定价： 345元 / 折扣价： 294 元 加购物车

定价： 260元 / 折扣价： 221 元 加购物车

定价： 481元 / 折扣价： 409 元 加购物车

定价： 553元 / 折扣价： 471 元 加购物车

定价： 260元 / 折扣价： 221 元 加购物车

定价： 156元 / 折扣价： 133 元 加购物车

4.1 Titration techniques using KF reagent are one of the most widely used for the determination of water.4.2 Although the volumetric KF titration can determine low levels of water, it is generally accepted that coulometric KF titrations (see Test Method E1064) are more accurate for routine determination of very low levels of water. As a general rule, if samples routinely contain water concentrations of 500 mg/kg or less, the coulometric technique should be considered.4.3 Applications can be subdivided into two sections: (1) organic and inorganic compounds, in which water may be determined directly, and (2) compounds, in which water cannot be determined directly, but in which interferences may be eliminated by suitable chemical reactions or modifications of the procedure. Further discussion of interferences is included in Section 5 and Appendix X2.4.4 Water can be determined directly in the presence of the following types of compounds:Organic CompoundsAcetals EthersAcids (Note 1) HalidesAcyl halides Hydrocarbons (saturated and unsaturated)Alcohols Ketones, stable (Note 4)Aldehydes, stable (Note 2) NitrilesAmides OrthoestersAmines, weak (Note 3) Peroxides (hydro, dialkyl)Anhydrides SulfidesDisulfides ThiocyanatesEsters ThioestersInorganic CompoundsAcids (Note 5) Cupric oxideAcid oxides (Note 6) DesiccantsAluminum oxides Hydrazine sulfateAnhydrides Salts of organic and inorganic acids (Note 6)Barium dioxide  Calcium carbonate  NOTE 1: Some acids, such as formic, acetic, and adipic acid, are slowly esterified. When using pyridine-free reagents, commercially available buffer solutions can be added to the sample prior to titration. With formic acid, it may be necessary to use methanol-free solvents and titrants (1).4NOTE 2: Examples of stable aldehydes are formaldehyde, sugars, chloral, etc. Formaldehyde polymers contain water as methylol groups. This combined water is not titrated. Addition of an excess of NaOCH3 in methanol permits release and titration of this combined water, after approximate neutralization of excess base with acetic acid (see Note 9).NOTE 3: Weak amines are considered to be those with Kb value <2.4 × 10−5.NOTE 4: Examples of stable ketones are diisopropyl ketone, camphor, benzophenone, benzil, dibenzolacetone, etc.NOTE 5: Sulfuric acid up to a concentration of 92 % may be titrated directly; for higher concentrations see Note 13.NOTE 6: Compounds subject to oxidation-reduction reactions in an iodine-iodide system interfere.1.1 This test method is intended as a general guide for the application of the volumetric Karl Fischer (KF) titration for determining free water and water of hydration in most solid or liquid organic and inorganic compounds. This test method is designed for use with automatic titration systems capable of determining the KF titration end point potentiometrically; however, a manual titration method for determining the end point visually is included as Appendix X1. Samples that are gaseous at room temperature are not covered (see Appendix X4). This test method covers the use of pyridine-free KF reagents for determining water by the volumetric titration. Determination of water using KF coulometric titration is not discussed. By proper choice of the sample size, KF reagent concentration and apparatus, this test method is suitable for measurement of water over a wide concentration range, that is, parts per million to pure water.1.2 The values stated in SI units are to be regarded as 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. Specific warnings are given in 3.1.1.4 Review the current Safety Data Sheets (SDS) for detailed information concerning toxicity, first aid procedures, and safety precautions for chemicals used in this test procedure.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

