A comprehensive review of spatiotemporal pattern formation in systems driven away from equilibrium is presented, with emphasis on comparisons between theory and quantitative experiments. Examples include patterns in hydrodynamic systems such as thermal convection in pure fluids and binary mixtures, Taylor-Couette flow, parametric-wave instabilities, as well as patterns in solidification fronts, nonlinear optics, oscillatory chemical reactions and excitable biological media. The theoretical starting point is usually a set of deterministic equations of motion, typically in the form of nonlinear partial differential equations. These are sometimes supplemented by stochastic terms representing thermal or instrumental noise, but for macroscopic systems and carefully designed experiments the stochastic forces are often negligible. An aim of theory is to describe solutions of the deterministic equations that are likely to be reached starting from typical initial conditions and to persist at long times. A unified description is developed, based on the linear instabilities of a homogeneous state, which leads naturally to a classification of patterns in terms of the characteristic wave vector q0 and frequency ω0 of the instability. Type Is systems (ω0=0, q0≠0) are stationary in time and periodic in space; type IIIo systems (ω0≠0, q0=0) are periodic in time and uniform in space; and type Io systems (ω0≠0, q0≠0) are periodic in both space and time. Near a continuous (or supercritical) instability, the dynamics may be accurately described via "amplitude equations," whose form is universal for each type of instability. The specifics of each system enter only through the nonuniversal coefficients. Far from the instability threshold a different universal description known as the "phase equation" may be derived, but it is restricted to slow distortions of an ideal pattern. For many systems appropriate starting equations are either not known or too complicated to analyze conveniently. It is thus useful to introduce phenomenological order-parameter models, which lead to the correct amplitude equations near threshold, and which may be solved analytically or numerically in the nonlinear regime away from the instability. The above theoretical methods are useful in analyzing "real pattern effects" such as the influence of external boundaries, or the formation and dynamics of defects in ideal structures. An important element in nonequilibrium systems is the appearance of deterministic chaos. A greal deal is known about systems with a small number of degrees of freedom displaying "temporal chaos," where the structure of the phase space can be analyzed in detail. For spatially extended systems with many degrees of freedom, on the other hand, one is dealing with spatiotemporal chaos and appropriate methods of analysis need to be developed. In addition to the general features of nonequilibrium pattern formation discussed above, detailed reviews of theoretical and experimental work on many specific systems are presented. These include Rayleigh-Benard convection in a pure fluid, convection in binary-fluid mixtures, electrohydrodynamic convection in nematic liquid crystals, Taylor-Couette flow between rotating cylinders, parametric surface waves, patterns in certain open flow systems, oscillatory chemical reactions, static and dynamic patterns in biological media, crystallization fronts, and patterns in nonlinear optics. A concluding section summarizes what has and has not been accomplished, and attempts to assess the prospects for the future.

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Pattern formation outside of equilibrium

The use of a latent heat storage system using phase change materials (PCMs) is an effective way of storing thermal energy and has the advantages of high-energy storage density and the isothermal nature of the storage process. PCMs have been widely used in latent heat thermal-storage systems for heat pumps, solar engineering, and spacecraft thermal control applications. The uses of PCMs for heating and cooling applications for buildings have been investigated within the past decade. There are large numbers of PCMs that melt and solidify at a wide range of temperatures, making them attractive in a number of applications. This paper also summarizes the investigation and analysis of the available thermal energy storage systems incorporating PCMs for use in different applications.

Review on thermal energy storage with phase change materials and applications

We wrote it to be read by, and taught to, senior undergraduates and starting graduate students, rather than studied in a research laboratory. We wrote it using the same style and sentence construction that we have used in countless classroom lectures, rather than how we have written our countless (and much-less read) formal scientificpapers. In this respect particularly, wehave been deliberate in notreferencing the sources of every experimental fact or theoretical concept (although we do include some hints and clues in the chapters). However, at the end of each chapter we have included groups of references that should lead you to the best sources in the literature and help you go into more depth as you become more confident about what you are looking for. We are great believers in the value of history as the basis for under- standing the present and so the history of the techniques and key historical references are threaded throughout the book. Just because a reference is dated in the previous century (or even the antepenultimate century) doesn’t mean it isn’t useful! Likewise, with the numerous figures drawn from across the fields of materials science and engineering and nanotechnology, we do not reference the source in each caption. But at the very end of the book each of our many generous colleagues whose work we have used is clearly acknowledged.

Transmission Electron Microscopy

Humans perceive the three-dimensional structure of the world with apparent ease. However, despite all of the recent advances in computer vision research, the dream of having a computer interpret an image at the same level as a two-year old remains elusive. Why is computer vision such a challenging problem and what is the current state of the art? Computer Vision: Algorithms and Applications explores the variety of techniques commonly used to analyze and interpret images. It also describes challenging real-world applications where vision is being successfully used, both for specialized applications such as medical imaging, and for fun, consumer-level tasks such as image editing and stitching, which students can apply to their own personal photos and videos. More than just a source of recipes, this exceptionally authoritative and comprehensive textbook/reference also takes a scientific approach to basic vision problems, formulating physical models of the imaging process before inverting them to produce descriptions of a scene. These problems are also analyzed using statistical models and solved using rigorous engineering techniques Topics and features: structured to support active curricula and project-oriented courses, with tips in the Introduction for using the book in a variety of customized courses; presents exercises at the end of each chapter with a heavy emphasis on testing algorithms and containing numerous suggestions for small mid-term projects; provides additional material and more detailed mathematical topics in the Appendices, which cover linear algebra, numerical techniques, and Bayesian estimation theory; suggests additional reading at the end of each chapter, including the latest research in each sub-field, in addition to a full Bibliography at the end of the book; supplies supplementary course material for students at the associated website, http://szeliski.org/Book/. Suitable for an upper-level undergraduate or graduate-level course in computer science or engineering, this textbook focuses on basic techniques that work under real-world conditions and encourages students to push their creative boundaries. Its design and exposition also make it eminently suitable as a unique reference to the fundamental techniques and current research literature in computer vision.

