定价： 1177元 / 折扣价： 1001 元

定价： 975元 / 折扣价： 829 元

定价： 975元 / 折扣价： 829 元

定价： 819元 / 折扣价： 697 元

定价： 975元 / 折扣价： 829 元

定价： 1333元 / 折扣价： 1134 元 加购物车

5.1 This guide provides a protocol for detecting, characterizing, and quantifying nucleic acids (that is, DNA) of living and recently dead microorganisms in fuels and fuel-associated waters by means of a culture independent qPCR procedure. Microbial contamination is inferred when elevated DNA levels are detected in comparison to the expected background DNA level of a clean fuel and fuel system.5.2 A sequence of protocol steps is required for successful qPCR testing.5.2.1 Quantitative detection of microorganisms depends on the DNA-extraction protocol and selection of appropriate oligonucleotide primers.5.2.2 The preferred DNA extraction protocol depends on the type of microorganism present in the sample and potential impurities that could interfere with the subsequent qPCR reaction.5.2.3 Primers vary in their specificity. Some 16S and 18S RNA gene regions present in the DNA of prokaryotic and eukaryotic microorganisms appear to have been conserved throughout evolution and thus provide a reliable and repeatable target for gene amplification and detection. Amplicons targeting these conserved nucleotide sequences are useful for quantifying total population densities. Other target DNA regions are specific to a metabolic class (for example, sulfate reducing bacteria) or individual taxon (for example, the bacterial species Pseudomonas aeruginosa). Primers targeting these unique nucleotide sequences are useful for detecting and quantifying specific microbes or groups of microbes known to be associated with biodeterioration.5.3 Just as the quantification of microorganisms using microbial growth media employs standardized formulations of growth conditions enabling the meaningful comparison of data from different laboratories (Practice D6974), this guide seeks to provide standardization to detect, characterize, and quantify nucleic acids associated with living and recently dead microorganisms in fuel-associated samples using qPCR.NOTE 3: Many primers, and primer and probe combinations that are not covered in this guide may be used to perform qPCR. This guide does not attempt to cover all of the possible qPCR assays and does not suggest nor imply that the qPCR assays (that is, combinations of primers and probes, and reaction conditions) discussed here are better suited for qPCR than other qPCR assays not presented here. Additional, primers, primers and probes combination, and qPCR assay conditions may be added in the future to this guide as they become available to the ASTM scientific community. Guide D6469 reviews the types of damage that uncontrolled microbial growth in fuels and fuel systems can cause.5.4 Culture-based microbiological tests depend on the ability of microbes to proliferate in liquid, solid or semisolid nutrient media, in order for microbes in a sample to be detected.5.5 There is general consensus among microbiologists that only a fraction of the microbes believed to be present in the environment have been cultured successfully.5.6 Since the mid-1990s, genetic test methods that do not rely on cultivation have been increasingly favored for the detection and quantification of microorganisms in environmental samples.5.7 qPCR is a quantitative, culture-independent method that is currently used in the medical, food, and cosmetic industries for the detection and quantification of microorganisms.5.8 Since the early 2000s, qPCR methodology has evolved and is now frequently used to quantify microorganisms in fuel-associated samples, but there is currently no standardized methodology for employing qPCR for this application (1-6).3 The purpose of this guide is to provide guidance and standardization for genetic testing of samples using qPCR to quantify total microbial populations present in fuel-associated samples.5.9 Although this guide focuses on describing recommended protocols for the quantification of total microorganisms present in fuel-associated samples using qPCR, the procedures described here can also be applied to the standardization of qPCR assays for other genetic targets and environmental matrices.5.10 Genetic techniques have great flexibility so that it is possible to design a nearly infinite number of methods to detect and quantify each and every gene. Because of this flexibility of genetic techniques, it is important to provide a standard protocol for qPCR so that data generated by different laboratories can be compared.5.11 This guide provides recommendations for primers sequences and experimental methodology for qPCR assays for the quantification of total microorganisms present in fuel-associated samples.1.1 This guide covers procedures for using quantitative polymerase chain reaction (qPCR), a genomic tool, to detect, characterize and quantify nucleic acids associated with microbial DNA present in liquid fuels and fuel-associated water samples.1.1.1 Water samples that may be used in testing include, but are not limited to, water associated with crude oil or liquid fuels in storage tanks, fuel tanks, or pipelines.1.1.2 While the intent of this guide is to focus on the analysis of fuel-associated samples, the procedures described here are also relevant to the analysis of water used in hydrotesting of pipes and equipment, water injected into geological formations to maintain pressure and/or facilitate the recovery of hydrocarbons in oil and gas recovery, water co-produced during the production of oil and gas, water in fire protection sprinkler systems, potable water, industrial process water, and wastewater.1.1.3 To test a fuel sample, the live and recently dead microorganisms must be separated from the fuel phase which can include any DNA fragments by using one of various methods such as filtration or any other microbial capturing methods.1.1.4 Some of the protocol steps are universally required and are indicated by the use of the word must. Other protocol steps are testing-objective dependent. At those process steps, options are offered and the basis for choosing among them are explained.1.2 The guide describes the application of quantitative polymerase chain reaction (qPCR) technology to determine total bioburden or total microbial population present in fuel-associated samples using universal primers that allow for the quantification of 16S and 18S ribosomal RNA genes that are present in all prokaryotes (that is, bacteria and archaea) and eucaryotes (that is, mold and yeast collectively termed fungi), respectively.1.3 This guide describes laboratory protocols. As described in Practice D7464, the qualitative and quantitative relationship between the laboratory results and actual microbial communities in the systems from which samples are collected is affected by the time delay and handling conditions between the time of sampling and time that testing is initiated.1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard with the exception of the concept unit of gene copies/mL (that is, 16S or 18S gene copies/mL) to indicate the starting concentration of microbial DNA for the intended microbial targets (that is, bacteria, archaea, fungi).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 requirements and method of rating and testing for alloy chain slings. Only component parts compatible with alloy chain shall be used. Sling assembled by welding shall be fabricated by the electric or gas welding process, or both. The material shall undergo proof test to meet the prescribed mechanical requirements. Several grades of alloy chain sling shall conform to the specified working load limit values.1.1 This specification covers the requirements and method of rating and testing for alloy chain slings. Slings shall be assembled using components manufactured in accordance with Specification A391/A391M for Grade 80 chain, Specification A973/A973M for Grade 100 chain, and Specification A952/A952M for other components. This specification covers welded and mechanically assembled slings.1.2 This specification does not cover slings used at elevated temperatures (above 400 °F [200 °C]), in harmful or corrosive environmental conditions or for applications such as nonsymmetrical legs or loading.1.3 This specification is a performance and assembly specification. Other standards, such as OSHA 1910.184, ASME B30.9, and ASME B30.10, apply to the use of the products in this specification.1.4 The values stated in either inch-pound units or SI units are to be regarded separately as standard. Within the text, the SI units are shown in brackets. The values stated in each system are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used independently of the other, and values from the two systems shall not be combined.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

