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Prusak, Anne C. "Activated and constitutive chemical defenses in freshwater plants." Thesis, Available online, Georgia Institute of Technology, 2004:, 2004. http://etd.gatech.edu/theses/available/etd-06072004-131334/unrestricted/prusak%5Fanne%5Fc%5F200405%5Fms.pdf.
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Law, Philip John. "Design and scheduling of batch chemical plants /." [S.l.] : [s.n.], 1999. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=13342.
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com, m. nikraz@gmail, and Magid Nikraz. "Integration of Operational Tasks in Chemical Plants." Murdoch University, 2007. http://wwwlib.murdoch.edu.au/adt/browse/view/adt-MU20070417.150114.
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The overall, coordinated management of different operational tasks in a chemical plant can improve operational efficiency. These operational tasks can be hierarchically categorised, from the lowest to highest level, as: data acquisition; regulatory control; monitoring; data reconciliation; fault detection and diagnosis; supervisory control; scheduling; and planning. Although each of these tasks is responsible for a particular function, they are dependent on each other, which is why an approach wherein all the different tasks can be integrated into a single unified framework is desirable. While integration has important benefits such as a significant reduction in operator workload and improved decision making, its realisation presents considerable challenges. Few previous works have addressed this topic and even fewer have investigated recent computing paradigms which may greatly assist in the development of a unifying framework.
Multi-agent systems were introduced and investigated in this study as a possible means for achieving integration of operational tasks in chemical plants. Multi-agent systems are the subject of a sub-field of computing research known as agent-based computing. Agent-based computing represents a relatively recent and powerful high-level computing paradigm.
Initially, a number of software applications were developed for the purposes of this study to assist realisation of the operational tasks. To simplify the process of system development and provide guidance for those unfamiliar with multi-agent systems wishing to adopt the proposed technique, an extensive methodology was devised. The operational tasks were then integrated using the proposed methodology to form an integrated multi-agent system, with the pilot plant at Murdoch University being used as a test base for the solution. The results were positive and demonstrated that the proposed agent-based solution was able to effectively account for the pilot plant setting. It was concluded that, in addition to presently available integration techniques and base technologies, the agent-based approach to integration of operational tasks in chemical plants presents a viable alternative solution.
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Nikraz, Magid. "Integration of operational tasks in chemical plants." Nikraz, Magid (2007) Integration of operational tasks in chemical plants. PhD thesis, Murdoch University, 2007. http://researchrepository.murdoch.edu.au/741/.
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The overall, coordinated management of different operational tasks in a chemical plant can improve operational efficiency. These operational tasks can be hierarchically categorised, from the lowest to highest level, as: data acquisition; regulatory control; monitoring; data reconciliation; fault detection and diagnosis; supervisory control; scheduling; and planning. Although each of these tasks is responsible for a particular function, they are dependent on each other, which is why an approach wherein all the different tasks can be integrated into a single unified framework is desirable. While integration has important benefits such as a significant reduction in operator workload and improved decision making, its realisation presents considerable challenges. Few previous works have addressed this topic and even fewer have investigated recent computing paradigms which may greatly assist in the development of a unifying framework.
Multi-agent systems were introduced and investigated in this study as a possible means for achieving integration of operational tasks in chemical plants. Multi-agent systems are the subject of a sub-field of computing research known as agent-based computing. Agent-based computing represents a relatively recent and powerful high-level computing paradigm.
Initially, a number of software applications were developed for the purposes of this study to assist realisation of the operational tasks. To simplify the process of system development and provide guidance for those unfamiliar with multi-agent systems wishing to adopt the proposed technique, an extensive methodology was devised. The operational tasks were then integrated using the proposed methodology to form an integrated multi-agent system, with the pilot plant at Murdoch University being used as a test base for the solution. The results were positive and demonstrated that the proposed agent-based solution was able to effectively account for the pilot plant setting. It was concluded that, in addition to presently available integration techniques and base technologies, the agent-based approach to integration of operational tasks in chemical plants presents a viable alternative solution.
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Crooks, Colin Andrew. "Synthesis of operating procedures for chemical plants." Thesis, Imperial College London, 1992. http://hdl.handle.net/10044/1/7795.
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Park, Sangdae. "Scheduling and rescheduling for batch chemical plants." Thesis, University of Manchester, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.503081.
