Download or read book Integrated Intelligent Modeling Design and Control of Crystal Growth Processes written by and published by . This book was released on 2000 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Growth of single crystals is the critical beginning step for electronic, opto-electronic, MEMS and many other devices. This MURI program took an integrated approach towards modeling, design and control of crystal growth processes and in conjunction with growth and characterization experiments developed much better understanding of growth phenomena and materials defects. It led to the development of most comprehensive and accurate models that account for conduction, convection and volumetric, spectral radiation heat transfer, oscillatory and turbulent flows, transport and segregation of dopants and impurities, phase change, an applied magnetic and/or electric field, and generation and multiplication of crystal defects. Using state-of-the-art adaptive grid generation techniques and parallel algorithms, the models can perform three-dimensional, dynamic simulations. While establishing white beam x-ray topography as the leading technique for crystal characterization, this research led to many new theories for grow the behavior and defects. Advanced model-based control algorithms were developed for in-situ synthesis and Czochralski growth. Notable among many successful technology transfer projects are: AFRL-developed one-step in-situ synthesis and growth of indium phosphide crystals, growth of large diameter silicon carbide crystals, 500 mm diameter silicon tube growth, transport model for hydrothermal growth, wire saw technology and high yield polysilicon production. Besides involving numerous faculty, the project succeeded in training a large number of postdoctoral fellows and undergraduate and graduate students in crystal growth.
Download or read book Student Augmentation for Crystal Growth Research written by and published by . This book was released on 1999 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Three graduate students and one undergraduate student were supported to pursue research in the area of crystal growth and complement the research activities of AFOSR/DARPA MURI project on integrated intelligent modeling, design and control of crystal growth processes. One doctoral student worked on integrating the radiation heat transfer model into MASTRAPP, the crystal growth model developed by the Consortium for Crystal Growth Research. He also built a parallel processing algorithm. The other two Masters and one undergraduate students worked in the area of experimental methods to develop database for model validation. These students have developed a three-dimensional temperature field visualization technique using liquid crystals as tracers and digital imaging software for 3D reconstruction. Reconstruction of 3D field from a series of 2D images is a novel technique and can be used for flow and heat transfer analysis that is inherently three-dimensional and oscillatory, e.g., melt flow in Czochralski crystal growth.
Download or read book Proceedings of the ASME Heat Transfer Division 2000 Heat transfer in turbomachinery Artificial neural networks for thermal systems and materials processing and manufacturing Transport phenomena in materials processing and manufacturing Transport phenomena in composite materials processing Transport phenomena in spray and coating processing written by and published by . This book was released on 2000 with total page 444 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Crystal Growth Technology written by Hans J. Scheel and published by John Wiley & Sons. This book was released on 2011-09-22 with total page 521 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this book top experts treat general thermodynamic aspects of crystal fabrication; numerical simulation of industrial growth processes; commercial production of bulk silicon, compound semiconductors, scintillation and oxide crystals; X-ray characterization; and crystal machining. Also, the role of crystal technology for renewable energy and for saving energy is discussed. It will be useful for scientists and engineers involved in crystal and epilayer fabrication as well as for teachers and graduate students in material science, chemical and metallurgical engineering, and micro- and optoelectronics, including nanotechnology.
Download or read book Industrial Crystallization written by Narayan S. Tavare and published by Springer Science & Business Media. This book was released on 2013-11-11 with total page 550 pages. Available in PDF, EPUB and Kindle. Book excerpt: Incorporating all recent developments and applications of crystallization technology, this volume offers a clear account of the field's underlying principles, reviews of past and current research, and provides guidelines for equipment and process design. The book takes a balanced functional approach in its critical survey of research literature, and includes several problems based on real practical situations that illustrate theoretical development. Several new concepts and techniques used in process simulation and identification analysis are featured.
Download or read book Crystal Growth Processes Based on Capillarity written by Thierry Duffar and published by John Wiley & Sons. This book was released on 2010-03-30 with total page 566 pages. Available in PDF, EPUB and Kindle. Book excerpt: Crystal Growth Processes Based on Capillarity closely examines crystal growth technologies, like Czochralski, Floating zone, and Bridgman. The up-to-date reference contains detailed technical and applied information, especially on the difficulty of crystal shape control. Including practical examples and software applications, this book provides both theoretical and experimental sections. Edited by a well-respected academic with over twenty-five years of experience in this field, the text is an excellent resource for professionals in crystal growth as well as for students in understanding the fundamentals and the technology of crystal growth.
Download or read book Intelligent Control of Crystal Growth written by Ronald B. Sharpless and published by . This book was released on 1991 with total page 194 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Research in Progress written by and published by . This book was released on 1991 with total page 274 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Graphics Equipment for Real Time Animation and Virtual Design of Electronic Materials Processes written by and published by . This book was released on 1999 with total page 3 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Objective of this research equipment grant was to purchase computing equipment to upscale the local graphics infrastructure and to accomplish successfully the research tasks of AFOSR/DARPA MURI project on "Integrated, Intelligent Modeling, Design and Control of Crystal Growth Processes." As proposed, Silicon Graphics Onyx 2 Infinite Reality Graphics Rack System has been purchased and networked with other computers in the Process Modeling Laboratory. This computer has greatly enhanced the graphics capability in this laboratory and is being successfully used for process animation. This has allowed interaction with the computer science faculty and students to further expand our research program for virtual design and prototyping. The new facility is also helpful to some other NSF and industrial projects.
