Quality specifications

Many standard specifications have been laid down for the more important uses of ZnO (rubber, paints, and the pharmaceutical industry). For standards, see Table 1 ( Zinc oxide pigments Methods of analysis and Specification ). Various methods of classification are used, often based on the production process and the chemical 

Classification based on color codes is common in Europe, but is of limited value. Manufacturers have their own standards. In general, the terms silver seal and white seal indicate category A, and red seal category B. 

Zinc oxide has many uses. By far the most important is in the rubber industry. Almost half the world s ZnO is used as an activator for vulcanization accelerators in natural and synthetic rubber. The reactivity of the ZnO is a function of its specific surface area, but is also influenced by the presence of impurities such as lead and sulfates. The ZnO also ensures good durability of the vulcanized rubber, and increases its thermal conductivity. The ZnO content is usually 2-5%. 

The pharmaceutical and cosmetic industries use ZnO in powders and ointments because of its bactericidal properties. It is also used to form dental cements by its reaction with eugenol. 

In the field of glass, ceramics, and enamels, ZnO is used for its ability to reduce thermal expansion, to lower the melting point, and to increase chemical resistance. It can also be used to modify gloss or to improve opacity. 

Many standard specifications have been laid down for the more important uses of ZnO (rubber, paints, and the pharmaceutical industry). For standards, see Table 1.1 ( Zinc oxide pigments Methods of analysis and Specification ). Various methods of classification are used, often based on the production process and the chemical composition. The most well known are pharmacopeias (USP, BP DAB, Ph. Eur.) ISO 9298, T31 006 NF, ASTM D79 - 86 and ASTM D 4295 - 89. Table 2.13 shows a classification with typical data for commercially available zinc oxide grades (more detailed standard specifications see standards mentioned above). 

Normally manufactures have their own standards. The terms gold seal, silver seal, red seal, green seal and white seal are still common in Europe. 

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The Superplus with its RON and MON greater than or equal to 98 and 88 respectively. These two values do not correspond to official specifications but to quality specification sheets drawn up by French auto manufacturers. Strictly according to the rules, Superplus is only a variety of a top quality Eurosuper. 

In order to meet French manufacturers fuel quality specifications, a diesel fuel should contain a detergent additive whose effectiveness will have been demonstrated by the procedure described previously. 

Product quality specification Contractual agreements Capacity and availability Concurrent operations Monitoring and control Testing metering Standardisation Flaring and venting Waste disposal Utilities systems... 

One of the primary objectives of production operations is to deliver product at the required rate and quality. Therefore the product quality specification and any agreed contract terms will drive the activities of the production operations department, and will be a starting point for determining the preferred mode of operation. The specifications, such as delivery of stabilised crude with a BS W of less than 0.5%, and a salinity of 70 g/m, ... 

Quality Specifications. Because of the extreme sensitivity of polyamide synthesis to impurities ia the iagredients (eg, for molecular-weight control, dye receptivity), adipic acid is one of the purest materials produced on a large scale. In addition to food-additive and polyamide specifications, other special requirements arise from the variety of other appHcations. Table 8 summarizes the more important specifications. Typical impurities iaclude monobasic acids arising from the air oxidation step ia synthesis, and lower dibasic acids and nitrogenous materials from the nitric acid oxidation step. Trace metals, water, color, and oils round out the usual specification Hsts. 

Secondary System. The water quality specifications for the feedwater and blowdown water in a recirculating steam generator (RSG) and the ... 

Some standard industrial quality specifications for n- and isobutyraldehyde are given in Table 3. Many times, however, specification limits are tailored to individual customer requirements. 

Quality Specifications. Eggs are downgraded according to specific conditions of the shell. 

Recychng (or reuse) refers to the use (or reuse) of materials that would otherwise be disposed of or treated as a waste product. A good example is a rechargeable battery. Wastes that cannot be directly reused may often be recovered on-site through methods such as distillation. When on-site recoveiy or reuse is not feasible due to quality specifications or the inability to perform recoveiy on-site, off-site recoveiy at a permitted commerci recoveiy facihty is often a possibility. Such management techniqiies are considered secondaiy to source reduc tion and should only oe used when pollution cannot be prevented. 

In order to verify that the products or services meet the specified requirements you will need to carry out tests, inspections, assessments, etc. and these need to be performed against unambiguous standards of acceptability. You need to establish for each requirement that there are adequate criteria forjudging compliance. You need to establish how reliable is reliable , how safe is safe , how clean is clean , how good is good quality . Specifications often contain subjective statements such as good commercial quality, smooth finish, etc., and require further clarification in order that an acceptable standard can be attained. The secret is to read the statement then ask yourself if you can verify it. If not, select a standard that is attainable, unambiguous, and acceptable to both customer and supplier. 

