Need concept

Determination of mission needs Concept studies approval... 

In their influential self-determination theory, Deci and Ryan developed the basic psychological needs concept, an organismic theory to explain why certain kinds of activities are motivating (Deci Ryan, 1985, 2000 Krapp Prenzel, 2011). They identified three basic needs as highly important for motivation the perception of autonomy, of competence, and of social embeddedness. For school education, Prenzel (1997) extended these needs by three additional factors the perception of relevance, the interest of the educator, and the quaUty of instruction. 

It is always exciting and stimulating to probe needed concepts and devices in pneumatic conveying. Bringing modem technology to a field that has often been classified as low-tech is rewarding. In our laboratory as well as in others, there are some unique developments worth noting. 

The terms standards and specifications are constantly confused and interchanged in everyday use. The general opinion is that they are synonymous yet these two terms cover different concepts. Therefore, they — as well as the organizations that are responsible for their development — need to be defined. 

The idea that unsymmetrical molecules will orient at an interface is now so well accepted that it hardly needs to be argued, but it is of interest to outline some of the history of the concept. Hardy [74] and Harkins [75] devoted a good deal of attention to the idea of force fields around molecules, more or less intense depending on the polarity and specific details of the structure. Orientation was treated in terms of a principle of least abrupt change in force fields, that is, that molecules should be oriented at an interface so as to provide the most gradual transition from one phase to the other. If we read interaction energy instead of force field, the principle could be reworded on the very reasonable basis that molecules will be oriented so that their mutual interaction energy will be a maximum. 

To extract infomiation from the wavefimction about properties other than the probability density, additional postulates are needed. All of these rely upon the mathematical concepts of operators, eigenvalues and eigenfiinctions. An extensive discussion of these important elements of the fomialism of quantum mechanics is precluded by space limitations. For fiirther details, the reader is referred to the reading list supplied at the end of this chapter. In quantum mechanics, the classical notions of position, momentum, energy etc are replaced by mathematical operators that act upon the wavefunction to provide infomiation about the system. The third postulate relates to certain properties of these operators ... 

Slater and Kirkwood s idea [121] of an exponential repulsion plus dispersion needs only one concept, damping fiinctions, see section Al.5.3.3. to lead to a working template for contemporary work. Buckingham and Comer [126] suggested such a potential with an empirical damping fiinction more than 50 years ago ... 

Consider two distinct closed thermodynamic systems each consisting of n moles of a specific substance in a volnme Vand at a pressure p. These two distinct systems are separated by an idealized wall that may be either adiabatic (lieat-impemieable) or diathermic (lieat-condncting). Flowever, becanse the concept of heat has not yet been introdnced, the definitions of adiabatic and diathemiic need to be considered carefiilly. Both kinds of walls are impemieable to matter a permeable wall will be introdnced later. 

With the advent of short pulsed lasers, investigators were able to perfonn time resolved coherent Raman scattering. In contrast to using femtosecond pulses whose spectral widtii provides the two colours needed to produce Raman coherences, discussed above, here we consider pulses having two distinct centre frequencies whose difference drives the coherence. Since the 1970s, picosecond lasers have been employed for this purpose [113. 114], and since the late 1980s femtosecond pulses have also been used [115]. Flere we shall briefly focus on the two-colour femtosecond pulsed experiments since they and the picosecond experiments are very similar in concept. 

For the Berry phase, we shall quote a definition given in [164] ""The phase that can be acquired by a state moving adiabatically (slowly) around a closed path in the parameter space of the system. There is a further, somewhat more general phase, that appears in any cyclic motion, not necessarily slow in the Hilbert space, which is the Aharonov-Anandan phase [10]. Other developments and applications are abundant. An interim summai was published in 1990 [78]. A further, more up-to-date summary, especially on progress in experimental developments, is much needed. (In Section IV we list some publications that report on the experimental determinations of the Berry phase.) Regarding theoretical advances, we note (in a somewhat subjective and selective mode) some clarifications regarding parallel transport, e.g., [165], This paper discusses the projective Hilbert space and its metric (the Fubini-Study metric). The projective Hilbert space arises from the Hilbert space of the electronic manifold by the removal of the overall phase and is therefore a central geometrical concept in any treatment of the component phases, such as this chapter. 

When constructing more general molecular wave functions there are several concepts that need to be defined. The concept of geometry is inhoduced to mean a (time-dependent) point in the generalized phase space for the total number of centers used to describe the END wave function. The notations R and P are used for the position and conjugate momenta vectors, such that... 

The free energy differences obtained from our constrained simulations refer to strictly specified states, defined by single points in the 14-dimensional dihedral space. Standard concepts of a molecular conformation include some region, or volume in that space, explored by thermal fluctuations around a transient equilibrium structure. To obtain the free energy differences between conformers of the unconstrained peptide, a correction for the thermodynamic state is needed. The volume of explored conformational space may be estimated from the covariance matrix of the coordinates of interest, = ((Ci [13, lOj. For each of the four selected conform-... 

In discussing science we also need to define its scope, as well as the methods and views (concepts) involved in its pursuit. It is also useful to think about what science is not, although this can sometimes become controversial. Significant and important studies such as those concerned with the fields of sociology, politics, or economics increasingly use methods that previously were associated only with the physical and biological sciences or mathematics. However, I believe these... 

This chapter covers a number of concepts or properties that did not relate to material discussed in earlier chapters. Some of these techniques are seldom needed. Others just do not merit a chapter of their own because they are easy to apply. 

The section on applications examines the same techniques from the standpoint of the type of chemical system. A number of techniques applicable to biomolecular work are mentioned, but not covered at the level of detail presented throughout the rest of the book. Likewise, we only provide an introduction to the techniques applicable to modeling polymers, liquids, and solids. Again, our aim was to not repeat in unnecessary detail information contained elsewhere in the book, but to only include the basic concepts needed for an understanding of the subjects involved. 

A major trend in organic synthesis, however, is the move towards complex systems. It may happen that one needs to combine a steroid and a sugar molecule, a porphyrin and a carotenoid, a penicillin and a peptide. Also the specialists in a field have developed reactions and concepts that may, with or without modifications, be applied in other fields. If one needs to protect an amino group in a steroid, it is advisable not only to search the steroid literature but also to look into publications on peptide synthesis. In the synthesis of corrin chromophores with chiral centres, special knowledge of steroid, porphyrin, and alkaloid chemistry has been very helpful (R.B. Woodward, 1967 A. Eschenmoser, 1970). 

The nebulization concept has been known for many years and is commonly used in hair and paint spays and similar devices. Greater control is needed to introduce a sample to an ICP instrument. For example, if the highest sensitivities of detection are to be maintained, most of the sample solution should enter the flame and not be lost beforehand. The range of droplet sizes should be as small as possible, preferably on the order of a few micrometers in diameter. Large droplets contain a lot of solvent that, if evaporated inside the plasma itself, leads to instability in the flame, with concomitant variations in instrument sensitivity. Sometimes the flame can even be snuffed out by the amount of solvent present because of interference with the basic mechanism of flame propagation. For these reasons, nebulizers for use in ICP mass spectrometry usually combine a means of desolvating the initial spray of droplets so that they shrink to a smaller, more uniform size or sometimes even into small particles of solid matter (particulates). 

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