bluuebunny/crossref_metadata_2025 huggingface dataset:
Epilogue
Authors: Kennel Charles F.
Published: November 2020

The reader who has endured to the end, and even the one who skips to the end to see why he should read what is in the middle, deserves an answer to certain questions. Why, for example, did we employ a writing style so at odds with prevailing standards of scientific exposition? Of what use is it to read so much “anecdotal science”? Why, most of all, why did we place such a light emphasis upon theory, or for that matter, quantitative experimental results? The reader need only look as far as the comparison between the rates of transport due to viscosity and reconnection for an answer. These estimates were made with “back-of-theenvelope accuracy” in the 1960s, they are still made the same way on the eve of the twenty-first century, and we still do not know how the two systems of convection interact when they are time dependent. Magnetospheric physics, despite thirty-five years of the most intense, world wide activity, is still in the stage of paradigm clarification. It is, contrary to what one hears in many quarters, not a mature subject at all. There had been such optimism when the space age opened. A few rocket flights, a few spacecraft, and we thought we would know, really know, what the earth’s space environment was like. And in a sense, we learned, we really did learn. Standing out there in the solar wind was a bow shock and a magnetosphere of convecting plasma connecting to highly time-variable auroral displays. These first broad brush strokes of the picture were created by a confident, mid-twentiethcentury command technology, and it seemed that only a few more strokes would fill the canvas. Yet as time passed, the pattern seemed no clearer than it had at the beginning. It turned out that we were painting our picture as a pointillist would, each spacecraft, each ground experiment a single dot. Seurat, as he painted, had a clear idea of the picture he wanted to create, but we had to wait for our picture to emerge, one dot a time, dots of one color at a time.
Drug Administration and Drug Effectiveness
Authors: Saltzman W. Mark
Published: November 2020

There is some comfort to thinking of the human body as an elaborate bag of chemicals. Chemicals can be produced; chemicals can be added or replaced; chemicals are (sometimes) inexpensive. In fact, several decades ago, it was widely reported that the chemicals in the human body were worth about $1. Other investigators estimate the value at closer to $6 million (particularly if the chemicals are purchased from scientific suppliers). True dollar value aside, we often imagine that our bodies can be supplemented, mended, and improved through the addition of “missing” chemicals. Perhaps for this reason, the modern practice of healing usually involves medicine, an agent or elixir given as treatment. The new millennium finds us rich in the knowledge of agents; advanced in the art of harvesting or synthesizing remedies; steadfast in the belief that cancer, heart disease, and neurodegeneration will eventually yield to these potions. Our skill in making medicine is far-reaching. Today, it would be difficult to find the person who has not personally experienced the healing force of antibiotics, vaccines, or modern chemotherapy. Unfortunately, it would be equally difficult to find the person who has not endured the premature death of a friend or relative due to untreatable infection or cancer. So we continue to search for better therapeutics. Better medical treatments do not always require stronger medicine. The effectiveness of chemical agents depends on the method of administration, so treatments can often be improved by finding optimal drug formulations or delivery systems. For example, Banting and Best demonstrated control of diabetes by insulin injection in 1922. But early use of insulin was difficult: multiple daily injections were required and the effects were difficult to control. Insulin preparations have changed dramatically since that time; recombinant human insulin is now available in addition to highly purified insulin from animals. Today, the formulation of insulin is advanced: various formulations provide rapid or delayed action with long or short duration, so insulin therapy can be tailored to the needs of an individual. Intensive, individualized therapy decreases the long-term consequences of diabetes [1].
Diffusion and Drug Dispersion
Authors: Saltzman W. Mark
Published: November 2020

Most biological processes occur in an environment that is predominantly water: a typical cell contains 70-85% water and the extracellular space of most tissues is 99%. Even the brain, with its complex arrangement of cells and myelinated processes, is ≈ 80% water. Drug molecules can be introduced into the body in a variety of ways; the effectiveness of drug therapy depends on the rate and extent to which drug molecules can move through tissue structures to reach their site of action. Since water serves as the primary milieu for life processes, it is essential to understand the factors that determine rates of molecular movement in aqueous environments. As we will see, rates of diffusive transport of molecules vary among biological tissues within an organism, even though the bulk composition of the tissues (i.e., their water content) may be similar. The section begins with the random walk, a useful model from statistical physics that provides insight into the kinetics of molecular diffusion. From this starting point, the fundamental relationship between diffusive flux and solute concentration, Fick’s law, is described and used to develop general mass-conservation equations. These conservation equations are essential for analysis of rates of solute transport in tissues. Molecules that are initially localized within an unstirred vessel will spread throughout the vessel, eventually becoming uniformly dispersed. This process, called diffusion, occurs by the random movement of individual molecules; molecular motion is generated by thermal energy.
Evidence That NC Does Not Equal P
Authors: Greenlaw Raymond , Hoover H. James , Ruzzo Walter L.
Published: November 2020

