In this opening chapter you will be introduced to the extent to which health care products contribute to the delivery of therapeutic and diagnostic procedures across a massive array of clinical problems and solutions. Included here are examples of long-term implantable devices, procedures of regenerative medicine, the diagnosis of disease and injury, and the specialized delivery of drugs and genes. You will then see how biomaterials science has evolved in order to optimize the performance of these products. The concepts of biomaterials science are introduced, along with a general discussion of the requirements of biomaterials and their essential characteristics.

Health care products in medical practice

You are an observer in a busy doctor’s clinic on a Monday morning during a cold wet month of the winter. This is a large polyclinic, which includes not only primary care physicians but a plethora of specialists, who deal with the diagnosis and uncomplicated treatments for a variety of conditions, ranging from dental and ophthalmological conditions, to neonatal care, trauma, geriatric complaints and common infectious diseases. A few hundred meters away is a major teaching hospital, able to deal with virtually every acute and chronic condition that is likely to be seen in this mid-size industrial city, which encompasses people of all ages and genetic background.

The military failure to resolve the war in 1914 surprised soldiers in Germany and everywhere else. It also surprised civilian leaders in all the belligerent countries, who now confronted unanticipated and unprecedented challenges. They had to redirect the productive energies of society towards the massive demands of industrial warfare. The first year and a half of the war established the framework of mobilization in all these lands. Public institutions invaded economies and societies, as vast material and moral resources were channeled to military ends.

The transition to new modes of organization for war took place everywhere by improvisation during the first months of the conflict, but some of the belligerent powers were better able than others to adjust. Imperial Germany, which in 1914 was reputed to be the most efficiently organized society on earth, faced major impediments to meeting the challenges. Deficiencies in the organization of mobilization contributed to the mounting burdens of war on the home front. They also fed the political controversies that attended the prolongation of the war.

Bureaucratic foundations

Institutions were a fundamental problem. Germany's reputation for bureaucratic efficiency was deceptive, for the country's basic administrative structures were fragmented among federal, state, and local institutions. Administrative particularism had its champions, but it posed grave obstacles to the execution of common policies in a national emergency.

The institutions of military administration, which were conceived with national emergency in mind, only compounded the difficulties. These institutions were as much geared to the wrong century as was Schlieffen's plan. They were designed to mobilize forces rapidly in the event of war (or revolution) and to provide basic services and security at home during a limited period of crisis, as they had in 1870–1. Their legal foundation was the Prussian Law of Siege, which had first been promulgated in 1851 and then taken over into the imperial constitution in 1871. Upon declaration of national emergency, this law specified that executive power passed into the hands of the corps commander in each of the country's twenty-four military districts. Because these commanders accompanied their corps into battle, however, their executive powers devolved to their seconds-in-command, the so-called deputy commanding generals.

Traditional application of thermodynamics to engineering problems involves processes that are flowing. For example, an engineer might design a refrigerator in which a refrigerant is pumped in a continuous cycle through a coil of tubing, or a generator where steam is pumped in a power cycle through several pieces of equipment. Hence, engineering has placed a lot of emphasis on balances in flowing systems. Such flow systems involve time as an independent variable. However, thermodynamics applies only to equilibrium states, and the introduction of time is strictly forbidden. The study of time-dependent processes actually falls within the domains of transport phenomena and non-equilibrium thermodynamics.

Whereas the field of transport phenomena is relatively well advanced and well understood, non-equilibrium thermodynamics is a developing field of research, and the fundamental postulates are by no means agreed upon [11, 94].

We will restrict ourselves here to the simplest of such time-dependent systems. Namely, we will assume that our system is in a local state of equilibrium. Such an assumption allows us to use the quantities derived for equilibrium systems as local variables that depend upon position and time. This simplification is usually applicable whenever the local response time of a system is much smaller than the time scale of the whole process. In this way, we can simplify many engineering flow problems to equivalent equilibrium thermodynamics problems.

For good or evil, all physical processes observed in the Universe are subject to the laws and limitations of thermodynamics. Since the fundamental laws of thermodynamics are well understood, it is unnecessary to limit your own understanding of these thermodynamic restrictions.

In this text we lay out the straightforward foundation of thermodynamics, and apply it to systems of interest to engineers and scientists. Aside from considering gases, liquids and their mixtures – traditional problems in engineering thermodynamics – we consider also the thermodynamics of DNA, proteins, polymers, and surfaces. In contrast to the approach adopted by most traditional thermodynamics texts, we begin our exposition with the fundamental postulates of thermodynamics, and rigorously derive all steps. When approximations are necessary, these are made clear. Therefore, the student will not only learn to solve some standard problems, but will also know how to approach a new problem on safe ground before making approximations.

