bluuebunny/crossref_metadata_2025 huggingface dataset:
Barometry
Authors: Brock Fred V. , Richardson Scott J.
Published: November 2020

The objective of barometry is to measure the static pressure exerted by the atmosphere. Static pressure is the force per unit area that would be exerted against any surface in the absence of air motion. It is an isotropic, scalar quantity. Dynamic pressure is the force per unit area due to air motion. It is a vector quantity, following the wind vector. This chapter is concerned with determining the static air pressure and doing so in the presence of air motion (wind) that requires special measurement techniques. The Earth’s atmosphere exerts a pressure on the surface of the Earth equal to the weight of a vertical column of air of unit cross-section. Since air is a fluid, this pressure, or force, is exerted equally in all directions. The static pressure at the surface is given by where g(z) = acceleration due to gravity at height z above sea level in ms-2, and ρ = density as a function of height, kg-3. The SI unit of pressure is the pascal, abbreviated as Pa. In meteorology, the preferred unit of pressure is the mb or the hPa (equivalent magnitude). Table 2-1 lists some conversion factors for units currently in use in pressure measurement and also for some units no longer favored. Standard sea level pressure in various units is shown in table 2-2. The last line of table 2-2 refers to the units of Ibf in-2,also called psi (pounds per square inch). Pressure measurements are often called absolute (psia), gauge (psig), or differential (psid). Absolute pressure is simply the total static pressure exerted by the gas (or fluid) and so the barometric pressure is also the absolute pressure. Gauge pressure is the pressure relative to ambient atmospheric pressure. Pressure in an automobile tire is measured relative to atmospheric pressure so it is gauge pressure, not absolute pressure. Differential pressure is the pressure relative to some other pressure. Gauge pressure is a special case of differential pressure. In addition to the static pressure there is a dynamic pressure exerted by wind flow.
Hygrometry
Authors: Brock Fred V. , Richardson Scott J.
Published: November 2020

The objective of atmospheric humidity measurements is to determine the amount of water vapor present in the atmosphere by weight, by volume, by partial pressure, or by a fraction (percentage) of the saturation (equilibrium) vapor pressure with respect to a plane surface of pure water. The measurement of atmospheric humidity in the field has been and continues to be troublesome. It is especially difficult for automatic weather stations where low cost, low power consumption, and reliability are common constraints. Pure water vapor in equilibrium with a plane surface of pure water exerts a pressure designated e's. This pressure is a function of the temperature of the vapor and liquid phases and can be obtained by integration of the Clausius-Clapeyron equation, assuming linear dependence of the latent heat of vaporization on temperature, L = L0(1+∝ (T-T0)], where T0 = 273.15K, L0 = 2.5008 x 106Jkg-1, the latent heat of water vapor at T0, Rv = 461.51Jkg-1K-1, the gas constant for water vapor, e's0 = 611.21 Pa, the equilibrium water vapor pressure at T = T0, and ∝ = - 9.477 x 10-4 K-1 = average rate of change coefficient for the latent heat of water vapor with respect to temperature. Since water vapor is not a perfect gas, the above equation is not an exact fit. The vapor pressure as a function of temperature has been determined by numerous experiments.
Introduction
Authors: Bramadat Paul A.
Published: November 2020

One warm Sunday evening in September 1993, I found myself walking aimlessly around the McMaster University campus. Earlier the same week, I had seen a poster advertising “Church at the John,” an event organized by the McMaster chapter of the Inter-Varsity Christian Fellowship (IVCF). Since I was academically interested in conservative Protestantism, and since at that point I knew no one in the city, I decided, for lack of other options, to attend this meeting. What I found there fell completely outside my expectations, prompted an elaborate series of questions, and ultimately resulted in the present book. Since I assumed that the meeting would be small, I worried that being ten minutes late might draw unwanted attention to my presence. As I descended the stairs of the Downstairs John (or simply “the John”), McMaster’s largest student bar, I could hear the noises of a large group of people. I thought I might have misread the poster a few days earlier; when I entered the bustling room, I was virtually certain I had. Except for the well-lit stage at one end of the room, the John was dark, and almost six hundred people were crowded into a space designed for no more than four hundred and fifty. The room was narrow and long, with a low stage at one end, pool tables at the opposite end, and a bar along the side of the room. People were standing and sitting in the aisles, on the bar, and against the walls beneath the bikini-clad models and slogans that festooned the neon beer signs. I discreetly asked one person who was standing against the wall if this was the right room for the IVCF meeting, and he replied that it was. I looked at him more intently to determine if he was joking, but he just smiled at me politely and bowed his head. After a few confusing moments, I realized he was praying. I turned away from him and noticed that all the other people in the room had bowed their heads in a prayer being led by a demure young woman on the stage.
Otherness
Authors: Bramadat Paul A.
Published: November 2020

