Browsing by Subject "Molecular structure"
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Item A decision-based approach to the integration of chemical process design and control structure synthesis(Texas Tech University, 2004-05) Vasbinder, Eric Matthew; Hoo, Karlene A.; Rainwater, Ken; Mann, Uzi; Tock, Richard W.The control of a chemical plant is concerned with analysis, design, and implementation of control systems that facilitate the achievement of process safety, production rates, and product quality. Traditionally-, controller synthesis focused on individual unit operations rather than the entire plant. Thus, the resulting control strategies may be very far from optimal because the interactions and interdependencies among the units and the variables are not considered. Other obstacles that deter a plantwide controller synthesis focus include the large dimensionality of the problem, the multivariable nature of the controller design, input and output constraints, equipment constraints, and the high degree of nonlinearities associated with the transport, diffusion, and kinetic processes. A multitude of different approaches have been suggested for plantwide control structure synthesis. A large number of these approaches rely on experiential knowledge applied in a systematic manner, but the order in which the objectives are addressed is not consistent from one approach to the next. In this work, a novel and systematic approach to the design of plantwide control structures is presented with the objective of prioritizing among complementary and competing design, operational and control objectives. Once the priorities are identified, the controller design can be carried out using am- number of existing control theories. The methodology begins with addressing the dimensionality of the plantwide control problem by applying a decision-based approach, the modified analytic hierarchical process, to decompose the process flowsheet into smaller subsets of units, or modules, that address specific design and operational objectives. Once the modules are identified, they are analyzed using system-theoretic tools. Next, the control and manipulated variables are selected, the control structure is developed and validated for each module. The next step is to combine all the modules and their control structures and verify that together the performance of the plant and the control structure is stable and satisfactory. Several examples, simple to complex, are provided to demonstrate the efficacy of the approach.Item Host cell response to coronavirus infection(2001-08) Banerjee, Sangeeta; Kuziel, William AndrewItem The search for metastables and molecular ions in discharges(2002-05) McCluskey, Craig William, 1950-; Keto, John W.Improvements to and use of an existing Raman Induced Kerr Effect (RIKE) spectrometer [Bhatia et al., J. Opt. Soc. Am. B, 14(2):263–270, February, 1997.] are described. Primary improvements were the use of wedged windows on the sample chamber, a new method of monitoring birefringence, and the addition of a photomultiplier tube (PMT) and double monochromator for monitoring Coherent Anti-Stokes Raman Spectroscopy (CARS) signals. This spectrometer is controlled through a Computer Automation and Control (CAMAC) crate. The construction and operation of a Linear Discharge Cell (LDC), a High Voltage Constant Current Sink for consistent operation of the LDC, and a Transverse Electric Atmospheric (TEA) discharge chamber are described in detail, as is synchronization of the pulsed discharge in the TEA with the pulsed output of the YAG laser using Hewlett-Packard Versatile Link fiber optic components. The atmospheric gases oxygen, carbon dioxide, and nitrogen were investigated with CARS in both discharge and non-discharge conditions. The influence of nuclear spin on the spectra and line strengths observed for all three gases is discussed. The origins of oxygen’s triplet ground state are discussed as well as simultaneous transitions in the visible of two colliding, excited oxygen molecules whose individual energies are in the infrared. The oxygen metastable singlet delta was observed, though with insufficient signal-to-noise ratio to extract molecular constant information. Also discussed for carbon dioxide are the profusion of state naming conventions, Fermi splitting, the calculation of the temperature of the discharge, quantum interference in the change of relative intensity of the two peaks in the ν1/2ν2 Fermi dyad from non-discharge to discharge conditions, and upper level hotband lines that appear when the discharge is turned on. Quantum interference in carbon dioxide was consistently observed in the LDC but not in the TEA discharge, most likely because the amount of power dissipated in the TEA was on the order of 1% of that dissipated in the LDC and the gas temperature was much lower. The molecular radical N3 was sought without success, though spectrometer characteristics set an upper bound on its concentration in the discharge.