定价： 1333元 / 折扣价： 1134 元 加购物车

This specification covers manufacturing and joining requirements for peelable or skinned polyethylene (PE) pipe, which is PE pipe meeting the requirements of Specification D2513, with a peelable outer layer of polypropylene (PP). The peelable PP layer does not contribute to outside diameter and wall thickness used for pressure rating or tensile loading calculations.1.1 This standard specification covers manufacturing and joining requirements for peelable (skinned) polyethylene (PE) pipe, which is PE pipe meeting the requirements of Specification D2513, with a peelable outer layer of polypropylene (PP). These requirements are in addition to those in Specification D2513 for the PE pipe.1.2 The peelable PP layer does not contribute to outside diameter and wall thickness used for pressure rating or tensile loading calculations.1.3 The text of this standard references notes and footnotes which provide explanatory material. These notes and footnotes (excluding those in figures and tables) shall not be considered as requirements of the standard.1.4 Units—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.1.5 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

4.1 The United Nations Committee of Experts on the Transport of Dangerous Goods in their recommended regulations place materials having a flash point below 23 °C (73.5 °F) in Packing Group II. However, if viscous substances such as paint and related coatings, adhesives, polishes, etc., meet certain requirements, they can be placed in Group III along with materials having a flash point between 23 °C and 60.5 °C (73.5 °F and 140 °F). One of the requirements is that less than 3 % of clear liquid separates from the bulk of the material when subjected to this test method.4.2 At the present time most international regulatory bodies such as the International Civil Aviation Organization (ICAO) and the International Maritime Organization (IMO) use the U.N. Recommendations. It is anticipated that most national transportation regulatory bodies will adopt the U.N. Recommendations as their regulations for control of transportation of hazardous materials. At present the United States permits the transshipment of hazardous materials through the United States to other countries under regulations of the IMO and ICAO.1.1 This test method covers the determination of the amount of liquid separated as an upper layer in a 24-h period from viscous solutions or dispersions that contain dispersed solids such as paints, enamels, pigmented lacquers, adhesives, polishes, and other similar materials.NOTE 1: The amount of clear liquid that separates during this test is one of the criteria in the United Nations Recommendations on the Transportation of Dangerous Goods2 for the placement of flammable viscous liquids into packing groups related to flash points (See 4.1).1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.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

定价： 1775元 / 折扣价： 1509 元

定价： 1411元 / 折扣价： 1200 元

This specification covers electrically insulating, unbleached sulfate paper and paperboard used as layer insulation in coils, transformers, and other similar apparatus. The materials may also be used as turn insulation, slot liners, wedges, phase insulation, and separator papers in stranded wire/cable constructions. This specification does not include tissue for manufacture of capacitors. Other commonly used terms for the materials include soft coil wrap, dense coil wrap, kraft coil insulation, dry-finished kraft, and water-finished kraft. The materials covered in this specification are classified into four types according to density range and nominal thickness and should conform to the required values of ash content, alcohol-soluble material content, aqueous extract conductivity, water-soluble chloride content, fiber composition, moisture content, hydrogen ion concentration, pH, tensile strength, dielectric breakdown voltage, and conducting paths.1.1 This specification covers electrical grade unsized, unbleached sulfate paper and paperboard for use as layer insulation in coils, transformers, and similar apparatus. Other applications include, but are not limited to, turn insulation, slot liners, wedges, phase insulation, and separator papers in stranded wire/cable constructions. Tissue for the manufacture of capacitors is not included in this specification. Other commonly used designations include:1.1.1 Soft Coil Wrap,1.1.2 Dense Coil Wrap,1.1.3 Kraft Coil Insulation,1.1.4 Dry-Finished Kraft, and1.1.5 Water-Finished Kraft.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.

