General Remark

There is no general answer to this question. Too few cycles lead to incomplete convergence and four or six seems to be the minimum even in very well-behaved refinements. Too many cycles will not hurt the refinement but can waste computing time. I usually use 10 cycles less if a refinement converges very well, and more when needed. You can tell that a refinement converges when the values for Mean shift/esd and Maximum become very small (ideally 0.000, but 0.01 or even 0.1 is acceptable in early stages of the refinement). 

The effect of the occurrence, within a generalized reaction scheme, of chemical steps, multielectron transfers, or an rds that is a dissociation or combination step (i.e., one that involves a change of stoichiometric coefficients) wiU be examined as well as mechanisms where the rds (and hence the ovCTaU reaction) has a stoichiometric number greater than 1. This latter case is more complicated than these others and, since it is the only mechanistic situation in a consecutive reaction scheme that can give 

If a step within the general mechanism does not involve an electron transfer, its involvement in determining the potential dependence of the rate will depend on whether it occurs as the rds. If some step, c, limited by the rds, is a chemical step, its quasi-equilibrium expression will be 

This term is obviously independent of potential and so its effect is only a trivial one, which is that is multiplied in among all the other quasi-equilibrium constants (UKiS). Note that reaction order in Eq. (42) could be 1. 

However, if the rds itself is a chemical step, the transition state does not involve electron transfer and hence P plays no part in the net rate, i.e. 

In this case, the potential dependence of the net rate manifests itself indirectly through that of the surface activities of the intermediates, Irds and Irds+1, if their prior formation involves electron-transfer reactions. This situation is described by the transfer coefficients developed previously [Eqs. (33a) and (33b)], where in these would be 0. 

To save space the following abbreviations have been generally used in Chapters 3, 4 and 5 abs (absolute), anhyd (anhydrous), aq (aqueous), atm (atmospheric), crystd (crystallised), crystn (crystallisation), crysts (crystallises), dec (decomposes), dil (dilute), distd (distilled), distn (distillation), evap (evaporate), evapd (evaporated), evapn (evaporation), filtd (filtered), h (hourfs]), pet ether (petroleum ether, ligroin), ppte (precipitate), ppted (precipitated), pptn (precipitation), satd (saturated), soln (solution), TLC (thin layer chromatography), HPLC (high pressure liquid chromatography), vac (vacuum), vol (volume). Other abbreviations used occasionally are self evident in meaning. 

Abbreviations of periodicals not included in this list are written in such a way that the periodical can be readily identified, e.g. Acta Chem Scand for Acta Chemica Scandinavica. 

There are about 20 amino acids in a protein hydrolysate. With a few exceptions, their general 

Belitz W. Grosch - P. Schieberle, Food Chemistry Springer 2009 

Valine, leucine, isoleucine, phenylalanine, tryptophan, methionine, threonine, histidine (essential for infants), lysine and arginine ( semi-essential ). 

Glycine, alanine, proline, serine, cysteine, tyrosine, asparagine, glutamine, aspartic acid and glutamic acid. 

In the simplest case, R=H (aminoacetic acid or glycine). In other amino acids, R is an aliphatic, aromatic or heterocyclic residue and may incorporate other functional groups. Table 1.1 shows the most important building blocks of proteins. There are about 200 amino acids found in nature (Fig. 1.1). Some of the more uncommon ones, which occur mostly in plants in free form, are covered in Chap. 17 on vegetables. 

CHEMICAL PROPERTIES OF TUNGSTEN METAL 1.3.1. General Remarks 

Although the main directing properties in tungsten s applications are of a pure physical nature (high melting point, high density, low vapor pressure, etc.), the chemical properties too are of special importance because they determine and limit the application fields of the metal in regard to diverse environments. It must be stated in advance that these properties are quite opposite. 

On die one hand, tungsten can be considered as a rather inert metal, which is resistant to many elements and compoimds. It is compatible with most ceramics and glasses up to high temperatures and shows good resistance to many molten metals. Tungsten is stable to mineral acids in the cold and is only slightly attacked at higher temperatures. 

In most of diese applications, either thoriated tungsten is used (service temperature 1700-1800 °C), or impregnated cathodes, based on Ba0/Al203/Ca0 additions (so-called dispenser cathodes service temperature 900-1250 °C). However, because of its radioactive nature, thoriated tungsten is currently being more and more replaced by timgsten with rare earth (RE) oxide additions or W-Zr02 (see also Section 6.2.2). 

For more information on electron emission, including interactions of tungsten with charged particles and atoms (secondary emission), the reader is referred to the compilation in a recently published handbook [1.38]. 

4 Truncation of the Many-body Perturbation Expansion General Remarks.—Perturbation theory forms the basis of a unique approach to the calculation of accurate expectation values in that it provides a clearly defined order parameter indicating the relative importance of various terms. This order 

In these studies, a modulation of the transport rate is imposed upon a steady-state rate. As noted in Section 10.3, the ideas can be generalised through the concept of a transfer function linking fluctuations in current to fluctuations in the velocity gradient normal to the electrode. There are two distinct themes in the literature one is to impose a flow with known fluctuation characteristics in order to deduce information about electrochemical processes occurring at or near the interface, this being the focus of the present review the other is to use the variations in limiting current to deduce the characteristics of the flow, with an emphasis on analysis of the fluctuations in current to deduce characteristics of turbulent flow [81-85]. 

In EHD impedance studies, the relaxation times for the different transport processes are obtained by variation of the modulation frequency of the flow. The utility of the technique relies on being able to separate out individual transport relaxation times. This is possible because, with EHD, each relaxation time will have a different functional dependence upon the perturbation. The theory and methodology were first developed for sinusoidal modulation of the flow velocity in a tube [20, 22]. The results 

An alternative approach is to impose random fluctuations upon the flow and then use Fourier analysis of the resultant current or potential fluctuations to obtain the transfer function. MartemYanov and Grafov [17, 87, 88] used a particularly simple method employing a paddle stirrer to generate a turbulent flow, with a uniform spectrum of fluctuations over the frequency range ( 100 Hz). This methodology was termed hydroelec- 

Of importance for any experimental technique which is to be used to fit some complex reaction model is the way in which experimental errors influence the result [93]. The error structure for the EHD method utilising the RDE has been analysed in detail by Orazem et al. [94]. These authors showed that information could reliably and accurately be extracted even at high modulation frequencies (up to 20 Hz). In principle the determination of Sc should only require data at low modulation frequency. They demonstrated that extraction of accurate values for Sc required data which had been recorded over a relatively wide frequency range and had been weighted according to a reliable model for the errors. They also showed that the EHD (7 - Cl) response could be fitted empirically to the form  

3 Recognition of Monomeric Guests by CDs and CD Derivatives 3.1 General Remarks 

For the quantification of molecular recognition, binding constant K and binding free energy AG° are defined by (1) and (2), respectively. Since determination of K requires at least measurable concentrations of each component, K and AG° can only be accurately determined for ICs of types II-IV  

5 Statistical Mechanics of Ideal Gases and Isotope Effects 4.5.1 General Remarks 

Statistical mechanics enables one to express the chemical potential i, for an ideal gas phase system in terms of the spectroscopic properties of individual gas phase molecules. The reader is referred to standard statistical mechanics texts (e.g. D. A. McQuarrie Statistical Mechanics , reading list) for the development of the relationship between the system Helmholtz free energy, A , and the corresponding canonical partition function Qi 

In Equations 4.51 and 4.52 k is Boltzmann s constant, T is the absolute temperature and the Eis s are the energy states of the molecules i. The statistical mechanical considerations in this book will refer to an ideal gas unless explicit mention is made to the contrary. For an ideal gas, a gas of non-interacting molecules, one can express the partition function Q of a collection of N molecules of species i in terms of the single molecule partition functions q as follows1 

Here the Sjs s are the energy levels of the individual molecules. Equation 4.53 follows from the use of Boltzman statistics for N distinguishable non-interacting molecules when the number of energy states of the N molecule system is very large compared to the number of molecules. The latter condition is satisfied for most systems of practical interest. For detailed consideration of this point, the reader should consult the McQuarrie reference. 

1 The authors recognize that the symbol q has previously been used for thermodynamic heat. In using the letter q to symbolize the molecular partition function, usual practice is being followed. This usage should not give rise to confusion. 

Most of the pKd values of free radicals have been determined by pulse radiolysis, and it is therefore useful to recall, how fast pK equilibria become established. In general, the reaction of H+ with an acid anion is practically diffusion-controlled [reaction (2) k ranging between 5 x 109 dm3 mol1 s1 and 5 X 1010 dm3 mol 1 s 1 (Eigen et al. 1964 Perrin et al. 1981)]. The same holds for the deprotonation of an acid by OH [reaction (3)]. The rates of reaction (4) can be calculated from the pKa value taking into account that Kw = [H+] x [OH ] = 1014 mol2 dm 6. 

the pKa values of an acid is only determined by its rate of dissociation [reaction (1)]. Hence, in a homologous series, electron-withdrawing substituents reduce the pKa value by rendering the environment of the acidic function more positive and thereby accelerating the rate of dissociation of the (positively charged) proton. In contrast, an electron-donating substituent increases the pKa value. 

The time required to reach equilibrium very much depends on the pKd value of the acid. An acid with a pKa value of 4, for example, deprotonates with a rate of 106 s Thus, the equilibrium is established within a few microseconds. On the other hand, an acid with a pKa value of 7 dissociates with a rate of ca. 103 s 1, and the equilibrium becomes established only on the millisecond time range. In a pulse radiolytic experiment, a large part of the radicals will thus have disappeared in bimolecular termination reactions, before an equilibrium is reached. Buffers speed-up the protonation/deprotonation reactions, and their addition can overcome this problem. Yet, they deprotonate acids and protonate their corresponding anions typically two to three orders of magnitude more slowly than OH and H+ (for a DNA-related example, see Chap. 10.4 for potential artifacts in the determination of pKa values using too low buffer concentrations, see, e.g., von Sonntag et al. 2002). 

This general phenomenon is also of some importance in the case of the protonation of radical anions which can protonate at a heteroatom or at carbon. Kineti-cally, protonation at the heteroatom is always faster even when protonation at carbon is thermodynamically favored. A case in point is the protonation of the Thy radical anion (Chap. 10.4). 

Interestingly, the pKa values of acetic acid and its corresponding radical are practically identical (Table 6.1 Neta et al. 1969 Schuchmann et al. 1989, see also Schuchmann et al. 2000). In this case, not only the anion, but also the acid experiences a gain in mesomery [reaction (9)]. 

Extension of some notions from the theory of schemes to the theory of formal schemes General remarks 

In the followingC (resp.) denotes a formal scheme (formal pre-scheme in the old terminology, EGA I 10.4.2). We assume tacitly that the formal schemes are locally noetherlani this implies that they are adic (EGA I 10.4.2 ) and that there is a largest Ideal of definition (EGA I 10.5.4 ). 

Comparison between some local rings. Let C/ = Spf A with A a J-adic ring put S= Spec A. Let S6 there are canonical local homo-morphisms (EGA Oj.7.6 ) 

Where completion means J-adic completion, the composition /t.X is the canonical homomorphism from a ring to its completion. Both X (EGA 0 7.6.15 and 6.2.3) and /t (EGA 0 7.6.18) are faithfully flat. From 

Also it is known that the above local rings have the same residue field (EGA 0 7.6.10 and 7.6.17 ). 