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The awareness for the schedule modification under process disturbances so-called rescheduling, has been growing in the area of chemical batch plants. For the last three decades, planning and scheduling have played a practical and crucial role in not only reducing the inefficiency of batch operations, but also increasing the productivity of batch plants. However, the off-line planning/scheduling can be very inefficient, or even infeasible to be performed when particularly certain undesirable disturbances occur during the operation period. In these cases, therefore, the schedule modification will be inevitably required to reduce or minimise the effects of the disturbances arisen. In this sense, a systematic methodology for the schedule modification is needed to support and guide decision-makers and operators. The development of the methodology is the main objective of this thesis, and the focus mainly lies on the integration between scheduling and rescheduling for chemical batch plants. Two different scheduling algorithms have been proposed in this thesis. The formulation (Model I) based on the concept of State-Task Network (STN) is proposed for the scheduling of multipurpose batch processes, while Model II facilitates the scheduling of multiple product batch plants. Both algorithms are based on the deterministic methods, and the global optimality can be guaranteed. Although Model I is formulated as a Mixed Integer Non-Linear Programming (MINLP) problem, the global optimality of Model I is guaranteed due to the convexity proved. On the other hand, Model II results in a Mixed Integer Linear Programming (MILP), hence the global optimality guaranteed. The performances of the scheduling algorithms are far better than other precedent algorithms, and the details of the computational results are shown in the corresponding sections. In particular, these two scheduling algorithms are reutilised as a deterministic-based rescheduling algorithms after certain modification such as fixing variables, adding or removing constraints, change of an objective function, etc. These modifications are highly dependent upon the given conditions, namely, case-by-case basis. Nevertheless, it provides us the good concept in the sense that the global optimality for the rescheduling can be guaranteed if non-convexity does not take place in the models by the modifications. As far as the global optimality for scheduling and rescheduling is guaranteed, the difference between scheduling and rescheduling will be the minimum (or maximum) effect caused by the disturbance occurred. On the other hand, heuristic or rule-based methods have advantages for the simplicity of the adaptation and/or the similarity with the original schedule, even though their optimality is not guaranteed. In multiple product batch plants, a rule-based method by using completion time algorithm is proposed for the processing time delays and unit failures. In contrast, a rule-based method for multipurpose batch processes is based on the recalculation of material balances that will be required for accommodating the losses of intermediates. For the selection of a rescheduling option against the disturbances arisen, the variability test has been performed in order to identify the most sensitive process variability, so called key variability. To identify the key variability, the accumulated loss of profit function has been introduced as a performance index. Then, the key variability against a process variation occurred has been determined by a variation with maximum index. Based on the key variability identified, the determination of a rescheduling option is made by the rescheduling methodology proposed. From the various examples tested, it is shown the that the approach proposed enables to guide for the selection of rescheduling options available by using the concept of key variability, and the identification of key variability provides good guidelines for decision-making of reactive schedule modification.
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Heikkilä, Anna-Mari. "Inherent safety in process plant design : an index-based approach /." Espoo [Finland] : Technical Research Centre of Finland, 1999. http://www.vtt.fi/inf/pdf/publications/1999/P384.pdf.
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Pennington, Daniel. "Chemical facility preparedness a comprehensive approach." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2006. http://library.nps.navy.mil/uhtbin/hyperion/06Sep%5FPennington.pdf.
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Thesis (M.A. in Security Studies (Homeland Security And Defense))--Naval Postgraduate School, September 2006.Thesis Advisor(s): Ted Lewis. "September 2006." Includes bibliographical references (p. 83-88). Also available in print.
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Cheow, J. C. "Implementation of adaptive control strategies on chemical plants." Thesis, Teesside University, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.376544.
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Johnston, James E. "Synthesis of control structures for complete chemical plants." Thesis, Massachusetts Institute of Technology, 1991. http://hdl.handle.net/1721.1/52937.
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Lakshmanan, Ramachandran. "Synthesis of operating procedures for complete chemical plants." Thesis, Massachusetts Institute of Technology, 1990. http://hdl.handle.net/1721.1/14269.
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Burton, Stephanie Gail. "A chemical investigation of Tulbaghia Violacea." Thesis, Rhodes University, 1990. http://hdl.handle.net/10962/d1015725.
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Tulbaghia violacea, a member of the family Alliaceae is indigenous to the Eastern Cape and is widely used as a herbal remedy for various febrile and gastro-enteric ailments, particularly in young children. Adverse effects, and even fatalities, have been reported following treatment with the plant extract. The project has involved synthesis of model compounds, chromatographic analysis of flavonoid and other constituents of the plant, and examination of the volatile components. Some fifteen flavones were synthesised as chromatographic models and in the course of this work, the development of a new method for synthesis of carboxylic anhydrides was completed. Use of the flavone standards permitted identification of the flavonols kaempferol and quercetin in hydrolysed glycosidic plant extracts. In addition, several sugars were identified, viz., D-glucose, D-fructose, L-arabinose and D-galactose as free sugars, and D-glucose, D-galactose , 1-rhamnose, D- fucose, D-xylose, 1-arabinose and D-fructose as glycosidic sugars, by g.l.c. and g. c. - m. s. analysis of derivatives of isolated sugar mixtures. The presence in the plant extracts of steroidal saponins was also demonstrated. The sulphur compounds, 2,4,5,7-tetrathiaoctane-2,2-dioxide and 2,4,5,7-tetrathiaoctane were isolated from the plant and characterised spectroscopically. This result, together with analysis of volatiles from the plant, has led to a proposal concerning the nature and origin of sulphur compounds in Tulbaghia violacea, showing close correlation with the sulphur compounds in Allium species. Investigation of the biological activity of Tulbaghia violacea extracts showed bacteriostatic activity, particularly of extracts which had not been heated, and which had been prepared from mature plants. Treatment of isolated smooth muscle preparations with Tulbaghia violacea extracts indicated the presence of a β-adrenergic agonist having an inhibitory effect on normal muscle contraction. The results of the investigations indicate that while there may be some basis for use of the plant as an antibacterial, or to treat colic, the adverse effects, caused possibly by the sulphur compounds and/or steroidal saponins present, may override the beneficial effects.