定价： 515元 / 折扣价： 438 元 加购物车

1.1 This test method covers the radial sectioning technique 2,3,4 for measurement of the thickness of thin surface layers, made by a wide variety of processes, on metals, alloys, carbides, and oxides. 1.2 This test method is applicable to measurement of a wide variety of surface layer types where the interface between the layer and substrate is discernible by natural color or reflectivity differences or by means of color or reflectivity differences due to etching or staining. 1.3 This test method does not pertain to layer thickness measurements made by analysis of compositional variations. 1.4 This test method deals only with the recommended test method and nothing in it should be construed as defining or establishing limits of acceptability for any coating method. 1.5 The measurement values stated are in the metric system, as defined in Standard E380. 1.6 This standard may involve hazardous materials, operations, and equipment. This standard does not purport to address all of the safety problems 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. For specific precautionary statements, see Section 7.

定价： 0元 / 折扣价： 0 元

1.1 This provisional specification defines the Open Systems Interconnection (ISO7498 : 1984) Layer 2 data link layer for dedicated short-range communication (DSRC) equipment operating in half-duplex mode.1.1.1 This provisional specification defines the Data Link Layer irrespective of the physical medium to be used. However, it is expected that the standard will be used in accordance with a three layer stack as defined by Subcommittee E17.51 and IEEE P1455 and illustrated in . A critical implication of the use of the Data Link Layer standard with PS 111 is the assumption that the data rate will be 500 Kbps on both the uplink and downlink.1.1.2 This provisional specification specifies dedicated short range communications between fixed equipment at the roadside, called a beacon or Road Side Equipment (RSE) and Mobile Equipment in vehicles, called a Transponder or On-Board Equipment (OBE). This standard does not address vehicle-to-vehicle communication or communication between different instances of RSE.1.1.3 This provisional specification adheres to the general DSRC architecture in which the RSE controls the medium, allocating its use to OBEs within range of the RSE.1.1.4 This provisional specification supports a variety of RSE configurations. It supports configurations where one RSE communicates with one OBE, as well as configurations where one RSE can communicate with several OBEs. It does not define any specific configuration or layout of the communication zone.1.1.5 This provisional specification does not define to what extent different instances of RSE, operating in the vicinity of each other, need to be synchronised with each other.1.1.6 This provisional specification defines parameters to be used in negotiation procedures taking place between RSE and OBE.1.1.7 This provisional specification defines the following:Medium access control (MAC) procedures for the shared physical medium,Addressing rules and conventions,Data flow control procedures,Acknowledgement procedures,Error control procedures,Services provided to data link user(s), andFragmentation.1.1.8 There are two primary MAC modes, synchronous and asynchronous. Both modes support time-division multiple access half-duplex communications combined with a slotted aloha protocol for activation. The synchronous mode is characterized by a contiguous set of slots which is transmitted continuously and has fixed polling, data communications and activation phases. The asynchronous mode can vary the transmission of polling sequences, activation attempts or data communications.1.1.9 This provisional specification assumes that each RSE covers a limited part of the road (the communication zone) and that the OBE communicates with the RSE while passing through the communication zone.1.1.10 This provisional specification specifies the services required of the data link layer by the DSRC data link layer user, as viewed from the data link layer user, to allow a data link layer user entity to exchange packets with remote peer data link layer user entities. The services do not imply any particular implementation or any exposed interface.1.1.11 Not discussed in this provisional specification are signals that must be passed through the Data Link Layer from the Physical Layer to the Application Layer or vice versa in the OBE. These signals include indications of exceeding the wake-up threshold level (to control the OBE response in a small zone) and no carrier (to permit graceful shut down of the OBE if the OBE unexpectedly loses communications). It will be necessary to consider the implementation of these signals in OBE design.1.2 Overview1.2.1 All transmissions by either the RSE or OBE shall consist of a preamble and a frame. A preamble is an eight-bit sequence used for bit synchronization and is specified in Layer 1. A frame is a data link layer entity, which is the result of encapsulation of an application protocol data unit. The generic encapsulation process is shown in .1.2.2 An APDU is delivered from the application layer to the data link layer. If the APDU cannot be sent in a single