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.

A Simulation of Gas-Based, Endometrial-Ablation Therapy

Abstract: The method of numerical simulation has been employed to evaluate the use of a gas as a heating medium for endometrial ablation for the treatment of menorrhagia and uterine fibroids. The simulations encompassed fluid flow and heat transfer within the gaseous medium which serves to heat the uterine lining and the coupled heat conduction in the uterine tissue. For the case study featured here, helium at a temperature of 140 °C was employed as the heating medium. A total therapy duration of 6 min was modeled. The outcome of the simulation has provided quantitative information about the detailed necrosis depths that can be attained by the application of the therapy. In particular, necrosis depths on the order of 5 mm were achieved. It was also shown that by making use of a tailored pattern of fluid flow within the uterine cavity, particular zones on the uterine lining such as fibroids can be selectively targeted. Furthermore, the duration of the therapy needed to achieve a desired degree of necrosis can be predicted in advance. The advantages of a gas-based therapy relative to a liquid-based therapy are identified. Significant among these is the capability of the gas-based therapy to target specific zones which require treatment, while sparing healthy tissue. Another significant advantage of gas-based therapy is that it enables the use of higher temperatures which, in turn, allows the therapeutic process to be performed in a shorter time duration.

Bioreactor for the reconstitution of a decellularized vascular matrix of biological origin

Abstract: Acellular matrices derived from animal and human cadaveric donor vessels or other tubular matrices are appropriate candidates for the creation of tissue- en-gineered, small-diameter, muscular arteries. Engi-neering principles have been used to design a bio-reactor and the necessary auxiliary systems for the reconstitution of a previously decellularized vascular matrix. The bioreactor enables the attachment of cells to the luminal and/or exterior surfaces of the matrix. For the recellularization procedure, the matrix is situated within a sealed compartment in order to maintain a sterile environment. The matrix is rotated continuously to assure a spatially uniform re-constitution. The auxiliary systems that serve the bioreactor are: (a) an oxygenator, (b) peristaltic pumps, one for conveying the internal cell medium and the other for conveying the external cell medium, (c) motor and gearing to create steady and controlled rotation, (d) reservoirs for the containment of the two media, and (e) tubing to convey the respective fluids and to interconnect the bioreactor culture chamber to the various auxiliary components. A recellularized matrix produced by the bioreactor demonstrated its capabilities to reconstitute a previously decellularized scaffold.

Pattern formation outside of equilibrium

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.

Review on thermal energy storage with phase change materials and applications

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.

Transmission Electron Microscopy

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.

Computer Vision: Algorithms and Applications

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.