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The phenomenon of so‐called ‘order—disorder’ in crystals has few examples in the world of biological macromolecules. Thus, the crystal repetition may only approximately be covered by the unit cell. Commensurate multiples of the unit cell repeat produce sublattices of diffraction spots; a doubling of one unit cell producing a halving of the diffraction spot lattice. The case of incommensurate, i.e. noninteger multiples of a basic unit cell produce diffraction spots at some noninteger fraction between diffraction spots. We present case studies in this chapter. Technical challenges of resolving the sublattice reflections of up to 5 times the unit cell repeat, using synchrotron radiation, illustrate how to measure these diffraction data.

This chapter discusses the overwhelming role of the army in civil life and the harsher comeback of the police forces after 2011. It tackles the grandiose neo-liberal project of the New Cairo Capital erected by President Sisi.

Critical phenomena occur very close to a second-order phase transition. For example, a ferromagnet near its Curie point behaves quite similarly to a liquid near its critical point, and a superconducting transition is not very different from a second-order ferroelectric one. The simplest view of phenomena near a critical point, attributable in its general form to Landau, is of a universal character and therefore attributes certain common characteristics to all phase transitions. Although the Landau theory does not agree quantitatively with general experimental observations very close to a critical point, it provides much qualitative insight and also points to the origin of the breakdown of the simple theory as the critical point is approached. This chapter explores the Landau theory of critical phenomena and other modern theories of critical phenomena, experimental observation of static critical phenomena in ferroelectrics and antiferrodistortive transitions, dynamic scaling and soft modes, experimental observation of critical dynamics, displacement transitions, and order-disorder transitions.

Ionic motion in a double-well local potential can be cast theoretically in the language of cooperative magnetism. In this modern approach, the potential minima referred to are with respect to a generalized displacement co-ordinate describing the motion of all ions in a unit cell. The more traditional approach for potassium dihydrogen phosphate (KH₂PO₄ or KDP) and its isomorphs has been to concentrate on the specific motion of the hydrogens (which is of largest amplitude) and to include the motion of the other ions, if at all, in terms of a specific coupling mechanism. Thus, for example, any tunnelling characteristics in the more generalized scheme involve all the atoms, whereas the tunnelling character in the more traditional approach is specifically reserved for the hydrogens. This chapter deals with order-disorder ferroelectrics, theory and experiment regarding KDP-type ferroelectrics, other KDP ferroelectric isomorphs, (NH)H₂PO as a KDP-type antiferroelectric, triglycine sulphate and sodium nitrite.

The Introduction provides an overview of current theories of state formation and shows how the book contributes to those debates. It does so by developing a conceptual framework that incorporates crisis into theories of order. It treats crisis as something other than a temporary aberration from the normal operation of the state. Instead, it focuses on the ritual, bureaucratic and documentary practices undertaken in the name of the state that produce the illusion of the ordinary and the mundane. Chapter One also discusses why it is so important to maintain the illusion of the everyday and why it is so difficult to see behind the mask of the state. Central to the analysis are the mechanisms by which the delusional nature of state activity is rendered rational and routine. Equally important are the processes that undermine the effectiveness of these mechanisms.

This chapter explores how the slave system weakened the European religious and moral ideal that restricted sexuality and the family to Christian marriage in French New Orleans. Yet, it challenges the common view according to which the prevalence of métissage was the sign of a lenient racial regime. Sexual relationships across the racial line did not undermine racial formation; on the contrary, they contributed to reinforcing the system of racial domination. Rather than a general moral and religious disorder, what developed was a plural set of sexual and family values and practices that differed according to status, gender, and race.

Liquid crystal is a state of matter which has an intermediate order between liquids and crystals. While fluid in nature, the materials in liquid crystals posses an order in molecular orientation. As a result, the molecular orientation of liquid crystal is easily controlled by weak forces, a property that is extensively used in the application of liquid crystals to display devices. Liquid crystal is an example that the collective nature of soft matter is created by phase transition. This chapter discusses how the interaction between individual molecules creates spontaneous macroscopic ordering, and how it affects the material response to external forces. The phase transition in liquid crystals is an example of order–disorder transition, the general aspects of which can be seen in liquid crystals.

Thermoplastic polyurethane (TPU) has received considerable attention from both the scientific and industrial communities (Hepburn 1982; Oertel 1985; Saunders and Frish 1962). Applications for TPUs include automotive exterior body panels, medical implants such as the artificial heart, membranes, ski boots, and flexible tubing. Figure 10.1 gives a schematic that shows the architecture of TPU, consisting of hard and soft segments. Hard segments, which form a crystalline phase at service temperature, are composed of diisocyanate and short-chain diols as a chain extender, while soft segments, which control low-temperature properties, are composed of difunctional long-chain polydiols with molecular weights ranging from 500 to 5000. The soft segments form a flexible matrix between the hard domains. TPUs are synthesized by reacting difunctional long-chain diol with diisocyanate to form a prepolymer, which is then extended by a chain extender via one of two routes: (1) by a dihydric glycol chain extender or (2) by a diamine chain extender. The most commonly used diisocyanate is 4,4’-diphenylmethane diisocyanate (MDI), which reacts with a difunctional polyol forming soft segments, such as poly(tetramethylene adipate) (PTMA) or poly(oxytetramethylene) (POTM), to produce TPU, in which 1,4-butanediol (BDO) is used as a chain extender. There are two methods widely used to produce TPU: (1) one-shot reaction sequence and (2) two-stage reaction sequence. The reaction sequences for both methods are well documented in the literature (Hepburn 1982). It should be mentioned that MDI/BDO/PTMA produces ester-based TPU. One can also produce ether-based TPU when MDI reacts with POTM using BDO as a chain extender. TPUs are often referred to as “multiblock copolymers.” In order to have a better understanding of the rheological behavior of TPUs, one must first understand the relationships between the chemical structure and the morphology; thus, a complete characterization of the materials must be conducted. The rheological behavior of TPU depends, among many factors, on (1) the composition of the soft and hard segments, (2) the lengths of the soft and hard segments and the sequence length distribution, (3) anomalous linkages (branching, cross-linking), and (4) molecular weight.

Metallurgy is basically about mixtures involving at least one metal and, through composition and processing, strategies to achieve better properties for various applications. Forming mixtures of two or more elements can enhance the advantageous properties of solids. Such a mixture is termed an alloy. Such properties include improved hardness or ductility, which involve suppressing or enhancing permanent deformations under the influence of external stresses. This chapter begins by discussing phase equilibrium, covering the Gibbs phase rule, binary mixtures, the chemical potential of a dilute alloy, characteristic binary phase diagrams, and examples of phase diagrams. The discussions then turn to order–disorder transitions, the isolated charged impurity, and the electronic structure of alloys. A sample problem is also provided at the end of the chapter.