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Metali, Faizah Haji. "Factors controlling Al accumulation in plants : effects of phylogeny, soil conditions and external nutrient supply." Thesis, University of Aberdeen, 2010. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=165794.
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I used a data-set of 986 plant species (from 493 genera in 195 families) obtained from a literature search and a new data collection for 58 tropical tree species (from 31 genera in 18 families) growing in two contrasting forest types in Brunei Darussalam: mixed dipterocarp forest on moderately infertile ultisols and fluvisols, and heath forest on acidic and nutrient-poor spodosols. I provide statistical evidence for the existence of discreet groups of species representing Al accumulators and non-Al accumulator based on foliar Al concentrations. The threshold foliar Al concentration was higher for tropical plants (range 2.3-3.9 mg Al g-1) than temperate plant (1.1 mg Al g-1). Species’ mean log foliar Al concentration was also higher for tropical (0.73 ± 1.11 mg Al g-1) than temperate plants (0.16 ± 1.07 mg Al g-1). I used the tropical Al accumulating shrub Melastoma malabathricum L. as a study species to test the hypotheses that growth would be stimulated by Al addition. Growth of M. malabathricum seedlings was stimulated by Al addition when the external supply of macronutrients was very low, and this growth response was associated with an increase in net assimilation rate and specific leaf area. Foliar Al concentration was positively correlated with foliar concentrations of Ca and Mg across 16 Al accumulator species sampled in the field study in Brunei Darussalam, while foliar Al and K concentrations were correlated positively in M. malabathricum seedlings growing in the solution culture experiments. These positive correlations contradict the hypothesis that Al inhibits the uptake of nutrient cations and they may contribute to the positive growth response to Al addition in Al accumulator plants.
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Flagg, Melissa L. "Bioprospecting, chemical investigations and drug discovery from Chilean plants." Diss., The University of Arizona, 2000. http://hdl.handle.net/10150/284167.
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This dissertation, completed as part of an International Cooperative Biodiversity Group (ICBG) Program, encompasses the field collection, taxonomic determination, bioassay-guided isolation, and chemical characterization of three plants native to Chile, each of which was collected using a distinct collection approach. Chuquiraga ulicina ssp. ulicina , collected by the ecological or environmental strategy, yielded ten compounds including four novel taraxastane-type triterpenoids, 3β-acetoxy-6β-hydroxytaraxasta-20-ene (1), 6β-hydroxytaraxast-20-en-3-one (2), 6β-hydroxytaraxasta-20-ene 3β-palmitate (3), and 3β, 6β-dihydroxytaraxasta-20-ene (4), together with the known triterpenoids lupeol (5), lupenyl acetate (6), lupenone (7), friedelinol ( 8), 3β-acetoxy-30-nor-lupan-20-one (9), and 30-norlupan-3β-ol-20-one (10). Lupeol (5) was the only compound to show antitubercular activity. Sphacele salviae, collected by the ethnobotanical or ethnomedical approach, allowed the isolation of three known compounds, including the two abietane diterpenoids carnosol ( 11) and rosmadial (12), as well as one pentacyclic triterpenoid, ursolic acid (13). Greigia sphacelata, collected according to the random approach, afforded nine compounds. These include the two novel flavanones 5,7,3'-trihydroxy-6,4' ,5'-trimethoxy flavanone (14) and 5,3'-dihydroxy-6,7,4',5 '-tetramethoxy flavanone (15), as well as four known phenylpropanoids, 1,3-O-di-trans-p-coumaroylglycerol (16), 1-O-trans-cournaroylglycerol (17 ), 1-(ω-feruloyldocosanoyl)glycerol and 1-(ω-feruloyltetracosanoyl)glycerol (18), and trans-ferulic acid 22-hydroxy docosanoic acid ester (19), and three known pentacyclic triterpenoids, arborinone (20), arborinol (21), and isoarborinol (22).
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Harris, Darby M. "MOLECULAR AND CHEMICAL DISSECTION OF CELLULOSE BIOSYNTHESIS IN PLANTS." UKnowledge, 2011. http://uknowledge.uky.edu/pss_etds/3.