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Computer Vision: Algorithms and Applications

Review on thermal energy storage with phase change: materials, heat transfer analysis and applications

The effects of swirl on the rate of mass flow and on the velocity field in the throat region of axi-symmetric nozzles are studied analytically and experimentally. In the analytical phase, methods are developed for treating either the direct or the inverse problem for flow in de Lavai and annular nozzles, taking account of either weak or strong swirl. The experiments were performed in an annular nozzle, with swirl being imparted to the flow by adjustable vanes situated upstream of the test section.

Compressible swirling flow through convergent-divergent nozzles

Reverse osmosis issues relating to pressure drop, mass transfer, turbulence, and unsteadiness

This investigation was performed in order to quantify the validity of the assumed constancy of the overall heat transfer coefficient U in heat exchanger design. The prototypical two-fluid heat exchanger, the double-pipe configuration, was selected for study. Heat transfer rates based on the U = constant model were compared with those from highly accurate numerical simulations for 60 different operating conditions. These conditions included: (a) parallel and counter flow, (b) turbulent flow in both the pipe and the annulus, (c) turbulent flow in the pipe and laminar flow in the annulus and the vice versa situation, (d) laminar flow in both the pipe and the annulus, and (e) different heat exchanger lengths. For increased generality, these categories were further broken down into matched and unmatched Reynolds numbers in the individual flow passages. The numerical simulations eschewed the unrealistic uniform-inlet-velocity-profile model by focusing on pressure-driven flows. The largest errors attributable to the U = constant model were encountered for laminar flow in both the pipe and the annulus and for laminar flow in one of these passages and turbulent flow in the other passage. This finding is relevant to microchannel flows and other low-speed flow scenarios. Errors as large as 50% occurred. The least impacted were cases in which the flow is turbulent in both the pipe and the annulus. The general level of the errors due to the U = constant model were on the order of 10% and less for those cases. This outcome is of great practical importance because heat-exchanger flows are more commonly turbulent than laminar. Another significant outcome of this investigation is the quantification of the axial variations of the temperature and heat flux along the wall separating the pipe and annulus flows. It is noteworthy that these distributions do not fit either the uniform wall temperature or uniform heat flux models.

Quantitative Assessment of the Overall Heat Transfer Coefficient U

Pharmaceutical and biological materials require thermally controlled environments when being transported between manufacturers, clinics, and hospitals. It is the purpose of this report to compare the life cycle impacts of two distinct logistical approaches to packaging commonly used in cold chain logistics and to identify the method of least environmental burden. The approaches of interest are single-use packaging utilizing containers insulated with either polyurethane or polystyrene and reusable packaging utilizing containers with vacuum-insulated panels. This study has taken a cradle-to-grave perspective, which covers material extraction, manufacture, assembly, usage, transportation, and end-of-life realities. The functional unit of comparison is a 2-year clinical trial consisting of 30,000 individual package shipments able to maintain roughly 12 L of payload at a controlled 2–8 °C temperature range for approximately 96 h. Published life-cycle inventory data were used for process and material emissions. A population-centered averaging method was used to estimate transportation distances to and from clinical sites during container use. Environmental impacts of the study include global warming potential, eutrophication potential, acidification potential, photochemical oxidation potential, human toxicity potential, and postconsumer waste. The average single-use approach emits 1,122 tonnes of CO2e compared with 241 tonnes with the reusable approach over the functional unit. This is roughly a 75 % difference in global warming potential between the two approaches. Similar differences exist in other impact categories with the reusable approach showing 60 % less acidification potential, 65 % less eutrophication potential, 85 % less photochemical ozone potential, 85 % less human toxicity potential, and 95 % less postconsumer waste. The cradle-to-gate emissions of the single-use container were the overwhelming cause of its high environmental burden as 30,000 units were required to satisfy the functional unit rather than 772 for the reusable approach. The reusable container was about half the mass of the average single-use container, which lowered its transportation emissions below the single-use approach despite an extra leg of travel. The reusable logistical approach has shown to impose a significantly smaller environmental burden in all impact categories of interest. A sensitivity analysis has shown some leeway in the degree of the environmental advantage of the reusable approach, but it confirms the conclusion as no case proved otherwise.

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Ephraim M Sparrow

Papers

Compressible swirling flow through convergent-divergent nozzles

Reverse osmosis issues relating to pressure drop, mass transfer, turbulence, and unsteadiness

Quantitative Assessment of the Overall Heat Transfer Coefficient U

An environmental impact comparison of single-use and reusable thermally controlled shipping containers

Impingement heat transfer at a circular cylinder due to an offset or non-offset slot jet