Methods of estimation

When estimating the operating and maintenance costs for various options, it is recommended that the actual activities which are anticipated are specified and costed. This will run into the detail of frequency and duration of maintenance activities such as inspection, overhaul, painting. This technique allows a much more realistic estimate of opex to be made, rather than relying on the traditional method of estimating opex based on a percentage of capex. The benefits of this activity based costing are further discussed in Section 13.0 and 14.0. 

This provides a method of estimating an iron(lll) salt. After reduction the iron(II) salt is titrated with manganate(VII) solution. 

A method of estimating small amounts of water in organic liquids (and also in some inorganic salts) is that of Karl Fischer. The substance is titrated with a mixture of iodine, sulphur dioxide and pyridine dissolved in methyl alcohol. The essential reaction is ... 

The reaction provides a method of estimating copper(Il) since the liberated iodine may be titrated with sodium thiosulphate ... 

In spite of the three methods of estimating open question that needs to be investigated further in the future. The above expressions are order of magnitude estimates and not exact formulas. 

This method of estimating urea is more accurate than the hypobromitc method (p. 458) and is used extensively for accurate metabolic work. 

Panasyuk V.V., Andreikiv A.V., Kovchik S.E. (1977) Methods of estimating the fracture toughness of structural materials. Kiev (in Russian). 

A modified method of estimating the OI for fibrous or finely divided ceUulosic materials has been developed (53). The fibers or powdered materials are first pressed iato disks, then the OI is measured ia the usual way. 

Indirect methods of estimating sorption have been used when actual measurement of sorption isotherm is impossible (44). For instance, sorption coefficients have been estimated from soil organic carbon and a specific surface of soil, and from semiempidcal equations using pesticide properties. 

AH the foregoing faciUties form part of the spectmm of options that, in addition to the permanent system data bank, enable the engineer to get the most out of a flow-sheeting system. The following Hst shows the physical properties that are often required for process simulation. The methods of estimating these properties, when direct measurements are not available, are indicated in the references following the properties (also see Thermodynamic properties). 

Standard method of estimating percent protein from nitrogen content (% N). 

When experimental data are not available, methods of estimation based on statistical mechanics are employed (7,19). Classical kinetic theory suggests a contribution to CP of S R for each translational degree of freedom in the molecule, a contribution of S R for each axis of rotation, and of R for each vibrational degree of freedom. A cmde estimate of CP for small molecules can be obtained which neglects vibrational degrees of freedom ... 

Another method of estimating autoignition temperatures is to compare values for a compound with other members of its homologous series on a plot vs. carbon number as the temperature decreases and carbon number increases. Affens gives a formal procedure for such estimation. 

Clearly, the value of Cinv affects both the annual cash income and the net annual profit. Since annual cash incomes are the basic data for (NPV) and (DCFRR) methods of estimating profitability, the actual value per unit of inventory is of direcl importance for chemical engineers engaged in economic assessments. 

Reduce the effect of bias by using statistic ly proven methods of estimation based on experience. 

Typical methods are those of F. C. Zevnik and R. L. Buchanan [Chem. Eng. Progi , 59, 70-77 (Feb. 1963)] and J. H. Taylor Eng. 6-Proc. Econ., 2, 259-267, 1977). The former is mainly a graphical method of estimating the cost per functional unit (Cp) based on the capacity, the maximum pressure, the maximum temperature, and the materials of construction. The Taylor method requires the determination of the costliness index, which is dependent on the complexity of the process. A simpler method was suggested by S. R. Timms (M.Phil. thesis, Aston University, England, 1980) to give the battery hmits cost for gas phase processes only in U.S. dollars with a Marshall and Swift index of 1000. The simple equation is... 

In general, the step count method of estimation can be apphed to any special situation to derive a model equation for that particular industry or group of processes. 

Equipment Costs The cost of dehvered equipment forms the basis of most methods of estimating the fixed-capital cost. The equipment required can usually be divided into (1) processing equipment, (2) equipment for handling and storage of raw materials, and (3) finished products handling and storage equipment. 

A rough method of estimating the piping factor as a percentage of the total delivered cost of major process equipment (excluding instruments and electrical items) was presented by E. S. SokuUu in the form... 

This section discusses some of the items considered in the start-up costs for a coal gasification project, along with the methods of estimating each item. 

Examples chosen for this category include the operations of vapor/liquid separation, heat transfer, and fluid flow. The Underwood method of estimating the... 

In general conclusion, the HMO and SCF methods both appear able to make reasonably accurate predictions about the stabilization in conjugated moleeules. The stabilization is general for benzenoid compounds but quite restricted in nonbenzenoid systems. Because the HMO method of estimating stabiUty is based on the ideas of HMO theory, its general success vindicates the ability of this very simplified MO approach to provide insight into the structural nature of the aimulenes and other conjugated polyenes. More sophisticated MO methods, of course, are now accessible and should be applied for more detailed analysis of the structures of these molecules. 

Methods of estimating gaseous effluent concentrations have undergone many revisions. For a number of years, estimates of concentrations were calculated from the equations of Sutton, with the atmospheric dispersion parameters C, C, and n, or from the equations of Bosanquet with the dispersion parameters p and Q. More common approaches are based on experimental observation that the vertical distribution of spreading particles from an elevated point is... 

Chapter 5 describes simplified methods of estimating airborne pollutant concentration distributions associated with stationary emission sources. There are sophisticated models available to predict and to assist in evaluating the impact of pollutants on the environment and to sensitive receptors such as populated areas. In this chapter we will explore the basic principles behind dispersion models and then apply a simplified model that has been developed by EPA to analyzing air dispersion problems. There are practice and study problems at the end of this chapter. A screening model for air dispersion impact assessments called SCREEN, developed by USEPA is highlighted in this chapter, and the reader is provided with details on how to download the software and apply it. 

Arecoline is usually stated to be present to the extent of 0-1 per cent., but Chemnitius gives the yield of hydrobromide as 0-35 to 0-4 per cent. Arecaidine and guvacine occur in smaller quantities, whilst guvacoline and arecolidine are found only in minute amounts. Alkaloidal assay processes for areca nuts have been published by Bourcet, and the National Formulary Committee, and Bond has described a method of estimation for arecoline hydrobromide. A microchemical test for the identification of arecoline has been devised by Gornyi. ... 

Tobacco and its alkaloids have long ceased to have any therapeutic importance, but their extensive use as insecticides and the demand for nicotine for the manufacture of nicotinic acid have stimulated interest in processes of extraction and methods of estimation. On the latter subject there is a voluminous literature, of which critical resumes have been published by various authors.Recent work on this subject has been specially concerned with (1) the development of miero- and semi-miero-methods suitable for estimating nieotine in tobacco smoke and the distribution of nieotine on sprayed garden produce, in treated soils and in tobaeeo leaves,(2) the study of conditions necessary to ensure satisfactory results in using particular processes, " and (3) methods of separation and estimation of nicotine, nomicotine and anabasine in mixtures of these bases. ) In the United States and in Russia considerable interest is being shown in the cultivation of types of tobacco rich in nicotine, in finding new industrial uses for tobacco and its alkaloids, and in possible by-products from tobacco plants such as citric and malic acids, i " Surveys of information on tobacco alkaloids have been published by Jackson, i Marion and Spath and Kuffner. ... 

Owing to the use of lupin seeds for feeding animals, much attention has been given to the selection of species free from the more toxic alkaloids of the group, particularly sparteine, to methods of removing alkaloids from the seeds, a subjeet on which there is an extensive literature and to methods of estimating alkaloids in lupins on which a critical review has been published by Brahm and Andresen. ... 

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