Throughout the previous three chapters, I have introduced (i) the set of questions A I am asking in this book, (2) four members of the IVCF, and (3) the ways these believers communicate among themselves and with non-Christians. By now it should be clear that IVCF students often feel separated from their non-Christian peers and professors. Moreover, as I have explained, many IVCF students feel that McMaster privileges the beliefs, values, and worldviews associated with liberalism, pluralism, materialism, and permissivism. According to Reginald Bibby, this evangelical perception is largely correct: . . . Education stands out as an institution that not only has been strongly influenced by individualism and relativism but also has done much to legitimize the two themes. Indeed, the mark of a well-educated Canadian is that he or she places supreme importance on the individual while recognizing that truth is relative. To decry individual fulfilment or to claim to have found the truth would be a dead giveaway that one has not graced the halls of higher learning. (1990:71) . . . This situation marginalizes, alienates, or (to make a verb of an adjective) others evangelical students who generally do not embrace these traditions (or many core elements of these traditions). However, although it might appear that IVCF students would suffer unrelenting and agonizing psychological difficulties during their years at McMaster, the majority of IVCF members do not seem to share such an experience. On the contrary, most IVCF participants I met struck me as no less sane, healthy, contented, and well adjusted than the non-Christian students I have met during the many years I have spent in Canadian universities. In fact, I have found that, with a few exceptions, evangelicals at McMaster seem slightly “happier” than non-Christian students. This obviously unscientific impression is consistent with Frankel and Hewitt’s (1994) findings that involvement in religious groups during one’s university years is positively correlated with higher levels of physical and psychological “well-being.” This observation raises an obvious question: how do evangelicals retain these relatively high levels of psychological well-being in an institution that not only ignores their values and beliefs but also, according to IVCF students, often promotes “anti-Christian” principles? The main insiders’ (or “emic”) answer to this question is simply that well-being is a natural by-product of a personal relationship with God (Little 1988:38).
Witnessing at McMaster and Abroad
Authors: Bramadat Paul A.
Published: November 2020

At a Friday lunch meeting in October 1996, a local fundamentalist pastor spoke passionately to a group of eight IVCF students. The meeting was held, as usual, in the corner of a large multipurpose room in the basement of Divinity College. Several of the students seemed uncomfortable with the young preacher’s zealous approach, somewhat out of place in the midafternoon of the week before midterm exams. The preacher exhorted: Are you excited about your faith? You and you and you [pointing]. I mean, are you really excited that Jesus voluntarily came down to earth and died for each one of your sins? Your sins. That’s pretty exciting if you ask me. I don’t think I deserved it, do you? And now, in this place, how are you sharing your faith? Are you doing all you can to spread your faith in our Lord to the world? Are you sharing your faith with your professors through your papers and with your friends in class? Or do you not believe that the power of God is great enough to protect you? Mac is the most challenging mission field because what is at the forefront of the teaching today will be at the forefront of thinking tomorrow. And some people will tell you that this university is a non-Christian place. But I tell you that this is true, but not completely true. Actually, this university is a pagan place. So, again, what did Paul do? He went to the world of the lost people and did not expect them to come to him. Are you doing this? Are you going to the world of the lost people all around you or are you waiting for them to come to you? . . . And don’t forget: you are disciples of Jesus Christ cleverly disguised as students who have to go to the world of the lost people and not expect them to come to you. It’s like people here don’t know they’re lost. It’s like convincing a sick person they’re sick. But we have to do it.
Conclusion
Authors: Bramadat Paul A.
Published: November 2020

In The Struggle for America’s Soul: Evangelicals, Liberals, and Secularism (1989), Robert Wuthnow summarizes the support for the conventional notion that university education and religiosity are incommensurate in some fundamental way: “Virtually all surveys and polls, whether of the general public, college students, church members, or clergy, show inverse relations between exposure to higher education and adherence to core religious tenets, such as the existence of God, the divinity of Christ, the divine inspiration of the Bible, life after death, religious conversion, and the necessity of faith in Christ for salvation” (1989:145). Given the congruity of the surveys and polls to which Wuthnow refers, how can one explain either the sheer size of the McMaster IVCF chapter or its success at facilitating the retention of its members’ faith commitments? On the surface, it seems reasonable to expect that a religious group devoted to markedly conservative ideas and values would not flourish at a secular university. Since precisely this is happening at McMaster, we are left with three possible explanations. First, one could argue that these two hundred evangelicals are totally unaffected by the secularizing effects university education is supposed by some scholars to have on believers. This hypothesis is obviously untenable, because students consistently speak of their frustrations about the secular ethos of the campus. Second, one could suggest, following Hammond and Hunter (1984:233), that these believers inhabit a well-fortified “Christian ghetto,” the natural consequence of living among so many nonbelievers. I have suggested throughout this text that IVCF members do, indeed, have access to an evangelical fortress that protects them and their besieged subculture from certain elements of secularism. However, this interpretation overlooks another major source of the group’s strength: that in a variety of ways the IVCF facilitates constructive interaction between its members and non-Christians, interaction that is not oriented primarily toward witnessing. The third and, I would argue, most plausible ‘explanation of the vitality of the McMaster IVCF is that this group helps its members to mediate difference (Warner 1997a:219). In other words, the IVCF provides its members with a framework within which to negotiate contracts between its members’ evangelical convictions and the university’s broadly liberal and pluralistic conventions.
Concepts of Evolutionary Modeling and Evolutionary Algorithms
Authors: Krzanowski Roman M. , Raper Jonathan
Published: November 2020