As already remarked in the introduction, the formulation of the laws governing heterogeneous equilibria by Bakhuis Roozeboom1 was partly based on his studies on gas hydrates. Although the general laws he derived are certainly correct, and have marked an important step in the development of physical chemistry, Roozeboom and his contempories were mistaken in the nature of the phase diagram of gas hydrates gas hydrates are not stoichiometric 

When studying heterogeneous equilibria involving clathrates, one is faced with peculiar difficulties owing to the hysteresis effects mentioned in the introduction the solute in a clathrate crystal of hydroquinone, for instance, will not come to thermodynamic equilibrium with the vapor in which it is placed. Consequently it is impossible, or at least very difficult, to measure the equilibrium vapor pressure of the solute in a clathrate by placing some crystals in a tensometer (cf. the experiments of Wynne-Jones and Anderson,58 and those of Leech and Richards reported by Powell33). 

The largely prevailing view is that, besides the hydroxyl groups, also the molecular water is bound directly to the co-ordinatively unsaturated surface Ti ions. Combined TPD and IR data indicate that there are 2 to 3 molecules per nm of such strongly adsorbed water on the surface of Ti02 . The removal of this chemisorbed water from the surface of rutile requires, in general, the heating above 470 

The mode (or modes) of bonding of the second kind (weakly adsorbed) of molecular water, removed by outgassing at room temperature, appears less clear. Hydrogen bonding to the surface OH groups and adsorption at the isolated surface ions have been alternatively suggested. 

1 The above estimate was based upon comparison with the theoretical size of an OH group located on the surface of a solid, taken as 0.127 nm . This implies, however, that, under the saturation coverage, a significant amount of surface sites remain unoccupied. For example, in the case of the (001) plane of anatase, the portion of unoccupied sites would be of 33 per cent  

2 The concept of permeability of the oxide surface to the ions, known as the porous double-layer model, has originally been advanced to explain extremely large surface charges observed with some Si02 samples  

The above considerations are applicable to the titanium dioxide samples prepared and pretreated following the standard procedures. The presence of significant amounts of impurities or, for example, the high-temperature pretreatment of the Ti02 samples lead usually to a more or less important decrease of the extent of hydroxylation. 

Mass spectra can be recorded by using any one of several different systems of instrumentation. The inlet system can be either a hot reservoir inlet, a direct-probe inlet, or a gas-liquid chromatography (g.l.c.) inlet. The type of instrumentation and, especially, the inlet system may cause differences in the spectra recorded. However, with modern commercial instruments, these differences are generally small. Combined gas-liquid chromatography-mass spectrometry (g.l.c.-m.s.) has become increasingly important, and is particularly valuable for investigating complex mixtures. Gas-liquid chromatography of carbohydrates and their derivatives is the subject of articles in this Series.  

Most underivatized mono- and oligo-saccharides are thermally unstable and nonvolatile, and are therefore unsuitable for mass-spectrometric analyses. For m.s., the sugars must be converted into volatile derivatives this is especially important when g.l.c. is used in combination with m.s. Direct derivatization (for example, by acetylation) of a sugar generally generates an anomeric mixture of compounds that should be fractionated before introduction into the mass spectrometer. It is often advantageous 

Contrary to common belief, the Tafel equation as represented by Eqs. (1) or (4), with b given by Eq. (5), virtually never represents the electrode-kinetic behavior of electrochemical processes (except probably simple ionic redox reactions that have minimal chemical coupling of one kind or another, p. 125) in particular with reference 

In this section the bases of the above remarks are documented from previous literature and from new results recently reported. 

Documentation and Examples of the Experimentally Observed Dependence of 6 on T and the Behavior of a with T 

Historically, the h.e.r. has often been taken as a prototype process for discussions of the principles of electrode kinetics however, the behavior of this process at various metals is far from that represented by Eqs. (1) or (4) with 

Following the first indication in the work of Stout that b can be independent of temperature, Bockris and Parsons, and Bockris et showed that a similar effect arose in the h.e.r. at Hg in methanolic HCl between 276 and 303 K below these temperatures, b apparently varied in the conventional way with T. However, the derived a values showed a considerable spread. Variations of the temperature effect in b were discussed in terms of the possible influence of impurities but an overall assessment of all other, more recent, observations of the dependence of 6 on T for various types of reactions leads to the conclusion that the unconventional dependence is not due to some incidental effect of impurities. In fact, in another paper, Bockris and Parsons suggested that the temperature dependence of p for the h.e.r. at Hg arose because of expansion of the inner region of the double layer with temperature. They also noted that, formally, for b to be independent of T, the entropy of activation should be a function of electrode potential. 

The unsubstituted compounds 118 and 120 must be prepared via a large number of steps involving simple building blocks. This method has little preparative value. Moreover, the unsubstituted X -phosphorins appear to be so reactive that they are rather difficult to handle. Thus, the emphasis in synthesis has been placed on the preparation of 2.4.6-tri-substituted derivatives, which will be dealt with exclusively in this section. 

Three primary synthetic sequences have been developed  

1) Treatment of pyrylium salts with aryl-(or alkyl)-phosphines or their bis-hydroxymethyl derivatives. 

3) Transformation of X -phosphorins to other X -phosphorin-derivatives. Methods 2) and 3) allow for the highest degree of synthetic variation. X -Phos- 

The fact that X -phosphorins are not basic, as discussed above, matches the finding that phosphorinium ions 127, corresponding to the well-known pyridinium ions 126, caimot be isolated. However, they play a key role as interm iiates in many syntheses, since they are easily attacked by nucleophiles, forming X -phos-phorins 128. 

In this paragraph a short description is given of a representative number of prototypes of the element structures. Typical sections and/or projections are shown, also in order to present a few more complex (derivative) structures. 

Crystal details and numerical values (such as lattice parameter data, etc.) for the different elements are reported in Chapter 5 together with other elemental properties. 

Crystal data summarized first are those characteristic of structures of metallic elements, typically having highly symmetric and dense atomic arrangements. Only a few notes are reported for the close-packed structures (Mg, Cu types), since for these structures several details are presented in 3.7.6 and 3.9.2.I. Subsequently, particular structures observed for a few selected specific metals and, finally, a few typical structures of non-metallic elements are described. 

Notice that the structures presented in this paragraph are unary structures, that is one species only is present in all its atomic positions. In the prototypes listed (and in the chemically unary isostructural substances) this species is represented by a pure element. In a number of cases, however, more than one atomic species may be equally distributed in the various atomic positions. If each atomic site has the same probability of being occupied in a certain percentage by atoms X and Y and all the sites are compositionally equivalent, the unary prototype is still a valid structural reference. In this case, from a chemical point of view, the structure will correspond to a two-component phase. Notice that there can be many binary (or more complex) solid solution phases having for instance the Cu-type or the W-type structures. Such phases are formed in several metallic alloy systems either as terminal or intermediate phases. 

The data presented in the previous chapters, as well as the data from investigations of single-phase forced convection heat transfer in micro-channels (e.g., Bailey et al. 1995 Guo and Li 2002, 2003 Celata et al. 2004) show that there exist a number of principal problems related to micro-channel flows. Among them there are (1) the dependence of pressure drop on Reynolds number, (2) value of the Poiseuille number and its consistency with prediction of conventional theory, and (3) the value of the critical Reynolds number and its dependence on roughness, fluid properties, etc. 

All available experimental data (except the data by Peng and Peterson 1996 Peng and Wang 1998) show that the friction factor is inversely proportional to the Reynolds number, i.e., A = const/Re. The constant depends on the micro-channel shape only and agrees fairly well with the result of a dimensional analysis carried 

3 Velocity Field and Pressure Drop in Single-Phase Flows 

Concerning the critical Reynolds number, several groups of experiments related to laminar-to-turbulent flow can be set apart (Tables 3.5 and 3.6)  

The ratio of t/t, which is characteristic of the possibility of vortices, does not depend on the micro-channel diameter and is fully determined by the Reynolds number and L/d. The lower value of Re at which f/fh 1 can be treated as a threshold. As was shown by Darbyshire and Mullin (1995), under conditions of an artificial disturbance of pipe flow, a transition from laminar to turbulent flow is not possible for Re 1,700, even with a very large amplitude of disturbances. 

16 Dupont, J. and Spencer, J. (2004) Angewandte Chemie International Edition, 43 (40), 5296-5297. 

Denicourt-Nowicki, A., Olivier-Bourbigou, H., and Roucoux, A. (2008) Inorganic Chemistry, 47 (19), 9090—9096. Leger, B., Denicourt-Nowicki, A., Roucoux, A., and Olivier-Bourbigou, H. 

72 Dupont, J., and Suarez, P.A.Z. (2006) Physical Chemistry Chemical Physics, 

94 Calo, V., Nacci, A., Monopoli, A., and Cotugno, P. (2009) Angewandte Chemie International Edition, 48 (33), 6101-6103. 

127 Moreno-Manas, M. and Pleixats, R. (2003) Accounts of Chemical Research, 36 (8), 638-643. 

If it is impossible for steric reasons to adopt torsion angles in the desired range (i.e. in S7), the systems try to minimize the occupation of the neighboring rap2 lone pair orbitals with low torsion angles. This is achieved by 

Relief of the repulsion of coplanar np2 lone pair orbitals by np2 - no interactions 

This kind of an rap2- -racr interaction may lead to a marked bond lengths alternation the extreme structural effect of such an interaction is certainly found for S7, but also other neutral and cationic polychalcogen compounds frequently exhibit this interaction. 

This means that upon oxidation of neutral chalcogens giving the polychalcogen cations, electron density is removed from the occupied rap2 lone pair orbitals.15,16 From a molecular orbital (MO) view of such interactions 

For example, such n -n bonds are observed in the structures of Te64+ and the exo-endo structure of E82+ (see below). 

While a fluorescent molecule transits in a focused laser beam (during a few ms), it undergoes cycles of photon absorption and emission so that its presence is signaled by a burst of emitted photons, which allows us to distinguish the signal from 

The point is now to estimate the maximum number of photons that can be detected from a burst. The maximum rate at which a molecule can emit is roughly the reciprocal of the excited-state lifetime. Therefore, the maximum number of photons emitted in a burst is approximately equal to the transit time divided by the excited-state lifetime. For a transit time of 1 ms and a lifetime of 1 ns, the maximum number is 106. However, photobleaching limits this number to about 105 photons for the most stable fluorescent molecules. The detection efficiency of specially designed optical systems with high numerical aperture being about 1%, we cannot expect to detect more than 1000 photons per burst. The background can be minimized by careful dean-up of the solvent and by using small excitation volumes ( 1 pL in hydrodynamically focused sample streams, 1 fL in confocal exdtation and detection with one- and two-photon excitation, and even smaller volumes with near-field excitation). 

Focusing on selected aspects, a few reviews have covered SAM-controlled electrometallization [29], [30, 183]. Reviewing work published over the past 15 years, the following sections summarize the current state-of-the-art and discuss the different routes currently pursued. For this purpose we first start with a brief account of metal deposition on a clean metal substrate [29] 

Beside O P D it is well known that metal deposition can also take place at potentials positive of 0. For this reason called underpotential deposition (UPD) it is characterized by formation of just one or two layer(s) of metal. This happens when the free enthalpy of adsorption of a metal on a foreign substrate is larger than on a surface of the same metal [ 186]. This effect has been observed for a number of metals including Cu and Ag deposited on gold ]187]. Maintaining the formalism of the Nernst equation, deposition in the UPD range means an activity of the deposited metal monolayer smaller than one ]183]. 

