve the coplanar geometry.1.4 Portable and bench retroreflection measuring equipment may be used to determine RA values provided the geometry and appropriate substitution standard reference panels, measured in accordance with this test method, are utilized. In this case the methods of Procedure B in Practice E809 apply. Additional information on the use of portable retroreflectometers may be found in Test Method E1709.1.5 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： 646元 / 折扣价： 550 元 加购物车

5.1 The coefficient of linear thermal expansion, α, between temperatures T1 and T2 for a specimen whose length is L0 at the reference temperature, is given by the following equation:Where L1 and L2 are the specimen lengths at temperatures T1 and T2, respectively. α is, therefore, obtained by dividing the linear expansion per unit length by the change in temperature.5.2 The nature of most plastics and the construction applications for which plastic lumber and plastic lumber shapes are used, make –30 to 140°F (–34.4 to 60°C) a practical temperature range for linear thermal expansion measurements. Where testing outside of this temperature range or when linear thermal expansion characteristics of a particular plastic are not known through this temperature range, particular attention shall be paid to the factors mentioned in 1.2 and it is possible that special preliminary investigations by thermo-mechanical analysis, such as what is prescribed in Practice D4065 for the location of transition temperatures, will be required, in order to avoid excessive error. If such a transition point is located, a separate coefficient of expansion for a temperature range below and above the transition point shall be determined. For specification and comparison purposes (provided it is known that no transition exists in this range), the range from –30 to 140°F (–34.4 to 60°C) shall be used. (For reference, glass transition and melting point temperatures of typical resins used in plastic lumber products are given in Appendix X2 of this test method.)1.1 This test method covers the determination of the coefficient of linear thermal expansion for plastic lumber and plastic lumber shapes to two significant figures. The determination is made by taking measurements with a caliper at three discrete temperatures. At the test temperatures and under the stresses imposed, the plastic lumber shall have a negligible creep or elastic strain rate, or both, insofar as these properties would significantly affect the accuracy of the measurements.1.1.1 This test method details the determination of the linear coefficient of thermal expansion of plastic lumber and plastic lumber shapes in their “as manufactured” form. As such, this is a test method for evaluating the properties of plastic lumber or shapes as a product and not a material property test method.1.2 The thermal expansion of plastic lumber and shapes is composed of a reversible component on which it is possible to superimpose changes in length due to changes in moisture content, curing, loss of plasticizer or solvents, release of stresses, phase changes, voids, inclusions, and other factors. This test method is intended to determine the coefficient of linear thermal expansion under the exclusion of non-linear factors as far as possible. In general, it will not be possible to exclude the effect of these factors completely. For this reason, the test method can be expected to give a reasonable approximation but not necessarily precise determination of the linear coefficient of thermal expansion.1.3 Plastic lumber and plastic lumber shapes are currently made predominately with recycled plastics where the product is non-homogeneous in the cross-section. However, it is possible that this test method will also be applicable to similar manufactured plastic products made from virgin resins or other plastic composite materials.1.4 The values stated in inch-pound units are to be regarded as the standard. The SI units given in parentheses are for information only.1.5 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.NOTE 1: There is no known ISO equivalent to this standard.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 procedure can be used to limit the need for screening tests prior to performing a test for estimating the LC50 of a non-reactive and non-electrolytic chemical to the fathead minnow. By eliminating the screening test, fewer fish need be tested. The time used for preparing and performing the screening test can also be saved. The value obtained in this procedure can be used as the preliminary estimate of the LC50 in a full-scale test.5.2 Estimates can be used to set testing priority of groups of non-reactive and non-electrolytic chemicals.5.3 If the estimated value is more than 0.3 times the experimental value, the mechanism of action is probably narcosis. If less, the effect concentration is considered to reflect a different mechanism of action.5.4 This practice estimates a maximum LC50, that is, non-reactive and non-electrolytic chemicals are at least as toxic as the practice predicts, but may have a lower LC50 if acting by a more specific mechanism. Data on a chemical indicating a lower toxicity than predicted should be considered suspect or an artifact because of limited solubility of the test material.1.1 This practice covers a procedure for estimating the fathead minnow (Pimephales promelas) 96-h LC50 of nonreactive (that is, covalently bonded without unsaturated residues) and nonelectrolytic (that is, require vigorous reagents to facilitate substitution, addition, replacement reactions and are non-ionic, non-dissociating in aqueous solutions) organic chemicals acting solely by narcosis, also referred to as Meyer-Overton toxicity relationship.21.2 This procedure is accurate for organic chemicals that are toxic due to narcosis and are non-reactive and non-electrolytic. Examples of appropriate chemicals are: alcohols, ketones, ethers, simple halogenated aliphatics, aromatics, and aliphatic substituted aromatics. It is not appropriate for chemicals whose structures include a potential toxiphore (that structural component of a chemical molecule that has been identified to show mammalian toxicity, for example CN is known to be reponsible for inactivation of enzymes, NO2 for decoupling of oxidative phosphorylation, both leading to mammalian toxicity). Examples of chemicals inappropriate for this practice are: carbamates, organophosphates, phenols, beta-gamma unsaturated alcohols, electrophiles, and quaternary ammonium salts.1.3 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