This book is about evolutionary algorithms as applied to spatial and geographic phenomena. Why are we writing this book? Do these new algorithms deliver solutions to our modeling and data analysis problems that conventional methods cannot handle? Or will they just fade away, as have so many other “new” ideas from the past, some eventually finding their way into a museum of computer and conceptual contraptions? It is not our purpose here to attempt to present answers to all of these questions. This is not because we lack expertise but because we do not yet know the answers. However, what we can do, and what we intend to do in this book, is to offer the reader a proper perspective within which to look at evolutionary models. For some, this perspective may prove disappointing, as we will not to solve all known information modeling ills. However, our perspective will help the reader to understand evolutionary computer methods and related concepts, and to use them in appropriate applications and models. In other words, we guarantee that the reader will not be disappointed in coming to a clear understanding as to what evolutionary modeling is all about. Admittedly, other books already serve this purpose. What we offer here, which we feel is unique, is a perspective on the new area of the application of evolutionary models—the area of spatial and geographic phenomena. We shall begin with a broad introduction to models and modeling. This introduction will go well beyond the scope of computer science and geographic information systems (GISs) and will touch upon wider philosophical issues. We believe that modeling is a serious undertaking and it may have serious consequences for the modeler, the modeling subject, and even the lay public. In this introductory chapter, our objective is to assist the reader in coming to understand the modeling business as we see it (and would like others to see it). Modeling is as old as human civilization. Models shape what we are, how we define our reality, known saying: and what forms our thoughts may take.
Airspace Sectoring by Evolutionary Computation
Authors: Delahaye Daniel
Published: November 2020

When joining two airports, aircraft must follow routes and beacons; these beacons are necessary for pilots to know their position during navigation and because of the small number of beacons on the ground they often represent crossing points of different airways. Crossing points may generate conflicts between aircraft when their trajectories converge on it at the same time and induce a risk of collision. At the dawn of civil aviation, pilots solved conflicts themselves because they always flew in good weather conditions (good visibility) with low-speed aircraft. In contrast, modern jet aircraft do not enable pilots to solve conflicts because of their high speed and their ability to fly with bad visibility. Therefore, pilots must be helped by an air traffic controller on the ground who has a global view of the current traffic distribution in the airspace and can give orders to the pilots to avoid collisions. As there are many aircraft simultaneously present in the sky, a single controller is not able to manage all of them. Airspace is then partitioned into different sectors, each of them being assigned to a controller. Sectoring is currently done in an empirical way by some airspace experts who apply rules they have learned with experience. The sectoring modifications are usually due to traffic evolution over long period and when a sector is regularly overloaded it has to be modified. To reach this aim, an ad hoc commission meets to identify new boundaries for the sectors in order to balance the workload. Afterward, sectoring is updated (until new problems arise). This way of working is relevant because it takes into account several practical aspects but has a limited effect on the local zone it treats. This process can be improved with an automatic approach in order to give a solution to the sectoring problem in the whole airspace and that solution could be refined by experts. Before specifying a mathematical description of our problem, it is necessary to set out our framework to introduce some simplifications for our model.
God, the Master Craftsman
Authors: Lienhard John H.
Published: November 2020

