定价： 605元 / 折扣价： 515 元

定价： 0元 / 折扣价： 0 元 加购物车

定价： 605元 / 折扣价： 515 元 加购物车

定价： 0元 / 折扣价： 0 元 加购物车

定价： 0元 / 折扣价： 0 元 加购物车

定价： 0元 / 折扣价： 0 元 加购物车

定价： 481元 / 折扣价： 409 元

定价： 345元 / 折扣价： 294 元

定价： 605元 / 折扣价： 515 元

定价： 481元 / 折扣价： 409 元

定价： 156元 / 折扣价： 133 元 加购物车

5.1 General—Hydrogen sulfide is nearly ubiquitous. It occurs naturally in volcanic gases, in sulfur springs and fumaroles, in decaying of plant and animal protein, and in intestines as a result of bacterial action. Hydrogen sulfide is a serious hazard to the health of workers employed in energy production from hydrocarbon or geothermal sources, in the production of fibers and sheets from viscose syrup, in the production of deuterium oxide (heavy water), in tanneries, sewers, sewage treatment and animal waste disposal, in work below ground, on fishing boats, and in chemical operations, including the gas and oil industry.5.2 In 29 CFR 1910.1000, the Federal Occupational Safety and Health Administration designates that worker exposure to certain gases and vapors must not be exceeded in workplace atmospheres at concentrations above specific values, averaged over a certain time span. Hydrogen sulfide is included in this list. Refer also to NIOSH Criteria for a Recommended Standard, Occupational Exposure to Hydrogen Sulfide.5.3 This practice will provide means for the determination of airborne concentrations of hydrogen sulfide.5.4 This practice provides means for either personal or area sampling and for short-term or time-weighted average (TWA) measurements. Refer to Threshold Limit Values for Chemical Substances in the Work Environment.1.1 This practice covers the detection of hydrogen sulfide gas by visual chemical detectors. Included under visual chemical detectors are: short-term detector tubes (1),2 long-term detector tubes (2), and length-of-stain dosimeters (3). Diffusion tubes are not included under this practice because they are not direct reading, and spot tests are not included because of their poor accuracy. The sample results are immediately available by visual observation, thus no analytical equipment is needed.1.2 This practice reflects the current state-of-the-art for commercially available visual length-of-stain detectors for hydrogen sulfide. Any mention of a specific manufacturer in the text or references does not constitute an endorsement by ASTM.1.3 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 and health practices and determine the applicability of regulatory limitations prior to use.

定价： 0元 / 折扣价： 0 元

3.1 Although it is possible to observe and measure each of the several characteristics of the ELCD under different and unique conditions, in particular its different modes of selectivity, it is the intent of this practice that a complete set of detector specifications should be obtained at the same operating conditions, including geometry, gas and solvent flow rates, and temperatures. It should be noted that to specify a detector's capability completely, its performance should be measured at several sets of conditions within the useful range of the detector. The terms and tests described in this practice are sufficiently general so that they may be used at whatever conditions may be chosen for other reasons.3.2 Linearity and speed of response of the recorder used should be such that it does not distort or otherwise interfere with the performance of the detector. Effective recorder response should be sufficiently fast so that it can be neglected in sensitivity of measurements. If additional amplifiers are used between the detector and the final readout device, their characteristics should also first be established.1.1 This practice covers testing the performance of an electrolytic conductivity detector (ELCD) used as the detection component of a gas chromatographic system.1.2 This practice is directly applicable to electrolytic conductivity detectors that perform a chemical reaction on a given sample over a nickel catalyst surface under oxidizing or reducing conditions and employ a scrubber, if needed, to remove interferences, deionized solvent to dissolve the reaction products, and a conductivity cell to measure the electrolytic conductivity of ionized reaction products.1.3 This practice covers the performance of the detector itself, independently of the chromatographic column, in terms that the analyst can use to predict overall system performance when the detector is coupled to the column and other chromatographic system components.1.4 For general gas chromatographic procedures, Practice E260 should be followed except where specific changes are recommended herein for the use of an electrolytic conductivity detector. For definitions of gas chromatography and its various terms see Practice E355.1.5 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 Although it is possible to observe and measure each of the several characteristics of a detector under different and unique conditions, it is the intent of this practice that a complete set of detector specifications be obtained at the same operating conditions, including geometry, flow rates, and temperatures. To specify a detector's capability completely, its performance should be measured at several sets of conditions within the useful range of the detector. The terms and tests described in this practice are sufficiently general so that they may be used under any chosen conditions.4.2 Linearity and speed of response of the recorder should be such that it does not distort or otherwise interfere with the performance of the detector. Effective recorder response should be sufficiently fast so that its effect on the sensitivity of measurement is negligible. If additional amplifiers are used between the detector and the final readout device, their characteristics should first be established.1.1 This practice covers testing the performance of a nitrogen/phosphorus thermionic ionization detector (NPD) used as the detection component of a gas chromatographic system.1.2 This practice applies to an NPD that employs a heated alkali metal compound and emits an electrical charge from that solid surface.1.3 This practice addresses the operation and performance of the NPD independently of the chromatographic column. However, the performance is specified in terms that the analyst can use to predict overall system performance when the detector is coupled to the column and other chromatographic components.1.4 For general chromatographic procedures, Practice E260 should be followed except where specific changes are recommended in this practice for the use of a nitrogen/phosphorus (N/P) thermionic detector.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 safety information, see Section 5, Hazards.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

4.1 This practice provides a method for the in-road installation of an inductive loop detector that consists of wire loops, lead-in wires, and lead-in cable. The practice is intended for installing wires in saw cuts made in the roadway surface and not for installing preformed loops that may be encased in a protective enclosure such as plastic conduit. Typical components of an inductive loop detector system are illustrated in Fig. 1. Modern inductive loop detector electronic units are capable of detecting vehicles even if the wire loop is laid on reinforcing steel before concrete is placed.FIG. 1 Inductive Loop Detector System (Notional) (2)1.1 This practice describes the recommended procedure for installing inductive loop detectors in sawed slots in roadway pavement for use as a traffic monitoring device or to actuate traffic control devices such as a traffic signal. Although the practice is not intended for installing preformed loops, the practice does contain information of value for this type of loop, such as recommendations for the number of turns of loop wire, number and direction of twists in the lead-in wire and cable, splice location (if needed), and grounding options.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