5.1 This test method covers the measurement of thermal properties for engine coolants (aqueous or non-aqueous) and related fluids.5.2 With each single measurement, the thermal conductivity (λ) and thermal diffusivity (α) are measured directly, and volumetric heat capacity (VHC) is determined by the relationship:5.3 The test method is transient and requires only a small amount of specimen and a short duration of time (0.8 s) to run a measurement. These attributes minimize heat convection in the liquid.5.4 The brief application of current to the sensor wire adds very little heat to the test specimen and ten repetitive tests may be applied at 30 s intervals without causing any significant convection or temperature drift.1.1 This test method covers the use of a transient hot wire liquid thermal conductivity method and associated equipment (the System) for the determination of thermal conductivity, thermal diffusivity and volumetric heat capacity of aqueous engine coolants, non-aqueous engine coolants, and related fluids. The System is intended for use in a laboratory.1.2 The System directly measures thermal conductivity and thermal diffusivity without the requirement to input any additional properties. Volumetric heat capacity is calculated by dividing the thermal conductivity by the thermal diffusivity of the sample measured.1.3 This test method can be applied to any aqueous or non-aqueous engine coolants or related fluid with thermal conductivity in the range of 0.1 to 1.0 W/m∙K.1.4 This test method excludes fluids that react with platinum.1.5 The range of temperatures applicable to this test method is –20 to 100 °C.1.6 This test method requires a sample of approximately 40 mL.1.7 The System may be used without external pressurization for any fluid having a vapor pressure of 33.8 kPa (4.9 psia) or less at the test temperature.1.8 For a fluid having a vapor pressure greater than 33.8 kPa (4.9 psia) at the test temperature, external pressurization is required (see Annex A2).1.9 The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are provided for information only and are not considered standard.1.10 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.1.11 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

A1.2 A1.2.1 These tests and requirements are used to evaluate loading and operating procedures; verify the accuracy of proportioning and indicating systems; and determine if mixing uniformity has been degraded by excessive wear or by accumulations of hardened concrete, or both (Note A1.1).NOTE A1.1: The method of loading the batching-mixing unit, proper maintenance, and other factors may have an effect on the ability of the unit to produce uniformly mixed concrete. For this reason, the use of this test method not only measures the efficiency of the mixer, but also the combined effect of the method of loading and operating the unit.A1.2.2 This annex provides additional procedures and cautions that are necessary in the application of existing test methods and practices when used to determine the uniformity of freshly mixed concrete.AbstractThis specification covers concrete made by volumetric batching and continuous mixing. Requirements for quality of concrete shall be either as hereinafter specified or as specified by the purchaser. When the requirements of the purchaser differ from this specification, the purchaser's specification shall govern. This specification does not cover the placement, consolidation, finishing, curing, or protection of the concrete after delivery to the purchaser. Tests and criteria for batching accuracy and mixing efficiency are specified herein. Materials such as cement, aggregates, water, ground granulated blast-furnace slag, air-entraining admixtures, and chemical admixtures shall conform to the requirements covered in this specification. The material shall be subjected to the following test methods: compression test specimens; compression tests; yield; unit weight; air content; slump; and temperature.1.1 This specification covers concrete made from materials continuously batched by volume, mixed in a continuous mixer, and delivered to the purchaser in a freshly mixed and unhardened state as hereinafter specified. Requirements for quality of concrete shall be either as hereinafter specified or as specified by the purchaser. When the requirements of the purchaser differ from this specification, the purchaser's specification shall govern. This specification does not cover the placement, consolidation, finishing, curing, or protection of the concrete after delivery to the purchaser. Tests and criteria for batching accuracy and mixing efficiency are specified herein.1.2 The values stated in either SI units, shown in brackets, 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 nonconformance with the standard.1.3 This specification references notes and footnotes which provide explanatory material. These notes and footnotes (excluding those in tables and figures) shall not be considered as requirements of this specification.1.4 This standard does not purport to address all 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. (Warning—Fresh hydraulic cementitious mixtures are caustic and may cause chemical burns to skin and tissue upon prolonged use.2)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 This test method sets forth a procedure by which duplicate catalyst samples can be compared either on an interlaboratory or intralaboratory basis. It is anticipated that catalyst producers and users will find this test method of value.4.2 Discrimination of the samples for which this procedure is recommended must be exercised when considering carrier (support) materials that sorb appreciable quantities of hydrogen or could cause an alteration of the state of the catalyst during pretreatment, or both, (that is, sintering or metal occlusion). These materials must be identified by the user and experimented with to determine the most significant conditions of measurement.4.3 This test method provides a measure of the total hydrogen uptake (volume of hydrogen at STP, cm3/g of catalyst) without specifying the nature of the hydrogen-platinum interaction. Persons interested in using hydrogen uptake data to calculate percent platinum dispersion in a specific catalyst should be aware of carrier (support) interactions, spillover effects, and other phenomena related to the hydrogen uptake capabilities of the catalyst in question.1.1 This test method covers the determination of the chemisorption of hydrogen at 298 K (25 °C) on supported platinum catalysts that have been reduced in flowing hydrogen at 723 K (450 °C). It incorporates a static volumetric vacuum technique at constant volume.1.2 The test method is intended for use on unused supported platinum on alumina catalysts of loadings greater than 0.3 weight %. Data on other supports and lower platinum loadings were not tested.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： 590元 / 折扣价： 502 元 加购物车