Al-Enezi, G., Fawzi, N., and Elkamel, A. (1999) Development of regression models to control product yields and properties of the fluid catalytic cracking process. Petroleum Science e[ Technology, 17, 535. 

(1971) Linear programming models for plant operations planning. British Chemical Engineering, 16, 685. 

Rinard, I.H., Shinnar, R., and Sapre, A.V. (1995) Dynamics and control of fluid catalytic crackers 1. Modelling of the current generation of FCC s. Industrial Engineering Chemistry Research, 34, 1228. 

Baughman, D.R. and Liu, Y.A. (1995) Neural Networks in Bioprocessing and Chemical Engineering, Academic Press, San Diego, CA. 

Bodington, C.E. (1995) Planning, Scheduling, and control Integration in the Process Industries, McGraw Hill, New York. 

A highly efficient reagent for removing electrophilic and nucleophilic impurities is neutral aluminium oxide, which is used immediately before preparation of the solution or during the voltammetric measurement  

Because of the extremely high mobility of the redox equilibria (see Fig. 13) rapid consecutive reaction of just one member of the system will disturb these equilibria. For the same reason kinetic stability is the crucial property for detection and isolation of one or more components of the redox system. E. g. 52sem can be easily determined by UV/VIS- and ESR-spectroscopy in spite of Ksem being as small as 0.003. In contrast 21B with Ksem 6 10 and the corresponding system with two (CH2)3-bridges (Ksem 6 10 ) could not be characterized by their UV/VIS-spectra because they decay too rapidly. 

Unfortunately in quite a few cases voltammetric data become inaccessible because the electroactive compound is adsorbed on the electrode. By variation of the electrode material, the concentration of the different solutes, the solvent and the scanning time adsorption phenomena may occasionally be overcome. 

The most important solvent effects will be discussed in the following sections. 

The mission of clinical research is to provide scientifically appropriate and accurate information about new treatments in patients, keeping the safety of the patient as absolute priority referring to the law of Hippocrates Nil nocere (Not to harm). An additional ethical aspect of clinical research is the demand of high scientific standards. Therefore ... at the start of the trial, there must be a state of clinical equipoise regarding the merits of the regimens to be tested, and the trial must be designed in such a way as to make it reasonable to expect that, if it is successfully conducted, clinical equipoise will be disturbed (Freedman, 1987). 

As in other domains of medicine, there is an unabated demand for new, more efficacious psychiatric drug treatment with a better tolerability and side-effect profile. But is it really desirable to add further to the long list of psychophannaceuticals with their often similar properties of actions This question certainly must be answered in the affirmative for several psychiatric indications because there is a perceived lack of  

Given the need for development and clinical testing of novel drugs in patients, and the right of each patient to benefit from optimal treatment, there is obviously a conflict of putposes in clinical research that has been and still is evaluated differently at different times and under different circumstances. Opinion today is that a patient should, whenever possible, be the master of his own fate and not be delivered defenseless to the doctor an opinion that has been reflected in laws and guidelines. 

This seventy-seventh volume of the lARC Monographs reviews sixteen industrial organic chemicals, seven of which have previously been evaluated one or more times. For these seven substances, the most recent previous evaluations are summarized below. Since these previous evaluations, new data have become available, and these have been incorporated into the monographs and taken into consideration in the present evaluations. 

limited evidence S, sufficient evidence ND, no dat I, inadequate evidence 2A, probably carcinogenic to humans 2B, possibly carcinogenic to humans 3, cannot be classified as to its carcinogenicity to humans 

This volume includes evaluations of the carcinogenicity of several chemical intermediates or additives to which a large number of workers are exposed in various industries. Information on the extent of occupational exposures to many of these compounds in the United States was available from the National Occupational Exposure Survey (NOES) conducted by the United States National Institute for Occupational Safety and Health (NIOSH). NOES was a nationwide observational survey conducted in a sample of 4490 establishments from 1981 to 1983. The target population was defined as employees working in establishments or job sites in the United States of America employing eight or more workers in a defined list of Standard Industrial Classifications. 

Aromatic amines such as those evaluated in this volume are sometimes used commercially and/or in laboratory studies as their strong acid (e.g., hydrochloride) salts. The carcinogenicity of an amine and that of its strong acid salts are expected to be qualitatively similar, as the salts dissociate readily imder physiological conditions. 

Although epidemiological studies of some of the industries where exposure to chemicals considered in this volume occurs have been conducted, exposure to many of these chemicals has rarely been specifically assessed for epidemiological purposes. Quantitative estimates of historical exposure are often not available and therefore it is difficult to identify highly exposed subgroups or to estimate individual exposures. Without such data, it is difficult to evaluate exposure-response relationships which might, in some cases, allow cancer excesses to be attributed to specific agents when there is mixed exposure. 

In a semiclassical picture, the rate kda of nonadiabatic charge transfer between a donor d and an acceptor a is determined by the electronic coupling matrix element Vda and the thermally weighted Franck-Condon factor (f C) [25, 26]  

In line with the Franck-Condon principle, the electron transfer occurs at the seam of the crossing between diabatic (localized) states of donor and acceptor. The electronic coupHng is the off-diagonal matrix element of the Hamiltonian defined at the crossing point. 

From a fundamental point of view, one may prefer to determine the electron donor-acceptor coupHng directly from diabatic states. This procedure has certain advantages [36], in particular when one is interested in a detailed investigation of electron correlation effects. Computational strategies that rely on adiabatic (delocahzed) states are in general simpler to apply and thus more common [27]. 

Several such approaches for calculating electronic coupling matrix elements Vda have been proven to be useful. Most of them employ a two-state approximation [27, 28] where one assumes that donor and acceptor elec- 

Greater selectivity in purification can often be achieved by making use of differences in chemical properties between the substance to be purified and its contaminants. Unwanted metal ions may be removed by precipitation in the presence of a collector (see p 49). Sodium borohydride and other metal hydrides transform organic peroxides and carbonyl-containing impurities such as aldehydes and ketones in alcohols and ethers. Many classes of organic chemicals can be purified by conversion into suitable derivatives, followed by regeneration. This chapter describes relevant procedures. 

For a number of other chemicals, the starting point for these reviews was the last full summary and evaluation. The summarized statements prepared previously were incorporated with data published since the previous evaluation. These mini-monographs were prepared for those chemicals for which new epidemiological data and/or experimental carcinogenicity data were available that required review and acceptance by the full plenary meeting of invited experts, because changes in the classifications were anticipated. 

To minimize repetition in this very large undertaking, certain changes in procedure 

The Genetic and Related Effects data presented in the Monographs are also available in the form of Graphic Activity Profiles (GAP) prepared in collaboration with the United States Environmental Protection Agency (EPA) (see also Waters et al., 1987) using software for personal computers that are Microsoft Windows compatible. The EPA/IARC GAP software and database may be downloaded free of charge from WWW. epa. gov/gapdb. 

I ARC (1982) lARC Monographs on the Evaluation of the Carcinogenic Risk of Chemicals to 

Humans, Supplement 4, Chemicals, Industrial Processes and Industries Associated with 

In a foregoing section, we mentioned that field forces (e,g., of the electric or elastic field) can cause an interface to move. If they are large enough so that inherent counterforces (such as interface tension or friction) do not bring the boundary to a stop, the interface motion would continue and eventually become uniform. In this section, however, we are primarily concerned with boundary motions caused by chemical potential changes. From irreversible thermodynamics, we know that the dissipated Gibbs energy of the discontinuous system is T-ab, where crb here is the entropy production (see Section 4.2). Since dG/dV = dG/dV = crb- T/ A ), we have with Eqn. (4.8) at the boundary b 

Boundaries between solids transmit shear stress, particularly if they are coherent or semicoherent. Therefore, the strain energy density near boundaries changes over the course of solid state reactions. Misfit dislocation networks connected with moving boundaries also change with time. They alter the transport properties at and near the interface. Even if we neglect all this, boundaries between heterogeneous phases are sites of a discontinuous structural change, which may occur cooperatively or by individual thermally activated steps. 

Experiments have shown that A f for oxide spinel formation is on the order of 10 4cm at ca. 1000°C [C.A. Duckwitz, H. Schmalzried (1971)]. Using Eqns. (10.45) and (10.46) with the accepted cation diffusivities (on the order of 10 10 cm2/s), one can estimate from j% that each A particle crosses the boundary about ten times per second each way. In other words, quenching cannot preserve the atomistic structure of a moving interface which developed during the motion by kinetic processes. This also means that heat conduction is slower than a structural change on the atomic scale, unless one quenches extremely small systems. 

AB can then grow either by nucleation in the supersaturated segment, by continuous addition at sites of repeatable growth on the boundary, or by recurring AB nucleation on the interface plane. In view of the commonly occurring misfit at most boundaries, it is probable that sufficient growth sites are normally available. 

Let us conclude this section with a few general remarks. If we assume phase boundary rate control, the rate of advance is co-determined by the interface mobility, which in turn is related to the mobilities of the atoms in the interface. We note that 1) the directional dependence of mobilities or diffusivities in the interface may be quite pronounced (depending on 5) and 2) the mobilities or diffusivities depend on the component chemical potentials, which change over time at the interface until diffusion control eventually becomes rate determining. 

In the last chapter, equations were derived for the particle-scattering factor, the mean-square radius of gyration, the diffusion coefficient and the first cumulant of the dynamic structure factor. All these have the common feature that, for homopolymers at least, they can be written in the following form  

The equations for copolymers are a little more complicated but can be reduced to similar expressions, as will be shown later in this chapter. Moreover, if Gaussian statistics is obeyed for the subchains connecting two chain elements j and k, we have 

As already mentioned in the Introduction, the exact solution of the main equation of quantum mechanics - the Schrodinger equation - lies beyond the potentialities of modem mathematics and computer technology. But a number of important inferences about the behaviour, structure and properties of a given quantum-mechanical many-particle system can be drawn without solving this equation, just by examining its symmetry properties. 

Symmetry concepts come about in physics in two ways. First, since any physical process occurs in a real space, we have to make use of one or another coordinate system. The isotropy and homogeneity of space make physically meaningful only those mathematical relationships that remain unchanged under rotations of the axes of the coordinate system, and that impose fairly rigorous constraints on the possible physical laws. Second, every physical object and process features a symmetry which should be taken into account by the physical theory. 

A common idea underlying particular forms of symmetry is the invariance of a system under a certain set (group) of transformations. The normally considered forms of symmetry are rotational symmetry, which is based on the equivalence of all directions in space, and permutation symmetry, which is caused by identical particles. The operations of the geometrical symmetry group are responsible for appropriate conservation laws. So, the rotational symmetry of a closed system gives rise to the law of conservation of angular momentum. 

The group of rotations of a three-dimensional space stands apart in atomic spectroscopy. This is mostly due to the high accuracy of the central field approximation, on which the entire modem theory of complex atoms and ions is based. 

