Processing information sources

Assessment Phase The assessment phase aims to collect data needed to identify and analyze pollution-prevention opportunities. Assessment of the facility s waste-reduction needs includes the examination of hazardous waste streams, process operations, and the identification of techniques that often promise the reduction of waste generation. Information is often derived from obsei vations made during a facihty walk-through, interviews with employees (e.g., operators, line workers), and review of site or regulatory records. One professional organization suggests the following information sources be reviewed, as available (Ref. 7) ... 

Management policies are the source of many of the preconditions that give rise to systems failures. For example, if no explicit policy exists or if resources are not made available for safety critical areas such as procedures design, the effective presentation of process information, or for ensuring that effective communication systems exist, then human error leading to an accident is, at some stage, inevitable. Such policy failures can be regarded as another form of latent human error, and will be discussed in more detail in Section 2.7. 

The following techniques can be used to collect data about human performance in CPI tasks and provide input to task analysis methods described in Section 4.3. These data can include process information critical for the task, control strategies used by the workers, diagnostic plans etc. A distinction can be made among data collection methods that provide qualitative data (such as interviews, observations, and sources of documentation) and methods that can be used to measure aspects of performance (such as activity analysis, simulations, and information withholding). The latter methods can provide more precise data which can be quantified. 

Emission factors are emission rales dclcrniincd by regulatory agencies based on data generated from a given source that arc nornialized to some unit of production or rale of chemical use. These factors are compiled for industries, processes or sources. Tliis information is used to esliniale einission rates without a detailed analysis. The emission factor must be closely related to die... 

A variety of sources were used to identify the patent associated with particular commercial products and to serve as a source of process information. These include the following ... 

Food additives (like color additives) can be added at various processing stages, but the additions are commonly made at the latest production stage before final marketing to ensure optimal functionality of the additive in the product as sold. Residues of additives used at earlier production stages may be present still in the final formulation. However, if they do not have further functions at that stage, they are considered process aids (to help preparation but without technological effects in the finished product) and are not indicated on labels. Some additives also decompose over time so that the levels present at the end of shelf life may be quite low. Several techniques and information sources can be used to assess contamination levels of chemicals ... 

To proceed with a design, the designer must first assemble all the relevant facts and data required. For process design this will include information on possible processes, equipment performance, and physical property data. This stage can be one of the most time consuming, and frustrating, aspects of design. Sources of process information and physical properties are reviewed in Chapter 8. 

Both the CMP and information process in Fig. 3.1 have been simplified in comparison with the representations in Figs. 2.1 and 2.2 because sample preparation has not been considered here and the measurement begins with the measuring sample as information source from which the signals are obtained. 

Preliminary Hazard Analysis. The next step in the process is the development of a PHA. This analysis is the core of the FSS program and as such is vital in eliminating or reducing the inherent hazards associated with this laboratory operation. The PHA is used to further analyze the data identified in the PHL. This enhances the hazard control data base and provides specific recommended corrective action for the resolution of hazardous conditions. A combination of the informational sources used in the PHL development and any additional design information should be used in PHA development. 

Appropriate skills must be made available during the development of process documentation. For example, for a large facility, process engineers, chemists, and health and safety specialists should be involved. These staff members should have access to appropriate information sources, including ... 

Releases of thiocyanate to soil result from anthropogenic and natural sources. Anthropogenic releases occur primarily from direct application in herbicidal formulations (e.g., amitrol-T, a mixture of ammonium thiocyanate and amino-1,2,4-triazole) and from disposal as byproducts from industrial processes. Nonanthropogenic sources include damaged or decaying tissues of plants from the family Brassica (e.g., mustard, rape) (Brown and Morra 1993). Thiocyanate has been detected in soil samples collected at 2 of the 8 hazardous waste sites, and in sediment samples at 3 of the 8 hazardous waste sites where thiocyanate has been detected in some medium (HazDat 1996). The HazDat information used includes data from both NPL and other Superfund sites. 

The previous section concentrated on the management of a hard and soft sensors network. This is an important step since the information sources must be carefully checked before being further used. This section will be devoted to the diagnosis of the overall biological state of the process. In particular, it will illustrate that the use of the Evidence theory approach improves the fault diagnosis system in terms of modularity and d3mamical adaptation. 

Table 4-2 lists the facilities in each state that manufacture or process chloroform, the intended use, and the range of maximum amounts of chloroform that are stored on site. The data listed in Table 4-2 are derived from the Toxics Release Inventory (TRI93 1995). Only plants from 3 states (associated with the 4 plants noted above) actually generate chloroform as an end-product for sale or distribution. In most cases, chloroform is a chemical intermediary, impurity, or waste by-product at the 172 facilities included in the TRI survey. Only certain types of facilities were required to report therefore, this is not an exhaustive list. In some cases, facility names are not available or numeric values for amounts of chloroform produced, stored, transferred, or released are missing. This complicates making comparisons between the TRI listings and information from other information sources. 

Unifying disparate information sources into a single data model is an intrinsically difficult process. Even when the same kinds of information are collected in different places, it is done so for different reasons, which are reflected in data organization. A common example is extraction of information from scientific literature, where the goal is to make a collection of a particular kind of data. Since the origins of the data are research papers, such efforts often result in document databases where the article is the primary entity and the content is represented by various attributes (e.g., lists of referenced molecules). However, a document-oriented database is rarely suitable for the specific requirements of most scientific investigations. Such efforts often invert ... 

A lot of technology is required to achieve effective federation of disparate information sources. The Cabinet design is such that the computer does a tremendous amount of data processing to deliver a simple and powerful interface to the user. This is contrary to traditional database design that focuses on processing efficiency at the cost of flexibility and simplicity. Fortunately, current computers are more than adequate to do this job well. By the standards of the last few years, current desktop computers are supercomputers (and they are stiU getting faster and more capable each year). 

This chapter has shown many examples of the use of CALPHAD methods, ranging from an unusual application in a binary system, through complex equilibrium calculations to calculations for 10-component alloy systems. In all cases the use of CALPHAD methods has enhanced the understanding of processes, clearly defined alloy behaviour and provided vital information for other models, etc. It is also clear that equilibrium calculations can be used in many different areas and under a surprising number of different conditions. For numerous reasons, modelling will never completely replace experimental measurement. However, die quantitative verification of the accuracy of CALPHAD calculations now means that they can be seriously considered as an information source which can be used as an alternative to experimental measurement in a number of areas and can also enhance interpretation of experimental results. 

Maintenance The maintenance expense consists of two components, namely, materials and labor, approximately 60 and 40 percent, respectively. Company records are the oest information sources, however, a value of 6 to 10 percent of the fixed capital investment is a reasonable figure. Processes with a large amount of rotating equipment or that operate at extremes of temperature and/or pressure have higher maintenance requirements. 

The Depocrete process is estimated by the vendor to cost from 100 to 200 per metric ton. Information Source D16658Z, vendor hterature... 

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