Adam awoke on the eighth day of creation, measuring his newly gained creative powers. In a harsh, forbidding world, somewhere to the east of Eden, Adam flexed new muscles and smiled. “That garden was nothing,” he chuckled. “We’re well rid of it. I’ll build a garden that’ll put it to shame.” That eighth day of creation was, in fact, very late in time. Adam had hunted and gathered in the garden for four million years. Then, just the other day—only about thirty thousand years ago—he came into the dense, self-reinforcing, technical knowledge that has, ever since, driven him further and further from the garden. We are a willful, apple-driven, and mind-obsessed people. That side of our nature is not one that we can dodge for very long. Perhaps the greatest accomplishment of the eleventh-century Christian church was that it forged a tentative peace with human restlessness. All the great monotheistic religions of the world have honored God as Maker of the world, but the medieval Christian church went much further: It asserted that God had manifested himself in human form as a carpenter—a technologist, a creator scaled to human proportions. It seemed clear that if we are cast in God’s image, then God must rightly be honored as the Master Craftsman. The peace forged between the medieval Church and Adam’s apple was wonderfully expressed by an anonymous fourteenth-century Anglo-Saxon monk who sang: . . . Adam lay ibounden, bounden in a bond. Four thousand winter, thought he not to long. And all was for an appil, and appil that he tok, As clerkès finden, written in their book. Ne had the appil takè ben, Ne haddè never our lady, a ben hevenè quene. Blessèd be the time that appil takè was Therefore we moun singen, Deo Gracias! . . . In the mind of that monk, taking the apple of technological knowledge was the first step in spinning out the whole tapestry of the biblical drama that had left him at last with the comfort of his Virgin Mary. So he sang “Deo Gracias,” picked up his compass and square, and went to work. No wonder medieval Christianity was such a friend to the work of making things.
Looking Inside the Inventive Mind
Authors: Lienhard John H.
Published: November 2020

An inventor—any creative person—knows to look under the surface of what things seem to be, to learn what they are. I have been able to find only one constant in the creative mind. It is that surprise is the hidden face of the coin of invention. In their operetta Pinafore, Gilbert and Sullivan warn us: . . . Things are seldom what they seem, Skim milk masquerades as cream; Highlows pass as patent leathers; Jackdaws strut in peacock’s feathers. . . . For example, an engineer designing a highway system wants to include crossroads between the major arteries. Common sense says that crossroads will increase driver options and speed traffic. Only very keen insight, or a complex computer analysis, reveals that crossroads tend to make matters worse. They often create localized traffic jams where none would otherwise occur. We are caught off guard when common sense fails us. Yet it is clear we would live in a deadly dull world if common sense alone were sufficient to lead us through all the mazes around us. If what we learn is no more than what we expect to learn, then we have learned nothing at all. Sooner or later, every student of heat flow is startled to find out that insulation on a small pipe can sometimes increase heat loss. Common sense is the center of gravity we return to after our flights of fancy. But it is the delicious surprise—the idea that precedes expectation—that makes science, technology, and invention such a delight. A wonderful old expression calls creativity “a fine madness,” and it is. Invention lies outside the common ways and means. If it is sane to respond predictably to reality, then invention surely is madness. A well-known riddle shows us something of the way that madness works. You are asked to connect nine dots, in a square array, with four straight lines. Each line has to continue from the end of the last line. The problem seems to have no solution.
Science Marries into the Family
Authors: Lienhard John H.
Published: November 2020

The old Latin word scientia was not much used to designate ordered knowledge until recent times. Galileo would not have called himself a scientist, nor would Newton or Leibniz. Even two hundred years ago Lavoisier still called himself a natural philosopher. Yet each of those people contributed to the radical change that turned natural philosophers into today’s scientists. The change was complex. Roughly speaking, it could be called the evolution of the scientific method. It began during the 1480s, when the new printed books first included accurate illustrations of an observed world. Until then, first Christians and then Moslems had adhered to the Platonist idea that truth is to be reached by deduction far more than by observation. Throughout the sixteenth century the new observational sciences of botany, anatomy, descriptive geometry, geography, and ethnography all took form. In a series of bold steps the new media of print and illustration wrenched a world still shaped around Platonist thinking. Then, in the early sixteen hundreds, Galileo Galilei and Francis Bacon in particular codified the changes that had been afoot. Galileo did more than anyone to establish the methods of the new science, and Francis Bacon framed its philosophical stance. In 1620 Bacon wrote down the new view of nature in unmistakable terms in his Novum Organum. He directly contradicted the Platonists’ belief that truth is to be found in the human mind when he said, “That which nature may produce or bear should be discovered, not imagined or invented.” For over a century, a new breed of scientists had been learning how to take better account of empirical fact than medieval scientists had done. Now Bacon told us flatly that this was the only proper way to practice science. After 1600 Europe gained two new tools of inquiry, both of which led away from medieval thinking. The shift to observational science was certainly strengthened by new kinds of measuring instruments. Clock making was a technology that had led to a new precision in mechanisms. The seventeenth century gave us the telescope, the thermometer, the vacuum pump, and the microscope.
Inventing America
Authors: Lienhard John H.
Published: November 2020