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Plant cell walls are complex structures that must not only constrain cellular turgor pressure but also allow for structural modification during the dynamic processes of cell division and anisotropic expansion. Cell walls are composed of highly glycosylated proteins and polysaccharides, including pectin, hemicellulose and cellulose. The primary cell wall polysaccharide is cellulose, a polymer composed of high molecular weight !- 1,4-glucan chains. Although cellulose is the most abundant biopolymer on Earth, there is still a lot to learn about its biosynthesis and regulation. This research began by applying a variety of analytical techniques in an attempt to understand differences in cell wall composition and cellulose structure within the plant body, between different plant species and as a result of acclimation by the plant to different environmental conditions. Next, a number of different Arabidopsis thaliana lines possessing mutations affecting cell wall biosynthesis were analyzed for changes in cellulose structure (crystallinity) and biomass saccharification efficiency. One of these mutants, isoxaben resistance1-2 (ixr1- 2), which contains a point mutation in the C-terminal transmembrane region (TMR) of cellulose synthase 3 (CESA3), exhibited a 34% lower biomass crystallinity index and a 151% improvement in saccharification efficiency relative to that of wild-type. The culmination of this research began with a chemical screen that identified the molecule quinoxyphen as a primary cell wall cellulose biosynthesis inhibitor. By forward genetics, a semi-dominant mutant showing strong resistance to quinoxyphen named aegeus was identified in A. thaliana and the resistance locus mapped to a point mutation in the TMR of CESA1. cesa1aegeus occurs in a similar location to that of cesa3ixr1-2, illustrating both subunit specificity and commonality of resistance locus. These drug resistant CESA TMR mutants are dwarfed and have aberrant cellulose deposition. High-resolution synchrotron X-ray diffraction and 13C solid-state nuclear magnetic resonance spectroscopy analysis of cellulose produced from cesa1aegeus, cesa3ixr1-2 and the double mutant shows a reduction in cellulose microfibril width and an increase in mobility of the interior glucan chains of the cellulose microfibril relative to wild-type. These data demonstrate the importance of the TMR region of CESA1 and CESA3 for the arrangement of glucan chains into a crystalline cellulose microfibril in primary cell walls.
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Cuervo, Alfredo Carabot. "Chemical studies on steroidal sapogenin producing plants of Venezuela." Thesis, University of Portsmouth, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.255340.
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Garoosi, Ghasem-Ali. "A chemical gene switch for use in transgenic plants." Thesis, University of Liverpool, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.366250.
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Murakami, Yoshihiro. "Development of a Scheduling System for Large Chemical Plants." Kyoto University, 1998. http://hdl.handle.net/2433/182358.
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Chua, Eng Sway. "Integrated management system for multi-purpose batch chemical plants." Thesis, Imperial College London, 1995. http://hdl.handle.net/10044/1/7880.
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Palowitch, Bernard L. (Bernard Louis). "Fault diagnosis of process plants using causal models." Thesis, Massachusetts Institute of Technology, 1987. http://hdl.handle.net/1721.1/14666.
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Saeed, Auday Esmail. "Integrated design of chemical plants with energy conservation (the design of an energy efficient styrene plant)." Thesis, University of South Wales, 1990. https://pure.southwales.ac.uk/en/studentthesis/integrated-design-of-chemical-plants-with-energy-conservation-the-design-of-an-energy-efficient-styrene-plant(27fb4dfc-5ed8-40ff-a747-c302c43415da).html.
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Energy consumption is one of the main areas in the study of chemical process design. It is usually referred to as the critical element that is continuously needed for running a chemical process, and is daily effected by the prices of energy. Therefore, poor designs which are not energy integrated normally lead to less profit due to high consumption of energy. These simple economics are the reason for tackling the area of energy integration in process design. A styrene production process is taken to be the model process for carrying out the design work incorporating the various energy integration techniques. A thorough review of the published work in this subject area was the first step in this research work. This has been followed by calculating mass and energy balances around the overall plant and the individual process steps, so that information about flowrates and energy consumed and released was obtained for the base case. After this all the possible distillation sequence configurations were tested in order to find the sequence that required least energy compared with all the other possible sequences. This step is the first part of integrating the distillation train. The second part considered the heat exchanger network associated with the distillation train and this has been taken in the context of overall process integration. "Pinch technology" was used as an aid for targeting the minimum hot and cold utilities required, designing the heat exchanger network that was compatible with the minimum use of utility and to seek further improvements on the process heat exchanger network which made it capable of recovering even more energy. Utility supplies are designed with respect to the process design, hence the next step considered the interaction between the utility and process design. Thus, the utilities were introduced in a more efficient way, resulting in a better heat exchanger network and increasing the interprocess heat exchange. Finally the steam and power system in the styrene plant was tested in order to determine how much this system had benefited due to the overall efficiency of energy supply and demand.
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Balogh, Zsuzsanna. "Chemical hydrology of vascular plant growth : role of root-fungus associations." Online access for everyone, 2006. http://www.dissertations.wsu.edu/Dissertations/Summer2006/z%5Fbalogh%5F071806.pdf.
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Bahri, Parisa A. "A new integrated approach for operability analysis of chemical plants." Connect to full text, 1995. http://hdl.handle.net/2123/4015.
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Thesis (Ph. D.)--University of Sydney, 1996.Title from title screen (viewed on February 3, 2009) Submitted in fulfilment of the requirements for the degree of Doctor of Philosophy to the Dept. of Chemical Engineering. Degree awarded 1996, thesis submitted 1995. Includes bibliographical references. Also issued in print.
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Yoon, Hyung-Jae Alexander. "Heat and work integration in the synthesis of chemical plants." Thesis, Massachusetts Institute of Technology, 1990. http://hdl.handle.net/1721.1/92622.
