3.1 Alumina-silica refractory brick is produced from various combinations of alumina and silica-containing materials. These bricks can vary in chemical composition from almost 100 % alumina and little silica to almost 100 % silica and little alumina. It is therefore useful to establish a classification scheme based on physical properties and chemical analysis. One group, fireclay brick, is classified based on physical properties since some overlap of alumina and silica content can occur. A second group, high-alumina brick, is classified primarily based on alumina content. The classification allows those familiar with refractory materials to group similar products from various suppliers in a standard and consistent manner.1.1 This classification covers machine-made fireclay and high-alumina refractory brick, and its purpose is to set forth the various classes and types of these materials in accordance with their normal and characteristic properties, which are important in their use.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 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.

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4.1 This test environment is believed to give an accelerated ranking of the relative or absolute degree of stress-corrosion cracking susceptibility for different brasses. It has been found to correlate well with the corresponding service ranking in environments that cause stress-corrosion cracking which is thought to be due to the combined presence of traces of moisture and ammonia vapor. The extent to which the accelerated ranking correlates with the ranking obtained after long-term exposure to environments containing corrodents other than ammonia is not at present known. Examples of such environments may be severe marine atmospheres (Cl−), severe industrial atmospheres (predominantly SO2), and super-heated ammonia-free steam.4.2 It is not possible at present to specify any particular time to failure (defined on the basis of any particular failure criteria) in pH 7.2 Mattsson’s solution that corresponds to a distinction between acceptable and unacceptable stress-corrosion behavior in brass alloys. Such particular correlations must be determined individually.4.3 Mattsson's solution of pH 7.2 may also cause stress independent general and intergranular corrosion of brasses to some extent. This leads to the possibility of confusing stress-corrosion failures with mechanical failures induced by corrosion-reduced net cross sections. This danger is particularly great with small cross section specimens, high applied stress levels, long exposure periods and stress-corrosion resistant alloys. Careful metallographic examination is recommended for correct diagnosis of the cause of failure. Alternatively, unstressed control specimens may be exposed to evaluate the extent to which stress independent corrosion degrades mechanical properties.1.1 This practice covers the preparation and use of Mattsson’s solution of pH 7.2 as an accelerated stress-corrosion cracking test environment for brasses (copper-zinc base alloys). The variables (to the extent that these are known at present) that require control are described together with possible means for controlling and standardizing these variables.1.2 This practice is recommended only for brasses (copper-zinc base alloys). The use of this test environment is not recommended for other copper alloys since the results may be erroneous, providing completely misleading rankings. This is particularly true of alloys containing aluminum or nickel as deliberate alloying additions.1.3 This practice is intended primarily where the test objective is to determine the relative stress-corrosion cracking susceptibility of different brasses under the same or different stress conditions or to determine the absolute degree of stress corrosion cracking susceptibility, if any, of a particular brass or brass component under one or more specific stress conditions. Other legitimate test objectives for which this test solution may be used do, of course, exist. The tensile stresses present may be known or unknown, applied or residual. The practice may be applied to wrought brass products or components, brass castings, brass weldments, and so forth, and to all brasses. Strict environmental test conditions are stipulated for maximum assurance that apparent variations in stress-corrosion susceptibility are attributable to real variations in the material being tested or in the tensile stress level and not to environmental variations.1.4 This practice relates solely to the preparation and control of the test environment. No attempt is made to recommend surface preparation or finish, or both, as this may vary with the test objectives. Similarly, no attempt is made to recommend particular stress-corrosion test specimen configurations or methods of applying the stress. Test specimen configurations that may be used are referenced in Practice G30 and STP 425.21.5 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. (For more specific safety hazard statements see Section 8.)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.

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1.1 Scope This part of IEC 71 constitutes an application guide and deals with the selection of insulation levels of equipment or installations for three-phase electrical systems. Its aim is to give guidance for the determination of the rated withstand

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4.1 When two dissimilar metals in electrical contact are exposed to a common electrolyte, one of the metals can undergo increased corrosion while the other can show decreased corrosion. This type of accelerated corrosion is referred to as galvanic corrosion. Because galvanic corrosion can occur at a high rate, it is important that a means be available to alert the user of products or equipment that involve the use of dissimilar metal combinations in an electrolyte of the possible effects of galvanic corrosion.4.2 One method that is used to predict the effects of galvanic corrosion is to develop a galvanic series by arranging a list of the materials of interest in order of observed corrosion potentials in the environment and conditions of interest. The metal that will suffer increased corrosion in a galvanic couple in that environment can then be predicted from the relative position of the two metals in the series.4.3 Types of Galvanic Series: 4.3.1 One type of Galvanic Series lists the metals of interest in order of their corrosion potentials, starting with the most active (electronegative) and proceeding in order to the most noble (electropositive). The potentials themselves (versus an appropriate reference half-cell) are listed so that the potential difference between metals in the series can be determined. This type of Galvanic Series has been put in graphical form as a series of bars displaying the range of potentials exhibited by the metal listed opposite each bar. Such a series is illustrated in Fig. 1.4.4 Use of a Galvanic Series: 4.4.1 Generally, upon coupling two metals in the Galvanic Series, the more active (electronegative) metal will have a tendency to undergo increased corrosion while the more noble (electropositive) metal will have a tendency to undergo reduced corrosion.4.4.2 Usually, the further apart two metals are in the series, and thus the greater the potential difference between them, the greater is the driving force for galvanic corrosion. All other factors being equal, and subject to the precautions in Section 5, this increased driving force frequently, although not always, results in a greater degree of galvanic corrosion.1.1 This guide covers the development of a galvanic series and its subsequent use as a method of predicting the effect that one metal can have upon another metal can when they are in electrical contact while immersed in an electrolyte. Suggestions for avoiding known pitfalls are included.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. Specific precautionary statements are given in Section 5.1.4 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.

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Specifies the cryptographic functions for establishing symmetric keys using a lattice-based polynomial public key encryption algorithm and the associated parameters for key generation (see Note 1). The mechanism supported is key transport, where one party selects keying material and conveys it to the other party with cryptographic protection. The keying material may consist of one or more individual keys used to provide other cryptographic services outside the scope of this Standard, e.g. data confidentiality, data integrity, or symmetric-key-based key establishment. The standard also specifies key pair generators and corresponding key pair validation methods supporting the key transport schemes

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1. Scope 1.1 This Guide covers the consideration of environmental impacts in product standards. It is intended for standard w riters; its purpose is (a) to raise awareness that provisions in product standards can affect the environment in both nega

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This PDF includes GI #2. 1. Scope This Specification is intended to apply to power-operated radio transmitting equipment designed to be used on standard supply circuits in accordance with the rules of Part I of this Code. This will include all typ

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