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Ephraim M Sparrow

Bio: Ephraim M Sparrow is an academic researcher from University of Minnesota. The author has contributed to research in topics: Heat transfer & Heat transfer coefficient. The author has an hindex of 77, co-authored 552 publications receiving 27226 citations. Previous affiliations of Ephraim M Sparrow include National Science Foundation & University of Illinois at Chicago.


Papers
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Journal ArticleDOI
TL;DR: The fluid flow, mass transfer, and heat transfer associated with the evaporation of a liquid from a partially filled rectangular cavity have been modeled both rigorously and approximately and then evaluated numerically.
Abstract: The fluid flow, mass transfer, and heat transfer associated with the evaporation of a liquid from a partially filled rectangular cavity have been modeled both rigorously and approximately and then evaluated numerically. A uniform tangential velocity was prescribed at the top of the cavity, and the side and bottom walls of the cavity were adiabatic. All of the numerical results were for the evaporation of water into an air ambient having various degrees of humidity. The modeling studies demonstrated that results of high accuracy for the evaporation rate and for the temperature at the gas-liquid interface could be obtained without having to solve the conservation equations for the liquid zone. The interface temperatures corresponding to convection-driven evaporation deviated only slightly from those for diffusion-driven evaporation ( i.e., no convection). Furthermore, the variation of the evaporation rate with the ambient temperature and relative humidity was found to be very similar for the convection-driv...

2 citations

Journal ArticleDOI
TL;DR: In this article, the authors determined the efficiency of solar absorption of honeycomb structure attached to collecting base surface on which incoming solar energy impinges directly on the base surface by using a honeycomb.
Abstract: Determination of efficiency of solar absorption of honeycomb structure attached to collecting base surface on which incoming solar energy impinges directly on base surface

2 citations

Journal ArticleDOI
TL;DR: In this paper, the authors considered laminar flow in a channel from which a blocked branch line emanates at right angles, and the channel and the branch line constitute a solution domain that is nonregular with respect to computer codes structured to deal with domains that are rectangular.
Abstract: Consideration is given to laminar flow in a channel from which a blocked branch line emanates at right angles. The channel and the branch line constitute a solution domain that is nonregular with respect to computer codes structured to deal with domains that are rectangular. As an application of a technique devised by Patankar, the nonregular domain was transformed into a rectangular domain within which the fluid experiences a stepwise change of viscosity, taking on infinite viscosity in regions where flow is not to exist. Numerical solutions were obtained for parametric values of the channel Reynolds number and of the dimensionless length of the blocked branch line. The results showed that the greatest disturbance of the main flow by the presence of the branch line occurs at low Reynolds numbers, but that the recirculation bubble in the branch line is more vigorous at high Reynolds numbers. The pressure drop in the channel is diminished by the presence of the branch line. The extent of the diminution is ...

2 citations

Journal ArticleDOI
TL;DR: In this article, mutual dependent heat and mass transfer for laminar gas flow in a parallel-plate channel is investigated analytically, and the analysis of the problem requires simultaneous treatment of the energy and mass diffusion equations, with coupling provided by the boundary conditions.
Abstract: Mutually dependent heat and mass transfer for laminar gas flow in a parallel-plate channel is investigated analytically. Sublimation occurs at one of the channel walls, while the other wall is nonsubliming. Both walls are thermally insulated from the external environment. The analysis of the problem requires simultaneous treatment of the energy and mass diffusion equations, with coupling provided by the boundary conditions. Mathematical expressions are derived and numerical results are presented for various quantities that characterize the heat and mass transfer processes. Comparisons are made with the case of symmetric transfer (i.e., both walls actively participating). In general, unsymmetric transfer is found to slow down the axial development of the temperature and mass fraction fields. On a fait une analyse du transfert de la chaleur et de la masse (deux facteurs inter-dependants dans le cas d'un ecoulement laminaire de gaz dans un canal a plateaux paralleles. La sublimation ne s'est faite que sur une paroi du canal; les deux parois etaient isolees au point de vue thermique du milieu externe. L'analyse du probleme a exige le traitement simultane des equations de diffusion d'energie et de masse, les conditions-limites formant un raccord. On a deduit des expressions mathematiques et presente des resultats numeriques pour differentes qunntites qui caracterisent les procedes de transfert de la chaleur et de la masse. On a fait des comparaisons avec le cas du transfert symetrique (ou les deux parois out une participation active). En general, on a trouve que le transfert asymetrique ralentissait le developpement axial des champs de temperature et de friction de masse.

2 citations


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Journal ArticleDOI
TL;DR: A comprehensive review of spatiotemporal pattern formation in systems driven away from equilibrium is presented in this article, with emphasis on comparisons between theory and quantitative experiments, and a classification of patterns in terms of the characteristic wave vector q 0 and frequency ω 0 of the instability.
Abstract: 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.

6,145 citations

Journal ArticleDOI
TL;DR: 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.
Abstract: 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.

4,482 citations

BookDOI
01 Jan 1996
TL;DR: The client would like to get a larger, approximately 3 cm in diameter, well fixed tissue sample, together with a detailed report of the clinical presentation, gross, and microscopic lesions, along with the submission of samples prepared in a similar manner by the client for processing.
Abstract: 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.

4,412 citations

Book
30 Sep 2010
TL;DR: Computer Vision: Algorithms and Applications explores the variety of techniques commonly used to analyze and interpret images and takes a scientific approach to basic vision problems, formulating physical models of the imaging process before inverting them to produce descriptions of a scene.
Abstract: 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.

4,146 citations

Journal ArticleDOI
TL;DR: In this paper, a review of the history of thermal energy storage with solid-liquid phase change has been carried out and three aspects have been the focus of this review: materials, heat transfer and applications.

4,019 citations