America was not discovered, it was invented. Its name was invented; its machines were invented; its way of life was invented. America sprang from the minds of that unlikely breed of people who were able to pack up a few belongings and step into a great unknown. That step into the expanse of a new continent unleashed astonishing creative energy. America was an adventure of the mind. The land seemed to reach into infinity, and minds opened to fill it. The colonists had limited recourse to the European intellectual mainstream. They were poorly equipped, but they were freedom-driven and freedom-shaped. They were free of method and free of tradition. They were free to create a new life. Colonial technology was so molded by the imperative to be free that it is hard to talk about it without being drawn into that infectious drive. You cannot just report it; you have to celebrate it. As I look back at the early episodes of The Engines of Our Ingenuity upon which this chapter is based, it is clear that I too was drawn in. My first impulse in reworking this material for print was to tone it down and mute my enthusiasm. In the end I did not do so. History gives us too few moments with such verve. Why not go back and be the irrepressible child that America itself once was? The need to rediscover the childhood of our nation is great. We are drifting into a new sobriety. It was in my generation that we first lost a war. We no longer take our leadership in productivity for granted. We have found that we have a capacity for failure, and that we do not always emerge as the good guys. We have deconstructed our heroes until they seem to be heroes no more. But they were heroes. Any chapter on colonial technology inevitably yields up the names of Jefferson (no mean inventor himself), Fulton (with his thumb in so many pies), and the towering figure of Benjamin Franklin. These people appear here not because they were the only heroes we had, but because they were true paragons of colonial creativity.
Taking Flight
Authors: Lienhard John H.
Published: November 2020

The recurring fantasies of my childhood were dreams of flight. I doubt I differed from other children in my imaginings, and in my childish way I seriously tried to achieve flight. I jumped from the garage roof into snowbanks. I scaled trees and cliffs. I swung on ropes. It’s a good thing my mother never learned just how hard I worked at leaving the earth. Sprained ankles and bruised ribs eventually convinced me that my body was earthbound even if my mind was not. I turned to model airplanes. I lived inside those lovely, light, buoyant structures. They carried me with them into the sky. My inner eye gazed down on the land from their vantage above. This craving to fly is bred in the bone of our species. The old legends come out of the past with such conviction that we know some core of truth must undergird them. In Chapter 2 I refer to documented experiments with flight in the ninth and eleventh centuries. The Chinese flew humans in kites as early as the sixth century. One of the oldest and oddest intimations of early flight came out of the Cairo Museum in 1969. An Egyptian doctor named Khalil Messiha was studying the museum’s collection of ancient bird models. He found that all the models but one were similar. That one was made of sycamore wood. It was a little thing with a seven-inch wingspan. It caught Messiha’s attention because he saw it through the eyes of his childhood. He remembered the shapes and forms he had worked with when he built model airplanes as a boy. This was not a bird at all; it was a model airplane, and that was impossible. Yet the other birds had legs; this had none. The other birds had painted feathers; this had none. The other birds had horizontal tail feathers like a real bird. Perhaps that was the most important difference. Birds do not have to be stable in flight because they can correct their direction; but a model airplane needs a vertical rudder to keep it moving straight.
Major Landmarks
Authors: Lienhard John H.
Published: November 2020

Toward the end of the twentieth century we saw countless inventories of inventions and achievements—the top twenty scientific breakthroughs of the millenium, the fifty most important people of the century, and so on. I am of two minds when I look at such lists. On the one hand, they rightly celebrate and draw our attention to much good that has been done. On the other hand, as we noted in Chapter 4, a vast portion of real accomplishment goes on below our level of perception. That point recurs in Chapter 14. So much of the creativity that defines us as people is inevitably left off such lists. It would be a futile exercise to correctly identify any definitive list of the most influential machines of all time. Yet some inventions really are landmarks. I have selected from among the first year’s Engines of Our Ingenuity radio programs a set of starting points that strongly propagate forward in time. Some might be obvious choices; others might not. But each can rightly be called a landmark because it sits squarely on some major highway of subsequent development. There is, of course, only one place to begin such a list, and that is with the great progenitor of machines—the first machine most people will name. We begin with the wheel, which has become such a universal and familiar icon of our technological world that we forget the enormous conceptual leap it embodied. The wheel was almost surely invented somewhere within the borders of present-day Iran or Iraq, five and a half millennia ago. That in itself is surprising because it happened so late in human history. The wheel was also confined within Europe and Asia for a long time. Wheels were hardly seen in the American hemisphere until European settlers began bringing them into regular use in the sixteenth century. There is evidence that the eleventh-century inhabitants of what we now call Mexico had the concept, but we have no evidence of its general use. Of course, you and I have lived our entire lives with a hundred thousand different forms of the wheel.
Displaying Information Maps and Graphs
Authors: Headrick Daniel R.
Published: November 2020