Download or read book Multiscale Modeling and Control of Crystal Shape and Size Distributions Accounting for Crystal Aggregation Evaluation of Continuous Crystallization Systems and Run to run Control written by Joseph Sangil Kwon and published by . This book was released on 2015 with total page 377 pages. Available in PDF, EPUB and Kindle. Book excerpt: Crystallization plays a vital role in separation and purification methods for the production of therapeutic drugs. Considering the fact that crystal size and shape distributions have a significant influence on the bioavailability of drugs such as the dissolution rate, filterability, and stability as a carrier to the target site, the production of crystals with desired size and shape distributions is of particular interest to the pharmaceutical industry. Motivated by these considerations, this dissertation focuses on the development of a multiscale modeling and simulation framework for crystallization processes that elucidates the relationship between molecular-level processes like crystal nucleation, growth and aggregation and macroscopically-observable process behavior and allows computing optimal design and operation conditions. Using protein crystallization as a model system, the multiscale framework encompasses: a) equilibrium Monte-Carlo modeling for computing solid-liquid phase diagrams and determining initial crystallization conditions that favor crystal nucleation, b) kinetic Monte-Carlo modeling for simulating crystal growth and aggregation and predicting the evolution of crystal shape distribution, and c) integrated multiscale computation linking molecular-level models and continuous-phase macroscopic equations, covering both batch and continuous crystallization systems. The multiscale model parameters and predictions are calibrated and tested with respect to available experimental data. Then, this dissertation addresses model predictive controller designs that utilize the insights and results from the multiscale modeling work and real-time measurements of solute concentration and temperature to manipulate crystallizer conditions that lead to the production of crystals with desired size and shape distributions. To enhance the ability of the predictive controller to deal with batch-to-batch parametric drifts, a common problem in industrial crystallization owing to changes, for example, in the pH level or impurity concentration in the feedstock container, a run-to-run-based model parameter estimation scheme will be presented that uses moving horizon estimation principles to update the predictive controller model parameters after each batch and leads to the consistent production of crystals of desired shape at the end of each batch.
Download or read book Modeling and Control of the Czochralski Crystal Growth Process written by Denise Marie Martinez and published by . This book was released on 2001 with total page 236 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Modeling Dynamics and Control of the Czochralski Crystal Growth Process written by Ning Duanmu and published by . This book was released on 2006 with total page 324 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Czochralski crystal growth is a widely used technology for manufacturing semiconductor crystals. Currently, semiconductor manufacturers desire to increase the crystal diameter in order to minimize the unit cost per chip during wafer processing while also reducing dislocation density and micro defect level in order to fabricate circuits with decreasing line widths. However, the ability to meet these advanced manufacturing objectives is limited by the current process control architecture since it has not been explicitly designed to deal with important process complexities including the nonlinear and time varying dynamics and cross coupled physics. In order to design a better control system, a process model is developed to reflect the real equipment features of commercial scale Czochralski crystal growth furnaces and capture the fundamental process physics governed by heat and mass transport processes. The model is used to study the system dynamic characteristics and input-output relations in order to develop an improved control structure and control algorithm.
Download or read book DOE s Multiprogram Restructuring written by United States. Congress. House. Committee on Energy and Commerce. Subcommittee on Energy and Power and published by . This book was released on 1994 with total page 236 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Modeling Simulation and Design of High Pressure Crystal Growth Processes written by and published by . This book was released on 1995 with total page 172 pages. Available in PDF, EPUB and Kindle. Book excerpt: Major research goals for this STTR project in Phase I were (a) development of a high-resolution process model suitable for high pressure crystal growth (HPCG), (b) special experiments for thermophysical property measurement, and (c) a preliminary design of an advanced HPCG furnace to transfer the DoD technology of "one-step in-situ synthesis and MLEK growth of InP crystals" for commercialization. An extraordinary progress was made in all of these areas. Several meetings were held with Rome Laboratory researchers to identify the shortcomings of the prsent furnace and needs for the future generation high pressure systems. A computer model, MASTRAPP was developed that is better than all other existing numerical models for multiphase, multicomponent processes with moving boundaries and free surfaces. MASTRAPP2d with a reference manual is now available for distribution to the interested groups of researchers. New experiments were designed to obtain property data for InP density, thermal conductivity, electrical resistivity and phosphorus vapor pressure. A preliminary design for an advanced HPCG furnace was developed based on these experiments, extensive HPCG simulations and process details from Rome Laboratory. jg p1.
Download or read book Delay Modeling and Long range Predictive Control of Czochralski Growth Process written by Dhaval Shah and published by . This book was released on 2009 with total page 170 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work presents the Czochralski growth dynamics as time-varying delay based model, applied to the growth of La3Ga5.5Ta0.5O14 (LGT) piezoelectric crystals. The growth of high-quality large-diameter oxides by Czochralski technique requires the theoretical understanding and optimization of all relevant process parameters, growth conditions, and melts chemistry. Presently, proportional-integral- derivative (PID) type controllers are widely accepted for constant-diameter crystal growth by Czochralski. Such control systems, however, do not account for aspects such as the transportation delay of the heat from crucible wall to the crystal solidification front, heat radiated from the crucible wall above the melt surface, and varying melt level. During crystal growth, these time delays play a dominant role, and pose a significant challenge to the control design. In this study, a time varying linear delay model was applied to the identification of nonlinearities of the growth dynamics. Initial results reveled the benefits of this model with actual growth results. These results were used to develop a long-range model predictive control system design. Two different control techniques using long range prediction are studied for the comparative study. Development and testing of the new control system on real time growth system are discussed in detail. The results are promising and suggest future work in this direction. Other discussion about the problems during the crystal growth, optimization of crystal growth parameters are also studied along with the control system design.
Download or read book Det indiska dramat written by and published by . This book was released on 1927 with total page 368 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Handbook of Crystal Growth written by Tatau Nishinaga and published by . This book was released on 1994 with total page 755 pages. Available in PDF, EPUB and Kindle. Book excerpt:
