EVAL method

Degradative methods based on pyrolysis are the subject of renewed interest due to the identification power offered by gas chromatography-mass spectrometric systems (GC-MS) (Wershaw and Bohner, 1969 Martin et al., 1977 Meuzelaar et al., 1977 Bracewell and Robertson, 1976). There are two main pyrolysis techniques (1) controlling the decomposition kinetics by temperature programming and (2) the use of quasi-instantaneous heating (e.g.. Curie point pyrolysis). The later technique avoids most recombination reactions, but does not allow kinetic control. The pyrolysis effluent can be detected directly (Rock-Eval method) or after chromatographic fractionation. 

OCL uses a Smalltalk-based block syntax to allow you to define some kinds of functions conveniently and inline, but it does not provide corresponding type rules for this based on generic types. For our discussion here, we treat blocks as first-class functions and use the syntax (T1 X T2 X T3 -> T ) for such a function. This is purely a syntactic convenience functions can be modeled as objects. Any function f (a,b) c can be described as an object with a single method eval (a, b) c. Thus,... 

For a step size of h = 10-5 s evaluate the left-hand side of this equation for species A, B, and C using the a s found in previous problem. It was stated in the text that the implicit method is unconditionally stable. Is this statement borne out by your numerical evalation ... 

The chemical compositions of oil shales and oil shale kerogen have been studied extensively (20). However, little work has been done to integrate chemical composition data in order to aid in the selection of suitable extracting processes. In this study, five analysis methods were used to chemically characterize the samples. These methods included Rock-Eval analysis, Fischer analysis, Xi C NMR, Ultimate analysis, and X-ray diffraction mineral analysis. 

D.C. Kunerth, K.L. Telschow and J.B. Walter, Characterization of porosity distributions in advanced ceramics a comparison of ultrasonic methods. Materials Eval, 47 (1989) 571. 

W. Huang and S.l. RokhUn, Low-frequency normal incidence ultrasonic method for thin layer characterization. Materials Eval, 11 (1993) 1279. 

Rock-Eval pyrolysis (Espitalie et al., 1977) was applied to immature ancient marine sediments by Herbin and Deroo (1979) and to recent marine sediments by Debyser and Gadel (1981). This technique results in information similar to elemental analysis, but the procedure is much faster, cheaper, and easier. However, it seems necessary to modify this method for use in recent sediments, where organic matter is thermally labile and rich in oxygen. This problem is currently under investigation at the Institut Francais du Petrole. 

The results of open-system pyrolysis (Rock-Eval II) have been used to specify the kinetic parameters controlling maturation. Hydrocarbon yield rates as determined by these experiments are shown in Fig. 6.9a. Both nonlinear optimization technique (Levenberg-Marquardt method Press et al. 1986 Issler and Snowdon 1990) and linear methods are used to determine the values of the reaction parameters Aj, Ej, andX, . This technique minimizes an error function by comparing the hydrocaibon release rates, Sj, calculated by Eq. 6.9 and those rates measured in open-system pyrolysis. An example of the spectrum of activation energies obtained from this analysis is shown in Fig. 6.9b. 

In the topological pharmacophore methods [527 — 531], e.g. LOGON [527, 528, 530], LOGANA [528 — 530], and EVAL [531], Free Wilson-type indicator variables... 

Once the features are defined and the compounds are coded according to their presence or absence a classification of the compounds regarding their activity should be performed. This is always a good approach even if continuous activity data are available. The classification into an active and inactive class will increase the clearness of the analysis and will speed up the procedure. If there are not obvious limits the methods of exploratory data analysis can be used to refine meaningful threshold values. The coded stmctures together with the classification and (if known) continuous activity data will form the input information of the EVAL procedure. 

RockEval (also Rock-Eval, RockEval analysis) A rapid analytical method that utilizes pyrolysis to provide a semi-quantitative measure of the relative proportions of hydrogen, carbon and oxygen in bulk sedimentary organic matter. The instrument heats sediment samples to measure the amounts of hydrocarbons and hydrocarbon-like substances that escape at different temperatures from the organic matter contained in the sediment. The unit also calculates the amount of CO2 created during thermal decomposition of the organic matter. The results of Rock-Eval pyrolysis can help to identify the biotic sources of sediment organic matter. 

During the discussion on pyrolysis experiments we will refer to the Rock Eval thermal method, commercially used for the evaluation of PSR and maturation of sedimentary organic matter. This method employs an open system programmed pyrolyser purged with He carrier gas into various detectors for monitoring hydrocarbons, CO2 and a modified version with a sulfur detector. The use of this method for the evaluation of rocks containing type II-S kerogens is well documented (see Spiro, 1991 Baskin and Peters, 1992). 

R 327 M. Auger, Biological and Pharmaceutical Applications of Solid-State NMR Spectroscopy , Can. J. Anal. Sci. Spect., 2002, 47,184 R 328 K. Awazu and H. Kawazoe, Strained Si-O-Si Bonds in Amorphous SiOa Materials A Family Member of Active Centers in Radio, Photo, and Chemical Responses , J. Appl. Phys., 2003,94, 6243 R 329 T. Babadagli and S. Al-Salmi, A Review of Permeability-Prediction Methods for Carbonate Reservoirs Using Well-Log Data , SPE Reserv. Eval. Eng., 2004, 7, 75... 

C. Permeability coefficients of poly(vinyl alcohol) andEVAL-F fix>m different laboratories are very different according to the measuring conditions and film preparation methods because poly(vinyl alcohol) and EVAL-F are very sensitive to humidity. 

R. G. Garmon, End group determinations, Techn. Methods Polym. Eval. 4(1), 31 (1975). 

Rock eval pyrolysis from its inception in 1977(referred to in Luniger and Schwark ) has become a widely used technique for geochemical characterization of organic matter in sediments. Two references have been included here that will lead interested persons into the rich hterature in this area. One of these studies in particulars describes the method in some detail. 

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