4.1 This test method covers the determination of the air content of freshly mixed concrete. It measures the air contained in the mortar fraction of the concrete, but is not affected by air that may be present inside porous aggregate particles.4.1.1 Therefore, this is the appropriate test to determine the air content of concretes containing lightweight aggregates, air-cooled slag, and highly porous or vesicular natural aggregates.4.2 This test method requires the addition of sufficient isopropyl alcohol, when the meter is initially being filled with water, so that after the first or subsequent rollings little or no foam collects in the neck of the top section of the meter. If more foam is present than that equivalent to 2 % air above the water level, the test is declared invalid and must be repeated using a larger quantity of alcohol. Addition of alcohol to dispel foam any time after the initial filling of the meter to the zero mark is not permitted.4.3 The air content of hardened concrete may be either higher or lower than that determined by this test method. This depends upon the methods and amounts of consolidation effort applied to the concrete from which the hardened concrete specimen is taken; uniformity and stability of the air bubbles in the fresh and hardened concrete; accuracy of the microscopic examination, if used; time of comparison; environmental exposure; stage in the delivery, placement and consolidation processes at which the air content of the unhardened concrete is determined, that is, before or after the concrete goes through a pump; and other factors.1.1 This test method covers determination of the air content of freshly mixed concrete containing any type of aggregate, whether it be dense, cellular, or lightweight.1.2 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The inch-pound units are shown in brackets. 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.1.3 The text of this standard references notes and footnotes that provide explanatory information. These notes and footnotes (excluding those in tables and figures) shall not be considered as requirements of 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use. (Warning—Fresh hydraulic cementitious mixtures are caustic and may cause chemical burns to skin and tissue upon prolonged exposure.2)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