Not all those who contributed to the culture of information were members of the bourgeoisie. In the area of visual representation, two names—Cassini and Harrison—illustrate how widely the culture of information had spread to all classes of society. For over a century, four generations of Cassinis dominated French astronomy and cartography. The founder of this illustrious lineage, Giovanni Domenico Cassini (1625 –1712), was a professor of astronomy at the University of Bologna when he was recruited to head the Paris Observatory in 1669. He became a French citizen, changed his name to Jean-Dominique Cassini, and entered into the privileged elite of the Old Regime. At the observatory, Jean Cassini discovered the rotation of the planets and developed a method of determining longitude by sighting the moons of Jupiter. He also launched the most elaborate cartographic project of his time, the map of France known as “la carte de Cassini.” His son Jacques Cassini (1677–1756), known as Cassini II, succeeded him at the observatory and as a member of the French Academy of Sciences. Jacques carried on his father’s work of measuring the arc of the meridian—a necessary but preliminary step in constructing an accurate map of France. In this effort, which was to take fifty years, Jacques Cassini was seconded by his son César-François Cassini de Thury (1714 –1784), known (of course) as Cassini III, who was also a member of the Academy and director of the observatory. When César-François died in 1784, his son Jacques-Dominique (1748 – 1845), count of Cassini (Cassini IV), carried on as head of the observatory, member of the academy, and director of the map project. The Cassinis’ Carte de France, completed in 1793, was a masterpiece of Old Regime cartography. Jacques­ Dominique’s son Gabriel (1784 –1832) broke with the family tradition and became a botanist. In contrast to this story of distinction and privilege, John Harrison’s life was one of struggle and hardship, rewarded by success only at the very end. Harrison (1693 –1776) was the son of a carpenter who taught himself how to build clocks.
Synthesis of Complex Life Objects from Glider
Authors: Niemiec Mark D.
Published: November 2020

Life, like many other cellular automata, contains many interesting objects, such as still lifes, oscillators, spaceships, spaceship guns, puffer trains, breeders, and the like. While many of these, like blocks, blinkers, and gliders, occur naturally with great frequency, there are many others that occur infrequently, and countless others that have never yet been observed in any natural context. This chapter deals with methods for synthesizing such complex objects from simple building blocks, such as gliders or other easy-to-synthesize objects. Once an object can be shown to be built in this manner, the object may be used as a building block in larger relocatable structures, such as Turing machines or universal constructors. In addition, the existence of a natural synthesis of an object from a bounded number of gliders implies that the object will form naturally in a sufficiently large, sufficiently sparse field [2]. Inasmuch as this chapter deals mainly with practical aspects of object synthesis, rather than theoretical ones, it may resemble a talk on chemical engineering, rather than abstract mathematics. All figures shown here, unless otherwise specified, show “before” and “after” images of collision sequences; the “before” sequences are shown on the left with dark cells, and the “after” sequences to the right of them in lighter cells. In some cases, unwanted debris is also generated and must be removed later; this debris is shown in the lightest color. There are several basic ways in which objects can be synthesized. The most common objects occur in great abundance in nature, so there are many random collisions of a small number of gliders that will produce them. There have been many random broth experiments conducted in Life, in which fields initialized to random initial configurations have been run until they became periodic, and then the resulting ash analyzed. The results of two such series of experiments, performed by Achim Flammenkamp [1] and Heinrich Koenig [3], are available on the Web. If the objects are sorted in order of decreasing frequency of natural occurrence, the list is also in order of increasing synthesis cost in gliders (with a few rare objects out of place).
Universal Cellular Automata Based on the Collisions of Soft Spheres
Authors: Margolus Norman H.
Published: November 2020

Fredkin’s Billiard Ball Model (BBM) is a continuous classical mechanical model of computation based on the elastic collisions of identical finite-diameter hard spheres. When the BBM is initialized appropriately, the sequence of states that appear at successive integer time steps is equivalent to a discrete digital dynamics. Here we discuss some models of computation that are based on the elastic collisions of identical finite-diameter soft spheres: spheres which are very compressible and hence take an appreciable amount of time to bounce off each other. Because of this extended impact period, these Soft Sphere Models (SSMs) correspond directly to simple lattice gas automata—unlike the fast-impact BBM. Successive time steps of an SSM lattice gas dynamics can be viewed as integer-time snapshots of a continuous physical dynamics with a finite-range soft-potential interaction. We present both two-dimensional and three-dimensional models of universal CAs of this type, and then discuss spatially efficient computation using momentum conserving versions of these models (i.e., without fixed mirrors). Finally, we discuss the interpretation of these models as relativistic and as semiclassical systems, and extensions of these models motivated by these interpretations. Cellular automata (CA) are spatial computations. They imitate the locality and uniformity of physical law in a stylized digital format. The finiteness of the information density and processing rate in a CA dynamics is also physically realistic. These connections with physics have been exploited to construct CA models of spatial processes in Nature and to explore artificial “toy” universes. The discrete and uniform spatial structure of CA computations also makes it possible to “crystallize” them into efficient hardware [17, 21]. Here we will focus on CAs as realistic spatial models of ordinary (nonquantum- coherent) computation. As Fredkin and Banks pointed out [2], we can demonstrate the computing capability of a CA dynamics by showing that certain patterns of bits act like logic gates, like signals, and like wires, and that we can put these pieces together into an initial state that, under the dynamics, exactly simulates the logic circuitry of an ordinary computer.
Continuous-Valued Cellular Automata in Two Dimensions
Authors: Rucker Rudy
Published: November 2020