Thermodynamics gives interrelationships between the properties of matter. Often these relationships are non-intuitive. For example, by measuring the volume and heat capacity as functions of temperature and pressure, we can find all other thermodynamic properties of a pure system. Then, we can use relations between different thermodynamic properties to estimate the temperature rise of a fluid when it is expanded in an insulated container, or, we can use such data to predict the boiling point of a liquid. In Chapter 2, we introduce the necessary variables to describe a system in thermodynamic equilibrium.

The text considers the ideal gas and van der Waals equations of state in some detail. In addition to these, we summarize here several more-accurate equations of state. This appendix presents but a small fraction of such equations. A more comprehensive discussion of the quality of such equations is given in [118].

Note that all fluid equations of state reduce to the general ideal gas at low densities. For small deviations from ideal behavior, the virial expansion is the most reliable. However, it is not appropriate for predicting vapor–liquid equilibria. The cubic equations of state are straightforward to use and computationally simple. However, some sacrifice must be made for accuracy. Of these, the Peng–Robinson, Soave–Redlich–Kwong, and Schmidt–Wenzel equations are usually superior. However, all cubic equations are suspect near the critical region. For an excellent review of many such equations, see [5]. If computational ease should be sacrificed for accuracy, the Benedict–Webb–Rubin and the Anderko–Pitzer equations are usually more accurate.

The parameters in the cubic PVT equations of state are usually determined from the critical properties of a fluid, and these equations are given. Critical values for a few substances are given in Table D.3 in Appendix D. More values can be found from the NIST web page. If the critical values of a substance are not known, they may be estimated from group methods on the basis of the chemical structure of the substance. These methods are reviewed in [102].

It began, to use the formula familiar in today's newspapers, with an “act of state-sponsored terrorism.” The archduke Francis Ferdinand was the heir apparent to the Habsburg throne of Austria–Hungary; when, on June 28, 1914, a Serbian student shot him and his wife to death in Sarajevo, the capital of the Austrian province of Bosnia, the act provoked astonishment and outrage throughout Europe. Public excitement quickly receded, however, despite lingering rumors in the newspapers – subsequently substantiated – that officials of the Serbian government had been complicit in the assassination. In Germany and elsewhere the summer season had begun. The onset of warm weather signaled travel for those who could afford it; and, for those who could not, it brought less idle adjustments in the annual rhythms of life in town and countryside.

In Berlin, as elsewhere, the events in Sarajevo provoked a series of fateful deliberations during the first weeks of July. The German leadership concluded that the assassination carried far-reaching implications for German security. Austria–Hungary was Germany's principal ally. The Serbian affront promised to encourage discontent not only among the South Slav inhabitants of Austria–Hungary but also among the other ethnic groups that made up the Habsburg monarchy. In the eyes of the German leaders, the logic of this process boded the dissolution of the monarchy and, ultimately, Germany's full diplomatic and military isolation in Europe.

This alarming prospect loomed over the consultations in the German capital. The decisions that emerged out of these deliberations have themselves given rise to a bitter dispute among professional historians. At the center of the dispute stands the German chancellor, Theobald von Bethmann Hollweg (see Plate 1), the civilian head of the German federal government. Some historians, with Fritz Fischer in the lead, have argued that Bethmann seized upon the assassination as the pretext to launch a long-planned war of aggression, whose goal was German hegemony on the European continent. The preponderance of evidence now suggests instead, however, that the chancellor pursued a somewhat more cautious policy, which grew out of his anxiety over the future of the Austrian monarchy, whose survival, he believed, did justify the risk of a European war. Bethmann was strengthened in this belief by the country's leading soldier, the chief of the army's General Staff, Helmuth von Moltke. Moltke's calculations were technical.

Thermodynamics is the combination of a structure plus an underlying governing equation. Before designing plays in basketball or volleyball, we first need to lay down the rules to the game – or the structure. Once the structure is in place, we can design an infinite variety of plays and ways that the game can run. Some of these plays will be more successful than others, but all of them should fit the rules. Of course, in sports you can sometimes get away with breaking the rules, but Mother Nature is not so lax. You might be able to convince your boss to fund construction of a perpetual-motion machine, but the machine will never work.

In this chapter we lay the foundation for the entire structure of thermodynamics. Remarkably, the structure is simple, yet powerfully predictive. The cost for such elegance and power, however, is that we must begin somewhat abstractly. We need to begin with two concepts: energy and entropy. While most of us feel comfortable and are familiar with energy, entropy might be new. However, entropy is no more abstract than energy – perhaps less so – and the approach we take allows us to become as skilled at manipulating the concept of entropy as we are at thinking about energy. Therefore, in order to gain these skills, we consider many examples where an underlying governing equation is specified. For example, we consider the fundamental relations that lead to the ideal-gas law, the van der Waals equation of state, and more sophisticated equations of state that interrelate pressure, volume, and temperature.