When constructing many-electron wave functions it is necessary to ensure their antisymmetry under permutation of any pair of coordinates. Having introduced the concepts of the CFP and unit tensors, Racah [22, 23] laid the foundations of the tensorial approach to the problem of constructing antisymmetric wave functions and finding matrix elements of operators corresponding to physical quantities. 

The usual products obtained from metal insertion reactions are shown in Table 3. They are used as starting materials for any axial ligand substitution processes. 

For brevity, the material will be presented in reaction schemes and tables. As far as possible, the dyads Ru/Os, Rh/Ir, Pd/Pt, and Ag/Au will be treated together. The homology of these pairs is expected due to the fact that the size of the two respective ions is very similar (lanthanoid contraction ). 

The quote by Schleyer that computational chemistry is to model all aspects of chemistry by calculation rather than experiment tells us that practically every mechanistic question can be tackled by computational methods. This is true in principle, but it says nothing about the quality of the computed numbers, and Coulson said, Give us insights, not numbers , which emphasises this point and relates to the fact that it is easy- fortune or curse - to compute numbers. This chapter presents some guidelines regarding the value and the interpretation of the numbers when it comes to elucidating reaction mechanisms with computational chemistry approaches. 

Chemistry is knowing the energy as a function of the nuclear coordinates. 

Describing properties is knowing the energy changes upon adding a perturbation. 

Computational methods typically employ the Born-Oppenheimer approximation in most electronic structure programs to separate the nuclear and electronic parts of the Schrodinger equation that is still hard enough to solve approximately. There would be no potential energy (hyper)surface (PES) without the Born-Oppenheimer approximation -how difficult mechanistic organic chemistry would be without it  

Potential energy surfaces are at the heart of all mechanistic chemical interpretations. Nevertheless, it is important to distinguish between pictorial presentations of mechanistic 

In mechanisms B and C, on the contrary, the iminium ion is first attacked by the carboxylate, which forms the hydrogen-bonded intermediate 20. Then substitu- 

Mechanism B may explain why in many cases chiral isocyanides (e.g. 11) give no asymmetric induction at all [21]. Indeed, the isocyanide is not involved in the transition state. In mechanism C the substitution by the isocyanide is rate-limiting and reversible formation of 20 originates a pre-equilibrium. Although (R)-20 should be kinetically favored, (S)-20 may be more stable because of the destabilizing interac- 

The competition between mechanisms B and C has been invoked in order to explain the surprising inversion of diastereoselectivity achieved by a simple variation of the overall reactant concentration at low concentration (S)-19 prevails, while at high concentration (R)-19 is formed in greater amounts [22, 23], An increase in concentration of the isocyanide is indeed expected to favor mechanism B over C, because it accelerates the isonitrile attack, making it non-rate-limiting. The concentration of the other components has the same effect for all mechanisms. 

Also the reaction temperature has been shown to have a remarkable effect on the extent of diastereoselectivity. Low temperatures seem to favor the formation of (S) diastereoisomers. This may be explained supposing that mechanisms A and C are more entropically disfavored than mechanism B. Therefore the entropy component in AG is higher and the decrease of rate on lowering the temperature is less pronounced. 

In conclusion, the hypothesis that the Ugi reaction proceeds, at least in polar solvents, through the competing mechanisms B and C seems reasonable, and may explain some unexpected experimental results. The intervention of mechanism A, especially in non-polar solvent, may not, however, be definitely ruled out. 

The following lemma is crucial for the remainder of this section. 

Let us first look at the case where i = 1. In this case, our assumption says that s e Rj(h) h. Thus, if j is odd, 

Corollary 10.1.2 Let i and j be positive integers, let h and k be elements in L such that h / k. Then we have the following. 

The claim holds obviously if n = 0. Let us, therefore, assume that 1 n. 

Since s Ln, there exists an element r in L 1 such that s rL. From r G Ln 1 we obtain, by induction, an integer i with 1 i n and an element l in L such that r  

In the simplest case multivariate data are obtained by acquiring measurements of several features. Because of this the data are often considered as multidimensional. Both notions are used without considering the number of objects characterized by the measurements. Typically, in multivariate data analysis, one has to cope with both problems many objects and features. 

If we do have, and include, a priori knowledge in addition to the measurements or numerical data we should use methods from the second family of basic data analysis methods. Here the data are considered to be grouped in respect of the objects, or maybe in respect of the features. Within this family we may further distinguish between non-causally and causally determined data, or by analogy with correlation and regression, we may distinguish between multivariate relationships and dependencies. 

Dependencies are mainly investigated by multiple or multivariate regression (one dependent and several independent variables), by multidimensional multivariate regression or partial least squares regression (several dependent and several independent variables), and by the method of simultaneous equations (explicitly allowing for corre- 

Chemometrics in Environmental Analysis. J. W. Einax, H. W. Zwanziger, S. GeiC Copyright 1997 WILEY-VCH Verlag GmbH ISBN 3-527-28772-8 

Sometimes canonical correlation or canonical analysis is referred to as a central technique with factor and correspondence analysis considered in one branch (having no causal concepts) and multivariate regression and discriminant analysis in the other branch (based on causal concepts). 

If the forces causing adsorption were known with a sufficiently high degree of accuracy and if their dependence on the distance of the adsorbed atom or molecule from the adsorbing surface were also exactly known, it would, theoretically, be possible to calculate the change in potential energy accompanying the act of adsorption. 

Though we know the exact laws of the mutual attraction of two ions and though we have also a fair knowledge of some other forces which may participate in adsorption phenomena, there are other forces, especially the repulsion forces, of which the magnitude and the dependence on distance are hardly known. 

It is true that all molecular and atomic forces ultimately find their root in the mutual behavior of the constituent parts of the atoms, viz., the nuclei and the electrons. They may theoretically all be derived from the fundamental wave equations. It is, however, convenient, as in other branches of physics and chemistry, to treat the various forms of mutual interaction of atoms as different forces, acting independently. We shall therefore follow the usual procedure and treat such forces as the nonpolar van der Waals (dispersion) forces, the forces of the electrostatic polarization of atoms or molecules by ions or by dipoles, the mutual attraction or repulsion Coulomb forces of ions and of dipoles, the exchange forces leading to covalent bonds, the repulsion forces due to interpenetration of electronic clouds, together with the Pauli principle, etc., all as different, independently acting forces. 

In all cases at least two of these forces act simultaneously a summation of their contributions to the adsorption energy over all participant atoms has to be made for each of the participating forces separately. Such a summation can in principle be applied with any desired degree of accuracy to some of the forces mentioned, provided that the distances between the participating atoms are exactly known. 

The nitration of toluene to TNT is carried out by successive introduction of nitro groups. Such a method is justified from the points of view both of safety and economy as it permits the most efficient use of acids and produces a final product of high purity due to the purification of the intermediate products obtained in the separate stages of the process. 

Nitration is commonly carried out in three stages, said less often in two 

The principle of economical acid usage is simply achieved by using the spent acid from a higher nitration stage for the lower stage, after it has been fortified to the required concentration. 

The diagram presented below illustrates the reactions occurring, and shows the average composition of the products and heat effects of the reactions. Another diagram (Gorst [4]) gives the yields of nitration of intermediate compounds. 

For example, Kharasch found that phenylmagnesium bromide reacts with acetone slightly faster than with acetaldehyde (krel 1.4)65a). In other cases, aldehydes are somewhat more reactive65b). The polar and highly reactive alkyllithium compounds 64b) are even less selective 66) (Equation 7). 

2 A 1 1 mixture of benzaldehyde and acetophenone reacts with 1 part methyllithium in ether (0 °C, 60 sec) to form a 1 1 mixture of aldehyde and ketone adducts with little side products 66 . Under slightly different reaction conditions a 2 3 ratio is obtained 76). 

In subsequent investigations the generality of the above behavior was established for n-alkyltitanium compounds 21,22 77,78). For example, quenching ethyllithium 25 with chlorotitanium triisopropoxide 3 affords 9, which reacts in situ with a 1 1 mixture of 19 and 20 to afford essentially only the aldehyde adduct 23 (Equation 9) 77). 25 itself reacts at 0 °C almost statistically  

Essentially complete chemoselectivity ( 99%) is also observed in reaction of 6, 9 and 10 with mixtures of aliphatic aldehydes (e.g., hexanal) and ketones (e.g., 2-hepta-none)77). The results show that the difference in activation energy (AAG ) for aldehyde and ketone addition must amount to several kcal or more. In fact, preliminary kinetic studies involving 26 and 27 reveal a relative rate of krel = k26/k27 = 223 79 . 

3 Secondary Grignard compounds isomerize to primary isomers in the presence of catalytic amounts ofTiCl48w. 

Finally, it should be noted that flow maldistribution, prevailing thermal conditions, and the possible differences in the prevailing flow regime in small- 

The effect of the medium on the position of equilibrium can be considered from two points of view (a) comparison of the gas-phase and solution equilibrium constants, and (b) comparison of the equilibrium constants for different solvents. Unfortunately, few equilibrium reactions have been studied both in the gas and liquid phases [5, 6j. These are primarily non-ionic reactions where the interaction between reacting molecules and solvent is relatively small e.g. the Diels-Alder dimerization of cyclo-pentadiene). In this chapter, therefore, equilibria which have been examined in solvents of different polarity will be the main topic considered (except for acid-base reactions described in Section 4.2.2). 

Let us consider a simple isomerization reaction A B in the solvents I and II, whose abilities to solvate A and B are different. This corresponds to the Gibbs energy diagram shown in Fig. 4-1. 

for equilibria, the logarithm of the equilibrium constant is proportional to the standard molar Gibbs energy change, AG°, according to Eq. (4-3), 

Solvents and Solvent Effects in Organic Chemistry, Third Edition. Christian Reichardt Copyright 2003 WILEY-VCH Verlag GmbH Co. KGaA, Weinheim ISBN 3-527-30618-8 

The required standard molar Gibbs energies of transfer can be obtained from activity coefficient measurements, using Eq. (4-3a), 

Considerable modification of the low temperature mechanism is necessary in order to explain observations made at higher temperatures. In competitive pairs of elementary steps, the reaction with the higher activation energy is progressively favoured as the temperature is increased. Decomposition processes become more important, and the high temperature oxidations show enhanced CO yields because of acyl radical decomposition [105] 

Above 400 °C, radicals which play little part in the oxidation below 150 °C may have considerable kinetic importance. Thus, the HO2 radical will now readily abstract hydrogen atoms 

Furthermore, if the HO2 concentration is able to become sufficiently high, the reaction 

Further complications will arise from reaction of alkyl radicals, produced by (6), with the reactants and with other radicals. 

A review of earlier observations has been given recently [42], and the following is an outline of the more essential points. 

The span of oxidoreduction potentials in which the different reaction centers 

HermetischeChhstentum iso iktuit, 1690-91 new edition, 1710), whose title and contents betray a mish-mash of theosophy, alchemy, Kabbalah, and Hermetism. 

Some works in eighteenth-century Germany still evidence interest in the Corpus Hermeticum. In the nineteenth century it was above all the Anglo-Saxon countries that took up the thread, but not before the second half of the century. In France, we should mention the work of Louis Menard Hermes Trismegiste. Traduction complete, precedee d une etude surTorigine des libres hermetiques (Paris, 1866, several times reissued). 