Why should we believe that NC does not equal P? One form of evidence is that many people have tried, but failed, to show them equal. More persuasive, perhaps, is the way they have failed, or rather, the character of the limited successes. Specifically, known approaches consistently leave a large gap between what we know how to solve by highly parallel algorithms, and general problems in P. In outline, the state of the art is as follows. General simulations are not fast: The best known parallel simulations of general sequential models give very modest improvements, basically reducing sequential time T to parallel time T/logT or √T, depending on the parallel model. Furthermore, 2TΩ(1) processors are needed to achieve even these modest improvements. Fast simulations are not general: Rapid simulations of sequential models by highly parallel models are known only for rather weak sequential models. Natural approaches provably fail: Certain natural approaches to highly parallel simulation are provably insufficient. Equivalently, in certain natural structured models of computation (Borodin [41]), one can prove that the analogs of NC and P are not equal, and indeed are separated by a nearly exponential gap, as suggested by the two points above. In this chapter we will present this evidence in more detail. The nature of the available evidence renders this chapter, especially Section 5.4, somewhat more technical than the rest of Part I. The reader may wish to skim or skip it, at least on first reading. First, consider the Generic Machine Simulation Problem introduced in Section 4.1. Intuitively, why should we expect this problem to be hard to parallelize? Notice that we defined the problem in terms of Turing machines as a technical convenience; they are not in any way fundamental to the result.
Mathematics Between Source And Trap: Uncertainty In Hydrocarbon Migration Modeling
Authors: Kacewicz Marek
Published: November 2020

Petroleum geology provides a wide spectrum of data that differs from frontier to mature areas. Data quality and quantity control which mathematical methods and techniques should be applied. In this paper two mathematical methods are shown: fuzzy-set theory and possibility theory as applied to permeability prediction and stochastic modeling of traps and leaks. Both methods are used in the modeling of hydrocarbon migration efficiency. Examples of how data uncertainty may affect final assessment of oil accumulation are presented. The complexity of petroleum geology and its importance to society stimulate research in different scientific areas including mathematical geology, which is becoming steadily more important. Armed with workstations, mainframes, and supercomputers, research laboratories in the petroleum industry investigate sophisticated mathematical techniques and develop complex mathematical models which can speed and improve exploration and lower total exploration costs. Together with classical analysis of geological, geochemical, and seismic data, mathematics provides an additional tool for basin research. The elements of petroleum systems—maturation, expulsion and primary migration, secondary migration, seals, reservoirs, and traps—may be better described by properly applied mathematical techniques. The complexity of petroleum geology and its importance to society stimulate research in different scientific areas including mathematical geology, which is becoming steadily more important. Armed with workstations, mainframes, and supercomputers, research laboratories in the petroleum industry investigate sophisticated mathematical techniques and develop complex mathematical models which can speed and improve exploration and lower total exploration costs. Together with classical analysis of geological, geochemical, and seismic data, mathematics provides an additional tool for basin research. The elements of petroleum systems—maturation, expulsion and primary migration, secondary migration, seals, reservoirs, and traps—may be better described by properly applied mathematical techniques. The applicability of mathematical methods differs in frontier and mature areas and depends upon the quality and quantity of available information. Frontier areas for which data are mostly qualitative require methods which can handle imprecise and limited information easily. Fuzzy-set theory with fuzzy inference algorithms and artificial intelligence are useful approaches. Cokriging and "soft" geostatistical approaches also may be helpful.
A Solution To The Percentage -Data Problem In Petrology
Authors: Timothy Whitten E. H.
Published: November 2020