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Gonzalez, Robert. "Optimal design, scheduling and operation of pipeless batch chemical plants." Thesis, Georgia Institute of Technology, 1995. http://hdl.handle.net/1853/11102.
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Ruiz, Diego. "Fault diagnosis in chemical plants integrated to the information system." Doctoral thesis, Universitat Politècnica de Catalunya, 2001. http://hdl.handle.net/10803/6420.
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La contribución que se pretende con esta tesis se refiere a la implantación de un sistema de diagnosis de fallos en plantas químicas completas integrado al sistema de supervisión, gestión y control de la producción.El sistema de diagnosis de fallos que se presenta consiste en una combinación de un sistema de reconocimiento de patrones basado en redes neuronales artificiales y un sistema de inferencia basado en la lógica difusa. La información necesaria para desarrollar el sistema de diagnosis incluye los datos históricos, un análisis de riesgo y operabilidad y un modelo de la planta química. La entrada al sistema son las mediciones directas o indirectas de la planta y la salida consiste en una señal para cada fallo (0: no fallo; 1: fallo). Primero se definen los fallos posibles. La red neuronal se entrena con datos históricos de fallos ocurridos en el pasado, con el objeto de reconocer los patrones respectivos. En el caso de que no se posean los datos históricos de alguno de los fallos, por ejemplo porque nunca hayan ocurrido, se obtienen los patrones mediante la simulación, usando el modelo de la planta. El sistema de lógica difusa contiene un conjunto de reglas si-entonces que pueden ser de dos tipos: las basadas en el conocimiento de la planta, mediante el análisis de riesgo o la experiencia con la simulación, y las basadas en la experiencia con el uso de la red neuronal, previamente entrenada. Otro aspecto novedoso es la posibilidad de entrenar la red neuronal con "características" extraídas de las variables medidas mediante su pre-procesamiento con wavelets. Esta variante permite obtener un alto rendimiento del sistema de diagnosis en plantas químicas discontinuas y continuas complejas. Para optimizar los parámetros de los componentes del sistema de diagnosis se propone un índice de rendimiento. Además, se utiliza el índice de rendimiento para comparar el sistema propuesto con otros métodos.
Las señales dadas por el sistema de diagnosis pueden ser usadas por el sistema de programación de la producción para actualizar el plan de la manera más efectiva, por el sistema de control para actuar en forma automática y por los operadores de planta como soporte para la toma de decisiones. Se han sentado las bases para la traducción de la salida del sistema de diagnosis para su utilización por los demás niveles del soporte informático. Se usa una estrategia basada en el análisis de riesgo y operabilidad de la planta.
El sistema propuesto es consecuencia de sucesivas mejoras, al trabajar con diferentes casos de estudio. Los escenarios académicos corresponden a una planta química continua con una corriente de reciclo y un reactor discontinuo. Los casos a escala de planta piloto corresponden a escenarios construidos en la UPC: un reactor de gasificación, un reactor semicontinuo y una planta discontinua multipropósito. Los escenarios industriales corresponden a dos refinerías de azúcar y a un sector de una planta petroquímica.
El sistema propuesto muestra ser ventajoso respecto a otros métodos tanto en cuanto a la rapidez de diagnosis como en cuanto a su capacidad para aislar los fallos. La simplicidad del desarrollo y la flexible estrategia de implementación del sistema propuesto auguran un futuro promisorio a la tecnología presentada. Nuevas líneas de investigación se pueden emprender mediante el desarrollo de un sistema de gestión de las alarmas. Otro aspecto importante es la posibilidad de participar en la estandarización de las interfaces del programa de diagnosis.
The pretended contribution of this thesis deals with the implementation of a fault diagnosis system in chemical plants integrated to the monitoring, management and control system. The proposed fault diagnosis system consists in a combination of a pattern recognition approach based on artificial neural networks and an inference system based on fuzzy logic. The information needed to develop the fault diagnosis system includes the historical data, the hazard and operability study and the model of the chemical plant. The inputs to the system are the direct or indirect measurements from the plant and the output consists in a signal for each fault (0: no fault; 1: fault). First, the possible faults are defined. The artificial neural network is trained with historical data of faults occurred in the past, with the aim of recognising the respective patterns. In the case that the corresponding historical data are not available, for example due to the no occurrence of the fault, the patterns are obtained through simulation, using the plant model. The fuzzy logic system contains a set of if-then rules that can be of two types: those based in the process knowledge, by the hazard analysis or by the experience with simulation, and those based on the experience with the use of an artificial neural network, previously trained. Other novel aspect is the possibility of artificial neural network training by using signals features that are extracted by its pre-processing using wavelets. This alternative allows a higher fault diagnosis system performance in batch and complex continuous chemical plants. In order to optimise the parameters of the components of the fault diagnosis system, a performance index is proposed. The performance index is also utilised to compare the proposed fault diagnosis system against other methods.
The signals provided by the fault diagnosis system can be used by the scheduling system to update the schedule in the most effective way, by the control system to take automated control actions and by plant's operators as support for decision-making. The basis of the translation of the system output, for its utilisation at other levels in the information system, has been settled.
