定价： 515元 加购物车

4.1 Sampling is as important as testing. If the sampling is improperly done, the sample of the material will be in error, and the analysis will not represent the true properties of the material, and it may be impossible or impracticable to take another sample; whereas, if the sample is properly taken and the analysis is in error, another analysis can readily be made of the original sample.4.2 Samples may be taken for either of the following two purposes:4.2.1 To represent as nearly as possible an average of the bulk of the materials sampled, or4.2.2 To ascertain the maximum variation in characteristics which the material possesses.4.3 A good sampling plan has the following characteristics:4.3.1 It protects the consumer against the acceptance of a bad batch of material.4.3.2 It protects the producer against the rejection of a good batch of material.4.3.3 It gives long-range protection to the consumer.4.3.4 It encourages the producer to keep his process in control.4.3.5 It minimizes the cost of sampling, inspection of testing, and administration.4.3.6 It provides information concerning the quality of the product.4.4 Sampling Integrity—When one takes a sample, one is attempting to represent a batch or lot of material with that sample. Different forms of pitch, and pitch in different types of containers, need to have different sampling plans and appropriate sampling equipment. Each sampling plan should be designed so that it accomplishes its objective, which is to ascertain the characteristics or quality of a batch or lot of material.1.1 This practice covers procedures for sampling pitch at points of manufacture, storage, and delivery.1.2 The values stated in SI units are to be regarded as standard. The values 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. Specific warning statements are given in Section 11.1.4 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： 646元 加购物车

定价： 590元 加购物车

定价： 590元 加购物车

定价： 515元 加购物车

定价： 571元 加购物车

定价： 646元 加购物车

定价： 590元 加购物车

定价： 571元 加购物车

定价： 646元 加购物车

定价： 571元 加购物车

定价： 590元 加购物车

This practice covers determination of the quantitative and qualitative species composition of fish in a specified area. The successful use of this technique is dependent on: (1) preventing fish from escaping the sample area and (2) retrieving all affected fish, which may take up to three days. This practice is useful in both short- and long-term studies for management and impact assessment purposes. The sample area is blocked off with a small mesh net(s) and the volume of water to be treated is calculated. The required quantity of rotenone is diluted and distributed throughout the water column in the sample area. All fish should be affected and they should be collected for processing.1.1 This practice covers determination of the quantitative and qualitative species composition of fish in a specified area. The successful use of this technique is dependent on: (1) preventing fish from escaping the sample area and (2) retrieving all affected fish, which may take up to three days.1.2 Advantages: 1.2.1 Easily detoxified.1.2.2 All native freshwater fish are susceptible, but it has low toxicity to mammals and birds.1.2.3 At low concentrations fish toxicity depends on species, age, and size.1.2.4 The suffocating action is reversible.1.3 Limitations: 1.3.1 It is less effective in cold (below 20°C) and highly alkaline water.1.3.2 Smaller fish and those without air bladders usually do not float.1.3.3 Completely random selection of sample areas is not possible.1.3.4 Overkill beyond sample area can sometimes occur.1.3.5 Food web organisms may be eliminated.1.4 Applications—This practice is useful in both short- and long-term studies for management and impact assessment purposes. It is adaptable to both lotic and lentic situations in littoral and limnetic areas.1.5 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.1.6 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. For specific hazards, see Section 7.1.7 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： 515元 加购物车

4.1 Identification of the source of a spilled oil is established by comparison with known oils selected because of their possible relationship to the spill, that is, potential sources. Generally, the suspected source oils are from pipelines, tanks, etc., and therefore pose little problems in sampling compared to the spilled oil. This practice addresses the sampling of spilled oils in particular, but could be applied to appropriate source situations, for example, a ship's bilge.1.1 These practices describe the procedures to be used in collecting samples of waterborne oils (see Practice D3415), oil found on adjoining shorelines, or oil-soaked debris, for comparison of oils by spectroscopic and chromatographic techniques, and for elemental analyses.1.2 Two practices are described. Practice A involves “grab sampling” macro oil samples. Practice B can be used to sample most types of waterborne oils and is particularly applicable in sampling thin oil films or slicks. Practice selection will be dictated by the physical characteristics and the location of the spilled oil. These two practices are:  SectionsPractice A (for grab sampling thick layers of oil, viscous oils or oil soaked debris, oil globules, tar balls, or stranded oil)  9 to 13Practice B (for TFE–fluorocarbon polymer strip samplers) 14 to 171.3 Each of the two practices is designed to collect oil samples with a minimum of water, thereby reducing the possibility of chemical, physical, or biological alteration by prolonged contact with water between the time of collection and analysis.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. For specific hazards statements, see Section 7.1.6 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： 515元 加购物车

定价： 712元 加购物车