We explore a variety of two-dimensional continuous-valued cellular automata (CAs). We discuss how to derive CA schemes from differential equations and look at CAs based on several kinds of nonlinear wave equations. In addition we cast some of Hans Meinhardt’s activator-inhibitor reaction-diffusion rules into two dimensions. Some illustrative runs of CAPOW, a. CA simulator, are presented. A cellular automaton, or CA, is a computation made up of finite elements called cells. Each cell contains the same type of state. The cells are updated in parallel, using a rule which is homogeneous, and local. In slightly different words, a CA is a computation based upon a grid of cells, with each cell containing an object called a state. The states are updated in discrete steps, with all the cells being effectively updated at the same time. Each cell uses the same algorithm for its update rule. The update algorithm computes a cell’s new state by using information about the states of the cell’s nearby space-time neighbors, that is, using the state of the cell itself, using the states of the cell’s nearby neighbors, and using the recent prior states of the cell and its neighbors. The states do not necessarily need to be single numbers, they can also be data structures built up from numbers. A CA is said to be discrete valued if its states are built from integers, and a CA is continuous valued if its states are built from real numbers. As Norman Margolus and Tommaso Toffoli have pointed out, CAs are well suited for modeling nature [7]. The parallelism of the CA update process mirrors the uniform flow of time. The homogeneity of the CA update rule across all the cells corresponds to the universality of natural law. And the locality of CAs reflect the fact that nature seems to forbid action at a distance. The use of finite space-time elements for CAs are a necessary evil so that we can compute at all. But one might argue that the use of discrete states is an unnecessary evil.
Moments of the Flow Variables, Part II : The Effective Conductivity
Authors: Rubin Yoram
Published: November 2020

Many applications require primary information such as average fluxes as a prelude to more complex calculations. In water balance calculations one may be interested only in the average fluxes. For both cases the concept of effective conductivity is useful. The effective hydraulic conductivity is defined by where the angled brackets denote the expected value operator. The local flux fluctuation is defined by the difference qi(x) — (qi(x)). Its statistical properties as well as those of the velocity will be investigated in chapter 6. To qualify as an effective property in the strict physical sense, Kef must be a function of the aquifer’s material properties and not be influenced by flow conditions such as the head gradient and boundary conditions (Landauer, 1978). Our goal in this chapter is to explore the concept of the effective conductivity Kef and to relate it to the medium’s properties under as general conditions as possible. Additionally, we shall explore the conditions where this concept is irrelevant and applicable, the important issue being that Kef is defined in an ensemble sense, but for applications we need spatial averages. Several methods for deriving Kef will be described below. The general approach for defining Kef includes the following steps. First, H is defined as an SRF and is expressed with the aid of the flow equation in terms of the hydro-geological SRFs (conductivity, mostly) and the boundary conditions. The H SRF is then substituted in Darcy’s law and an expression in the form equivalent to (5.1) is sought. If and only if the coefficient in front of the mean head gradient is not a function of the flow conditions will it qualify as Kef. The derivation of the effective conductivity employs the flow equation. In steady-state incompressible flow, for example, Laplace’s equation is employed. Solutions derived under Laplace’s equation are applicable, under appropriate conditions, for other physical phenomena governed by the same mathematical model. For example, the electrical field in steady state is also described by Laplace’s equation.
Crete
Authors: Fant Clyde E. , Reddish Mitchell G.
Published: November 2020