Hermetism still has an underground influence in the nineteenth century, more or less diffuse, whose importance is only beginning to be recognized. On its influence on Anglo-Saxon literature, see especially the important study of E. L. Tuveson, cited below, section 6A. Naturally all its repercussions cannot be mentioned in the limited compass of this survey, which is restricted to some of the most obvious manifestations of explicit Hermetism. 

The pyrolysis of one molecular species may consist of one or more pyrolytic reactions occurring simultaneously or sequentially. The path of a pyrolytic process depends on the experimental conditions. Mainly for polymers, after a first decomposition reaction step, it is common to have subsequent steps. In this case, the polymeric chain scission, for example, is followed by other pyrolytic reactions of the small molecules generated from the polymer. Therefore, pyrolysis of both small and large molecules occurs in the pyrolysis of a polymer. The result is a complex sequence of chemical reactions with a variety of compounds generated. 

When composite materials are pyrolysed, more than one molecular species is subject to thermal degradation. However, for composite materials each component can be considered as starting the pyrolytic process independently, which reduces somewhat the complexity of the problem. 

The pyrolytic process is commonly performed In an inert atmosphere or even at low pressure. However, it is not always possible to perform the process in gas phase (such as for polymers). Even in gas phase, but mainly in condensed phase, a series of chemical interactions may occur between different pyrolysis products. This, in addition to the multi-step characteristics, makes the result of the pyrolytic process extremely complex. The individual reaction types taking place during pyrolysis can, however, be studied independently. 

Another important issue concerns the intracellular buffers used. We have obtained good results with a potassium glutamate/HEPES buffer (see below). Whenever it might be important, the concentrations of free calcium ions have to be carefully controlled by the use of chelators. As the active concentration of free calcium for exocytosis in insulin-secreting cells ranges from 0.1 (xM (basal) to 10 xM (maximal stimulatory levels) with an EC50 at 2 xM, EGTA is a suitable chelator (Vallar ef ai, 1987). 

Clostridial Toxins and Endocrine Secretion Their Use in Insulin-Secreting Cells 223 

All solutions should be carefully adjusted to the correct pH. For intracellular solutions use ultrapure KOIH (Merck) to minimize further addition of calcium. 

Krebs-Ringer/HEPES buffer (KRH) without added calcium NaCI 125 mM KCI 5 mM MgS04 2 mM KH2PO4 1.2 mM HEPES 25 mM EGTA 0.4 mM adjust the pH to 7.4 with NaOH. Store in 20 ml aliquots at -20°C and warm to 37°C before use. This buffer is used to prewash the cells. The actual concentration of free calcium is about 10 [xM. 

2x concentrated intracellular buffer (KG) potassium-glutamate 255 mM NaCI 10 mM MgS04 14 mM FfEPES 40 mM adjust the pH to 7.0 with ultrapure KOH (Merck). Store in 20ml aliquots at -20°C. 

Efficient parallel synthesis of larger numbers of single defined compounds plays an ever more important role in dmg research. While it is possible to manually synthesize mixtures of large numbers of compounds on a solid phase employing the spHt-and-mix method, in parallel single compound synthesis a number of reaction vessels equal to the number of desired final products has to be handled (at least in the final step of the synthetic sequence) [l]. This latter approach clearly benefits from, or even requires assistance of some sort of robotic equipment/ devices. 

1) Obvious exceptions to this are compound libraries generated on beads by the mix-split technique, which are subsequently tested in single-bead assays. Here, the amount of compound obtained after cleavage from a single bead is sufficient to perform the biological assay. This is the classical one bead - one compound situation, whereby resin-bound compounds are synthesized in mixtures and sequestered before cleavage. In cases where 

Equipment for carrying out reactions in an automated or parallel fashion has become available that should meet virtually all requirements and budgets. Broadly speaking, this equipment can be categorized as follows  

In the following, an overview of equipment that is currently available commercially is presented. Especially in the early days of combinatorial chemistry, when little was available commercially, a significant number of companies designed and built their own robotic equipment. These proprietary solutions, as well as peptide synthesizers, are not listed herein. 

The data in the tables below are taken from company brochures and flyers, websites or from personal contacts at conferences, exhibitions, etc. This compilation reflects the state of affairs as of October 2004. For details which are beyond the scope of this review and to obtain the most up-to-date information, the reader is referred to the manufacturers websites (see Section 8.5). 

Since s L, there exists an element r in such that s G rL. Prom 

Both X-ray and neutron diffraction analyses are ineffective for locating hydrogen in 

Regardless of the microscopic phenomena, protonic conductivity is critically sensitive to the water content inside crystals and on their surface. Intrinsically nonconductive materials may apparently exhibit proton transport in wet environments due to adsorbed and/or condensed water. Consequently, numerous reports on the conductivity of compacted powders at 90-100% relative humidity, when vapor condensation in pores cannot be avoided, are excluded from consideration. Heating or cooling may cause H2O loss or uptake from the atmosphere, thus altering the conditions for proton transport in crystals. In such situations, the apparent found 

The third principal application of the electron spin resonance technique is to the study of paramagnetic transition metal ions in biochemical systems. Most examples are complexes of copper, iron, manganese, chromium, cobalt and molybdenum. Other metals such as titanium, vanadium and nickel are sometimes employed as structural probes. Only four of these ions, Cu , Mn, Gd and VO , are seen in ESR spectroscopy at room temperature under virtually all conditions. Therefore, they are of special importance. 

In this section, we briefly introduce the ESR parameters that are obtained for Mn , Co , Fe , Ni and Cu complexes, using as example one liganding molecule, the antitumor agent, bleomycin, which binds to a multitude of metal ions. The section terminates with an example from the ESR spectra of cupric complexes. Although the discussion of this example is lengthy, the techniques are applicable to other paramagnetic metals. Some limitations of the standard ESR technique are discussed prior to a survey of some of the more sophisticated methods that are available. 

Identification of paramagnetic metal ions is straightforward because each metal ion has sufficiently distinct ESR parameters [5-7,18,195,196]. The principal magnetic axes, defined by dimensionless g values, the interaction of the electron spin with the nuclear spin, defined by the hyperfine coupling constants, and spin-lattice relaxation times characterize each paramagnetic ion. 

Like Mn , high-spin Fe is usually in a strongly distorted octahedral environment in biological materials and only the transition between the 1/2 magnetic levels is 

The ESR spectrum for unoxygenated Co(II)Blm is characteristic of a five-coordinate configuration with an unpaired electron in the dl orbital. The spectrum exhibits two major sets of features with g 2.3 and g 2.03. Hyperfine coupling to 

0 mol) was added with agitation. The pH of the mixture was adjusted to 8.0 using concentrated HC1 and the suspension was stirred for 4 hours until a pale yellow slurry was obtained. The solids were filtered off and purified via slurrying in methanol (30.0 L) followed by filtration. Upon drying under house vacuum at ambient temperature for four days, 5.47 kg of solids (6) were obtained with a yield of 82% and HPLC purity above 80%. XH NMR (D20) S 4.72 (s, 2H), 7.02-7.19 (m, 4H). Anal. Calc, for C9H603FNa-H20 C, 48.66 H, 3.63. Found C, 48.64, H, 3.74. 

To a 22 L reactor equipped with agitator and gas diffuser was added EDTA (3.35 g, 

The chemical professionals, chemical engineers, and chemists, devote most of their fomial educational efforts to the study of technology and science. From courses in chemistry, physics, thermodynamics, kinetics, transport phenomena, unit operations, and design, the engineer or chemist learns about the laws of nature and how to describe physical phenomena in useful ways. To function in a tmly useful manner, however, today s chemical professional must understand much more than science and technology. The dynamic professional must understand the complex economic and sociopolitical factors which affect the application of technical and scientific expertise. 

As a number of technical alternatives are developed, economic issues must be considered. At today s prices and availability of supplies, which process is more efficient in resource utilization Are raw material prices and availability 

most of the technical problems in coal conversion are solvable, and 

As a student, the future chemical professional takes courses in basic economics and social science as well as perhaps business courses that develop skills and give insight into economic and sociopolitical factors. To be used effectively, this nontechnical knowledge should be related to the technical and scientific knowledge while the student is in school. 

This text is written to help bridge the gap between the technical and nontechnical education. The text material emphasizes those aspects along the technical-economic side of the triangular diagram, with frequent departures into the sociopolitical aspects where appropriate. Case studies and outside collateral readings may be used to illustrate interactions between all three decisive factors. For appropriate case studies, one should consider those published by the Harvard Business School. 

When radiation interacts with a sample scattering or diffraction occurs due to spatial and temporal correlations in the sample. In this section, the basic quantities and correlation functions will be introduced. In elastic and quasi-elastic scattering experiments the most important quantity is the magnitude of the so-called scattering vector given 

The nitration of aromatic compounds is a fundamental reaction [7] of utmost importance to the chemical industry. Many different regimens for this unit-process are known [8]. Nitrations have been described in microreactors [9-11] and during our own work with microreactors we have also gained experience with nitrations [12]. We have shown that it is possible to generate, in the laboratory, smaller amounts of chemicals using micro reactors, exemplified by the continuous nitration of 8.6 g of N-methoxycarbonyl-l,2,3,4-tetrahydro-isoquinoline over 6 full days. In an unlimited period of time one could produce unlimited amounts of chemicals with a single microsystem. Since this is unrealistic we are not 

For the phase 2 development work, larger kilogram amounts of the key component are needed, and we thought a continuous nitration process could be very advantageous for several reasons. 

We wanted to find the optimal conditions for the nitration in the laboratory on a small scale and subsequently transfer these conditions directly into the much larger scale of a pilot plant. 

Another aspect is the safety of nitrations. Batches of several hundred liters bear a substantial oxidation hazard. Very often the nitration products are explosives. By using microreactors the holdup volume is reduced to the micro- or milliliter scale and even in the production scale this volume ranges in the lower liter scale. 

S regular. Conversely assume S regular in s. From the remarks in 3.1 2 above follows that the condition of EGA 0 17-3.3 d is fulfilled therefore if is regular in s. Therefore  

Normal and regular formal schemes. A formal scheme if is normal 

Hence normality of rf implies S normal in all closed points, hence normality everywhere 

Because the oxidation state of chromium alters its biological effects, the effects of tri-valent and hexavalent chromium will be discussed separately. When chromium is released into the air, water or soil, factors in the environment may cause oxidation or reduction of the chromium that will affect its subsequent impacts. For example, hexavalent chromium may be rapidly reduced to the trivalent state if there is ample organic matter in the soil. Alternatively, oxidizing compounds in the soil may cause conver- 

Several transition metal complexes, especially those with d4 to d1 metal ion configuration, can exist either in the low-spin (LS) or high-spin (HS) states. Exceptionally, they can exist also in an intermediate-spin (IS) state. When the high-spin state is the ground one, this is not altered by temperature variation. However, when the ground state is the low-spin, a spin transition to the high-spin state can occur. Whether the spin transition is observable within the accessible temperature interval depends upon the individual substance and its microscopic properties (electronic structure, vibration spectrum). 

Substances in the low-spin and the high-spin states differ in a number of physical properties. Therefore the spin transition can be monitored by several techniques, as summarised in Table 9.1. 

Spin crossover (SC) was observed for the first time by Cambi and Cagnasso [1]. This phenomenon was reviewed in a number of excellent reviews [2-7]. Because of its possible technological utilisation [8,9], spin crossover is widely studied at present. The usual induction of spin crossover is based on temperature variation but pressure and concentration variations may lead to the same effect. Recently, optical induction has been involved and such experiments were termed the LIESST (Light Induced Excited Spin State Trapping) and the reverse LIESST effects [7]. 