All liquid fuels and oils manufactured and sold in the United States since 1919 must comply with the engineering standards and quality specifications published by the American Petroleum Institute... 

Unlike potable and industrial waters, for which quality specifications are laid down, there can be no universal regulation as to the concentration or degree to which any of these is acceptable. The receiving body, which has to use its judgement in each case, will lay down allowable limits. 

The design of production plants for the manufacture of the three categories of product varies considerably. Fine chemicals are usually produced in batch reactors, which may also be used for the production of a variety of similar products. Fine chemicals usually have demanding product quality specifications and, consequently, a significant fraction of the production costs are involved in product purification and testing. Intermediate volume chemicals have less rigorous quality specifications than fine chemicals and are usually manufactured in product-specific-plants, either as batch or continuous flow processes. Bulk chemical production plants usually operate continuous flow processes... 

Traditionally, the mix of pretreatment equipment required to meet a specific FW volume and quality specification is provided as a permanent installation under a capital project, although today there is a growing global market in outsourced water services. Typically, vendors such as Ecolochem, Inc., a world leader in this type of service, provide trailer-mounted, mobile water-processing equipment that can be... 

Programmable logic control (PLC) systems, which automatically control the RO process to sustain output and quality specifications... 

The quality specification of alkylbenzenes is dependent upon the desired performances of the product, which can only be tested under practical conditions. 

GL39 Quality specifications Test Procedures and Acceptance Criteria for new Veterinary Drug Substances and New medicinal Products Chemical Substances... 

It has been proposed " that the mechanism(s) of action of gymnemic acids and ziziphins is a biphasic, model-membrane penetration-process. The model suggested that the modifier molecules interact first with the receptor-cell plasma-membrane surface. It was postulated that this initial interaction involves a selective effect on taste perception, including the transduction and quality specification of the sweet stimuli, and selective depression of sweetness perception. Following the initial interaction, the modifier molecules interact with the membrane-lipid interior to produce a general disruption of membrane function and a nonselective effect on taste... 

Fraser CG, Hyltoft Peterson P (1999) Analytical performance characteristics should be judged against objective quality specifications. CUn Ghem 45 321-322. 

Residue study protocols typically either include quality specifications for analytical procedures or refer to a written analytical method that includes such specifications. The protocol for an LSMBS should also include analytical quality specifications, either directly or by reference to a method. Analytical specifications usually include minimum and maximum recovery of analyte from fortified control samples, minimum number of such fortifications per set of samples, minimum linearity in calibration, minimum stability of response to injection of calibration solutions, and limits of quantitation and of detection. 

Similar considerations were taken into account throughout the process of designing the study and committing the design to a protocol. In addition to analytical quality specifications, decisions were made regarding definitions of limits of detection and quantitation, levels of apparent residues at which confirmation was required, and how such confirmation would be achieved. All of these decisions were based on fulfilling the objectives of the study while operating within unavoidable time and resource constraints. 

In the OPMBS, the lead laboratory developed the analytical method for all analytes in ah commodities. The same laboratory validated the method for each commodity, to demonstrate that all the specific analytes for the commodity could be determined in accordance with analytical quality specifications. The method was then provided to the other three laboratories, each of which validated the method for its assigned commodities, to ensure that the method performed properly using the laboratory s equipment and personnel. 

The total stream and individual component flows do not normally need to be shown to a high precision on the process flow-sheet at most one decimal place is all that is usually justified by the accuracy of the flow-sheet calculations, and is sufficient. The flows should, however, balance to within the precision shown. If a stream or component flow is so small that it is less than the precision used for the larger flows, it can be shown to a greater number of places, if its accuracy justifies this and the information is required. Imprecise small flows are best shown as TRACE . If the composition of a trace component is specified as a process constraint, as, say, for an effluent stream or product quality specification, it can be shown in parts per million, ppm. 

Defining hydrogen fuel quality specifications is a high priority for the Roadmap. Such specifications must be quantified at the vehicle-station interface and must consider how the presence of small amounts of contaminants affects the performance and durability of fuel cell and balance of plant material compatibility of onboard and stationary hydrogen storage systems and the operation and maintenance of hydrogen production, purification, and delivery systems. Most importantly, fuel quality specification must consider... 

Successful start-up of operations means that production is accomplished safely at planned rates and product is manufactured to the desired quality specifications. Experience shows that, in moving from small scale to commercial equipment, the following variables are important ... 

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