定价： 515元 / 折扣价： 438 元 加购物车

5.1 Assumptions: 5.1.1 The well discharges at a constant rate.5.1.2 Well is of infinitesimal diameter and is open through the full thickness of the aquifer.5.1.3 The nonleaky confined aquifer is homogeneous, isotropic, and areally extensive except where limited by linear boundaries.5.1.4 Discharge from the well is derived initially from storage in the aquifer; later, movement of water may be induced from a constant-head boundary into the aquifer.5.1.5 The geometry of the assumed aquifer and well are shown in Fig. 1 or Fig. 2.5.1.6 Boundaries are vertical planes, infinite in length that fully penetrate the aquifer. No water is yielded to the aquifer by impermeable boundaries, whereas recharging boundaries are in perfect hydraulic connection with the aquifer.5.1.7 Observation wells represent the head in the aquifer; that is, the effects of wellbore storage in the observation wells are negligible.5.2 Implications of Assumptions: 5.2.1 Implicit in the assumptions are the conditions of a fully-penetrating control well and observation wells of infinitesimal diameter in a confined aquifer. Under certain conditions, aquifer tests can be successfully analyzed when the control well is open to only part of the aquifer or contains a significant volume of water or when the test is conducted in an unconfined aquifer. These conditions are discussed in more detail in Practice D4105/D4105M.5.2.2 In cases in which this practice is used to locate an unknown boundary, a minimum of three observation wells is needed. If only two observation wells are available, two possible locations of the boundary are defined, and if only one observation well is used, a circle describing all possible locations of the image well is defined.5.2.3 The effects of a constant-head boundary are often indistinguishable from the effects of a leaky, confined aquifer. Therefore, care must be taken to ensure that a correct conceptual model of the system has been created prior to analyzing the test. See Guide D4043.NOTE 2: Slug and pumping tests implicitly assume a porous medium. Fractured rock and carbonate settings may not provide meaningful data and information.5.3 Practice D3740 provides evaluation factors for the activities in this standard.NOTE 3: 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 practice covers an analytical procedure for determining the transmissivity, storage coefficient, and possible location of boundaries for a confined aquifer with a linear boundary. This practice is used to analyze water-level or head data from one or more observation wells or piezometers during the pumping of water from a control well at a constant rate. This practice also applies to flowing artesian wells discharging at a constant rate. With appropriate changes in sign, this practice also can be used to analyze the effects of injecting water into a control well at a constant rate.1.2 The analytical procedure in this practice is used in conjunction with the field procedure in Test Method D4050.1.3 Limitations—The valid use of this practice is limited to determination of transmissivities and storage coefficients for aquifers in hydrogeologic settings with reasonable correspondence to the assumptions of the Theis nonequilibrium method (see Practice D4106) (see 5.1), except that the aquifer is limited in areal extent by a linear boundary that fully penetrates the aquifer. The boundary is assumed to be either a constant-head boundary (equivalent to a stream or lake that hydraulically fully penetrates the aquifer) or a no-flow (impermeable) boundary (equivalent to a contact with a significantly less permeable rock unit). The Theis nonequilibrium method is described in Practices D4105/D4105M and D4106.1.4 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 nonconformance with the standard. Reporting of results in units other than SI shall not be regarded as nonconformance with this standard.1.5 All observed and calculated values shall conform to the guidelines for significant digits and rounding established in Practice D6026.1.6 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 the 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 the consideration of a project’s many unique aspects. The word “Standard” in the title of this document 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

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 test method can be used to quickly determine the lubricating ability of fully-formulated lubricants used as mechanical transmission fluids (MTF) to display a frictional behavior against materials used in synchronizers of mechanical gears in automotive vehicles. This test method has found to be complementary to bench tests (for example, Test Method D5579 and CEC L-66-99) by using the present test conditions. This test method is a material and application oriented approach based on inputs from field experiences for characterizing the frictional behavior (coefficient of friction (cof)) using random, discrete, and constant parameter combinations as seen in field experiences. Users of this test method should determine whether results correlate with field performance or other applications prior to commercialization.1.1 This test method covers a procedure for determining the coefficient of friction of lubricants (fluids) tribologically interacting with materials used in synchronizers in mechanical transmission (MT) gears under high-frequency linear-oscillation motion using the SRV test machine. A flat areal contact geometry is applied.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