Statisticians have demonstrated the iriappropriateness of percentage data for petrological purposes except when transformations (e.g., log-ratios) are used to avoid inherent closure. Use of open variables for chemical data (perhaps weight per unit volume, g/100cc) would avoid this problem and permit traditional petrological work to be undertaken. Virtually all compositional data used in petrology are expressed as percentages (e.g., SiO2 wt%, muscovite vol%, Si wt%) or parts per million. Geologists depend on percentage and ppm data for studies of petrogenesis, spatial variability, etc. However, for over four decades, statisticians and mathematical geologists have given dire warnings about the dangers of drawing conclusions from percentage (or ratio) data. In consequence, petrological literature abounds with disclaimers about possible adverse effects that closure constraints (stemming from use of percentage data) may have. The abundant warnings have given little help to geologists for two reasons. First, the precise impact of closure on petrologic analyses and conclusions has been unclear or abstract. Second, a practical and realistic way of avoiding closure in petrology has not been apparent. Problem avoidance might involve either (a) applying statistical or mathematical transformations to standard percentage data to escape the inherent closure constraints that importune petrological conclusions, or (b) using meaningful petrological variables that are free of closure constraints so that traditional thinking and data manipulation can be used without problem. Transformation has been advocated for geological work by Aitchison (e.g., 1982); this approach, which presents considerable geological difficulties, is briefly reviewed here. No attention appears to have been given to the simple approach of using closure-free variables, which is the main subject of this paper. Closed data are compositional data that have a constant sum. Open data can have any value and do not have the constant-sum constraint. Standard rock chemical analyses are closed because the oxides (or elements, etc.), expressed as percentages, sum to 100; in consequence, at least one negative correlation between the variables must exist (Chayes, 1960). The problem of closure is obvious in two-variable systems. In a quartz-feldspar rock, for example, if quartz percentage increases, feldspar must decrease, so there is inherent negative correlation between the components.
Information and communication
Authors: Schenck Douglas , Wilson Peter
Published: November 2020

The central theme of this book is the representation of information in a formal and precise manner. We therefore have to try and describe what information is before we can go on and talk about its representation. Also, we need to indicate why we want to utilize a formal means of representation. We are all experts in the subject of information — we use it every day. Unfortunately, information is an intangible and it is difficult to talk about intangibles; most of the time we do not even think about such matters but rest comfortably with an intuitive feel for such things. Good question! According to Webster’s, information is, among other things, 1: The communication of or reception of knowledge or intelligence 2a: Knowledge obtained from investigation, study or instruction 2b: The attribute inherent in and communicated by one or two or more alternating sequences or arrangements of something (as nucleotides in DNA or binary digits in a computer program) that produces specific effects 2c: A signal or character (as in a communication system or computer) representing data. From the same source, we learn that data is Factual information (as measurements or statistics) used as a basis for reasoning, discussion, or calculation. The salient words that we are concerned with are knowledge, communication and data. In general we are concerned about information in the real world. To make matters more precise, we introduce our own definition of information. Definition 1 Information is knowledge of ideas, facts and/or processes. Information can be communicated, that is it may be transferred between two or more partners. (Strictly speaking, as the producer and user of information may be one and the same, only a single ‘partner’ may be involved.) This may be done in real time or there may be a delay between one partner sending the information and another receiving it. For example, the authors wrote this document long before anyone else read it. Consequently, information storage is just a special case of communication. The ultimate goal in information modeling is to formulate descriptions of real world information so that it may be processed and communicated efficiently without any knowledge of its source and without making any assumptions.
Constant Depth Prefix Circuits With Unbounded Fan-In
Authors: Lakshmivarahan S. , Dhall Sudarshan K.
Published: November 2020

It is well known that among the three classes of the PRAM models, namely, CRCW, CREW, and EREW, the CRCW models are the weakest, in the sense that, they permit concurrent read/write by processors. Accordingly, algorithms on the CRCW model mainly concentrate on the core computations without much ado about data access. Consequently, this model, at least in principle, allows for the design of the fastest algorithm for a problem. It is intriguing to ask how fast prefixes can be computed on the CRCW models. Since CRCW models are equivalent to the unbounded fan-in circuits (refer to Chapter 2), the task of developing the fastest algorithms for the prefix problems is pursued in the context of the unbounded fan-in circuits. Recall from Chapter 2, that while the standard measures, such as, size and depth are still used to quantify the goodness of unbounded fanin circuits, the size of the circuit is measured by the total number of edges incident on all of its operation nodes, instead of by the number of operations nodes. It turns out that the size and depth of unbounded fanin circuits for computing prefixes, depends critically on the structure of the underlying semigroup from which the input elements are drawn. The principal result of this concluding Chapter may be stated as follows: There exists unbounded fan-in parallel prefix circuits of constant depth and polynomial size if, and only if, the underlying semigroup is group free. The proof of this result involves a very clever synthesis of a number of ideas drawn from different directions — structure of group free semigroups, their relations to a special class of regular sets, called non-counting regular sets, the relation of this latter class of regular sets to yet another class of regular sets defined by star-free regular expressions, and the design of a special class of finite state deterministic automata called RS machines that accept star-free regular expressions. In this context, it is convenient to define the notion of small circuits as the class of circuits with constant depth and polynomial size.
Convection techniques
Authors: Schmickler Wolfgang
Published: November 2020

