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定价： 1177元 / 折扣价： 1001 元 加购物车

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定价： 352元 / 折扣价： 300 元 加购物车

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定价： 605元 / 折扣价： 515 元 加购物车

定价： 1177元 / 折扣价： 1001 元 加购物车

定价： 590元 / 折扣价： 502 元 加购物车

5.1 To overcome the inadequacies of conventional spectrophotometric measurement techniques when nonhomogeneous materials are measured, a large integrating sphere may be used.4,5 Since the beam employed in such spheres is large in comparison to the disparaties of the materials being tested, the nonisotropic nature of the specimen being measured is essentially averaged, or integrated out of the measurement, in a single experimental determination.5.2 Solar and photopic optical properties may be measured either with monofunctional spheres individually tailored for the measurement of either transmittance5 or reflectance, or may be measured with a single multifunctional sphere that is employed to measure both transmittance and reflectance.45.3 A multifunctional sphere is used for making total solar transmittance measurements in both a directional-hemispherical and a directional-directional mode. The solar absorptance can be evaluated in a single measurement as one minus the sum of the directional hemispherical reflectance and transmittance. When a sample at the center of the sphere is supported by its rim, the sum of the reflectance and transmittance can be measured as a function of the angle of incidence. The solar absorptance is then one minus the measured absorptance plus transmittance.1.1 This test method covers the measurement of the absolute total solar or photopic reflectance, transmittance, or absorptance of materials and surfaces. Although there are several applicable test methods employed for determining the optical properties of materials, they are generally useful only for flat, homogeneous, isotropic specimens. Materials that are patterned, textured, corrugated, or are of unusual size cannot be measured accurately using conventional spectrophotometric techniques, or require numerous measurements to obtain a relevant optical value. The purpose of this test method is to provide a means for making accurate optical property measurements of spatially nonuniform materials.1.2 This test method is applicable to large specimens of materials having both specular and diffuse optical properties. It is particularly suited to the measurement of the reflectance of opaque materials and the reflectance and transmittance of semitransparent materials including corrugated fiber-reinforced plastic, composite transparent and translucent samples, heavily textured surfaces, and nonhomogeneous materials such as woven wood, window blinds, draperies, etc.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. (For specific safety hazards, see Note 1.)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

定价： 843元 / 折扣价： 717 元 加购物车

定价： 515元 / 折扣价： 438 元 加购物车

定价： 515元 / 折扣价： 438 元 加购物车

This specification covers requirements and test methods for poly(vinyl chloride) (PVC) large-diameter plastic gravity sewer pipe and fittings. Pipe requirements include workmanship, pipe dimensions, flattening resistance, impact resistance, pipe stiffness, gaskets requirements, joint tightness, extrusion quality, joining system, and markings. Test procedures shall include referee testing, quality control tests, test conditions, flattening tests, impact resistance, pipe stiffness, and acetone immersion test. Retest, rejection, inspection, certification, marking, delivery, and quality assurance shall conform to the requirements of this specification.1.1 This specification covers requirements and test methods for materials, dimensions, workmanship, flattening resistance, impact resistance, pipe stiffness, extrusion quality, joining system, and a form of marking for large diameters, 18 to 60 in. poly(vinyl chloride) (PVC) sewer pipe and fittings with integral bell elastomeric seal joints or solvent cemented sockets.1.2 The requirements of this specification are intended to provide pipe and fittings suitable for nonpressure drainage of sewage and surface water. Pipe and fittings produced to this specification should be installed in accordance with Practice D2321.NOTE 1: Industrial waste disposal lines should be installed only with the specific approval of the governing code authority since temperatures in excess of 140 °F (60 °C) and chemicals not commonly found in drains and sewers may be encountered.1.3 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.1.4 The following precautionary caveat pertains only to the test method portion, Section 8, of this specification: This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.5 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

4.1 Procedure A—This procedure is an index-type test which can be used as a guide for acceptance of commercial shipments of geosynthetics. The standard cone and pyramid test fixtures can establish critical height (ch) consistency with similar material from previous lots or different suppliers, as well as testing from other laboratories. However, due to the time required to perform tests, it is generally not recommended for routine acceptance testing.4.2 Procedures B and C—These procedures are performance tests intended as a design aid used to simulate the in-situ behavior of geosynthetics under hydrostatic compression. These test methods may assist a design engineer in comparing the ability of several candidate geosynthetic materials to conform to a site-specific subgrade under specified use and conditions. In procedure B, the pressure is increased until a failure is observed. In procedure C, a given set of conditions (pressure, temperature and test duration) are maintained constant and the performance of the system is observed at the end of the test.1.1 This test method evaluates the stress/time properties of geosynthetics by using hydrostatic pressure to compress the geosynthetic over synthetic or natural test bases consisting of manufactured test pyramids/cones, rocks, soil, or voids.1.2 This test method allows the user to determine the relative failure mode or points of failure for geosynthetics, or both.1.3 This test method offers two distinct procedures:1.3.1 Procedure A incorporates manufactured test pyramids or cones as the base of the testing apparatus. Procedure A is intended to create comparable data between laboratories, and can be used as a guide for routine acceptance tests for various materials.1.3.2 Procedures B and C incorporate site-specific soil or other material selected by the user as the test base of the testing apparatus. Procedures B and C are methods for geosynthetic design for a specific site.1.4 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.1.5 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. For a specific warning statement, see Section 6.1.6 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