A nuclear reaction is an interaction between two particles, a fast bombarding particle, called the projectile, and a slower or stationary target. The products of the reaction may be two or more particles. For the energies considered here ( 20 MeV), the products are also two particles (with the exception of fission, which is discussed in the next section). 

The particles in parentheses are the light particles, Xj being the projectile. Another representation for the reason is based on the light particles only, in which case the reaction shown above is indicated as an (x,X3) reaction. For example, the reaction 

Certain quantities are conserved when a nuclear reaction takes place. Four are considered here. For the reaction shown above, the following quantities are 

Many nuclear reactions proceed through the formation of a compound nucleus. The compound nucleus, formed after particle x, collides with X2, is highly excited and lives for a time of the order of 10 to 10 s before it decays to X3 and X4. A compound nucleus may be formed in more than one way and may decay by more than one mode that does not depend on the mode of formation. Consider the example of the compound nucleus 7N  

The modes of formation and decay of N are shown in the form of an energy-level diagram in Fig. 3.13. No matter how the compound nucleus is 

In Chapter 6 we mentioned the fact that all real changes have a direction which we consider natural. The transformation in the opposite sense would be unnatural it would be unreal. In nature, rivers run from the mountains to the sea, never in the opposite way. A tree blossoms, bears fruit, and later sheds its leaves. The thought of dry leaves rising, attaching themselves to the tree, and later shrinking into buds is grotesque. An isolated metal rod initially hot at one end and cold at the other comes to a uniform temperature such a metal rod initially at a uniform temperature never develops a hot and a cold end spontaneously. 

Yet the first law of thermodynamics tells us nothing of this preference of one direction over the opposite one. The first law requires only that the energy of the universe remain the same before and after the change takes place. In the changes described above, the energy of the universe is not one whit altered the transformation may go in either direction and satisfy the first law. 

The importance of being able to convert surplus propene into ethene has led to a great deal of industrially oriented research on the metathesis of propene, reaction (2). The forward reaction is slightly endothermic (AH = 1.7 kJ mol at 25°C) and the equilibrium proportion of propene is 65.9%, 62.6%, 59.4%, and 56.6% at 25, 125, 225, and 325°C, respectively (Kapteijn 1983b). 

The metathesis of propene has frequently been used as a probe of catalyst activity many references to this reaction will be found in Ch. 2. 

In view of the special position occupied by fluorine among the halogens in the periodic system, the preparation of its compounds is so different from that of the other halogen compoiuids that it is fitting to consider the fluorine compounds in a separate section. 

Inorganic fluorine compoiuids are prepared chiefly by the following methods  

Treatment of the oxides, hydroxides or carbonates with aqueous hydrogen fluoride. Most binary fluorides that do not luider-go hydrolysis may be prepared in this way (e.g., alkali fluorides, alkali hydrogen fluorides, alkaline earth fluorides, AIF3, SbFg, ZnFg, PbFg, HgF, AgF). 

Special reactions. These are so different from each other and occur so sporadically that they cannot be classified in any systematic way. For example, NFg may be prepared by electrolysis of molten ammonium hydrogen fluoride OFg is produced by attack of Fg on 2% sodium hj roxide solution and C Fg is formed from 3 + Og in a glow discharge tube cooled with liquid nitrogen. 

Some fluorine compounds may be prepared by any one of several methods (e.g., NOF from NO+ Fg or from NOBF + NaF), so that the choice of a method of preparation may be based on the availability of starting materials or apparatus. 

F ie 14.1 Schematic representation of the different types of surface treatment of concrete (o) organic coating, (fc) pore-lining treatments, (c) pore-blocking treatments, (d) thick cementitious coating, shotcrete or rendering, (6) 

Volume 11/29 presents the high-resolution spectroscopic data of diamagnetic and paramagnetic molecules as well as of molecular ions. For the diamagnetic species the publications up to the year of 2008 have been included. The paramagnetic species will follow later and cover the literature up to 2011. The spectroscopic information collected in this volume has been obtained principally fium measurements in the gas phase under reduced pressure. Thus, the parameters obtained represent those of the rmperturbed molecule, in very good approximation, and are useful standards for the comparison with properties of dense phases. 

Intemuclear distances are listed in the tables only for diatomic molecules and for some small open shell molecules. For all other polyatomic molecules the literature giving stractural information has been cited. New comprehensive compilations of stractural data can be found in the sub-volumes of 11/25 and 

There are certain technical limitations in the devulcanization of rubbers, and vulcanization is, in fact, not truly reversible (Pryweller, 1999). The partial devulcanization of scrap rubber will result in a degradation of physical properties. In many cases, this may limit the amount of substitution levels in high-tech applications such as passenger tires. But it can provide the compounder of less stringent products with an excellent low-cost rubber that can be used as the prime rubber or at very high substitution levels. According to Franta (1989), reclaim cannot be used for tread compounds in tires because every addition may decrease their resistance to wear. However, this statement has not been checked in case rubber devulcanized without an addition of chemicals. Considerable amounts of reclaim are consumed for carcasses of bias ply tires for cars if the compounds are of NR for carcasses of radial tires no reclaim is added. On the other hand, reclaim is added to compounds for bead wires and it may also be added to sidewalls. Within the framework of direct recycling options a number of applications for GRT outside the rubber industry have been proposed. Such applications include the use as a tiller in asphalt for the surface treatment of roads and as a rubberized surface for sport facilities. 

The virtues of photoinitiated cationic polymerization are rapid polymerization without oxygen inhibition, minimal sensitivity to water, and the ability to polymerize vinyl ethers, oxiranes (epoxides), and other heterocyclic monomers (see Table 10.7) that do not polymerize by a free radical mechanism. 

The different cations and anions of each molecule are covered in separate chapters. Most of the information on these ionic species results from gas-phase studies or quantum-chemical calculations. Only PHg and PHJ have been obtained to date as ions of salt-like compounds, either in solution or in the solid state PHg, e.g., in the alkali metal phosphides MPHg, where M = Li to Cs and PHJ, e.g., in the phosphonium halides PH4X, where X = Cl, Br, I. 

Specific features of non-linear steady states (beyond linear steady state) can be summarized as follows  

Srivastava and R.P. Rastogi, Transport Mediated by Electrified Interfaces, Elsevier, 

Chapman and T.G. Cowling, The Mathematical Theory of Non-Uniform Gases, Cambridge University Press, Cambridge, 1960. 

Prigogine, Non-Equilibrium Statistical Mechanics, Interscience, New York, 1962. 

de Groot and P. Mazur, Non-equihbrium Thermodynamics, North-HoUand Publishing, Co, Amsterdam, 1962. 

This book is obviously concerned with nuclear power plants, however, except for the aspects concerning the presence of radioactivity, the indications coming from operating experience are similar both for nuclear plants and for fossil-fuelled plants. Therefore, the indications and the suggestions from the latter are applicable to the nuclear power industry. 

There are many hundreds of important safety valves installed in a nuclear plant. Although they are components common to all process plants, the peculiar needs concerning perfect leak proofing, big sizes, quickness of action and high reliability demanded by nuclear plants make this component a particularly difficult one to build and maintain in compliance with regulations. As an example, the leak-proof specifications of some valves for nuclear plants were considered by many manufacturers, at the start of this industry, beyond the possibility of human technology . Obviously, system provisions do exist which may alleviate the task of the valves, such as redundancy and diversity incorporated in the design, however, even if these are considered, a valve remains one of the most critical components in a plant. 

It is evident that a large number of parameters are involved in the fabrication and testing of bulk adhesive specimens and adhesive joints these must be controlled if meaningful experimental data are to be obtained. Joint tests evaluate not only the mechanical properties of the adhesive, but also the degree of adhesion and the effectiveness of surface treatments. The standard test procedures listed by ASTM, BSI, DIN and other official bodies are essentially for testing adhesives and surface treatments rather than joints (e.g. Table 4.3). Unfortunately, most of these tests consist of joints in which the adhesive stresses are far from uniform. The designer and the researcher therefore have to select appropriate tests, and to know what the results mean in terms of their own particular investigations and applications. 

Adhesive tests may be used for various reasons, including(25)  

The last set of interactions is due to n bonding that may either occur in the Huckel sense and according to the (4n + 2) 71 electron rule or 

One of the special cases of coupled-cluster theory is the singles-and-doubles (CCSD) model [37]. The cluster operator Eq. (29) is restricted to contain only the singles and doubles excitation operators. The importance of this model can be seen from the fact that, for any coupled-cluster wave function, the singles and doubles amplitudes are the only ones that contribute directly to the coupled-cluster energy. In the explicitly correlated CCSD model the conventional cluster operator containing the T and T2 operators is supplemented with an additional term that takes care of the explicit correlation (written with red font) 

The derivation of the working expression can be done with the use of Wick s theorem, a di- 

The current Section is organized as follows in Subsection 4.2 the general information about the excitation operators, strong orthogonality projectors and correlation factors is 

The world-wide research budget expended on the development of new 

A variety of methods for establishing relationships between chemical structures and their biological activities have been applied C97, 99, 

2363- Because no satisfying theoretical model exists for structure-activity-relationships (SAR), it is not surprising that a complete empirical approach like pattern recognition has found some interest. Because of the high costs of synthesis and tests of a compound, even a pattern classifier with a rather high error rate (e.g. 30 %) would be economical Cl 073. 

The most difficult problem in pattern recognition applications to SAR-classifications is the formulation of meaningful descriptors that describe the molecular structure and are correlated with the classification problem. The widely used concept of a linear, binary classifier assumes a linear relationship between the structural properties (pattern components) x. and the biological activity. 

Excellent reviews of the application of pattern recognition techniques to structure-activity-relationships studies have been written by 

Infrared spectroscopy (IR spectroscopy) is a form of absorption spectroscopy, and is an important and easily applied method of qualitative and quantitative instrumental analysis of the molecule by means of this method it is possible to establish those functional groups of atoms which are present in the molecule and those which are not present, how they are linked, what 

The measured variable is the transmittance of the substance under analysis, as a function of the wave number 

Measurements are made in the infrared range of the spectrum between about 000 and 00 cm or 2.5 and 25 pm. The result of measurement is plotted as a curve and is termed the IR spectrum. The spectral ranges with low transmittance are known as absorption bands. The analytical significance of an IR spectrum is deduced primarily from the position of the bands and band groups within the spectrum and their intensity and form. 

Equipment manufacturers now offer Fourier-transform IR spectrometers as standard. These use the multiple-scan technique to analyze about 1 pg of 

The problem as far as water analysis is concerned is the detection limit of IR spectroscopy. This is in the percentage range, or under particularly favourable conditions in the range of mg/kg. 

In the literature there are several ways of classifying different types of models (cf. Roels and Kossen, 1978, and Sect. 2.4.3). From the viewpoint of process engineering, in this book distinctions will be made among macrokinetic, microkinetic, formal kinetic, and process kinetic models (see Fig. 2.14). The formal models that will be discussed individually in Chap. 5 are sometimes referred to in the literature as unsegregated or unstructured models that have a descriptive or predictive nature. 

