5.1 Broad-crested weirs can be used for accurate measurements of a wide range of flow rates, but their structural simplicity and sturdiness make them particularly useful for measuring large flows under field conditions.5.2 Because they require vertical sidewalls, broad-crested weirs are particularly adaptable to rectangular artificial channels or to natural and artificial channels that can readily be lined with vertical sidewalls in the immediate vicinity of the weir.1.1 This test method covers measurement of the volumetric flow rate of water in open channels with two types of horizontal broad-crested weirs: those having a square (sharp) upstream corner and those having a well-rounded upstream corner.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 and health practices and determine the applicability of regulatory limitations prior to use.

定价： 0元 / 折扣价： 0 元

4.1 This test method is intended for use in evaluating the binding to snowboard insert retention strength resulting from use. This test method may also be used to compare the durability of different materials and designs. This test method references ISO 10958-2, which is considered satisfactory for acceptance testing insert retention for snowboards.1.1 This test method covers the requirements and test method for snowboards with channel-mounting systems on which bindings are attached to the board by means of a removable insert and screws.1.2 This test method does not apply to snowboards for children with a mass less than 25 kg. It contains data for the manufacturer of snowboards, bindings, and retention devices concerning dimensions, tests, and other specifications for the binding mounting area.1.3 For snowboards with fixed inserts, see ISO 10958-2.1.4 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： 515元 / 折扣价： 438 元 加购物车

定价： 2366元 / 折扣价： 2012 元

4.1 Each type of weir and flume possesses advantages and disadvantages relative to the other types when it is considered for a specific application; consequently, the selection process often involves reaching a compromise among several features. This guide is intended to assist the user in making a selection that is hydraulically, structurally, and economically appropriate for the purpose.4.2 It is recognized that not all open-channel situations are amenable to flow measurement by weirs and flumes and that in some cases, particularly in large streams, discharges may best be determined by other means. (See 6.2.2.)1.1 This guide covers recommendations for the selection of weirs and flumes for the measurement of the volumetric flow rate of water and wastewater in open channels under a variety of field conditions.1.2 This guide emphasizes the weirs and flumes for which ASTM standards are available, namely, thin-plate weirs, broad-crested weirs, Parshall flumes, and Palmer-Bowlus (and other long-throated) flumes. However, reference is also made to other measurement devices and methods that may be useful in specific situations.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 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

4.1 A properly collected face channel sample that includes the total coal bed interval provides a sample that is a representative cross section of the coal bed at the point of sampling. Channel samples are taken for subsequent testing needed for evaluation of coal quality and characterization for commercial evaluations, for planning of mining operations to maintain coal quality, for the determination of coal rank in accordance with Classification D388, and for geologic coal resource studies.NOTE 1: Because of the potential for lateral variability, a sample may not represent the quality of the coal bed at another sample point. The reliability of the data generated from channel samples is dependent on the number and spacing of the sample points and the variability of the coal characteristics in a given area.NOTE 2: Sampling of the mine product for these purposes is unsatisfactory because of contamination of the product with out-of-seam material, selective mining of parts of a seam, inability to obtain samples from one or more specific locations in the mine, or other incompatibility of the purpose of sampling with the mining practice. Conversely, channel samples should not be used for evaluation of the quality of commercial shipments of the mine product, which should be sampled in accordance with Methods D2234/D2234M.1.1 This practice describes procedures for collecting a coal sample from a channel extending from top to bottom in the face of a coal seam in a mine.1.2 Units—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. For specific precautionary information, see Note 2.1.4 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 This test method is particularly useful to determine the discharge when it cannot be measured directly by some type of current meter to obtain velocities and with sounding weights to determine the cross section.5.2 Even under the best conditions, the personnel available cannot cover all points of interest during a major flood. The engineer or technician cannot always obtain reliable results by direct methods if the stage is rising or falling very rapidly, if flowing ice or debris interferes with depth or velocity measurements, or if the cross section of an alluvial channel is scouring or filling significantly.5.3 Under the worst conditions, access roads are blocked, cableways and bridges may be washed out, and knowledge of the flood frequently comes too late. Therefore, some type of indirect measurement is necessary. The contracted-opening method is commonly used on valley-floor streams.1.1 This test method covers the computation of discharge (the volume rate of flow) of water in open channels or streams using bridges that cause width contractions as metering devices.21.2 This test method produces the maximum discharge for one flow event, usually a specific flood. The computed discharge may be used to help define the high-water portion of a stage-discharge relation.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 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 This test method is particularly useful for determining the discharge when it cannot be measured directly by some type of current meter to obtain velocities and with sounding weights to determine the cross section.5.2 Even under optimum conditions, the personnel available cannot cover all points of interest during a major flood. Field personnel cannot always obtain reliable results by direct methods if the stage is rising or falling very rapidly, if flowing ice or debris interferes with depth or velocity measurements.5.3 Under the worst conditions, access roads are blocked, cableways and bridges may be washed out, and knowledge of the flood frequently comes too late to obtain direct measurements of flow. Therefore, some type of indirect measurement is necessary. The slope-area method is a commonly used method.1.1 This test method covers the computation of discharge (the volume rate of flow) of water in open channels or streams using representative cross-sectional characteristics, the water-surface slope, and coefficient of channel roughness as input to gradually-varied flow computations.2,31.2 This test method produces an indirect measurement of the maximum discharge for one flow event, usually a specific flood. The computed discharge may be used to help define the high-water segment of a stage-discharge relation.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 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 Flume designs are available for throat sizes of 1 in. (2.54 cm) to 50 ft (15.2 m) which cover maximum flows of 0.2 to 3000 ft3/s (0.0057 to 85 m3/s) (1) and (2).4 They can therefore be applied to a wide range of flows, with head losses that are moderate.5.2 The flume is self-cleansing for moderate solids transport and therefore is suited for wastewater and flows with sediment.1.1 This test method covers measurement of the volumetric flowrate of water and wastewater in open channels with the Parshall flume.1.1.1 Information related to this test method can be found in ISO 1438 and ISO 4359.1.2 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.