Forced convection can be used to achieve fast transport of reacting species toward and away from the electrode. If the geometry of the system is sufficiently simple, the rate of transport, and hence the surface concentrations cs of reacting species, can be calculated. Typically one works under steady-state conditions so that there is no need to record current or potential transients; it suffices to apply a constant potential and measure a stationary current. If the reaction is simple, the rate constant and its dependence on the potential can be calculated directly from the experimental data. Working under steady-state conditions has certain advantages; in particular the complications caused by double-layer charging are avoided. On the other hand, convection techniques require a greater volume of solution, and contamination of the electrode surface is even more of a problem than usual because the solution is constantly swept past the electrode surface. The simplest and most commonly used convection apparatus consists of a disc electrode rotating with a constant angular velocity ω. The disc sucks the solution toward its surface, much in the way a propeller would; as the solution approaches the disc, it is swept away radially and tangentially. The transport of the reacting species to the disc occurs both by convection and diffusion. Though the mathematics are complicated, the rate of transport can be calculated exactly for an infinite disc. A particularly nice feature of this setup is the fact that the transport is uniform so that the surface concentration of any reacting species is constant over the surface of the electrode. Right at the disc the convection current perpendicular to the surface vanishes.
Engineering Works
Authors: Graf William L.
Published: November 2020

The hydrologic, sedimentologic, and geomorphic processes of the Northern Rio Grande as outlined in the previous chapters do not operate under natural, undisturbed conditions. Numerous engineering structures and activities have modified the processes and forms, and so an explanation of the movement and storage of contaminants in the system requires knowledge of the channelization and dam construction in the region. Channelization works are usually directed toward controlling the horizontal position of the channel, keeping it aligned in an economically advantageous arrangement, and maintaining a clear path for floodwaters to prevent them from spilling over the banks. The imposition of an artificial, stable channel on a naturally unstable system is rarely completely successful, but even with partial success, the newly defined system is a radical departure from the natural one. Floodwaters usually flow through modified channels at higher velocities than they do through natural channels, and so they may transmit more sediment in the channel. Low flows, however, may deposit sediment in the engineered channel, thereby reducing its efficiency and raising its bed. The abandonment of previously active minor channels or braided sections provides new areas of colonization for riparian vegetation, which may enhance sedimentation when flows exceed the capacity of the designed channel. The construction of dams obviously disrupts river processes in the reservoir area but has indirect effects throughout the river system because of newly instituted controls on flood flows, normal low flows, and sediment discharges. The first engineering structures on the Rio Grande probably appeared about A.D. 1200. With the collapse of irrigation societies in the Salt and Gila River valleys in Arizona and in tributaries of the San Juan River in Colorado and New Mexico, migrants moved into the Rio Grande Valley. By the time of the Spanish incursions in the middle and late sixteenth century, the native population had developed extensive irrigation systems along the entire Northern Rio Grande to support numerous pueblos.4 Diversion works on the main stream probably consisted of brush and boulder structures that directed the water into canal entrances through the low banks. These structures probably washed away with each spring flood.
Simulation of Sediment and Plutonium Dynamics
Authors: Graf William L.
Published: November 2020

The empirical data reviewed in the previous chapters indicate that low levels of plutonium can be found in sediments of the Rio Grande system. It is not readily apparent why the concentrations are low, given that the concentrations in sediments of the upper Los Alamos Canyon are one to three times greater than those in the main river. The explanation of observed concentrations probably lies in the complexities of the water and sediment system. Flash floods on the tributary occasionally evacuate some of the relatively plutonium-rich sediments into the Rio Grande, but when they enter the main river they are subject to two river processes that produce low plutonium concentrations in sedimentary deposits: mixing and dispersal. The concentrations are diluted when the sediments from Los Alamos Canyon combine with the sediments from the Upper Rio Grande and from tributaries, which contain fewer contaminants. The dispersal of plutonium on a scale of tens of kilometers along the river also generally lowers the concentrations, although the river processes deposit the contaminated materials in specific places rather than diffusing them completely throughout the river system. The consequences of the river’s complex contaminated sediment processes can be illustrated by means of direct measurement, laboratory experiments, or numerical simulation, but only the last alternative is feasible. Because the mixing, diffusion, and deposition in the Rio Grande cannot be directly observed, no detailed empirical data about them are available. And in order to be feasible, laboratory experiments must duplicate the significant components of the real system using flumes, and physical models of the system require changes in scale that may result in inaccurate representations of the actual system. The sediment in physical models must be smaller than that in their real counterparts, for example, but because the water cannot be “scaled down” in the model, the fine sediment in the laboratory behaves differently from the coarser sediment it represents in the real system. Therefore, the only possible detailed analysis of the system of contaminant transport and storage in the Rio Grande is through a numerical simulation model.
Faxén Relations and Ellipsoidal Inclusions
Authors: Phan-Thien Nhan , Kim Sangtae
Published: November 2020