This specification covers general requirements for laboratory glass volumetric apparatus of Class A and B. The volumetric apparatus shall be manufactured from glass of suitable chemical and thermal properties, and shall be as free as possible from visible defects. Glasswares with a flat base shall stand firmly without rocking when placed on a level surface. For those requiring stoppers and stopcocks, glass stoppers shall be interchangeable while plastic stoppers used as alternative to glass ones shall be of inert plastic material. Stopcocks, on the other hand, shall permit smooth and precise control of outflow. Glasswares shall have clean, permanent graduation lines of uniform thickness confined to the cylindrical portions of their cross section, with the graduations lines being of Pattern I, II, or III and the unit of volume being cubic centimetre. Units of cubic decimeter or cubic millimetre may be used in special cases; however, only one unit of volume shall be used on the same piece of apparatus. Aside from graduation lines, the glassware shall bear inscriptions of the capacity, the temperature at which it is to be used, the method of use (whether to contain or to deliver), and for those that deliver though an outflow nozzle, the time required to empty the total nominal capacity with unrestricted outflow. Per service requirement, additional provisions may be specified as well.1.1 This specification covers general requirements common to glass volumetric apparatus. Specific dimensions and tolerances for applicable instruments are given in other specifications as cited throughout this specification. Glass must conform to Specifications E438 and be calibrated in accordance with Practice E542.1.1.1 Class A—Each instrument shall be marked with the letter A to signify compliance with applicable construction and accuracy requirements. Instruments may be marked with an identification marker (serial number) at the option of the manufacturer.1.1.2 Class B—General purpose instruments are of the same basic design as Class A. However, volumetric tolerances for Class B instruments shall be within twice the specified range allowed for Class A unless otherwise specified.1.2 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 piston or plunger operated volumetric apparatus (POVA), in particular, the requirements, operating conditions, and test methods. POVA covered by this specification are pipettes, dispensers (with and without valve), dilutors, and displacement burets (with and without valve). Single measurement, replicate delivery, durability, functional (such as tests for leakage, broken parts, existence of air bubbles, and contamination), volumetric, and gravimetric tests shall be performed and shall conform to the requirements specified.1.1 This specification covers requirements, operating conditions, and test procedures for piston or plunger operated volumetric apparatus (POVA), as well as requirements for pipette operator training and qualification.1.2 This specification is applicable to all types of POVA. The following precautionary caveat pertains only to the test procedure portion, Annex A1 and Annex A2, 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.1.3 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： 646元 / 折扣价： 550 元 加购物车

5.1 The volumetric flow rate is a measure of the flow characteristics of a metal powder. Measuring flow by volume compared with flow per unit mass eliminates the variable of the powder density and relates to the production practice of die filling by volume.5.2 The ability of a powder to flow and pack is a function of interparticle friction. As the surface area increases, the amount of friction in a powder mass also increases. Consequently, the friction between particles increases, giving less efficient flow and packing.5.3 Knowledge of the volumetric flow rate permits the part producer to estimate the number of parts that can be compacted per hour.5.4 This test may be part of the purchase agreement between metal powder producers and powder metallurgy (PM) part producers, or it can be an internal quality control test for any company using metal powders.1.1 This test method covers a laboratory procedure for the quantitative determination of the flow rate of a specific volume of a free-flowing metal powder or lubricated powder mixture.1.2 Units—With the exception of the values for mass, volume, and density, for which the use of the gram and the cubic centimetre unit is long-standing industry practice, 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： 515元 / 折扣价： 438 元 加购物车

5.1 Post dispensing volumetric expansion factor F indicates the ratio of the fully cured foam sealant volume and the initially dispensed foam sealant volume. For example, if the expansion factor F were 2, the fully cured foam would double its initial volume; therefore, one should fill 50 % of the cavity uniformly to anticipate the full coverage upon curing.5.2 Post dispensing volumetric expansion factor F does not predict the performance capability of the foam sealants of the suitability for the intended applications.5.3 This test method is intended to lend guidance in product selection as related to the post dispensing expansion characteristics of the aerosol foam sealants.5.4 This test method recognizes that the results are reflective of controlled laboratory conditions. Post dispensing expansion in field applications may vary according to temperature, humidity, and surfaces that the aerosol foam sealants are in contact with.1.1 This test method measures the volumetric expansion of aerosol foam sealants after dispensing.1.2 This test method provides a means for estimating the quantity of initial material required to dispense in order to fill a cavity.1.3 Aerosol foam sealants are used for a variety of applications intended to reduce airflow through the building envelope.1.4 This test method applies to two types of single component aerosol foam sealants: polyurethane and latex.1.5 There are no other known standard test methods to measure aerosol foam sealants post dispensing expansion.1.6 Values are reported in SI units only. Certain apparatus and supply items are referenced in inch-pound units for purchasing purposes.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