It cannot be expected that any kinetic model will be directly applicable to a real process situation. Mathematical modeling must start with the simplest type, but it must be reiterated, modified, and extended until eventually it leads to an adequate process kinetic model (see Fig. 2.17). In modeling, great value 

In connection with this discussion it might be said that a rather simple method of structuring, such as, for example, distinguishing between the quantity of protein and the quantity of nucleic acids present, can lead to a great number of otherwise inaccessible parameters (Reuss, 1977). This can make an important contribution to the understanding of intracellular events. For engineering calculations, however, the primary claim of simplicity must also be satisfied. Furthermore, within the scope of the analytical methods presently available, distinctions among models are often simply not possible (Boyle and Berthouex, 1974). 

The important characteristics of models to be considered for engineering purposes are 

The model presents a simplified picture of the complex structure of a process in terms of a few key variables. 

Branching can also occur by another mechanism for dienes, conjugated and otherwise. When the monomer first enters the polymer, it forms a unit containing a double bond. In some cases, this double bond very soon becomes incorporated in the same macromolecular chain by a process referred to as 

The solution of the master equation (5.37) contains all the information about the system that is required in practice. Unfortunately, closed form solutions cannot be obtained even for the large class of reactions that are not important in practice. 

We just mention some methods that have been used in simple special cases  

The most important technique is the generating function method that transforms the system of (ordinary) differential-difference equations into one partial differential equation. Examples will be given for illustrating the scope (and limit) of this method. 

Not being able to solve the master equation in the more general cases we are often satisfied by the determination of the first and second moments. Furthermore, different techniques can be applied to approximate the jump processes by continuous processes, which are more easily solvable. The clear structure of the stochastic model of chemical reactions allows the possibility of simulating the reaction. By simulation procedures realisations of the processes can be obtained. The methods for obtaining solutions will be illustrated by discussing particular examples. 

The reaction consists of one elementary reaction step with the rate constant k. For the absolute distribution Pfi) = ( (0 = j) the form of the master equation is  

Using a mathematical method, a scientific citation analysis of the literature on boron nitride has been performed it allows a qualitative and quantitative analysis of BN-related information [1]. 

In the first chapter, some concepts of importance to solid state chemistry were explained. In the present chapter, the essential questions which must be answered in connection with solid state reactions will be outlined by means of a few examples. In later chapters, these questions will be treated in more detail, and, wherever possible, quantitatively. 

A solid state chemical reaction in the classical sense occurs when local transport of matter is observed in crystalline phases. This definition does not mean that gaseous or liquid phases may not take part in solid state reactions. However, it does mean that the reaction product occurs as a solid phase. Thus, the tarnishing of metals during dry or wet oxidation is considered to be a solid state reaction. 

A question to be considered is whether the local fluxes of matter in multicomponent systems are coupled with each other so that, for example, a flux of component i induces a 

The characteristic of heterogeneous reactions is the occurrence of phase boundaries across which mass transport takes place. 

Chemical reactions between solid crystalline materials are in general exothermic. The reason for this is the high degree of order of crystalline phases, which means that the entropy difference between these phases is relatively small. Nevertheless, most solid state chemical reactions can easily be carried out isothermally, since, by virtue of the low reaction rates, the quantity of heat given off per unit time can easily be conducted away. Exceptions from this rule will be dealt with separately at appropriate places. 

The coolants that come into contact with the nuclear areas of the reactor plants, primarily the PWR primary coolant and the BWR reactor water, are contaminated even during plant normal operation with radionuclides formed by various nuclear reactions. However, the appearance of these radionuclides in the coolants does not cause any difficulties in plant operation since all the relevant circuits are designed for safe operation in the presence of radioactivity. 

Depending on the mechanism of their formation, these radionuclides can be divided up into three groups  

19 Clayden, J., Greeves, N., Warren, S., and Wothers, P. (2001) Organic Chemistry, Oxford University Press Inc., New York. 

42 Farina, V., Krishnamurthy, V., and Scott. W.J. (1998) The StiUe Reaction, John Wiley Sons Inc., New York. 

67 Santos, L.S., Dalmazio, L, Eberlin, M.N., Claeys, M and Augusti, R. (2006) Rapid Commun. Mass Spectrom., 20, 2104. 

69 Kesavan, P.C. and Sarma, L. (1995) Subcellular Biochemistry. Plenum, New York. 

83 Haines, H.A. (1985) Methods for the Oxidation of Organic compounds. Academic Press, New York. 

Handbook of Ion Chromatography, Fourth EditioiL Joachim Weiss. 

2 Thermal Decomposition 4.1.12.6.2.1 The N2F4 2NF2 Equilibrium Gas Phase 

Thermodynamic Data. Facile dissociation of gaseous tetrafluorohydrazine into two difluoro-amino radicals at temperatures between 20 and 250°C provoked a number of studies of that equilibrium. Reaction enthalpies, AH, that have been derived from experimental data by second-law analysis are given below  

Internal energy changes AU, which are the primary result of the analysis of ESR, IR, and UV data, are lower than AH by RT 0.6 kcal/mol at room temperature [3 to 6]. Heats of dissociation (from [1,5, 7]) were reanalyzed in the JANAF Tables [8] by third-law methods, see p. 319 where further reviews are compiled. The result of a second-law analysis of the temperature-dependent 260-nm NF2 absorption was preferred over that from a third-law analysis (AHgge = 21.05 0.10 kcal/mol). The latter value depended on the unknown distribution of trans- and gauche-N2F4 conformers a 1 1 mixture was assumed [6]. An ab initio MO calculation with a Gaussian basis set predicted AUJ= 11.9 kcal/mol and AH29s= 12.5 kcal/mol [11]. Data derived from appearance potentials are mentioned on p. 319. 

Values of the function -A(Gj-for temperatures between 375 and 462 K, for example, 42.794 cal-mol -K at 375 K and 42.689 cal-mol -K at 462 K, rely on the assumption that a 1 1 mixture of trans- and gauche-N2p4 dissociates into NF2 radicals [6]. 

An equilibrium constant of 8.8 x 10 atm at 25°C was derived from the pressure-dependent NF2 UV absorption. The N2F4 pressures varied between about 25 and about 800 Torr [1 ]. A more recent measurement at lower pressures between 2.5x10 and 4x10 Torr confirmed the earlier value, Kp = (7.0 1.1) xIO Torr ((9.2 1.4)x 10 atm) at 300 K [16]. Values of 2.4 X10 [1] (misquoted in [16]) and 1.3 x 10 atm [2] at 300 K were extrapolated from early (dp/dJ)y measurements at higher temperatures and pressures. The ratio of the termolecular NF2 recombination rate constant and bimolecular N2F4 dissociation rate constant (both measured at 298 K in Ar) yielded an equilibrium constant of (4 1) x 10 molecule/cm in fair agreement with directly measured [1] and calculated [8] values. 

The fact that quinones may form tt complexes with transition metals was first recognized by Sternberg et al. 53), who found that butyne reacts with iron pentacarbonyl in sunlight to afford duroquinone-iron tricarbonyl (XIX). These authors also reported that manganese pentacarbonyl hydride yields durohydroquinone under similar conditions whereas nickel carbonyl did not react 53a). However, more recent work has established that duro-quinone and some other substituted quinones are capable of forming Ni(0) complexes, most of which are surprisingly stable. 

Many other filtration-related factors exist that may influence the concentration of constituents in the dissolved fraction. This was demonstrated by Horowitz et al. (1992) in a systematic investigation of membrane filtration artefacts when determining Fe and Al in synthetic and natural waters. They found that the dissolved concentration of these elements was significantly influenced by the filter type, filter diameter, method of filtration, concentration 

The phase composition of the diffusion zone for reactive diffusion in multicomponent systems is rather difficult to predict [19-21]. The reason is that some of the phases which are present in the equihbrium phase diagram do not appear even after a long period of anneaHng [22, 23]. This effect depends on the initial composition of the samples and on the regime of diffusion interaction. Note that in an unHmited binary system, aU intermediate phases will sooner or later definitely appear. The increase of the number of components participating in diffusion results in an increase in the number of the possible regimes for 

1) (a) a pure component A (strictly speaking, a very dilute solution of B and C in 

3) (a) intermediate phase 1 (in an interval of concentrations [c, Cjr]) with the solid 

The diffusion couple pure A-solid solution (with a concentration of component B equal to c and zero concentration of A) is considered. At the annealing of such a (diffusion) pair, theoretically, there can be several alternative choices for the diffusion path for example, A-l- 8, A-l-2- 8, and A-2-l- 8. The formation 

1) Which diffusion path does the system choose.  

Stereoselective hydroformylation can be divided into diastereo- and enantioselec-tive (asymmetric) reactions. Enantioselective transformations can be conducted with the assistance of a chiral catalyst. But diastereoselective reactions can also benefit from a chiral catalyst by utilizing Masamuni s principle of matched/mismatched combinations of chiral substrate and chiral catalyst [1]. In this chapter, reference will be made only to ligands originally developed for asymmetric hydroformylation (AHF), but it is clear that they can also be used for diastereoselective transformations. 

Only the syntheses of those Ugands that exhibit either a superior catalytic performance with respect to regio- and enantioselectivity for a single prochiral olefin or have the potential for the highly selective AHF of a broader range of substrates will be discussed in detail here. 

Up to now, all studies point to the fact that chiral monodentate phosphorus Ugands do not fulfill the expectations for highly efficient AHF [10]. The most 

This chapter, which covers the period 1985 through 1993, continues the earlier presentations appearing in Borverbindungen 10, 1976, pp. 270/2, Boron Compounds 1st Suppl. Vol. 1, 1980, p. 1, Boron Compounds 2nd Suppl. Vol. 1, 1983, pp. 1/2, and Boron Compounds 3rd Suppl. Vol. 1, 1987, p. 1. 

Using space-time-resolved laser-induced fluorescence and plasma-induced emission spectroscopy, the interaction between BCI3 and Ar gives metastable and dissociation product densities that vary nonlinearly as Ar is diluted by BCI3. A model is proposed in which argon metastable states indirectly enhance molecular dissociation [7]. 

Interaction between B + and He was studied. The double-capture cross sections at high velocities are in reasonable agreement with scaled Oppenheimer-Brinkman-Kramers calculations, assuming the capture of independent electrons [8]. 

Before fnlly appreciating any concept of mass transport, an understanding of the frequently used term flux is necessary. It is simply the amonnt of flnid transported per unit time per unit area (perpendicular to the direction of transport). According to the well-known Pick s law, the flnx is proportional to the concentration difference of a moving gas between two points divided by the distance separating the points, and the proportionality constant is known as the diffusion coefficient or dif-fusivity (with nnits of distance /time). 

When transport occurs between phases, we usually express the flux as a function only of the concentration difference of the diffusing gas. The proportionality constant here is known as the mass transfer coefficient (with units of distance/time). More puristically, it is referred to as the phenomenological mass transfer coefficient, to distinguish it from other, often more useful, definitions. This is usually the chemical engineer s 

In cases where the reactants are present in two different phases, one of the reactants must diffuse from its phase into the other for reaction to occur there. If the distribution coefficients of the two reactants do not favor any particular phase, the reaction can occur in both the phases (particularly if both are liquid). Clearly, therefore, the rates of mass transfer of reactants between phases become an important consideration in heterogeneous systems in general. 