transmission, then it is subdivided into multiple packets. Each packet is then converted into an LPDU by appending a byte count, fragmentation and logical link control and status field to the beginning of each packet. The frame is then formed by appending a link address field, and media access control field to the beginning and a error detection check field to the end of each LPDU. Each frame is then sent to the physical layer, which appends the preamble and then transmits the data.1.2.3 The frames can be transmitted in one of two modes: synchronous or asynchronous. In the synchronous mode, frames are transmitted in one of three types of slots: frame control message, message data or activation. The slots are combined to form a continuously repeated TDMA frame, as shown in . Each TDMA frame begins with a frame control message slot (FCMS). The FCMS only contains a frame control frame which is a broadcast message from the RSE indicating the number of slots, the type of each slot and the size of the slots that compose the rest of the TDMA frame. For example, in , the frame control frame defines a TDMA frame composed of three additional slots, two slots for data transmission and the other slot for activation. The message data slot (MDS) contains a data message frame transmitted over either the downlink to a specific OBE or uplink from a specific OBE. In addition, there is an acknowledgement transmitted immediately after the data message frame in the opposite direction. The activation slot (ACTS) consists of activation windows which are time periods when any OBE is allowed to transmit in contention with other OBEs in order to attempt to activate. It is not necessary to have an activation slot in a TDMA frame.1.2.4 Assuming link establishment requires the transmission of a beacon service table (BST) from the RSE and negotiation of link parameters using a vehicle service table (VST), provides an example of a full link negotiation followed by a read/write operation in synchronous mode. (Note that the full link negotiation can be shortened to reduce the number of TDMA frames needed to complete a transaction.) In TDMA Frame #1, the OBE receives a BST from the RSE and decides to activate. The activation is also transmitted in TDMA Frame #1. In TDMA Frame #2, the frame control frame designates a downlink message data slot to obtain the VST. After the OBE transmits the VST in TDMA Frame #2, the RSE commands the OBE to support a read in TDMA Frame #3. In TDMA Frame #4, the frame control frame designates an uplink message data slot to read the data. In TDMA Frame #5, the frame control frame designates a downlink message data slot to write data to the OBE. A corresponding acknowledgement is transmitted by the OBE.1.2.5 In the asynchronous mode, communications with an OBE is always initiated with a frame control frame which is regularly broadcast by the RSE. Immediately following the frame control frame are a series of activation windows. The timing and structure of the frame control frame and activation windows can be made common to both synchronous and asynchronous operations (to minimize the differences between the two modes). It is expected that the frame control frame and the activation windows will be transmitted (or time allocated) periodically so that the RSE can poll its read zone for OBEs. When an OBE successfully activates, the RSE discontinues transmissions of the frame control frame to establish private communications with the OBE. These communications can occur asynchronously, that is, without a TDMA frame dividing time into slots. In addition, the specific sequence of frames transmitted is dependent entirely on the application layer. Once the private communications is completed, the RSE would then continue to poll using the frame control frame and activation windows. Note that opportunities to transmit on the downlink and uplink in the asynchronous mode are defined by windows which provide constraints on the start and end times for any frame transmissions. An activation window is a special case of an uplink window.1.2.6 As above, assuming link establishment requires the transmission of a beacon service table (BST) from the RSE and negotiation of link parameters using a vehicle service table (VST), provides an example of a typical read/write operation in asynchronous operation.1.2.7 Like the synchronous mode, the OBE receives the BST from the RSE and attempts to activate. The activation frame is transmitted in activation windows that immediately follow the frame control frame. Once the activation is established, the RSE commands the OBE to transmit a VST and allocates an uplink window for the OBE to transmit the VST. After the VST is received, the RSE commands the OBE to support a read and allocates an uplink window for the OBE to transmit the read response. The OBE transmits the data. Then, the RSE writes data to the OBE and receives a reply that the write was successfully completed.Note 1Provisional Standards require only subcommittee consensus and are published for a limited time of two years. The provisional process was used because it is anticipated that the United States Department of Transportation will be referring to this provisional specification in their rule making.