The proposed strategy is based on the hazard and operability analysis.
The proposed system is the result of successive improvements, by working with different case studies. The academic scenarios correspond to a continuous chemical plant with a recycle stream and a batch reactor. The pilot plant scale cases correspond to scenarios built at UPC: a reactor gasifier, a fed-batch reactor and a multipurpose batch chemical plant. The industrial scenarios correspond to two sugar refineries and a sector of a petrochemical plant.
The proposed system shows to be advantageous with respect to other methods in relation to the fastness of the diagnosis and also its capacity to isolate faults. The simplicity of the development and the flexible strategy of implementation of the proposed fault diagnosis system give a promising future to the presented technology. New research lines can be considered by developing the alarm handling system. Other important aspect is the possibility of the participation in the standardisation of the interfaces of the fault diagnosis program.
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Pattinson, Thomas. "Optimal sysnthesis of storageless batch plants using the Process Intermediate Storage Operational policy." Pretoria : [s.n.], 2007. http://upetd.up.ac.za/thesis/available/etd-08272008-125107/.
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Dhole, Vikas Raghunath. "Distillation column integration and overall design of subambient plants." Thesis, University of Manchester, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.292550.
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Distillation is the most widely used separation process in the chemical industry. It is also a highly energy intensive unit operation. Any thermal modifications in the distillation columns will normally affect the heat exchanger network (HEN) and the utility system. Pinch analysis offers a systematic approach for considering this effect ahead of column modifications i.e. integrating the columns with their background processes. However, the guidelines for column modifications mainly emerge from the analysis of the HEN and the utility system. The potentials for modifications in the columns are not fully exploited. The columns are largely treated as "black boxes". Within the thesis, a new approach to distillation column integration is proposed. It extends the current pinch analysis approach. Using insights from column thermodynamics, the potential for the various column modifications can be directly assessed ahead of design. This allows the designer to set heat load and temperature targets for the column modifications. A new set of thermal profiles for the column are developed. These provide insights into the effect of column modifications on the number of stages. Only a single converged simulation is sufficient to generate all the targeting information. These "column targets" when linked with the normal pinch analysis targets, provide an approach for column integration which directly identifies the modification potential in the distillation columns as well as the potentials in the HEN and the utility system, resulting in a more reliable approach in comparison to the conventional pinch analysis. A combined pinch and exergy approach is proposed for the overall design of subambient plants. Pinch analysis is mainly applicable for setting the most economic energy target ahead of design. These targets are mainly in the form of heat loads. The combined pinch and exergy analysis extends this application to heat and power targeting for subambient plants. Any subambient plant has three main components namely; the process, the HEN and the refrigeration system. All the three components are highly interlinked and a modification in anyone of the components affects the other two. The task of overall design becomes quite complex due to these interactions. The new approach allows the designer to resolve these interactions and set the most economic "shaftwork or power targets" ahead of deSign. It combines the three components into a single design task. The approach when linked with the column targets, identifies the potential column modifications and evaluates their benefits directly in terms of shaftwork, thus even by-passing the repeated column simulations. Thus the overall design procedure systematically modifies a given subambient plant considering its distillation system, the HEN, and the refrigeration system on a simultaneous basis. The procedure has been demonstrated on an ethylene cold end case study. Typically 15-20% shaftwork savings have been observed on flowsheets which have already undergone pinch analYSis. The approach can be extended for certain applications above ambient involving heat and power.
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Naseer, Zarga. "Chemical and physical changes associated with maturity of different plants and enhancement of nutritional value by chemical treatment of crop residues." Diss., This resource online, 1990. http://scholar.lib.vt.edu/theses/available/etd-07122007-103928/.
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Panahi, Mehdi. "Plantwide Control for Economically Optimal Operation of Chemical Plants : - Applications to GTL plants and CO2 capturing processes." Doctoral thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for kjemisk prosessteknologi, 2011. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-15210.
