Numerical Methods for Scientists and Engineers

The fifth edition of "Numerical Methods for Engineers" continues its tradition of excellence. Instructors love this text because it is a comprehensive text that is easy to teach from. Students love it because it is written for them--with great pedagogy and clear explanations and examples throughout. The text features a broad array of applications, including all engineering disciplines. The revision retains the successful pedagogy of the prior editions. Chapra and Canale's unique approach opens each part of the text with sections called Motivation, Mathematical Background, and Orientation, preparing the student for what is to come in a motivating and engaging manner. Each part closes with an Epilogue containing sections called Trade-Offs, Important Relationships and Formulas, and Advanced Methods and Additional References. Much more than a summary, the Epilogue deepens understanding of what has been learned and provides a peek into more advanced methods. Approximately 80% of the end-of-chapter problems are revised or new to this edition. The expanded breadth of engineering disciplines covered is especially evident in the problems, which now cover such areas as biotechnology and biomedical engineering. Users will find use of software packages, specifically MATLAB and Excel with VBA. This includes material on developing MATLAB m-files and VBA macros.

Numerical methods for engineers

Microscopy imaging often suffers from limited depth-of-field. However, the specimen can be "optically sectioned" by moving the object along the optical axis. Then different areas appear in focus in different images. Extended depth-of-field is a fusion algorithm that combines those images into one single sharp composite. One promising method is based on the wavelet transform. Here, we show how the wavelet-based image fusion technique can be improved and easily extended to multichannel data. First, we propose the use of complex-valued wavelet bases, which seem to outperform traditional real-valued wavelet transforms. Second, we introduce a way to apply this technique for multichannel images that suppresses artifacts and does not introduce false colors, an important requirement for multichannel optical microscopy imaging. We evaluate our method on simulated image stacks and give results relevant to biological imaging.

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Complex wavelets for extended depth‐of‐field: A new method for the fusion of multichannel microscopy images

A system for increasing the depth of field and decreasing the wavelength sensitivity and the effects of misfocus-producing aberrations of the lens of an incoherent optical system incorporates a special purpose optical mask into the incoherent system. The optical mask has been designed to cause the optical transfer function to remain essentially constant within some range from the in-focus position. Signal processing of the resulting intermediate image undoes the optical transfer modifying effects of the mask, resulting in an in-focus image over an increased depth of field. Generally the mask is placed at a principal plane or the image of a principal plane of the optical system. Preferably, the mask modifies only phase and not amplitude of light. The mask may be used to increase the useful range of passive ranging systems.

Extended depth of field optical systems

Organic thin film transistor (OTFT) based device modeling and circuit application is a rapidly emerging research area. Taking cognizance of this fact, our paper reviews various basic to advanced OTFT structures, their performance parameters, materials of individual OTFT layers, their molecular structures, OTFT charge transport phenomena, and fabrication techniques. The performance of p- and n-type conducting polymer and small molecule organic semiconductors are reviewed primarily in terms of field effect mobility, current on/off ratio, and operating voltage for various OTFT structures. Moreover, different organic/inorganic materials for realizing the dielectric layer, electrodes, and the substrate in an OTFT are analyzed. Some of the compact models that are essential for predicting and optimizing the device performance are described that takes into account the mobility enhancement factor and channel length modulation. A detailed study of the single gate, dual gate, vertical channel, and cylindrical gate O...

Organic Thin Film Transistors: Structures, Models, Materials, Fabrication, and Applications: A Review

Improvement in the depth of field is demonstrated by properly processing a succession of image samples. Due to the limited depth of field each image sample has in-focus as well as out-of-focus segments. By setting criteria for selecting the in-focus segments, an improved composite image is formed. Three algorithms for implementing this construction are discussed.

Image processing for extended depth of field

CdS Thin Film Transistor for Inverter and Operational Amplifier Circuit Applications

In this paper we present both finite element based and analytic model simulations of pentacene based organic thin film transistor. The finite element type simulation is done using Silvaco’s Atlas simulator and the analytic model simulation is performed using a Matlab code based on the standard transistor equations. Both the Atlas and Matlab simulations agree approximately with the published experimental result. The results of the simulations show a current ratio of 2.11×106 for Atlas and 1.8×107 for Matlab simulations. The threshold voltage extracted from the finite element type simulation is 1.1 V which is in good agreement with 1.2 V used for Matlab simulation. However, the contact resistance shows a quite significant variation between the two simulation mechanisms. The finite element type simulation gives a contact resistance of 10 kΩ whereas the Matlab simulation predicts a contact resistance 1.9 kΩ.

Simulation of top-contact pentacene thin film transistor

: Modern avionics equipment, such as super resolution direction-finding systems, now require resolutions on the order of 20 to 22 bits. Oversampled analog-to-digital converter architectures offer a means of exchanging resolution in time for that in amplitude and represent an attractive approach to implementing precision converters without the need for complex precision analog circuits. Using oversampling techniques based on sigma-delta modulation, a convenient tradeoff exists between sampling rate and resolution. One of the major advantages of integrated optics is the capability to efficiently couple wideband signals into the optical domain. Typically, sigma-delta processors require simple and relatively low-precision analog components and thus are well suited to integrated optical implementations. This thesis reviews the current sigma-delta methodology, the advantages of optical integrated circuits and presents the design of a second-order, integrated optical sigma-delta modulator. Simulation results for both a first and second order architecture are presented by evaluating the transfer characteristics numerically. Design parameters such as limit cycles are quantified and explained. Performance issues and future efforts are also considered. (AN)

Integrated optical sigma-delta modulators

The diffraction of light that is due to a converging sound field is interpreted and analyzed in terms of an eikonal ray theory. This theory, in combination with Feynman diagram techniques, indicates that the acousto-optic interaction is physically localized over a width of the sound field given roughly by the geometric mean of the sound’s wavelength and the sound field’s radius of curvature. Analytic results (for two diffracted orders) are in close agreement with 10-order numerical simulations, as long as sound amplitudes are not so strong as to violate assumptions made in the analytic model.

Ronald J. Pieper

Papers

Image processing for extended depth of field

CdS Thin Film Transistor for Inverter and Operational Amplifier Circuit Applications

Simulation of top-contact pentacene thin film transistor

Integrated optical sigma-delta modulators

Eikonal theory of strong acousto-optic interaction with curved wave fronts of sound