定价： 0元 / 折扣价： 0 元

4.1 This classification is intended to encourage uniformity in reporting properties of MLS and Metal Layer gaskets, to provide a common language for communications between producers and users, and to guide engineers and designers in the application and construction of commercially available gaskets.(A) This classification may also be used to classify Single Layer Steel (SLS) Gaskets.(B) Refer to Specification A666 or Specification A109/A109M for Stainless Steel and Low Carbon Steel, respectively. Other metals not referenced in the table or not covered by Specification A666 or Specification A109/A109M must be defined by the producer/user (that is, H – High Temperature Alloy).(C) Refer to Practice D1418 for general information regarding rubber coating types and use Classification D2000 to define the physical properties of the rubber. This physical property information is typically specified on the gasket drawing or the customer specification, or both.(D) Coated side as specified on part drawing.4.2 Suffix Table 2 is provided to allow hardness designation for Active, Inactive, or Load Stoppers.4.2.1 If suffixes are not to be used, only the basic callout from Table 1 is required. If a suffix is used for 1 layer, it must be specified for all layers, even if a “0” is used. It cannot be assumed that hardnesses of like layers are the same; if used, all layers must be specified separately. The first layer specified must be indicated on the part drawing. To use a hardness call-out, at the end of the base callout leave a space followed by the “HR” suffix with a series of suffix numbers to specify the hardnesses for each layer.4.2.1.1 Example: ASTM F2325, A32ANBW11 HR252—Example from Table 1 modified to add hardness requirement for the three metal layers. Active layers 1 and 3 are designated to be the same, 1/4 hard steel. Stopper layer 2 is designated to be full hard steel.1.1 This classification covers a means for specifying Multi-Layer Steel (MLS) and other Metal Layer Gaskets for Transportation Applications by application and construction. These structures are composed of one or more steel or metal layers of material, which may have coatings or embossments. Commercial materials designated as composite or enveloped gaskets are excluded from this classification and are covered by Classification F868 and Practice F336, respectively.1.2 Since all of the properties that contribute to gasket performance are not included, use of this classification as a basis for selecting an MLS or Metal Layer gasket is limited.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

4.1 One of the functions of a roofing aggregate is to shield the roofing membrane from sunlight that may be destructive to the roofing membrane. This test method measures the quantity of gravel needed to exclude light under arbitrary laboratory conditions. This test method need not be performed if the roofing membrane is not affected by light exposure.1.1 This test method measures the quantity of aggregate needed to provide an opaque layer under laboratory conditions. Aggregate size Numbers 1 through 8, as listed in Classification D448, may be tested.1.2 The values stated in either SI units 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 non-conformance with the 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

3.1 The overall thickness or caliper of resilient flooring is a basic physical property. However, conventional means of measuring the thickness, such as a hand micrometer or regular dial micrometer, are not applicable for foam-layer products due to the error from compressing the foam. This test method minimizes this type of measuring error and still retains the convenience and speed of measurement.3.2 Measurement of the product thickness may be required for quality control purposes or to ensure compliance with applicable specifications.1.1 This test method covers the determination of the thickness of resilient non-textile floor coverings containing a foam layer as part of the construction.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.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 applicable for wear layers with a minimum thickness of 0.001 in. (0.02 mm) to a maximum thickness of 0.1 in. (2.54 mm), where measurements within 0.0005 in. or 0.01 mm are tolerable.1.1 This test method covers the determination of the thickness of the wear layer of resilient non-textile floor coverings, in tile or sheet form, with or without felt backing or foam layer, by optical measurement.1.2 This test method is applicable for wear layers with a minimum thickness of 0.0004 in. (0.01 mm) to a maximum thickness of 0.1 in. (2.54 mm), where measurements within 0.0001 in. or 0.0025 mm are tolerable.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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.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： 515元 / 折扣价： 438 元 加购物车