A number of problems involving Stokes flows past rigid particles can be solved by using the well-known Faxén relations and multipole representation of the velocity field. Despite the analogy between the Stokes and Navier equations, the method does not seem to be widespread in the theory of elasticity. In this chapter, we derive Faxén relations and describe some applications involving spherical and ellipsoidal inclusions in an elastic matrix.
In the Tradition
Authors: Blum Bruce I.
Published: November 2020

Fifty years ago there were no stored-program binary electronic computers. Indeed, in the mid 1940s computer was a job description; the computer was a person. Much has happened in the ensuing half-century. whereas the motto of the 1950s was “do not bend, spindle, or mutilate,” we now have become comfortable with GUI wIMP (i.e., Graphic User Interface; windows, Icons, Mouse, and Pointers). whereas computers once were maintained in isolation and viewed through large picture windows, they now are visible office accessories and invisible utilities. whereas the single computer once was a highly prized resource, modern networks now hide even the machines’ geographic locations. Naturally, some of our perceptions have adapted to reflect these changes; however, much of our understanding remains bound to the concepts that flourished during computing’s formative years. For example, we have moved beyond thinking of computers as a giant brain (Martin 1993), but we still hold firmly to our faith in computing’s scientific foundations. The purpose of this book is to look forward and speculate about the place of computing in the next fifty years. There are many aspects of computing that make it very different from all other technologies. The development of the microchip has made digital computing ubiquitous; we are largely unaware of the computers in our wrist watches, automobiles, cameras, and household appliances. The field of artificial intelligence (AI) sees the brain as an organ with some functions that can be modeled in a computer, thereby enabling computers to exhibit “intelligent” behavior. Thus, their research seeks to extend the role of computers through applications in which they perform autonomously or act as active assistants. (For some recent overviews of AI see waldrop 1987; Crevier 1993.) In the domain of information systems, Zuboff (1988) finds that computers can both automate (routinize) and informate, that is, produce new information that serves as “a voice that symbolically renders events, objects, and processes so that they become visible, knowable, and sharable in a new way” (p. 9).
The Design Process
Authors: Blum Bruce I.
Published: November 2020

we have arrived at the last layer of the foundation. I now can begin a systematic analysis of design. As a brief reminder, this really is a book about the development of software applications. My thesis is that we can expect only limited improvement to software application and productivity by working within the current design paradigm (i.e, technological design). I believe that we must shift paradigms to exploit the special characteristics of software. But paradigm shifts are revolutions, and one cannot comprehend any new paradigm by extrapolating from the concepts and methods of the present paradigm. Thus, we must destroy before we can rebuild. In the physical sciences, the justification for destruction comes from outside the paradigm; phenomena are observed that are at variance with the models of normal science, and new theories are needed to explain them. Computer science and software engineering, however, are formalizations for free phenomena. In a sense, they are self-defining; they establish their own criteria for relevance and evaluation. If we are to replace those criteria, therefore, we must begin outside normal computer science. And that is the justification for these first two parts. Part I examines the meaning and limitations of science and provides an interpretation of design: the modification of the environment (or “changing existing conditions into preferred ones”). Part II looks at design from the perspective of those who make and use the designs. I deliberately remain outside the domain of computer science in my search for the knowledge that will be relevant to the subsequent examination of software. Once this knowledge has been assembled, Part III can enter into a less biased consideration of software and its role in the next millennium. Thus, the first two parts construct the context within which a new computer science can be defined, and Part III offers adaptive design as an illustration of what this new computer science can accomplish. where are we now in this odyssey? Chapter 1 begins with the traditional view in which the maturity of software engineering as a discipline is related to its utilization of computer science principles.
Design Methods
Authors: Blum Bruce I.
Published: November 2020