Crete is the largest and most southerly of all the Greek islands. It is also one of the most visited, due to both its beauty and its famous ancient sites. By far the best-known of these attractions is the spectacular Palace of Knossos, reconstructed over a period of thirty-five years by its discoverer, Sir Arthur Evans, who put more than a million dollars of his own money into the work. Scholars have criticized his reconstruction as a fanciful and not altogether accurate representation of the original, but millions of tourists delight in being able to see more at an ancient site than foundations, scattered stones, and a few columns. But Knossos is not the only dramatic ruin of antiquity on the island. Gortyna and Phaistos should not be missed, and for Christians the harbor of Kaloi Limenes (called Fair Havens in the New Testament) is a place of importance in the life of the Apostle Paul. Likewise, the Basilica of St. Titus at Gortyna commemorates the ministry of Titus, a Greek convert who was a disciple of Paul (Gal 2:3), as described in the New Testament book of Titus. Furthermore, Iraklion possesses an archaeological museum second only to the National Museum in Athens. The only site on Crete mentioned in the Bible, though Crete itself was said to be the place of the ministry of Titus (Titus 1:5), is the harbor of Kaloi Limenes (Good Harbor), referred to in the Book of Acts as Fair Havens (Acts 27: 8). After two thousand years, the site is known by the same name today. Even in New Testament times the place was distinguished only as the harbor for the nearby city of Lasea, a flourishing commercial city in the Roman period. Today the tranquil bay in its remote location harbors nothing more than sunbathers who visit its beaches to enjoy the beautiful waters of the Mediterranean. The site can be reached best by automobile, or by taking a bus from Iraklion to Moires/Mires.
Nicopolis
Authors: Fant Clyde E. , Reddish Mitchell G.
Published: November 2020

An ancient city whose name suggests the reason for its founding (“Victory City”), the site of Nicopolis today still gives indication of its power and size in the 1st century C.E. Caesar Augustus founded the city to celebrate his great victory at nearby Actium over the forces of Antony and Cleopatra. It has been called “the best site to appreciate the Roman conqueror’s transforming hand on ancient Greece’s landscape” (Christopher Mee and Antony Spawforth, Greece: An Oxford Archaeological Guide [Oxford: Oxford University Press, 2001], 389). Nicopolis lies on the northwestern shore of Greece in the province of Epirus. It can be reached on fine highways from Athens (approximately 5 hours), or by flights from Athens to Aktion (also known as Preveza airport), only 7 miles away, where an automobile ferry crosses every half hour to Preveza. (A tunnel has been recently completed that will make the future use of the ferry unnecessary.) Taxis are available for the short trip 5 miles west to Nicopolis. Taxis from the airport also can be reserved in advance; be sure to ask if the driver will wait for a visit to the site (approximately an hour), and always get the negotiated price in writing. The area is idyllic and beautiful, particularly the harbor and city of Preveza. The first cities in the area were established by Pyrrhus, king of the region of Epirus (who lent his name to the term “Pyrrhic victory,” referring to a costly battle, generally without real resolution). Nicopolis was founded by Octavian, later known as Caesar Augustus, to commemorate his epic victory over the combined fleets of Antony and Cleopatra at Actium (31 B.C.E.), one of the most important battles of antiquity. The crews of Antony’s warships had been weakened by the malarial fever they contracted in the area, and due to their fatigue they were never able to execute the head-on ramming techniques for which his heavier ships were noted. Octavian’s ships stayed well out of range until he perceived that the enemy was tiring, then they blocked the exit to the sea and destroyed much of Antony’s fleet of five hundred ships.
The Hittites: Hattusa and Yazïlïkaya
Authors: Fant Clyde E. , Reddish Mitchell G.
Published: November 2020

In many ways the ancient Hittite sites of Hattusa and Yazïlïkaya are among the most distinctive sites related to the Bible in the entire Mediterranean region. Unlike the majority of ancient cities of the Bible in both Turkey and Greece, these sites are not related to the Apostle Paul and the New Testament. In fact, they are only marginally related to the Old Testament. Nevertheless, the identification of this city in 1906 by the German archaeologist Hugo Winckler created a sensation in archaeological and biblical studies. Since 1986 the site of Hattusa has been included on the World Heritage List of UNESCO (the United Nations Educational, Scientific, and Cultural Organization). Prior to the 19th century, the Hittites were entirely unknown to the world except for their mention in the Bible. The biblical references to such a powerful kingdom, for which no other evidence existed, were met by skepticism and even outright disbelief. Scholars did not believe that so dominant an empire could disappear without a trace. Following the discovery in 1799 of the Rosetta Stone in Egypt by Napoleon’s soldiers, however, which unlocked the key to reading hieroglyphics, reference to the Hittites was also discovered in Egyptian sources. Most notable among these citations are references to a great battle between the Egyptians, led by Ramses II (likely the pharaoh of the Exodus tradition), and the Hittites at Kadesh (Syria). Also mentioned was a subsequent treaty, a nonaggression pact, wherein both nations pledged mutual support and agreed to establish Syria as the southern boundary of the Hittites’ power and the northern boundary of the Egyptians’ power. Modern discovery of the Hittites began in 1834, when Charles Texier located the ruins of the capital city of the Hittites, Hattusa, which he believed to be a city of the Medes. Correct identification of the city was not made until 1906, when the discovery of 2,500 fragments of cuneiform tablets allowed Hugo Winckler to recognize that the extensive ruins were in fact the Hittite capital city. Since that time excavations by the German Archaeological Institute and others have continued.