Another theory of mass transfer is based on the postulation that elements of the fluid impinge on the interface where they remain for a specified period of time during which they shed their load of reactant and then return to the body of the fluid. The contact time of an element with the interface can be constant for all elements (Higbie, 1935) or vary from elanent to element (Danckwerts, 1953). Such a postulation, sketched in 

In contrast, the method is successfully used for RF gels (Mathieu et al., 1997) probably because these organic gels have a strength and elasticity that can better withstand the stresses during freeze-drying (Koddenberg et al., 1998). 

In actual service, aging is caused by radiation, heat, and air as well as by mechanical loads and/or ambient media (air, water, oil, etc.). Their influence on aging is acquired separately in dedicated experiments in order to allow for a clear evaluation of individual influencing factors. Here, any synergetic or antagonistic effects from simuitaneously acting individual factors are disregarded. 

Heteropolyanions are polymeric oxoanions which are formed by the condensation of more than two different oxoanions (e.g., eq.(l)). Polyanions consisting of one kind of oxoanions are called isopolyanions. The term heteropoly compounds is used to indicate heteropoly acids (free acid forms) and their salts. 

A variety of polyanion structures are known. For example, the structure of the polyanion of so-called Keggin structure is shown in Fig. 3.74a. The heteropoly compounds having the Keggin structure are thermally more stable and rather e y obtained, so that investigations have been devoted mostly to this group. They are used as acid catalysts as well as oxidation catalysts in both hereto- and homogenous systems (cf. comprehensive review on heterogenous catalysis ). The principal merits of heteropoly compounds when they are used as solid acid catalysts are as follows.  

Hi) Some heteropoly compounds exhibit pseudo-liquid behavior which endows those compounds with unique catalytic properties. 

Heteropoly compounds are efficient catalysts for various reactions in solution, e.g. hydration, etheration and esterification. They usually exhibit much higher catalytic activities than mineral acids. The hi activities of heteropoly compounds are principally due to the strong acidity and the stabilization of reaction intermediates by complex formation. 

The bcc packing of polyanions (the primary structure) is illustrated on the right. Each [HSO2] bridges four polyanions as shown on the left.  

The most attractive feature of a-6T and a-8T crystals is undoubtedly the access that they provide to optical dichroism (absorption and luminescence) and charge transport anisotropy (carrier mobility) so that comparison can be made with what is currently observed in polycrystalline thin films and disordered polythiophenes. Beside a-6T and a-8T, a few studies have also been done on doped Q -4T(Q -Me)2 single crystals. 

The photoluminescence (PL) emission spectrum of the o -6T single crystal exhibits three vibronic components separated by ca. 0.19 eV, the most intense peaking around 640 nm [112], The PL quantum yield of has not been measured for single crystals but has been estimated between 10 and 10 for polycrystalline o -6T thin films. These values are much lower than those obtained in solution (0.35 to 0.40). 

Finally, Klein et al. report on the femtosecond time-resolved spectroscopy of a-6T single crystals and explain the induced absorption and stimulated emission by the decay of the singlet excitons to the lower Davydov band [113]. 

A canted spin structure may exist under certain conditions, see pp. 191, 206, and 217. Regarding the ferromagnetic phase, see the following section. 

The wetting of a planar substrate by a liquid is characterized by the macroscopic contact angle 6 (Fig. 5.5). The equilibrium condition for the contact line between the three phases solid, liquid and vapour, yields the value of 9  

This Young s equation relates the wetting angle to the three surface tensions the free metal surface tension y, the free substrate surface tension ys and the interfacial tension y.  

The thermodynamic work of adhesion, on the other hand, is the work required to pull apart a unit area of a liquid-solid interface, thus creating one solid-vapour and one liquid-vapour interface  

Equations (5.3.1) and (5.3.2) yield the Young-Dupre relationship between the work of adhesion and the wetting angle  

Two famihes of metal-oxide interfaces are traditionally distinguished the reactive and the non-reactive interfaces. At a non-reactive interface, the concentration of oxygen dissolved in the metal does not exceed the usual impurity concentration - a few parts per million (ppm). Chemical bonds between the oxide and the metal atoms may exist, but no displacement of atoms nor formation of a new interfacial compound takes place. If these latter elfects occur, the interface is said to be reactive. The border line between the two families is ill defined, mainly because it is very temperature dependent. 

The quasiharmonic approximation studied in Sects.5.2,3 gives reasonable results for the thermodynamic properties of crystals in which the anhar-monicity is weak and the force constants are renormalized by thermal expansion only. In crystals with very strong enharmonic interactions, however, this approximation breaks down. Examples are the vibrations in rare-gas solids, in particular solid helium, soft modes in ferro-electric phase transitions and melting processes. For these cases a method has been developed, the self-consistent harmonic approximation (SCHA), which allows a qualitative description of the effects of strong anharmonicity. 

The SCHA has been the subject of many papers starting with the pionerring work of BORN [5.34] and HOOTON [5.35]. Subsequently, a number of important and independent studies have been performed, each in a different formalism BOCCARA and SARMA [5.36], CHOQUARD [5.37], KOEHLER [5.38], HORNER [5.39], 6ILLIS et al. [5.40], and WERTHAMER [5.41]. 

The SCHA is based on the fact that if an atom in a crystal is executing oscillations of comparatively large amplitudes, it is not proper to treat 

In the harmonic or quasiharmonic approximations, the restoring force acting on the atom if this atom is displaced from its equilibrium position, is calculated on the basis that all the other atoms are rigidly fixed to their lattice sites. [Remember that the force constant [ or example, is 

The SCHA is formally again harmonic, that is, the true lattice system is to be approximated by some other effective harmonic lattice whose force constants and lattice parameter are to be optimally adjusted. The renormalized force constants are obtained from a self-consistency condition. Self-consistency is achieved by replacing the normal harmonic force constants by effective force constants which are thermal averages with respect to the effective harmonic Hamiltonian. 

The TPEs treated in this chapter are linear, segmented copolymers, typically of the (AB) build-up, where A and B represent the hard and soft blocks, respectively. The physical crosslinks in the TPEs usually originate from crystaUine 

Since the properties of TPEs can be adjusted by the synthesis, their modification via blending is less explored. For this reason, TPEs are predominantly used as modifiers i.e., minor phase components) in blends and 

These introductory notes on compatibility are important for the better understanding of one of the main advantages resulting from an inherent property of the blends prepared from condensation or functionalized polymers. At appropriate thermal treatment conditions (sufficiently high temperature and treatment duration, vacuum, catalyst, etc.), chemical reactions (additional condensation and transreactions) between condensation polymers in the melt [9], as well as in the solid state [10] can take place at the interfaces, as shown schematically below  

These reactions result in the formation of a copolymeric layer at the interface, playing the role of a compatibilizer, i.e., one deals with a self-compatibilization effect in that there is no need to introduce an extra synthesized copolymer of the blend components, as in the common approach [5]. Compatibilization can be effective only in the initial stages of chemical interaction. During prolonged thermal treatment, the reaction goes to completion and finally involves the entire amount of the molten blend components in the formation of block copolymers, thus transforming the homopolymeric (molten) blend into copolymers. 

In the case when (A) and (B) are crystallizable homopolymers, the block copolymers also crystallize. With the progress of the chemical interactions, the block copolymers may, however, convert into random copolymers. 

In the following sections, we will provide an overview of density matrix-based SCF theory that allows one to exploit the naturally local behavior of the one-particle density matrix for molecular systems with a nonvanishing HOMO-LUMO gap. Besides the density matrix-based theories sketched below, a range of other methods exists, including divide-and-conquer methods, Fermi operator expansions (FOE), °° Fermi operator projection (FOP), ° orbital minimization (OM), ° ° and optimal basis density-matrix minimization (OBDMM). ° ° Although different in detail, many share as a common feature the idea of (imposed or natural) localization regions in order to achieve an overall 0 M) complexity. This notion implies that the density matrix (or the molecule) may be divided into smaller 

The need to conduct the handling and storage of cryogenic liquids in a safe and responsible manner is obvious for moral, environmental and economic reasons. 

LPG and Other Cryogenic Liquid Mixtures, SpringerBriefs in Energy, DOI 10.1007/978-3-319-20696-7 9 

A good first point of reference is The Cryogenics Safety Manual A guide to good practice published by the British Cryogenics Council [1]. 

The Cryogenics Safety Manual is a useful guide to good practice for all operators and users handling cryogenic fluids. The Manual was first published in 1970 and it has since been revised in 1982,1991 and 1998 with afifth edition planned for 2016. 

Other references on safety include the volume by Zabetakis, on Safety with Cryogenic Fluids, published in 1967 [2], and the volume by Edeskuty and Stewart on Safety in the Handling of Cryogenic Fluids, published in 1996 [3]. 

The Instrumentation and Control (l C) of a nuclear research reactor (NRR) is the shell between the operator and the plant. 

This shell may be considered as comprised by two independent systems, the reactor protection system and the supervision and control system. All the instrumentation used for this shell can be classified in three groups nuclear instrumentation, non-nuclear instrumentation, and radioprotection instrumentation 

The technological process of the plant is divided into systems, most of these systems have to be provided with I feC equipment. 

As a result of history and experience or an appropriate functional analysis, these l C systems are co-ordinated into functional groups The borders of these functional groups are however not always coinciding with the borders of the respective system 

The principle of functional groups offers the following advantages 

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General Remarks. In the follo ving pages an account is given of the results which may be observed when an unknown organic compound is subjected to the following tests ... 

Note Additional procedural information plus interferences and general remarks will be found in J. A. Dean, ed.. Analytical... 

Potassium Leiuene sulphonate, 177 Potassium ethyl sulphate, 50 Potassium methyl sulphate, 50 Preparations, general remarks, 47 Pressure tube, glass, 24, 78 furnace, 24 metal, 227... 

GENERAL REMARKS. Including defects requiring attention and alterations since last examination or any departure from the relevant regulations. 

Hydrochloric acid Most of the general remarks in the last section dealing with sulphuric acid are also applicable to hydrochloric acid, but the chloride ion makes this acid a very aggressive one and the application of stainless... 

Referring again to the paper of Lunn and Senior, I conclude these general remarks and turn to the analytic determination of the number of isomers of certain special compounds. 

SOME GENERAL REMARKS UPON COLORIMETRIC DETERMINATIONS... 

Cobalt, sepn. of from nickel, (cm) 532 Codeine and morphine, D. of 740 Coefficient of variation 135 Colloidal state 418 See also Lyophilic, Lyophobic Colorimeters light filters for, 661 photoelectric, 645, 666 Colorimetric analysis 645 criteria for, 672 general remarks on, 645, 672 procedure, 675 solvent selection, 674 titration, 652... 

Some general remarks upon colorimetric determinations 672... 

Before proving this theorem, we will make some general remarks about the nature of the one-electron functions ipk(x) or spin orbitals. For the two values of the spin coordinate f — 1, such a function y)k(r, f) has two space components... 

A few general remarks about the absorption-edge method are in order here. For any element, only two absorption edges, the K and the Lm... 

Reduction from Functional Form to Algebraic Form is considered here to belong more properly to functional analysis rather than to numerical analysis, and neither an effective survey nor a representative sample of methods is possible in a few pages. Nevertheless, one or two general remarks may be in order. 

Before proceeding to describe the manufacture of the nitramines, RDX and Tetryl, a few general remarks about the preparation of nitramines... 

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