The previous chapter on the software process introduced two contrasting orientations: problem and product. Both orientations have the same objective: the efficient and effective creation of an automated response to a real-world problem. They differ only in the methods and tools used to achieve that end. In the product-oriented model, the difficulty of realizing a solution is accepted as the critical path. Thus, the approach applies the principle of separation of concerns and divides the process into two discrete activities: first establish the essential requirements of what is needed, and then build a product that will satisfy those requirements. As already noted, this model is appropriate when the requirements are stable or if the complexity of development is so great that a fixed specification is necessary to reduce risk. In contrast, the problemoriented model is valuable for real-world problems with open requirements (open both in the sense of initial uncertainty and of operational change). Unfortunately, it can be implemented only for domains in which the technology is relatively mature. For example, military applications that push the limits of technology have open requirements (i.e., they begin with uncertainty and are subject to modification as potential adversaries develop responses to newly introduced capabilities). In this domain, however, the technology may be too complex for development without frozen requirements. In other domains, such as interactive information systems, the technological challenges are sufficiently well understood to permit a problem-oriented approach with its one-step process model. The adaptive design paradigm proposed in this book is problem oriented. The instantiation I describe in the next two chapters creates interactive information systems. In principle, there is no reason why the adaptive design model may not be used for complex, real-time military applications; the fact that it has not been so used is a function of our knowledge of that domain and not a limitation of the paradigm. There always will be a fuzzy boundary about the technology that separates what we can and cannot do. At that boundary, we must rely on experimentation and hacking to gain understanding.
Optical Electromagnetics II
Authors: Thomas Michael E.
Published: November 2020

In this chapter the same basic topics are addressed as in the previous chapter, but now in the presence of matter. This greatly complicates the description of optical propagation and continues to be the primary topic of the remaining chapters. A formal structure is developed to handle absorption and scattering phenomena in general. The modeling of optical propagation is reduced to having to know the complex index of refraction of the medium. A macroscopic description represents the large-scale observable character of optical propagation. At this level, many models are phenomenological, but lead to important general properties, definitions, formulas, and the establishment of basic concepts. Because microscopic models to be presented in future chapters contain considerable detail, this section is an important prerequisite to the remaining text. Again, plane waves are a useful tool for the description of optical propagation. The Poynting vector, causality, and Poynting’s theorem are used to develop and derive quantities and relationships concerning radiometry and the flow of electromagnetic power at optical frequencies. Consider Maxwell’s equations again, but in the presence of linear isotropic matter. Now the constitutive relations will play a more important role and are the foundation of classical dispersion theory.
History as Natural History
Authors: Worster Donald
Published: November 2020

Charles Darwin has been moldering in his grave now for a full century. But it is not death with which we associate his name; it is life, in all its abundance and variety. In particular, the argument he made for the natural origin of life, including humans, has been one of the most influential ideas in the world over that century’s span. It was accepted a long while back by almost everyone within the reach of modern science, despite the persistent opposition of a raggle-taggle band of creationists. But for all that general acceptance, Darwin’s ideas have not yet become working principles among several large groups of scholars. Take history, for example: reading the journals and dissertations in this field reveals the profound, continuing influence of Adam Smith, Karl Marx, and Sigmund Freud, but still there is no Darwin in our history, at least not as a tradition of historical theory. Evolution and history remain, after a hundred years, separate realms of discourse. There is little history in the study of nature, and there is little nature in the study of history. I want to show how we can remedy that cultural lag by developing a new perspective on the historian’s enterprise, one that will make us Darwinians at last. It will require us to step back now and then from parliamentary debates, social mobility data, and the biographies of illustrious figures in order to examine more elemental questions that concern the long-running human dialogue with the earth. The contemporary disjunction between the study of history and of nature has a fairly obvious explanation. In the eighteenth-century world of the English parson-naturalist, there was no such split; antiquities and natural curiosities lay jumbled together in the same country cupboard. As we moved away from that small rural community, the old broad-gauged, integrative “natural history” began to fragment into specializations. History increasingly became an archival pursuit, carried on by urban scholars; there was less and less dirt on it. Recently, however, that drift toward an unnatural history has run up against a few hard facts: dwindling energy supplies, population pressures on available food, the limits and costs of technology.
Alternative Climate-Change Theories
Authors: Hoyt Douglas V. , Shatten Kenneth H.
Published: November 2020