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In this thesis, the systematic plantwide procedure of Skogestad (2004) is applied to two processes; 1- Post-combustion CO2 capturing processes, 2- Natural gas to liquid hydrocarbons (GTL) plants, in order to design economically efficient control structures, which keep the processes nearoptimum when disturbances occur. Because of the large magnitude of energy consumption in both these processes, optimal operation is of great importance. The self-optimizing concept, which is the heart of the plantwide procedure is used to select the right controlled variables in different operational regions, which when they are kept constant, indirectly give the operation close to optimum. The optimal is to reconfigure the self-optimizing control loops when the process is entered into a new active constraint region, but we try to arrive at a simple/single control structure, which does not need switching, where a reasonable loss in operating economic objective function is accepted. The CO2 capturing process studied here is an amine absorption/stripping system. The chosen objective function for this process is first to minimize the energy requirement while fixed CO2 recovery of 90% is met. This leads to one unconstrained degree of freedom. Maximum gain rule is applied and a temperature close to the top of the stripper is found as the best controlled variable. Further, we introduce penalty on CO2 amount released to the atmosphere, and this results in two unconstrained degrees of freedom. CO2 recovery and a temperature close to the top of the stripper are found as the best individual controlled variables in low feedrate. In higher flue gas flowrates, stripper heat input saturates and the self-optimizing method is repeated to select the right controlled variable for the remaining degree of freedom. We validate the propose control structures using dynamic simulations, where 5 different alternatives including decentralized control loops and multivariable controller are studied. We finally achieve a simple control structure, which handles a wide range of change in throughput and keeps the process close to optimum without the need for switching the control loops or updating the controlled variables setpoints by a costly real time optimizer. The GTL process modeled in this thesis includes an auto-thermal reformer (ATR) for synthesis gas production and a slurry bubble column reactor (SBCR) for the Fischer-Tropsch (FT) reactions. The FT products distribution is determined using a well-known Anderson- Schultz- Flory (ASF) model, where carbon component in CO (consumption rate is found based on the proposed rate by Iglesia et al.) is distributed to a range of hydrocarbons. ASF is a function of chain growth probability and the chain growth is a function of H2/CO ratio. We study different scenarios for chain growth and we arrive at a suitable model for optimal operation studies. The optimal operation is considered in two modes of operation. In mode I, natural gas feedrate is assumed given and in mode II, natural gas feedrate is also a degree of freedom. After optimization, in both modes, there are three unconstrained degrees of freedom. The best individual self-optimizing controlled variables are found and since the worst-case loss value is rather notable, combination of measurements is done, which reduces the loss significantly. Mode II happens when oxygen flowrate capacity reaches the maximum and we show that operation in mode II in this case is in snowballing region where operation should be avoided. Operation at maximum oxygen flowrate capacity is where maximum practical profit can be achieved.
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Wang, Wen-Bohr. "Optimization of expander plants /." Access abstract and link to full text, 1985. http://0-wwwlib.umi.com.library.utulsa.edu/dissertations/fullcit/8520757.
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Finch, Francis Eric. "Automated fault diagnosis of chemical process plants using model-based reasoning." Thesis, Massachusetts Institute of Technology, 1989. http://hdl.handle.net/1721.1/14194.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 1989.Science hard copy bound in 2 v.
Includes bibliographical references (leaves 300-307).
by Francis Eric Finch.
Ph.D.
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Baker, Rhoda. "Inclusion of input saturation in the design of dynamically operable plants." Master's thesis, University of Cape Town, 2000. http://hdl.handle.net/11427/5343.
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Bibliography: leaves 109-113.Dynamic operability reflects the quality with which a plant can be controlled using feedback, and is a function of both the design of the plant and its associated control system. A plant designed on the basis of steady-state considerations alone could exhibit poor dynamic characteristics, leading to a loss of economic performance and a reduced capacity to effectively handle safety and environmental constraints. This motivates the need for the development of quantitative techniques for dynamic operability assessment, as well as its incorporation into procedures for process plant design. Optimization-based approaches to dynamic operability assessment permit simultaneous consideration of performance-limiting factors of nonminimum phase characteristics, input constraints and model uncertainty, and also provide considerable flexibility in the choice of performance criteria, decision variables and constraints. Recent work has incorporated operability requirements as constraints within a single optimal plant design problem formulation (Mohideen et at., 1997; Bahri et at.,1996). Young and Swartz (1997) considered the rigorous inclusion of input saturation effects in optimizing control. Actuator saturation introduces discontinuities in the system model and, to avoid potential problems using a sequential optimization approach, two alternative formulations were proposed for solving the problem within a simultaneous solution framework. Input saturation discontinuities were handled by the introduction of slack variables and their inclusion in either bilinear or mixed-integer constraints resulting in a nonlinear or mixed-integer linear programming problem respectively. The formulations were applied to a linear system with dead time to find the economically optimal operating point for a controller with fixed structure and tunings when disturbance deviations are taken into account. It was shown that using a strictly linear controller in this case would lead to an overly conservative estimate of the feasible operating range and consequently, a suboptimal operating point.
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Venkatesan, Luke. "The development of frother optimisation techniques in full scale flotation plants." Master's thesis, University of Cape Town, 2013. http://hdl.handle.net/11427/5386.
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Includes abstract.Includes bibliographical references.