1.1 This specification provides the recommended criteria for specifying the construction of barrier systems for restricting access or ensuring human confinement, with the capability of defeating or seriously resisting any breaching attempts.1.2 No recommendation is made or implied as to the merits of the product of any particular manufacturer. Choice of product components selection for the barrier system should be made by the writers of the project based on their own perception of the merits of products for this application.1.3 The values stated in inch-pound units are to be regarded as the standard. The SI values stated in parentheses are provided for information only.

定价： 0元 / 折扣价： 0 元

5.1 The bioavailability of chemical elements is poorly related to the chemical composition of soils and plant growth media containing a mineral or any type of adsorbed phase. The chemical potential (pi for element, i,) is an intensity parameter (I), and the sorbed amount in equilibrium with the soil solution is a measure of the quantity (Q). These parameters for each element (essential or toxic) should be measured in the presence of other elements at or near the desired intensity. This test method is the only method that generates these results simultaneously for several elements. The computer software allows these values to be related to the total sorbed quantities of the different elements. For many substrates, it has been found that the theory for the method holds to the degree that vegetation has been established on many non-soil substrates and soil-water-food chain problems have been evaluated by this test method. This test method has been used on many sites in Pennsylvania and other locations to monitor the effect of sewage sludge applications on land as a source of essential elements for plants with no harmful effects on the food chain. It has also been used to evaluate synthetic soils produced from fly-ash alone or as a component of coal refuse for the establishment of vegetation on mine spoils, coal refuse piles, and abandoned mine lands.Note 1—The quality of the result produced by this standard is dependent on the competence of the personnel performing it, and the suitability of the equipment and facilities used. Agencies that meet the criteria of Practice D3740 are generally considered capable of competent and objective testing/sampling/inspection and the like. Users of this standard are cautioned that compliance with Practice D3740 does not in itself assure reliable results. Reliable results depend on many factors; Practice D3740 provides a means of evaluating some of those factors.1.1 This test method covers the determination of quantity (Q) and intensity (I) results for several elements in soils, spoils, fly-ash, and other soil substitutes to ascertain their suitability for the growth of vegetation and possible adverse effects of metals on the food chain.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 All measured and calculated values shall conform to the guidelines for significant digits and rounding established in Practice D6026.1.4 This standard does not purport to address all of the safety problems, 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