定价： 646元 / 折扣价： 550 元 加购物车

5.1 This guide is general and intended as a planning guide. To satisfactorily monitor a specific site, an investigator must sometimes design specific installation structures or modify those given in this guide to meet the requirements of the site in question. Because of the dynamic nature of the sediment transport process, the extent to which characteristics such as mass concentration and particle-size distribution are accurately represented in the monitoring program depends on the type of equipment used and method of collection of the SSC samples used to calibrate the optical readings. Sediment concentration is highly variable in both time and space. Numerous samples must be collected and analyzed with proper equipment and standardized methods for the rating of the optical equipment at a particular site (see Guide D4411 and Practice D3977).5.2 All optical equipment have an upper limit for valid readings, beyond which the meter will not read properly, commonly referred to as “blacking out.” If upper range of SSC are expected to cause optical instrument black out, then some other means should be devised, such as automatic pumping samplers, to collect samples during this period. See Edwards and Glysson (1)3 and Glysson (2) for information on collection of suspended sediment samples using pumping samplers. It should be noted that other technologies, such as lasers and acoustic dopplers, are also being used to monitor SSC continuously.5.3 The user of this guide should realize that because different technologies and different models of the same technology of turbidity meters can produce significantly different outputs for the same environmental sample, only one manufacturer and model of the turbidity meter can be used to develop the relationship between the SSC and turbidity readings at a site. If a different manufacturer or a different model type of turbidity meter is used, a new relationship will need to be develop for the site.1.1 This guide covers the equipment and basic procedures for installation, operation, and calibration of optical equipment as a surrogate for the continuous determination of suspended-sediment concentration (SSC) in open channel flow.1.2 This guide emphasizes general principles for the application of optical measurements to be used to estimate suspended-sediment concentration (SSC) in water. Only in a few instances are step-by-step instructions given. Continuous monitoring is a field-based operation, methods and equipment are usually modified to suit local conditions. The modification process depends upon the operator skill and judgment.1.3 This guide covers the use of the output from an optical instrument, such as turbidity and suspended-solids meters, to record data that can be correlated with suspended-sediment concentration. It does not cover the process of collecting data for continuous turbidity record, which would require additional calibration of the turbidity readings to the mean turbidity of the measurement cross section. For the purposes of this method it is assumed that the dependent variable will be mean cross-sectional suspended-sediment concentration data.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： 646元 / 折扣价： 550 元 加购物车

定价： 774元 / 折扣价： 658 元

This part of ISO/IEC 14165 describes the physical interface portions of a high performance serial link that supports the higher Upper Level Protocols (ULPs) associated with HIPPI, IPI, SCSI, IP and others.

定价： 1729元 / 折扣价： 1470 元

This part of ISO/IEC 14165 describes the signalling and physical requirements that may be utilized by Fibre Channel-2 (FC-2) level transport data at a rate in excess of 10 Gbit/s.

定价： 1593元 / 折扣价： 1355 元

定价： 1911元 / 折扣价： 1625 元

5.1 This test method is used where high accuracy of velocity or continuous discharge measurement over a long period of time is required and other test methods of measurement are not feasible due to low velocities in the channel, variable stage-discharge relations, complex stage-discharge relations, or the presence of marine traffic. It has the additional advantages of requiring no moving parts, introducing no head loss, and providing virtually instantaneous readings (1 to 100 readings per second).5.2 The test method may require a relatively large amount of site work and survey effort and is therefore most suitable for permanent or semi-permanent installations.1.1 This test method covers the measurement of flow rate of water in open channels, streams, and closed conduits with a free water surface.1.2 The test method covers the use of acoustic transmissions to measure the average water velocity along a line between one or more opposing sets of transducers—by the time difference or frequency difference techniques.1.3 The values stated in SI units are to be regarded as the 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. Specific precautionary statements are given in Section 6.1.5 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

定价： 2048元 / 折扣价： 1741 元