This specification covers dedicated short range communication (DSRC) physical layer using microwave in the 902 to 928 MHz band, it defines the open systems interconnection (OSI) layer 1, physical layer, for dedicated short-range communications equipment, operating in two-way, half-duplex, active and backscatter modes. The relevant downlink physical layer or OSI layer 1 parameters and the relevant uplink DSCR layer 1 parameters are presented in details. The interface parameters to DSCR data link layer are also presented.1.1 Purposes1.1.1 This specification defines the Open Systems Interconnection (OSI) layer 1, physical layer, for dedicated short-range communications (DSRC) equipment, operating in two-way, half-duplex, active and backscatter modes.1.1.2 This specification establishes a common framework for the physical layer in the 902 to 928 MHz LMS band. This band is allocated for DSRC applications by the FCC in Title 47, Code of Federal Regulations (CFR), Part 90, Subpart M and by Industry Canada in the Spectrum Management, Radio Standard Specification, Location and Monitoring Service (902-928 MHz), RSS-137.1.1.3 This specification defines an air interface for both wide-area (multi-lane, open road) and lane-based applications that enables accurate and valid message delivery between moving vehicles randomly entering a communications zone and fixed roadside communication equipment. This air interface also enables accurate and valid message delivery between moving or stationary vehicles and fixed or portable roadside communication equipment.1.1.4 This specification does not include associated measurement guidelines for verification of the formulated requirements in this specification. It is intended that readers will be able to refer to the ASTM standard on Technical Characteristics and Test Methods for Data Transmission Equipment Operating in the 902 to 928 MHz LMS Band for the measurement guidelines, when it is developed.1.1.5 This specification does not consider any one specific ITS application, but rather describes a communication means to be used by several ITS applications. This specification also may be used for any non-roadway environment that can utilize this type of dedicated short-range radio communication.1.1.6 While this specification defines frequencies and power levels that are compatible with the North American regulatory requirements, the technical methodology used in their selection can be utilized in other regions of the world.1.2 Equipment1.2.1 The DSRC equipment is composed of two principle components: road-side equipment (RSE) and on-board equipment (OBE) or transponder.1.2.2 The RSE controls the protocol, schedules the activation of the OBE, reads from or writes to the OBE, and assures message delivery and validity. It is intended for, but not restricted to, installation at a fixed location on the roadway.1.2.3 The OBE communicates with the RSE and is intended for, but not restricted to, installation in or on a motor vehicle.1.2.4 The RSE must be capable of communicating with closely spaced OBE in the same lane or closely spaced OBE in adjacent lanes.1.2.5 This specification provides requirements for the communication medium to be used for exchange of information between RSE and OBE. Active, backscatter, and dual-mode technologies are described.1.3 Structure1.3.1 This specification defines an open (non-proprietary) architecture using the simplified OSI seven-layer reference model (per ISO 7498). The following sub-section describe the relationships of the OSI layers that support DSRC.1.3.1.1 The physical layer (Layer 1) is defined as a half-duplex radio frequency medium, in the 902 to 928 MHz band. Layer 1 interfaces with Layer 2.1.3.1.2 The data link control layer (Layer 2) defines a Time Division Multiple Access (TDMA) messaging protocol in which both the downlink and uplink are completely controlled by the RSE. The data link control layer provides a mechanism to ensure reliable completion of each transaction in the communications zone. This layer includes data organization, sequence control, flow control, error detection and error recovery among other functions. Layer 2 interfaces with Layer 7.1.3.1.3 The application layer (Layer 7) defines specific functions and message formats to support ITS and other services. Implicit or pre-set message formats may be used. Data encryption, data certification, and manual OBE and RSE authentication may be performed.1.3.1.4 The functions of the network layer (Layer 3), transport layer (Layer 4), session layer (Layer 5), and presentation layer (Layer 6) are included where necessary in Layer 2 or Layer 7.1.3.2 The physical layer communications requirements for the signals sent from the RSE in the OBE are accounted for as downlink parameters. The requirements associated with the signals sent from the OBE to the RSE are accounted for as uplink parameters.1.3.3 Physical layer requirements related to the interface to other DSRC communications layers are accounted for in .1.4 The values stated in SI units are to be regarded as the standard.

定价： 0元 / 折扣价： 0 元

1.1 Scope For the purpose of compatible interconnection of data processing equipment via a local area network(LAN) using the token ring access method, this part of ISO/IEC 8802 a)Provides a general description of the token ring local area network (L

定价： 2366元 / 折扣价： 2012 元

Foreword to ISO/IEC 8802-5 : 1998/Amd. 1: 1998 This International Standard is part of a family of International Standards for Local and Metropolitan Area Networks. This family of International Standards deals with the Physical and Data Link layers a

定价： 2958元 / 折扣价： 2515 元