So far, we have primarily considered only the sun’s role in natural climatic change. This focus does not imply that the sun is the only cause of climatic changes, nor even the most important one. In the last chapter, we stated that solar and climatic changes have paralleled each other for the last four centuries and, therefore, on time scales of decades to centuries, solar variations might be a dominant driving force for natural variability. Many climatologists adamently disagree with this conclusion and suggest that other factors, both in the past and for the future, are far more important. In the future, mankind’s influences may increase and likely will dominate coming climate changes. One hypothesis suggests that the climate system varies randomly, first warming for a few decades and then cooling. Scientists who support this hypothesis believe that external influences need not necessarily cause internal changes. They view the Earth as a thermostat with a very wide interval (or band) of possible temperatures. In other words, the Earth’s mean temperature is not constrained to one precise equilibrium temperature. Several natural experiments contradict this belief. For example, following a volcanic eruption the Earth cools for a few months to a few years; then the temperature returns to its preemption values. This rapid return implies a narrow stable temperature band, with the climate system striving to return quickly to its equilibrium. As the time constant for the climate system is relatively short, it responds quickly to variable forcings. Similar arguments can be made using solar variations. For this reason, we discount the idea that unpredictable chaotic influences completely govern the climatic system. We will now review three additional forcing functions for climate, specifically volcanic aerosols, anthropogenic aerosols, and greenhouse gas warming. Modern climatologists consider these three forcings the most popular for explaining observed climatic changes. Yet just as the sun/climate connections can be harshly criticized, so can these three ideas, and we will treat these theories with skepticism. We will strive to adopt this same skeptical attitude for solar forcing of climate again in chapter 13.
Non-Equilibrium Phenomena in Liquids and Solutions
Authors: Fawcett W. Ronald
Published: November 2020

The topics considered up to this point have involved liquids and solutions at equilibrium. Attention is now turned to systems which are not at equilibrium, and the processes which occur spontaneously in such systems. The physical phenomena involved can be quite complex, so that the task faced in early experiments was to separate the various processes and understand the physical properties of the system which govern them. Consider what happens when a beaker of pure isothermal water is placed on a hot plate. The water near the bottom rises in temperature and a temperature gradient is set up. As a result heat flows from the bottom of the beaker, producing a gradual increase in temperature in the water at a given height above the bottom. In addition, the temperature varies with distance, being highest at the bottom and lowest at the top. Eventually, the temperature of the water in the beaker is uniform and equal to that of the hot plate, assuming that the water does not boil. However, the flow of heat is not the only process resulting from the heat source. The density of the hot water is less than that of the cold water, so that a convection process is set up in order to achieve uniform density. Convection results in cold water moving down into the hot region so that the flow of water molecules assists the flow of heat. The changes which occur in this system cannot be understood without considering both processes. A system undergoing an irreversible change involving an electrolyte is electrolysis in an electrochemical cell. When current flows between two copper electrodes in an aqueous solution of CuSO4 the charge in solution is carried by migration of Cu2+ ions moving in one direction and SO42− ions moving in the opposite. At the cathode, the incoming Cu2+ ions are reduced to metallic copper, thereby lowering the concentration of these ions in the electrode’s vicinity. At the anode, Cu metal is oxidized to produce Cu2+ ions in the solution, so that the local concentration of cations is increased.
Mathematical Aspects of Spectral Models
Authors: Krishnamurti T. N. , Bedi H. S. , Hardiker V. M.
Published: November 2020

In this chapter we provide an introduction to the topic of spherical harmonics as basis functions for a global spectral model. The spherical harmonics are made up of trigonometric functions along the zonal direction and associated Legendre functions in the meridional direction. A number of properties of these functions need to be understood for the formulation of a spectral model. This chapter describes some useful properties that will be used to illustrate the procedure for the representation of data sets over a sphere with spherical harmonics as basis functions. The calculations of Fourier and Legendre transforms and their inverse transforms are an important part of global spectral modeling, and these are covered in some detail in this chapter. Finally, this chapter addresses the formulation of two simple spectral models. One of these is a single-level barotropic model, and the other is a shallow-water model.
Mass Transfer
Authors: Bethke Craig M.
Published: November 2020

