Optimal heating profiles in tubular reactors with solid‐phase axial wall conduction for isothermal operation

This chapter discusses the application of MINLP methods in the synthesis of reactor networks with complex reactions and in the synthesis of reactor-separator-recycle systems. Despite the importance of reactor systems in chemical engineering processes, very few systematic procedures for the optimal synthesis of reactor networks have been proposed. The main reason for the scarcity of optimization strategies for reactor networks is the difficulty of the problem itself. The large number of alternatives along with the highly nonlinear equations that describe these systems have led to the development of a series of heuristic and intuitive rules that provide solutions only for simple cases of reaction mechanisms. Most of the studies considered single reactors with a specified mixing pattern and focused on investigating the effect of temperature distribution, residence time distribution, or catalyst dilution profile on its performance. In the sequel, we will briefly review the approaches developed based on their classification: (i) isothermal operation and (ii) nonisothermal operation. Trambouze and Piret (1959) proposed graphical and analytical criteria for selecting the type of reactor. Levenspiel (1962) reported heuristic rules for optimal yield and selectivity in stirred tank and tubular reactors. Aris (1964, 1969) applied dynamic programming to determine the optimal amounts of by-passes and cold streams in a multistage reaction system within a fixed structure. Gillespie and Carberry (1966) studied the Van der Vusse reaction with an intermediate level of mixing and demonstrated the potential advantages of recycle reactors for such a complex reaction. Horn and Tsai (1967) studied the effects of global and local mixing using the adjoint variables of optimization theory. Jackson (1968) proposed an algebraic structure for the reactor representation consisting of parallel ideal tubular reactors that were interconnected with side streams at various sink and source points. Different flow configurations and mixing patterns could be obtained by varying the number and the positions of the sink and source points, as well as the levels of the sidestreams. By deliberate manipulation of the flow configuration, potential improvements in the reactor performance coul be investigated. Ravimohan (1971) modified Jackson's model so as to handle cases of local mixing.

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Solid-phase immunoelectron microscopy for rapid diagnosis of enteroviruses

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100111240 ◽

1984 ◽

Vol 42 ◽

pp. 226-227 ◽

Cited By ~ 1

Author(s):

K. Pegg-Feige ◽

F. W. Doane

Keyword(s):

Electron Microscopy ◽

Cell Culture ◽

Immunoelectron Microscopy ◽

Detection Method ◽

Solid Phase ◽

Protein A ◽

Plant Viruses ◽

Rapid Diagnosis ◽

Virus Diagnosis ◽

Antiviral Antibody

Immunoelectron microscopy (IEM) applied to rapid virus diagnosis offers a more sensitive detection method than direct electron microscopy (DEM), and can also be used to serotype viruses. One of several IEM techniques is that introduced by Derrick in 1972, in which antiviral antibody is attached to the support film of an EM specimen grid. Originally developed for plant viruses, it has recently been applied to several animal viruses, especially rotaviruses. We have investigated the use of this solid phase IEM technique (SPIEM) in detecting and identifying enteroviruses (in the form of crude cell culture isolates), and have compared it with a modified “SPIEM-SPA” method in which grids are coated with protein A from Staphylococcus aureus prior to exposure to antiserum.

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Application of solid-phase immune electron microscopy to study physical and stability characteristics of enterically transmitted non-a, non-b hepatitis virus

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100102481 ◽

1988 ◽

Vol 46 ◽

pp. 80-81

Author(s):

Charles D. Humphrey ◽

E. H. Cook ◽

Karen A. McCaustland ◽

Daniel W. Bradley

Keyword(s):

Electron Microscopy ◽

Hepatitis A ◽

Hepatitis A Virus ◽

Solid Phase ◽

Etiologic Agent ◽

World Health ◽

Health Concern ◽

Morphological Identification ◽

Immune Electron Microscopy

Enterically transmitted non-A, non-B hepatitis (ET-NANBH) is a type of hepatitis which is increasingly becoming a significant world health concern. As with hepatitis A virus (HAV), spread is by the fecal-oral mode of transmission. Until recently, the etiologic agent had not been isolated and identified. We have succeeded in the isolation and preliminary characterization of this virus and demonstrating that this agent can cause hepatic disease and seroconversion in experimental primates. Our characterization of this virus was facilitated by immune (IEM) and solid phase immune electron microscopic (SPIEM) methodologies.Many immune electron microscopy methodologies have been used for morphological identification and characterization of viruses. We have previously reported a highly effective solid phase immune electron microscopy procedure which facilitated identification of hepatitis A virus (HAV) in crude cell culture extracts. More recently we have reported utilization of the method for identification of an etiologic agent responsible for (ET-NANBH).

