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This chapter discusses the use of energy in traditional farming. The evolution of agriculture appears to be a continuing effort to increase land productivity (to increase digestible energy yield) in order to accommodate larger populations. Owing to the overwhelmingly vegetarian diets of all traditional peasant societies, it is important to focus on the output of digestible energy produced in staple crops in general and grains in particular. The chapter first provides an overview of the link between food energy and the evolution of peasant societies before considering the commonalities and peculiarities of tools and machines used in agronomic practices. It then examines the dominance of grains in traditional agriculture, with particular emphasis on their energy density and nutritional content. It also analyzes routes to gradual intensification of agriculture, along with the persistence and innovation in traditional farming practices. Finally, it assesses the limits and achievements of traditional agriculture.

Astrophysical lasers in the visible and near-IR ranges have been discovered in the Weigelt blobs of the luminous blue variable (LBV) star Eta Carinae (η Car). This massive and luminous star is a most remarkable stellar object located close enough to be observed in great detail. Using speckle interferometry Weigelt and Ebersberger (1986) discovered three remarkably compact objects at an angular distance between 0.1’ and 0.3’ northwest of the star, which corresponds to distances from the star of the order of 1016 cm, a few light days. The objects have been called ‘the Weigelt blobs’ after their discoverer. The blobs are moving at low speeds of the order of 50 km/s and are producing many hundreds of intense, narrow emission lines unlike the spectra of any other known objects. Thus, the spectral lines from different parts of η Car have unique properties in many respects: intensity, spectral width, time, and position variations. This chapter shows that a number of spectral puzzles in the Weigelt blobs are conditioned by a high radiation energy density.

This chapter discusses several basic ideas and methods related to the calculation of the Casimir energies and forces using some simple models. The simplicity of these models means that cumbersome mathematical calculations can be avoided and they demonstrate the basic problems that will be repeatedly considered in the following chapters in a more sophisticated context. Important procedures such as regularization and renormalization of infinite quantities are illustrated, both physically and mathematically. Despite the elementary character of the chapter, the main physical situations where the Casimir effect arises (i.e., in regions with boundaries and in spaces with nontrivial topology) are discussed. Local and global approaches to the Casimir effect, and well-known formulas for the electromagnetic Casimir pressure and energy per unit area between two parallel ideal-metal planes are derived.

The structure of a system of retail centres as described by their size, composition, and location, is a result of competition among the centres for customers. The evolution of the system is described by a set of cost and revenue equations. The revenue equations include a distance decay parameter. When this parameter is below a critical value, retail activity tends to agglomerate in a major, centrally located centre; otherwise, it tends to be dispersed among a number of similar centres. This fundamental bifurcation appears in actual retail systems. It underlies such phenomena as itinerant medieval trade fairs, the historical migration of the major retail centre of cities like London and New York, and innovations like the department store, the regional mall, and power centres. Since a lower distance decay parameter is associated with higher energy densities, a direct link is established between spatial structure, energy, and technology.

Chapter 3 introduces the phasor representation, as well as the first mention of the expressions for energy density and energy flux. These key notions recur continually throughout the book in various contexts. Transmission through lossless dielectric materials is first treated, followed by energy storage and transmission through conductive, lossy materials in the low frequency limit. The second half of the chapter treats reflections and transmission, total internal reflection, real material interfaces, and plane-wave behaviours in a lossy, conductive medium at high frequency. The classical laws of reflection and refraction angles at interfaces are introduced as well as the Fresnel theory of amplitude, polarisation, and phase.

In this chapter, Manno and Balogh articulate a biophysical logic that complements the social, political, and ethical arguments against the unfettered extraction of fossil fuels. They argue that making a sound and rational decision about the future of energy requires approaching this issue from a broad systems perspective. Expanding on the ecological economics concept of Energy Return on Investment (EROI), Manno and Balogh offer WROI, Welfare Return on Investment, with an emphasis on quality of life and lifesaving measures for the planet.

A hard/permanent magnet can alone support a magnetic flux in a gap of a device; a soft magnet requires the assistance of an external electrical/magnetic input to do so. A hard/permanent magnet requires that _MH_c > M_s, the field it produces in a gap is proportional to its energy density product, (BH), and the demagnetizing portion of the hysteresis loop determines its performance for the intersection of the load line with the demagnetizing curve (matching magnet shape with materials selection) maximizing its energy product, (BH)_max. Permanent magnets have maximum coercive fields well below the theoretical limit (Brown’s paradox), due to the role of microstructure in determining the magnetization reversal process; nevertheless, permanent magnets are developed by maximizing all three parameters, M_s, H_C, and K₁, as well as T_C, to achieve high operating temperatures. Thus, the best permanent magnets contain RE elements for the localized, 4f-electron, single-ion anisotropy, and transition metals (TM) for their higher T_C and higher M_s. Soft magnets require large saturation magnetization and initial permeability, small coercive forces, and low hysteresis and eddy current losses. To maximize magnetization, look to the Slater–Pauling curve and work around variations of Fe–Co alloys. Many soft magnets also require very small magnetostriction to avoid related mechanical stress cycling; examples are crystalline alloys of Fe–Si and Fe–Ni, and amorphous alloys of (Fe–Co–Ni) with (Si, B). Nanostructured materials with grain size, D, smaller than the exchange correlation length, lead to an effective directional averaging of the magnetocrystalline anisotropy and their coercivity scales as D⁶. Intrinsic magnetization may be augmented by the exchange-spring mechanism, using a composite microstructure that benefits from the best attributes of the constituent phases; the hard phase furnishes the high H_c and K₁ values, while the soft phase contributes a large Ms value.