In previous chapters we have discussed the nature of the equilibrium state in geochemical systems: how we can define it mathematically, what numerical methods we can use to solve for it, and what it means conceptually. With this chapter we begin to consider questions of process rather than state. How does a fluid respond to changes in composition as minerals dissolve into it, or as it mixes with other fluids? How does a fluid evolve in response to changing temperature or variations in the fugacity of a coexisting gas? In short, we begin to consider reaction modeling. In this chapter we consider how to construct reactions paths that account for the effects of simple reactants, a name given to reactants that are added to or removed from a system at constant rates. We take on other types of mass transfer in later chapters. Chapter 12 treats the mass transfer implicit in setting a species’ activity or gas’ fugacity over a reaction path. In Chapter 14 we develop reaction models in which the rates of mineral precipitation and dissolution are governed by kinetic rate laws. Simple reactants are those added to (or removed from) the system at constant rates over the reaction path. As noted in Chapter 2, we commonly refer to such a path as a titration model, because at each step in the process, much like in a laboratory titration, the model adds an aliquot of reactant mass to the system. Each reactant Ar is added at a rate nr, expressed in moles per unit reaction progress, ξ. Negative values of nr, of course, describe the removal rather than the addition of the reactant. Since ξ is unitless and varies from zero at the start of the path to one at the end, we can just as well think of nr as the number of moles of the reactant to be added over the reaction path. A simple reactant may be an aqueous species (including water), a mineral, a gas, or any entity of known composition.
Petroleum Reservoirs
Authors: Bethke Craig M.
Published: November 2020

In efforts to increase and extend production from oil and gas fields, as well as to keep wells operational, petroleum engineers pump a wide variety of fluids into the subsurface. Fluids are injected into petroleum reservoirs for a number of purposes, including: • Waterflooding, where an available fresh or saline water is injected into the reservoir to displace oil toward producing wells. • Improved Oil Recovery (IOR), where a range of more exotic fluids such as steam (hot water), caustic solutions, carbon dioxide, foams, polymers, surfactants, and so on are injected to improve recovery beyond what might be obtained by waterflooding alone. • Near-well treatments, in which chemicals are injected into producing and sometimes injector wells, where they are intended to react with the reservoir rock. Well stimulation techniques such as acidization, for example, are intended to increase the formation's permeability. Alternatively, producing wells may receive “squeeze treatments” in which a mineral scale inhibitor is injected into the formation. In this case, the treatment is designed so that the inhibitor sorbs onto mineral surfaces, where it can gradually desorb into the formation water during production. • Pressure management, where fluid is injected into oil fields in order to maintain adequate fluid pressure in reservoir rocks. Calcium carbonate may precipitate as mineral scale, for example, if pressure is allowed to deteriorate, especially in fields where formation fluids are rich in Ca++ and HCO3- and CO2 fugacity is high. In each of these procedures, the injected fluid can be expected to be far from equilibrium with sediments and formation waters. As such, it is likely to react extensively once it enters the formation, causing some minerals to dissolve and others to precipitate. Hutcheon (1984) appropriately refers to this process as “artificial diagenesis,” drawing an analogy to the role of groundwater flow in the diagenesis of natural sediments (see Chapter 19). Further reaction is likely if the injected fluid breaks through to producing wells and mixes there with formation waters. There is considerable potential, therefore, for mineral scale, such as barium sulfate (see the next section), to form during these procedures.
Summary and Conclusions
Authors: Brown Alan W. , Carney David J. , Morris Edwin J. , Smith Dennis B. , Zarrella Paul F.
Published: November 2020

This book has taken the reader on a long journey through terrain that is at times difficult to negotiate. There are aspects of the integration problem that are open to interpretation, a source of heated debate, or perhaps undergoing great change in terms of people’s perceptions of the problems and solutions. We hope that the reader now has a better understanding of the range of issues that must be addressed and the viewpoints that are possible when the phrase “integrated CASE environment” is used. In this final chapter, we look back at the major points discussed earlier, and look ahead toward the future. Section 13.2 reviews the major themes that have been presented in this book. Section 13.3 highlights a number of avenues of work that provide hope for the future in this field. Section 13.4 concludes with a few final thoughts and observations. The three overall themes that have been used to provide a structure to the book are the following: • Understanding of CASE environment integration is enhanced by considering three levels at which integration occurs — end-user services, mechanism, and process levels. • CASE environment architectures are evolving toward a hybrid approach that combines elements of framework-centered and CASE tool-centered approaches. • The construction of an integrated CASE environment can usefully be viewed as a design activity in which design decisions are made based on a number of trade-offs that must be made. For the purposes of recapitulation, these themes are brought together and summarized briefly below. One of this book’s main conceptual tools for improving understanding of the many issues connected with CASE environment integration is a three-level model that distinguishes end-user services, mechanism, and process aspects of a CASE environment. By way of a summary of this model and its utility, we consider two tools that are integrated within a CASE environment. At the conceptual level, integration of the two CASE tools implies that the overlap, or coordination, between the functionality offered by those tools is well understood. For example, if one tool is a requirements capture tool and the other is a design and analysis tool, then the relationships between the functionality offered by those tools can be analyzed and discussed.