定价： 345元 / 折扣价： 294 元

定价： 605元 / 折扣价： 515 元

定价： 345元 / 折扣价： 294 元

定价： 481元 / 折扣价： 409 元 加购物车

定价： 260元 / 折扣价： 221 元 加购物车

定价： 260元 / 折扣价： 221 元 加购物车

5.1 Sulfate-reducing bacteria are widely distributed in marine and fresh water muds which, in consequence, frequently are laden with the hydrogen sulfide produced by these organisms during dissimilatory sulfate reduction.5.2 It has been reported that Desulfovibrio spp. can form as much as 10 g of sulfide per litre during active multiplication. Sulfate-reducing bacteria can cause the external or internal corrosion of water or wastewater pipelines and pipelines for petroleum and natural gas. The formation of galvanic cells by massive growth of sulfate-reducing bacteria under suitable conditions makes the corrosion much worse than just the effect of the hydrogen sulfide on the metal or concrete.1.1 These test methods cover the procedure for the detection and enumeration by the most probable number (MPN) technique of sulfate-reducing bacteria in water or water-formed deposits.1.2 Two media preparations are provided. Medium A which is prepared with reagent grade water, and Medium B which is prepared using the water to be sampled as the water source. Medium B is offered for those special conditions where sulfate-reducing bacterial strains have adapted to atypical non-fresh water environment.1.3 For the isolation and enumeration of thermophilic sulfate-reducing bacteria encountered in waters associated with oil and gas production, all broths, dilution blanks, and incubations must be maintained at temperatures of at least 45°C and preferably within 5°C at the sample temperature.1.4 The sensitivity of these test methods can be increased by purging the dilution blanks and tubes of media with nitrogen immediately prior to use.1.5 The analyst should be aware that adequate collaborative data for precision and bias statements as required by Practice D2777 are not provided. See Section 11 for details.1.6 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.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： 515元 / 折扣价： 438 元 加购物车

5.1 Ethanol is used as a blending agent added to gasoline. Sulfates are indicated in filter plugging deposits and fuel injector deposits. When fuel ethanol is burned, sulfates may contribute to sulfuric acid emissions. Ethanol acceptability for use depends on the sulfate content. Sulfate content, as measured by this test method, can be used as one measure of determination of the acceptability of ethanol for automotive spark-ignition engine fuel use.1.1 This test method covers a potentiometric titration procedure for determining the existent inorganic sulfate content of hydrous, anhydrous ethanol, and anhydrous denatured ethanol, which is added as a blending agent with spark ignition fuels. It is intended for the analysis of denatured ethanol samples containing between 1.0 mg/kg to 20 mg/kg existent inorganic sulfate.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. Material Safety Data Sheets are available for reagents and materials. Review them for hazards prior to usage.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 Sulfates and chlorides can be found in filter plugging deposits and fuel injector deposits. The acceptability for use of the fuel components and the finished fuels depends on the sulfate and chloride content.5.2 Existent and potential inorganic sulfate and total chloride content, as measured by this test method, can be used as one measure of the acceptability of gasoline components for automotive spark-ignition engine fuel use.1.1 This test method covers a direct injection ion chromatographic procedure for determining existent and potential inorganic sulfate and total inorganic chloride content in hydrous and anhydrous denatured ethanol and butanol to be used in motor fuel applications. It is intended for the analysis of ethanol and butanol samples containing between 1.0 mg/kg to 20 mg/kg of existent or potential inorganic sulfate and 1.0 mg/kg to 50 mg/kg of inorganic chloride.NOTE 1: Tertiary butanol is not included in this test method. 1-butanol, 2-butanol, and isobutanol are included in the testing and research report for this test method.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. Material Safety Data Sheets are available for reagents and materials. Review them for hazards prior to usage.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