Terminology Relating to Chain Link Fencing

定价： 590元 / 折扣价： 502 元 加购物车

This specification covers the physical requirements for zinc-5 % aluminum-mischmetal (Zn-5Al-MM) alloy-coated steel chain-link fence fabric before weaving. The physical properties to which the fabric should conform are weave form, size of mesh, size of wire, height of fabric, selvage, weight of coating, workmanship, and standard length of rolls.1.1 This specification covers zinc-5 % aluminum-mischmetal (Zn-5A1-MM) alloy-coated steel chain-link fence fabric, Zn-5A1-MM alloy-coated, before weaving.1.2 The values stated in inch-pound units are to be regarded as the 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

This specification covers standard colors for coated chain link fence materials such as chain link fence fabric, tension wire, posts, rails, gate frames, and fittings. Standard polymer colors include dark green, olive green, brown, and black.1.1 This specification covers standard colors for coated chain link fence materials such as chain link fence fabric, tension wire, posts, rails, gate frames, and fittings.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

This practice establishes the standard installation procedures for chain-link fences. It includes site preparation, post location, post setting, and terminal post bracing measures. Also included here are the detailed requirements for the top rail and tension wire, tie wires and clips, chain-link fabric, barbed wires, and gates.1.1 This practice covers the installation procedure for chain-link fence.1.2 This practice is intended primarily to guide those responsible for or concerned with the installation of chain-link fence.1.3 This practice does not intend to preclude any practice that has proven equal to or given better performance under varying conditions, that is, location, weather, intended use, materials, etc.1.4 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. For specific precautionary statements, see Section 13.1.6 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

This specification deals with poly(vinyl chloride), PVC and other conforming organic polymer-coated steel tension wire for use with chain-link fence. Tension wire, produced from three classes of wire coatings, is covered as follows: Class 1, consisting of a polymer coating extruded over zinc-coated or aluminum-coated or zinc-5 % aluminum-mischmetal alloy-coated steel wire; Class 2a, consisting of a polymer coating extruded and adhered to zinc-coated or aluminum-coated or zinc-5 % aluminum-mischmetal alloy-coated steel wire; and Class 2b, consisting of a polymer coating fused and adhered to zinc-coated or aluminum-coated or zinc-5 % aluminum-mischmetal alloy-coated steel wire. Materials shall be tested and the individual grades shall conform to specified values of wire size, breaking strength, metallic coating weight, PVC coating thickness, polymer-coated tension wire properties, and coil length.1.1 This specification covers PVC and other conforming organic polymer-coated steel tension wire for use with chain link fence. PVC and other organic polymer coatings hereinafter will be designated as polymer coating.1.2 Tension wire, produced from three classes of wire coatings, is covered as follows:1.2.1 Class 1, consisting of a polymer coating extruded over zinc-coated or aluminum-coated or zinc-5 % aluminum-mischmetal alloy-coated steel wire;1.2.2 Class 2a, consisting of a polymer coating extruded and adhered to zinc-coated or aluminum-coated or zinc-5 % aluminum-mischmetal alloy-coated steel wire; and1.2.3 Class 2b, consisting of a polymer coating fused and adhered to zinc-coated or aluminum-coated or zinc-5 % aluminum-mischmetal alloy-coated steel wire.1.3 The values stated in inch-pound units are to be regarded as the standard. The values given in parentheses are for information only.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