Production Characteristics

Regarding product characteristics, European specifications were established in 1992. They concern mainly the motor octane number (MON) that limits the olefin content and which should be higher than 89, and the vapor pressure, tied to the C3/C4 ratio which should be less than 1550 mbar at 40°C (ISO 4256). On the other hand, to ensure easy vehicle start-ups, a minimum vapor pressure for winter has been set which is different for each country and depends on climatic conditions. Four classes. A, B, C, and D, are thus defined in Europe with a minimum vapor pressure of 250 mbar, respectively, at -10°C (A), -5 C (B), 0°C (C) and -t-10°C (Z)). France has chosen class A. 

Product Characteristics Commercial butane Commercial propane LPG motor fuel (from NF EN 589) (see AFNOR document M 40-003)... 

A specification or standard for product characteristics is valid only if it is matched with references to well defined and recognized test methods, such that quality control tests conducted by the parties involved —client and supplier, for example— are comparable even if they are performed at different locations. 

There exists an important relationshiphetween the depositional environment, reservoir distribution and the production characteristics of a field (Figure 5.3). 

Depositional Environment Reservoir Distribution Production Characteristic... 

PVDE is manufactured using radical initiated batch polymerization processes in aqueous emulsion or suspension operating pressures may range from 1 to 20 MPa (10—200 atm) and temperatures from 10 to 130°C. Polymerization method, temperature, pressure, recipe ingredients, the manner in which they are added to the reactor, the reactor design, and post-reactor processing are variables that influence product characteristics and quaUty. 

Fillers (qv) are occasionally used in flexible slab foams the two most commonly used are calcium carbonate (whiting) and barium sulfate (barytes). Their use level may range up to 150 parts per 100 parts of polyol. Various other ingredients may also be used to modify a flexible foam formulation. Cross-linkers, chain extenders, ignition modifiers, auxiHary blowing agents, etc, are all used to some extent depending on the final product characteristics desired. 

In the United States, additional ramifications maybe expected from FDA s announcement of final regulations for new food labeling requirements under the directive of the Nutrition Labeling and Education Act of 1990 (2). Among other things, these regulations limit health claims that can be made on food labels. They also require new information on nutrient content, and limit the use of descriptors such as low and free in association with calories, fat levels, and other food product characteristics. 

Other techniques include oxidative, steam atmosphere (33), and molten salt (34) pyrolyses. In a partial-air atmosphere, mbber pyrolysis is an exothermic reaction. The reaction rate and ratio of pyrolytic filler to ok products are controlled by the oxygen flow rate. Pyrolysis in a steam atmosphere gives a cleaner char with a greater surface area than char pyroly2ed in an inert atmosphere however, the physical properties of the cured compounded mbber are inferior. Because of the greater surface area, this pyrolytic filler could be used as activated carbon, but production costs are prohibitive. Molten salt baths produce pyroly2ed char and ok products from tine chips. The product characteristics and quantities depend on the salt used. Recovery of char from the molten salt is difficult. 

Table 5. Product Characteristics and Capacity Data for Some Materials Treated in Belt Cooling Systems ...

Continuous oxidizers are usually operated at a constant temperature (260 °C) and a constant Hquid level with the production rate and product characteristics controlled by air rate and charging rate. 

A wide variety of mammalian cells are used in industrial practice and to accommodate the diversity, a variety of cell culture technologies have evolved depending on the cell line and product characteristics. 

Behavior. Diffusion, Brownian motion, electrophoresis, osmosis, rheology, mechanics, and optical and electrical properties are among the general physical properties and phenomena that are primarily important in coUoidal systems (21,24—27). Of course, chemical reactivity and adsorption often play important, if not dominant, roles. Any physical and chemical feature may ultimately govern a specific industrial process and determine final product characteristics. 

Better product characteristics are obtained through control of the rate at which supersaturation (cooling, evaporation, and addition of a nonsolvent or precipitant) is generated. An objective of the operation may be to maintain the supersaturation at some constant prescribed value, usually below the metastable limit associated with primary nucleation. For example, the batch may be cooled slowly at the beginning of the cycle and more rapidly at the end. 