This test method covers the procedures for determining soluble sulfate ions present in water or a filtrate using a photometer to measure the turbidity of precipitated barium sulfate. This test method also details a method for standardizing the photometer to be used. The soluble sulfate ions may be removed from clays or clay-water slurries by leaching with water during mixing and then filter pressing. An impractical number of washings would be needed to remove all sulfate ions, therefore, this test method should be considered only as a control test and not a quantitative analysis for sulfate ions. Test apparatus include a balance, high speed mixer, filter press, glass beakers, transfer pipets, spectrophotometer, measuring spoon, and other laboratory equipment. All reagents to be used should be of the required purity and concentration.1.1 This test method covers the determination of soluble sulfate ions present in water or a filtrate by means of a photometer measuring the turbidity of precipitated barium sulfate. A method of standardizing the photometer for this test method is also given.1.2 Soluble sulfate ions may be removed from clays or clay-water slurries by leaching with water during mixing and subsequent filter pressing. To remove all the sulfate ions would require an impractical number of washings; therefore, this test method should be considered a control test and not a quantitative analysis for SO4 ions.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： 515元 / 折扣价： 438 元 加购物车

3.1 This test method is used to determine the percent of total chromic oxide that is combined with hydroxyl and may serve as a measure of chrome fixation.1.1 This test method is intended for use in calculating the sulfate basicity of mineral tanned leather.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, health, and environmental 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

4.1 This test method provides a procedure for making a preliminary estimate of the soundness of aggregates for use in concrete and other purposes. The values obtained may be compared with specifications, for example Specification C33/C33M, that are designed to indicate the suitability of aggregate proposed for use. Since the precision of this test method is poor (Section 13), it may not be suitable for outright rejection of aggregates without confirmation from other tests more closely related to the specific service intended.4.2 Values for the permitted-loss percentage by this test method are usually different for fine and coarse aggregates, and attention is called to the fact that test results by use of the two salts differ considerably and care must be exercised in fixing proper limits in any specifications that include requirements for these tests. The test is usually more severe when magnesium sulfate is used; accordingly, limits for percent loss allowed when magnesium sulfate is used are normally higher than limits when sodium sulfate is used.NOTE 2: Refer to the appropriate sections in Specification C33/C33M establishing conditions for acceptance of coarse and fine aggregates which fail to meet requirements based on this test.1.1 This test method covers the testing of aggregates to estimate their soundness when subjected to weathering action in concrete or other applications. This is accomplished by repeated immersion in saturated solutions of sodium or magnesium sulfate followed by oven drying to partially or completely dehydrate the salt precipitated in permeable pore spaces. The internal expansive force, derived from the rehydration of the salt upon re-immersion, simulates the expansion of water on freezing. This test method furnishes information helpful in judging the soundness of aggregates when adequate information is not available from service records of the material exposed to actual weathering conditions.1.2 The values stated in SI or inch pound units shall be regarded separately as standard. The inch –pound units are shown in brackets. The values stated are not exact equivalents; therefore each system shall be used independently of the other. Combining values from the two systems may result in nonconformance.1.3 Some values have only SI units because the inch-pound equivalents are not used in practice.1.4 If the results obtained from another standard are not reported in the same system of units as used by this test method, it is permitted to convert those results using the conversion factors found in the SI Quick Reference Guide.2NOTE 1: Sieve size is identified by its standard designation in Specification E11. The alternate designation given in parentheses is for information only and does not represent a different standard sieve size.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

This specification covers unfabricated and fabricated forms of high purity hydrated calcium sulfate hemihydrate or dihydrate for surgical implants. The requirements of this specification apply to calcium sulfate combined with two molecules of water or two calcium sulfate molecules with one water mole but does not include calcium sulfate anhydrite and calcium sulfate forms that contain reinforcing phases, medicaments, biological agents, and other such additives. All covered materials should conform to the requirements for set time, compressive strength, and in vitro degradation.1.1 This specification covers material requirements for unfabricated and fabricated forms of hydrated calcium sulfate intended for surgical implants. Fabricated forms may include pressed and cast surgical implants in various geometric shapes. The calcium sulfate hemihydrate in the unfabricated form can be converted with the addition of water or other water-containing solutions to a fabricated calcium sulfate dihydrate form.1.2 The requirements of this specification apply to calcium sulfate combined with two molecules of water or two calcium sulfate molecules sharing one water molecule.Approximate chemical formulae:Calcium Sulfate DihydrateCaSO4·2H2O Calcium Sulfate HemihydrateCaSO4·1/2H2O or CaSO4·H2O·CaSO41.3 This specification specifically excludes calcium sulfate anhydrite and calcium sulfate forms that contain additives such as reinforcing phases, medicaments, biological agents, and so forth.1.4 The presence of processing aids does not exclude a product from the physical and mechanical requirements of this specification.1.5 Some provisions of Specification C59/C59M and Test Methods C472 apply. Special requirements that are detailed in this specification are included to characterize the material which will be used in surgical implants.1.6 The biological response to calcium sulfate in bone tissue has been well characterized by a history of clinical use (1-14)2 and by laboratory studies (15-18).1.7 The following precautionary caveat pertains only to the test method portion, Sections 4, 5, and 6, 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.1.8 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： 515元 / 折扣价： 438 元 加购物车

