The present chapter deals with the FVM as applied to the diffusion equation in one and two dimensions. In the FVM, the domain Ω is divided into a collection of nonoverlapping subdomains, called control volumes and the collection is called a mesh or grid.

Russia is neither a democracy nor a monolithic, one-party state, but rather an electoral autocracy in which multiparty elections are the primary means of acquiring power. Though these elections are not free and fair, they enable political competition among a variety of political actors. This chapter describes the key parties, movements, social cleavages, and issues that drive electoral behavior in this system. The chapter also highlights the undemocratic features of the system that constrain full and fair competition. These include the role of the hegemonic party, United Russia; the constraints placed on opposition forces; and the use of electoral manipulation by the regime. By examining the many tensions inherent to electoral autocracy, the chapter demonstrates how elections can both stabilize the regime and undermine it.

In this chapter, we will focus on solving the PDEs governing laminar flows of viscous incompressible fluids using the FVM (this chapter is a counterpart of Chapter 6 on FEM, where velocity–pressure and penalty finite element models of two dimensional flows of viscous incompressible fluids were presented). These equations are expressed in terms of the primitive variable, namely, the velocity field and the pressure. To begin with, we will consider isothermal flows (flows without the presence of the temperature effect), and demonstrate the use of the FVM for two-dimensional laminar flows of viscous incompressible fluids. Then cases of non-isothermal flows with both forced convection and natural convection will be considered in the sequel.

In Chapter 4 we considered finite element analysis of steady state heat transfer. When external stimuli (e.g., boundary conditions and internal heat generation) are independent of time, heat transfer in a medium may attain a steady state; otherwise, the temperature field changes with time (i.e., unsteady state). The governing equations of unsteady heat transfer are obtained using the principle of balance of energy. When unsteady equations are solved the temperature field reaches a steady state if the external stimuli are independent of time (i.e., the time dependence decays with time).

All numerical methods, including the FEM and FVM, ultimately result in a set of linear or nonlinear algebraic equations, relating the values of the dependent variables at the nodal points of the mesh. These algebraic equations can be linear or nonlinear in the nodal values of the primary variables, depending on whether the governing differential equations being solved are linear or nonlinear. When the algebraic equations are nonlinear, we linearize them using certain assumptions and techniques, such as the Picard method or Newton’s method.

Chapters 1 to 7 don’t give us many ways to organize data. S-expressions are great, but you might have noticed that they serve as a kind of high-level assembly language on top of which you have to craft your own data structures. For programming at scale, that’s not good enough—programmers need to define proper data structures whose shapes and contents are known.

Congratulations! You now have some solid skills using functions, types, modules, objects, and more. You also have a cognitive framework that you can use to learn new programming languages, and if you’re like my students, you’ll be pleasantly surprised at how broadly your skills apply. Now you get the dessert menu. As your server, I recommend some tasty treats: languages that are superlative, unusual, or popular. Many are widely recognized as interesting or important, and some are just to my personal taste. Together, they offer a variety of jumping-off points, ranging from younger, less proven ideas to fashionable ideas drawn from the headlines.

Contemporary Russian political dynamics are shaped by exceptionally strong conservative forces that stabilize a prevailing order, but also contain many sources of potential destabilization and change. By the beginning of 2022, Russia’s political order was dominated by President Vladimir Putin and his loyalists within formal institutions, such as United Russia, and informal networks of power led by political and economic elites. There are no political actors who are both powerful and critical of this order, which has been called “high Putinism.” A majority of citizens supported the concentration of power over the previous two decades and contributed to its consolidation through their beliefs and actions. All major channels of communication are firmly controlled by actors committed to disseminating the value, even necessity, of the current order. This highly centralized political order made it possible for Putin to launch a brutal and wholesale war on Ukraine in February 2022. Over the course of the past decade, three key pillars of support for the political current order and the war have been strengthened: (i) the state’s ability to instrumentalize formal institutions to prolong Putin’s and United Russia’s hold on power, (ii) the fact that the state controls virtually all media outlets, and (iii), finally, the government’s ability to generate relative economic prosperity. The war and sanctions are acutely threatening Russia’s economy, and have led to a crackdown on the last remaining independent media outlets.

Whether or not this political constellation will turn out to be stable or fragile depends in large part on whether citizens continue to support Putin. An increasingly assertive foreign policy toward the West had bought high approval ratings for some years. Despite its virtual monopoly over the levers of power, the Putin government has been increasingly afraid of street protest and has gone to great lengths to silence a small but vocal opposition, led by Alexei Navalny. Discontent stemming from failing institutions, pervasive corruption, mounting inequality, and economic hardship has the potential to undermine the balance between stability and fragility in contemporary Russian politics. The outcome of the war in Ukraine will certainly be a watershed moment, although we do not yet know how the war will end. The future of Russian politics will hinge on answers to the question whether Russian citizens will continue to support the Putin government, even with mounting economic and human costs of the war.

This chapter traces the evolution of the Russian oil and gas sector. We argue that, at least since 2000, Russia’s vast natural resources have been a source more of stability than of fragility for the economy. This is in part due to the distinctive history and role of fossil fuels in the context of a Soviet economy that was designed to be self-sufficient and thus diversified. While this did not prevent economic stagnation in the late Soviet period (1970s–80s) or a steep decline in production during the early years of post-Soviet transition (1992–99), it created the foundations for a petrostate that gradually came to be more resilient and adaptable in the face of fluctuations in energy prices, financial crises, and increasingly contentious relations with the West. Following 2000, while the state played an increasingly assertive role in the oil and gas industry, the government also adopted various measures to limit dependence on resource rents, to reduce vulnerability to sudden shifts in global energy prices, and to increase economic stability in the face of new geopolitical challenges. These included a Stabilization Fund, new budgetary practices to control spending and support other industries, diversification of supply flows and export composition, and intensified investment in new infrastructural projects. While there are now growing concerns over carbon emissions and the technological demands of further exploration, hydrocarbons have been mostly a positive force in the Russian economy. Whether that holds true following the war in Ukraine and the imposition of massive Western sanctions in 2022 remains to be seen.

In your prior programming experience, you may have used a procedural language such as Ada 83, Algol 60, C, Cobol, Fortran, Modula-2, or Pascal. Or you may have used a procedural language extended with object-oriented features, such as Ada 95, C#, C++, Eiffel, Java, Modula-3, Objective C, or Python—although these hybrid languages support an object-oriented style, they are often used procedurally.