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Identification of hepatitis a virus in cell cultures by solid phase immune electron microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100142815 ◽

1986 ◽

Vol 44 ◽

pp. 238-239

Author(s):

C.D. Humphrey ◽

T.L. Cromeans ◽

E.H. Cook ◽

D.W. Bradley

Keyword(s):

Electron Microscopy ◽

Liquid Phase ◽

Cell Cultures ◽

Rapid Detection ◽

Hepatitis A ◽

Hepatitis A Virus ◽

Solid Phase ◽

Immune Electron Microscopy ◽

Detection And Identification

There is a variety of methods available for the rapid detection and identification of viruses by electron microscopy as described in several reviews. The predominant techniques are classified as direct electron microscopy (DEM), immune electron microscopy (IEM), liquid phase immune electron microscopy (LPIEM) and solid phase immune electron microscopy (SPIEM). Each technique has inherent strengths and weaknesses. However, in recent years, the most progress for identifying viruses has been realized by the utilization of SPIEM.

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Dynamic studies of silicide-mediated crystallization of amorphous silicon

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100131395 ◽

1992 ◽

Vol 50 (2) ◽

pp. 1352-1353

Author(s):

C. Hayzelden ◽

J. L. Batstone

Keyword(s):

Ion Implantation ◽

Solid Phase ◽

Metallic Phase ◽

Single Crystal Substrate ◽

Free Electrons ◽

Melt Temperature ◽

Transmission Electron ◽

Crystal Substrate ◽

High Resolution Tem

Epitaxial reordering of amorphous Si(a-Si) on an underlying single-crystal substrate occurs well below the melt temperature by the process of solid phase epitaxial growth (SPEG). Growth of crystalline Si(c-Si) is known to be enhanced by the presence of small amounts of a metallic phase, presumably due to an interaction of the free electrons of the metal with the covalent Si bonds near the growing interface. Ion implantation of Ni was shown to lower the crystallization temperature of an a-Si thin film by approximately 200°C. Using in situ transmission electron microscopy (TEM), precipitates of NiSi2 formed within the a-Si film during annealing, were observed to migrate, leaving a trail of epitaxial c-Si. High resolution TEM revealed an epitaxial NiSi2/Si(l11) interface which was Type A. We discuss here the enhanced nucleation of c-Si and subsequent silicide-mediated SPEG of Ni-implanted a-Si.Thin films of a-Si, 950 Å thick, were deposited onto Si(100) wafers capped with 1000Å of a-SiO2. Ion implantation produced sharply peaked Ni concentrations of 4×l020 and 2×l021 ions cm−3, in the center of the films.

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TEM characterization of Au/Polysilicon interactions

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100176381 ◽

1990 ◽

Vol 48 (4) ◽

pp. 650-651

Author(s):

N. David Theodore ◽

Leslie H. Allen ◽

C. Barry Carter ◽

James W. Mayer

Keyword(s):

Solid Phase ◽

Single Crystal Silicon ◽

Chemical Vapor ◽

Electrical Contacts ◽

Silicon Substrates ◽

Crystal Silicon ◽

Transmission Electron ◽

Polysilicon Films ◽

The Stability

Metal/polysilicon investigations contribute to an understanding of issues relevant to the stability of electrical contacts in semiconductor devices. These investigations also contribute to an understanding of Si lateral solid-phase epitactic growth. Metals such as Au, Al and Ag form eutectics with Si. reactions in these metal/polysilicon systems lead to the formation of large-grain silicon. Of these systems, the Al/polysilicon system has been most extensively studied. In this study, the behavior upon thermal annealing of Au/polysilicon bilayers is investigated using cross-section transmission electron microscopy (XTEM). The unique feature of this system is that silicon grain-growth occurs at particularly low temperatures ∽300°C).Gold/polysilicon bilayers were fabricated on thermally oxidized single-crystal silicon substrates. Lowpressure chemical vapor deposition (LPCVD) at 620°C was used to obtain 100 to 400 nm polysilicon films. The surface of the polysilicon was cleaned with a buffered hydrofluoric acid solution. Gold was then thermally evaporated onto the samples.

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