Diying te.st.s. Drying tests should be conducted in those diyers still under consideration. These tests will determine the optimum operating conditions and the product characteristics and will form the basis for firm quotations from equipment vendors. 

Once a given type and size of dryer has been installed, the product characteristics and diying capacity can be changed only within relatively narrow limits. Tnus it is more economical and far more satisfac-... 

The recycle requirements of products in different apphcations can vaiy substantially depending upon the scale of operation, the ease of diying, and the finished-product specification. The location of reintroduction of undried material back into the diying medium has a significant impact upon the dryer performance and final-product characteristics. 

Another basic consideration is whether crystallization is best carried out on a batch basis or on a continuous basis. The present tendency in most processing plants is to use continuous equipment whenever possible. Continuous equipment permits adjusting of the operating variables to a relatively fine degree in order to achieve the best results in terms of energy usage and product characteristics. It allows the use of a smaller labor force and results in a continuous util-... 

The batch handling of wet or semidry crystalline materials is substantially more difficult than the storing and handling of dry crystalline materials. A batch operation has economic application only on a relatively small scale or when temperature or product characteristics require unusual precautions. 

Two main benefits accrue from a systems approach to materials handling and packaging. First, a trade-off of investment and operating costs is made possible nigher costs in some parts of a system become permissible in return for much lower costs in other parts. The net result is usually the lowest overall cost. If this is not the case, the reasons for incurring the higher costs can be identified and justified. The second benefit is that customers are not offended by ill-conceived packages, delivery vehicles, or product characteristics. 

From the above discussion, it follows that the quality and conformance to tolerance of the product characteristics should be designed in and not left to the process engineer and quality engineer to increase to the required level. In order to do this, designers need to be aware of potential problems and shortfalls in the capability of their designs. They therefore need a technique which estimates process capability and quantifies design risks. 

A value of Cp = 1.33 would indicate that the distribution of the product characteristics covers 75% of the tolerance. This would be sufficient to assume that the process is capable of producing an adequate proportion to specification. The numbers of failures falling out of specification for various values of Cp and Cp can be determined from Standard Normal Distribution (SND) theory (see an example later for how to determine the failure in parts-per-million or ppm). For example, at Cp = 1.33, the expected number of failures is 64 ppm in total. 

Are mechanisms in place to identify the need for statistical techniques required for verifying the acceptability of process capability and product characteristics ... 

The purpose of the control plan is to ensure that all process outputs will be in a state of control by providing process monitoring and control methods to control product and process characteristics. The control plan is covered in section 6 of the APQP manual. It consists of forms containing data for identifying process characteristics and helps to identify sources of variation in the inputs that cause product characteristics to vary. The APQP manual provides excellent guidance on the compilation and use of the control plan so no further guidance is given here. 

The standard requires that continuous improvement extend to product characteristics and process parameters with the highest priority on special characteristics. 

The next stage is to design the processes that have been identified. In many cases, existing processes may well satisfy the need but process approval may be required if the tolerance on product characteristics is much less than the currently demonstrated process capability. Process design is a subject outside the scope of ISO 9001 but is covered by clause 4.2.4.9 of ISO/TS 16949 and hence addressed in Part 2 Chapter 2. 

The standard requires controlled conditions to include the monitoring and control of suitable process parameters and product characteristics during production, installation, and servicing. 

How do you monitor and control process and product characteristics during installation ... 

Devices that you use for product verification at all stages in the quality loop need to be controlled and this includes devices used for inspection and test on receipt of product, in-process, and final acceptance before release to the customer. It also includes devices used during design and development for determining product characteristics and for design verification. Some characteristics cannot be determined by calculation and need to be derived by experiment. In such cases the accuracy of devices you use must be con-... 

To measure product characteristics, such as devices which measure mass, length, or time, or derivatives of these parameters... 

To form product characteristics, such as jigs, tools, and fixtures... 

To control processes that create product characteristics (such as sensors that indicate temperature, pressure, volume, etc.)... 

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