Now that we have a reasonably complete structure of thermodynamics, we can tackle more complicated problems. In the following section we introduce the concepts of local and global stability, and show how local stability puts restrictions on second-order derivatives. In Section 4.2 we see that application of local stability criteria to the proposed fundamental relations leads to predictions of spinodal curves, which indicate when substances will spontaneously change state. In Section 4.2.2 the application of global stability to a van der Waals fluid leads to predictions of vapor saturation curves and liquid saturation curves. These curves are sometimes called binodal curves (or coexistence curves), and can be predicted from PVT equations of state alone. We then show how thermodynamic diagrams useful for refrigeration, or power-cycle design, can be constructed from PVT relations in Section 4.4. Section 4.4.2 shows generically how one can make predictions of differences in thermodynamic quantities from any of the equations of state shown in Appendix B or from experimental data.

STABILITY CRITERIA

What happens if you take gaseous nitrogen and compress it, keeping the internal energy constant by removing heat? Eventually, the nitrogen begins to condense in the container, and you have a mixture of liquid and gaseous nitrogen. If you isolate this system and wait for a long time, then you see that the system is indeed at a stable equilibrium. From Section 2.8 we know that these two phases have the same temperature and pressure. How can that be? Why is some of the nitrogen happy to stay gaseous, while the rest saw fit to condense into a liquid? The two phases have the same temperature and pressure, yet they have different densities.

This book originated in another project, which is at once broader in scope and much narrower in focus. In deference to the principle that total war requires total history, I have been studying the comprehensive impact of the First World War in a single mid-sized German city. In conjunction with this project, I decided several years ago to explore the history of the war and German society with a class of undergraduate students at the University of Oregon. I discovered that there was no suitable text for such a course. The present volume grew directly out of discussions with students in that class. It is conceived in the first instance for readers like them, but it is also intended for others who are interested in the modern history of Germany and Europe, as well as the history of war and society. The scholarly apparatus is designed for those whom the text entices into further reading.

It is now a pleasure to repay my many intellectual debts with public gratitude. My thanks go first to my students in Oregon, my former home, for contributions that pervade the volume. In addition, I owe great thanks to a number of scholars who have offered comments on the manuscript as it progressed. They include Gerald Feldman, Wilhelm Deist, Belinda Davis, Stig Förster, and Richard Stites, who is now my colleague at Georgetown. My friend Bruce Wonder, who counts himself in the category of “informed general reader,” has also offered invaluable suggestions for the manuscript's improvement. My research assistant, David Freudenwald, provided much-needed help in my dealings with a number of libraries. Several institutions have also supported the manuscript in various stages of its gestation. My gratitude goes to the Gerda Henkel Foundation, which supported a year's research in Europe in 1991–2, the Graduate School at Georgetown University, which made possible several subsequent trips to Europe, and the Woodrow Wilson International Center for Scholars in Washington, DC, which providedme with the opportunity to complete the work in a stimulating atmosphere of intellectual exchange.

Preface to the Third Edition

When I began to work on the First World War in the late 1980s, I had no idea that I would still be writing about it on the occasion of its centenary. A lot has happened in the meantime. This volume has now gone through two English-language editions, as well as a German translation.

The pressure inside a soap bubble is slightly larger than that outside the bubble. If those two pressures were equal, the bubble would simply collapse. The liquid film that constitutes the bubble is under tension, and is therefore able to sustain the force imbalance that arises from that pressure difference. Throughout most of this text, we have focused our attention on the properties of bulk phases. The boundaries or interfacial regions between bulk phases at equilibrium exhibit a number of interesting properties that are often different from those of the bulk. These properties are particularly important in a wide variety of technologies, including nano-fabrication, ink-jet printing, coatings, and biotechnology. This chapter discusses a few extensions of ideas presented earlier in the text to determine the behavior of interfaces.

The study of the thermodynamics of surfaces usually adopts one of two conventions. In the approach of Gibbs [17], a sharp dividing surface is introduced between two distinct phases (e.g. a liquid and a vapor). In the approach of Guggenheim [51], the interfacial region has a finite volume Vσ, over which the thermodynamic properties of the system change gradually. The latter approach is followed closely in this chapter because it is more physically intuitive. We note, however, that in our discussion of mixtures and surface quantities we adopt the view that the volume of the interfacial region is so small as to be negligible. In that limit, we implicitly return to the Gibbs treatment of an interface.