Rhythmic and monotonously repetitive, but quite unpredictable in its details, the structure of the sea surface is an epitome of the natural world. Surface waves have been studied actively by mathematicians and physicists since the dawn of modern science. Though the phenomenon seems deceptively simple, it cannot be explained or predicted rigorously by existing theories. Nonlinear interactions between wind, waves, and currents cause theoretical problems as well as make it difficult to obtain comprehensive, interactive data sets. In response to wind and pressure changes at the air-sea interface, the ocean reacts with waves that occupy some nine spectral decades: from capillary waves, which undulate within a fraction of a second over distances smaller than one centimeter, to planetary waves with periods measured in years and wavelengths of thousands of kilometers. The dynamics of all these waves can be related to the set of equations discussed in Section 4.1. For that reason, a consideration of all wave forms could have been combined in the same chapter, but we found it more convenient to divide the subject into two parts. The present chapter deals exclusively with wind-generated waves at the sea surface. They determine the small-scale configuration of the air-sea interface and that affects the turbulent transfers, which are the topic of the following chapter. On the other hand, information and energy transports from the sea surface into the ocean interior by internal and inertial waves, depend upon the state of the upper layers of the ocean. This made it desirable to discuss these wave forms in Chapter 7, after the consideration of planetary boundary layers in Chapter 6. Small-amplitude or linear, harmonic surface waves are considered in Section 4.2. Analysis of these waves has been the classic approach to the topic. Linear waves represent an idealized abstraction, but their analysis does provide basic insights into actual wave dynamics. Linear approximations have to be abandoned when one considers the energy and the momentum of wave fields. This is the topic of Section 4.3. In Section 4.4 we discuss the various sources and sinks of wave energy and momentum.

Methods to assess the size of a population and the interactions between populations in terms of biomass (weight of living material) or energy content are described. Biomass can be expressed as wet weight, dry weight (DW), shell-free dry weight (SFDW), ash-free dry weight, or as the amount of organic carbon present. The energy content of a material may be determined directly by oxidation, either by potassium dichromate in sulphuric acid, or by burning in oxygen and determining the amount of heat liberated. The latter method—bomb calorimetry—is most convenient and is widely used in ecology, but it involves drying the material, and volatile substances can be lost. Methods to estimate standing-crop, energy density, feeding and assimilation, and production are reviewed. Energy budgets can usefully be summarized and compared if the efficiencies of various processes are calculated. Dynamic energy budget models are introduced.

“Electromagnetic energy” takes a hard look at the reasoning by which energy density and energy flow (Poynting vector) are deduced from Maxwell's equations. What can be proved and what, lacking proof, can be usefully said? It is argued that the conventional division of energy into density and flow is unproven but does not mislead. Picture of a pillbox.

A marketer should follow the maxim of the 4th century BC strategist Sun-zi, who said “Know self, know opponents, hundred battles, hundred victories.” We are the chemical processing industries (CPI), which is a collection of firms that manufacture and sell a range of products that involve chemistry and employ many chemical engineers. The buyers are consumers, businesses, governments, and foreigners. When we consider selling a product to a buyer, we pay particular attention to profitable and growing markets where our product has a relative advantage over competition. It takes a bold pioneer to introduce a new product that requires the creation of a new market. Let us study the sellers of chemical products, which are collectively called the CPI. These manufacturers are skilled in the use of chemical reactions and separations to make their products, and they employ many chemical engineers and chemists, often in highly responsible positions. Many of the firms in the CPI are also our suppliers of raw materials and intermediates, our customers for our products, and our competition in making and selling their products. The Statistical Abstract of the United States is published annually by the U.S. Census Bureau, which groups all the economic activities in the United States into 11 divisions by the Standard Industrial Classification (SIC). The manufacturing division is divided into 20 sections designated by two-digit numbers. The manufacturers that involve chemistry intensively are listed in table 9.1, by two 2-digit numbers, such as: 20 Food, 28 Chemicals, and 29 Petroleum Refining. The table lists the number of establishments, the number of employees and value of shipment in 1996. The SIC 28, “Chemical and Allied Products,” is the basic supplying industry to the other sectors. Table 9.1 also gives the subdivision of SIC 28 into three-digit subsectors, such as: 281 Industrial Inorganics, 283 Drugs, and 286 Industrial Organics. The subsectors of 281 and 286 form the core of the Chemical and Allied Products, as they provide raw material and intermediates for the rest of the subsectors, such as 282 Plastics and 287 Agricultural chemicals.

This chapter analyzes the response of solids to stress. The defining property of a solid is its ability to resist shape changes in the presence of external stresses. Stress, defined as force per unit area, can be divided into two classes: compression and shear. The remainder of the chapter derives expressions for the following: stress tensor, strain tensor, Hooke’s law, energy density, elastic module of cubic and hexagonal systems, distortions of a cubic crystal, elastic waves, elastic waves in a cubic crystal, isotropic media, viscosity in solids, and the measurement of elastic constants of materials. Sample problems are also provided at the end of the chapter.

Back to how peculiar the recipe to cook an inflationary universe is, with its mysterious cosmological constant and dark matter components. The arbitrary parameters of the Standard Model of particles are also many, and one of its predictions (the axion particle) still escapes detection. CERN’s CAST experiment, looking for—with no success—axions that the Sun could be emitting.