4.1 The ceric-cerous system provides a reliable means for determining absorbed dose to water. It is based on a process of reduction of ceric ions to cerous ions in acidic aqueous solution by ionizing radiation (1, 4, ICRU Report 80).NOTE 3: The ceric-cerous system described in the practice has cerous sulfate added to the initial solution to reduce the effect of organic impurities and to allow the potentiometric method of measurement. Other systems used for dosimetry include solutions of ceric sulfate or ceric ammonium sulfate in sulfuric acid without the initial addition of cerous sulfate. These other systems are based on the same process of reduction of ceric ions to cerous ions but are not included in this practice.1.1 This practice covers the preparation, testing, and procedure for using the ceric-cerous sulfate dosimetry system to measure absorbed dose to water when exposed to ionizing radiation. The system consists of a dosimeter and appropriate analytical instrumentation. For simplicity, the system will be referred to as the ceric-cerous system. The ceric-cerous dosimeter is classified as a type 1 dosimeter on the basis of the effect of influence quantities. The ceric-cerous system may be used as a reference standard dosimetry system or as a routine dosimetry system.1.2 This document is one of a set of standards that provides recommendations for properly implementing dosimetry in radiation processing, and describes a means of achieving compliance with the requirements of ISO/ASTM Practice 52628 for the ceric-cerous system. It is intended to be read in conjunction with ISO/ASTM Practice 52628.1.3 This practice describes both the spectrophotometric and the potentiometric readout procedures for the ceric-cerous system.1.4 This practice applies only to gamma radiation, X-radiation/bremsstrahlung, and high energy electrons.1.5 This practice applies provided the following conditions are satisfied:1.5.1 The absorbed-dose range is from 5 × 102 to 5 × 104 Gy (1).21.5.2 The absorbed-dose rate does not exceed 106 Gy s−1 (1).1.5.3 For radionuclide gamma-ray sources, the initial photon energy is greater than 0.6 MeV. For bremsstrahlung photons, the initial energy of the electrons used to produce the bremsstrahlung photons is equal to or greater than 2 MeV. For electron beams, the initial electron energy is greater than 8 MeV.NOTE 1: The lower energy limits are appropriate for a cylindrical dosimeter ampoule of 12-mm diameter. Corrections for dose gradient across the ampoule may be required for electron beams (2). The ceric-cerous system may be used at lower energies by employing thinner (in the beam direction) dosimeters (see ICRU Report 35).1.5.4 The irradiation temperature of the dosimeter is above 0°C and below 62°C (3).NOTE 2: The temperature coefficient of dosimeter response is known only in this range (see 5.2). Use outside this range requires determination of the temperature coefficient.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 and health 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： 506元 / 折扣价： 431 元 加购物车

5.1 The determination of sulfate and other dissolved constituents is important in identifying the source of brines produced during the drilling and production phases of crude oil or natural gas.1.1 This test method covers the turbidimetric determination of sulfate ion in brackish water, seawater, and brines. It has been used successfully with synthetic brine grade waters; however, it is the user's responsibility to ensure the validity of this test method to other matrices.1.2 This test method is applicable to waters having an ionic strength greater than 0.65 mol/L and a sulfate ion concentration greater than 25 mg/L. A concentration less than 25 mg/L sulfate can be determined by using a standard addition method.1.3 For brines having an ionic strength of less than 0.65 mol/L, refer to Test Methods D516.1.4 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 and health practices and determine the applicability of regulatory limitations prior to use.

定价： 0元 / 折扣价： 0 元