Electricity: basic concepts

Nelson, W.B., Basic Concepts and Distributions for Product Life, General Electric Technical Information Series, Report No. 74CRD311, 1974. 

On a smaller scale many new functional polymers are produced having valuable properties for electrical, optical or magnetic applications. There exist numerous metal catalysed processes and we will discuss only a few to explain basic concepts using both examples from bulk polymers and fine chemical, high-value polymers. 

The purpose of the present chapter is to introduce some of the basic concepts essential for understanding electrostatic and electrical double-layer pheneomena that are important in problems such as the protein/ion-exchange surface pictured above. The scope of the chapter is of course considerably limited, and we restrict it to concepts such as the nature of surface charges in simple systems, the structure of the resulting electrical double layer, the derivation of the Poisson-Boltzmann equation for electrostatic potential distribution in the double layer and some of its approximate solutions, and the electrostatic interaction forces for simple geometric situations. Nonetheless, these concepts lay the foundation on which the edifice needed for more complicated problems is built. 

ANALYZER (Reagent-Tape). The key to chemical analysis by this method is a tape (paper or fabric) that has been impregnated with a chemical substance that reacts with the unknown to form a reaction product on the tape which lias some special characteristic, e.g., color, increased or decreased opacity, change in electrical conductance, or increased or lessened fluorescence. Small pieces of paper treated with lead acetate, for example, have, been used manually by chemists for many years to determine the presence of hydrogen sulfide in a solution or in the atmosphere. This basic concept forms the foundation for a number of sophisticated instruments that may pietreat a sample gas, pass it over a cyclically advanced tape, and, for example, photo-metrically sense the color of the exposed tape, to establish a relationship between color and gas concentration. Depending upon tile type uf reactiun involved, the tape may he wet or dry and it may be advanced continuously or periodically. Obviously, there are many possible variations within the framework of this general concept. 

The term electromembrane process is used to describe an entire family of processes that can be quite different in their basic concept and their application. However, they are all based on the same principle, which is the coupling of mass transport with an electrical current through an ion permselective membrane. Electromembrane processes can conveniently be divided into three types (1) Electromembrane separation processes that are used to remove ionic components such as salts or acids and bases from electrolyte solutions due to an externally applied electrical potential gradient. (2) Electromembrane synthesis processes that are used to produce certain compounds such as NaOH, and Cl2 from NaCL due to an externally applied electrical potential and an electrochemical electrode reaction. (3) Eletectromembrane energy conversion processes that are to convert chemical into electrical energy, as in the H2/02 fuel cell. 

The cell model is a commonly used way of reducing the complicated many-body problem of a polyelectrolyte solution to an effective one-particle theory [24-30]. The idea depicted in Fig. 1 is to partition the solution into subvolumes, each containing only a single macroion together with its counterions. Since each sub-volume is electrically neutral, the electric field will on average vanish on the cell surface. By virtue of this construction different sub-volumes are electrostatically decoupled to a first approximation. Hence, the partition function is factorized and the problem is reduced to a singleparticle problem, namely the treatment of one sub-volume, called cell . Its shape should reflect the symmetry of the polyelectrolyte. Reviews of the basic concepts can be found in [24-26]. 

To illustrate the basic concepts and principles, picture a conduit carrying some commodity such as electric charge, or high-pressure water, or some chemical like hydrogen (H2). The flow rate of any such commodity is called a current and may be expressed as... 

A similar idea is exploited in recent work with the infrared (IR) echo, although with IR-active rather than Raman-active vibrations (35-42). Although the basic concepts in the Raman and IR echoes are the same, they each work best on different systems. The infrared echo is best for vibrations with strong IR transitions (and therefore potential for resonant energy transfer and sensitivity to local electric fields), for dilute solutes, and for systems with slow rotation. In contrast, the Raman echo is best for vibrations with strong Raman transitions (and generally weak IR transitions),... 

We shall start with the basic concept that in the oxides formed on metals, (the same also applies to sulfides and halides) transport of material particles occurs only by the motion of inherent defects (Eigen-Storstellen) present in the lattice these defects are assumed to consist essentially of simple particles in interstitial lattice sites or vacancies of the particles constituting the crystal. The free electrons or holes which are present for reasons of electrical neutrality are coupled to the migrating defects and move considerably more rapidly. 

In this book, we try to present the basic concepts in order to understand the mechanical and electrical failures of solid materials containing inherent defects or disorders. Our emphasis has been on the question why , rather than on the question when , and we concentrate mainly on the statistical aspects of their failure strength distribution. 

In addition, you learned some of science behind how certain electronics work. You learned that electricity is the flow of electrons, the difference between a conductor and nonconductor, the definition of static electricity, and the basic concepts of electromagnetic theory. 

Bjerrum (Bj) combined the Arrhenius and DH approaches by assuming a chemical equilibrium between ion-pairs and free ions [27], This concept takes into account interactions of ions at short range, which are not adequately described in DH theory. It also includes a theory for the mass action constant as a function of the dielectric constant e of the solvent. Many experimental investigations of the electrical conductance A, e.g. reviewed by Kraus [36], have confirmed Bjerrum s concept, which is the basic concept of many modern approaches. 

A more detailed description of different types of batteries and other electric energy storage systems for electric vehicles can be found in Sect. 5.3, while a description of the main characteristics and properties of fuel cells for automotive application is given here, starting from some basic concepts of electrochemistry and thermodynamic, and focusing the attention on the operative parameters to be regulated to obtain the best performance in the specific application. 

The basic concepts of linear response theory are best illustrated by considering the rotational diffusion model of an assembly of electric dipoles constrained to rotate in two dimensions due to Debye [14] which is governed by the Smoluchowski equation... 

Chapter 1 of the present volume provides the basic concepts related to the properties and characterization of the centres known as shallow dopants, the paradigm of the H-like centres. This is followed by a short history of semiconductors, which is intimately connected with these centres, and by a section outlining their electrical and spectroscopic activities. Because of the diversity in the notations, I have included in this chapter a short section on the different notations used to denote the centres and their optical transitions. An overview of the origin of the presence of H-related centres in crystals and guidelines on their structural properties is given in Chap. 2. To define the conditions under which the spectroscopic properties of impurities can be studied, Chap. 3 presents a summary of the bulk optical properties of semiconductors crystals. Chapter 4 describes the spectroscopic techniques and methods used to study the optical absorption of impurity and defect centres and the methods used to produce controlled perturbations of this absorption, which provide information on the structure of the impurity centres, and eventually on some properties of the host crystal. Chapter 5 is a presentation of the effective-mass theory of impurity centres, which is the basis for a quantitative interpretation... 

Electrochemistry is the branch of chemistry that deals with the interconversion of electrical energy and chemical energy. Electrochemical processes are redox (oxidation-reduction) reactions in which the energy released by a spontaneous reaction is converted to electricity or in which electrical energy is nsed to cause a nonspontaneous reaction to occur. Although redox reactions were discnssed in Chapter 4, it is helpful to review some of the basic concepts that will come np again in this chapter. 

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