In 2012, Anglo American Platinum assembled a technical task team of metallurgists for their concentrator operations. Although there has been extensive research in literature regarding the flotation response and behaviour of reagents, there still exists a gap between fundamental laboratory scale research and plant scale application. This thesis will focus on the development of techniques for optimising and characterising frother on a full scale plant using the Anglo American Platinum Bubble Sizer (AAPBS) which is a commonly used tool by the plant metallurgist. The techniques developed have been based on the application of fundamental research of frothers in literature. This thesis consists of three main focus areas: 1) Developing a technique for measuring the relationship between sauter mean bubble diameter and frother concentration on a full scale plant. 2) Developing a technique for estimating frother concentrations in process streams in full scale plant 3) Establishing whether the relationship between sauter mean bubble diameter and superficial gas velocity in a flotation bank of identical cells in series in a plant operating at frother concentration above the CCC is identical, and whether this can be used to detect the decrease of frother concentration to below the CCC at any point in the bank. Furthermore, the metallurgical performance of a bank with a decrease in frother concentration below the CCC midway through the bank was determined before and after the addition of frother, which was added as such that all the cells in the bank operate with a frother concentration above the CCC. There were two techniques investigated for measuring the relationship between sauter mean bubble diameter and frother concentration. Both techniques involved using the AAPBS and the use of forced air mechanically agitated tank cells. Technique 1 involved using the first rougher cell on a flotation plant, dosing frother at different rates into the cell to target different frother concentrations and then measuring the resultant bubble size whilst operating at a fixed air rate. The coalescence mechanism here was occurring in a three phase solids/aqueous/air system occurring in a continuous stirred tank. Similarly Technique 2 involved using the first rougher cell; however, the first cell was depleted of frother by bypassing the frother dosage line into the next cell. This was done to isolate the first rougher cell and to minimise disturbance to the rest of the rougher bank. Known concentrations offrother were made up in potable water and these were added into the AAPBS. Bubbles from the pulp phase enter the bubble riser tube which is long and narrow (3m x 25mm diameter) which is representative of two phase aqueous/air “plug flow” system. These bubbles coalesce to different degrees based on the known frother concentration. The resulting bubble size distribution was then be measured by taking photographs at the viewing pane of the AAPBS. The air rate in the cell was kept constant to within 0.7-0.9 cm/s and the photographs were analysed using software provided by stone three to determine the sauter mean bubble diameter and the bubble size distribution. Technique 1 was applied to Plant A UG2 concentrator which was using a polyglycol type frother called Betafroth 206C which has an undisclosed composition and a molecular weight of approximately 200 g/mol. The first rougher cell used was an Outokumpu 70 m3 forced air mechanically agitated tank cell. The results showed no clear relationship between sauter mean bubble diameter and frother concentration. Furthermore, the sauter mean bubble diameter was already very small and it appeared that the changes in between runs were more strongly linked to the superficial gas velocity than frother concentration. The fact that the sauter mean bubble diameter obtained was already small implied that the frother concentration in the cell was already high. This could have been due to an additional source of frother due to spillage or in the process water that potentially elevated the actual frother concentrations in the cell. Technique 1 also resulted in significant disturbances to the entire rougher bank because it involved changing the frother dosages to the bank. This would affect the flotation performance of the bank for a prolonged period and affect plant performance. Hence it was decided that technique 1 would not be suitable.
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Komlaga, Gustav. "Search for antiplasmodial compounds from Ghanaian medicinal plants." Thesis, Université Paris-Saclay (ComUE), 2015. http://www.theses.fr/2015SACLS265/document.
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Une enquête ethnobotanique a été menée en Bosomtwi et Sekyere Est Districts de la Région Ashanti, au Ghana, en utilisant des questionnaires validés pour identifier les plantes traditionnellement utilisées pour gérer le paludisme. Cinq plantes avec une utilisation élevée ont été sélectionnés et une extraction préliminaire des matières végétales sélectionnées effectuées avec de l'eau, le methanol, l'acétate d'éthyle et d'éther de pétrole. Les extraits ont été dosés pour l'activité antiplasmodiale utilisant les méthodes antiplasmodiales in vitro. Les deux les plus prometteuses plantes, Phyllanthus fraternus (Phyllanthaceae) et Bambusa vulgaris (Pocea) ont été choisis pour l'isolement bio-guidée de constituants bioactifs en utilisant des méthodes chromatographiques (par exemple TLC, flash chromatographie, HPLC semi-préparative). Élucidation de la structure des composés isolés ont été effectuées en utilisant des méthodes spectroscopiques (par exemple 1D et 2D Magnétique Nucléaires Résonance (MNR), infrarouge et spectrométrie de masse et leur activité antiplasmodiale étudiésAn ethnobotanical survey was conducted in Bosomtwi and Sekyere East Districts of the Ashanti Region, Ghana, using validated questionnaires to identify plants used traditionally to manage malaria. Five plants with high usage were selected and a preliminary extraction of the selected plant materials done using water, methanol, ethyl acetate and petroleum ether. The extracts were assayed for antiplasmodial activity using in vitro antiplasmodial methods. The two most promising plants, Phyllanthus fraternus (Phyllanthaceae) and Bambusa vulgaris (Pocea) were selected for bio-guided isolation of bioactive constituents using chromatographic methods (e.g. TLC, flash chromatography, semi-preparative HPLC). Structural elucidation of the isolated compounds were done using spectroscopic methods (e.g. 1D and 2D Nuclear Magnetic Resonance, Infrared and mass spectrometry) and their antiplasmodial activity studied
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Gray, Dean E. "Chemical quality in two medicinal plants : St. John's wort and purple coneflower /." free to MU campus, to others for purchase, 2000. http://wwwlib.umi.com/cr/mo/fullcit?p9974634.
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Helal, A. M. "Mathematical modelling and simulation of multistage flash (MSF) desalination plants." Thesis, University of Leeds, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.356426.
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Baldauf, Paul D. "Chemical industry security voluntary or mandatory approach?" Thesis, Monterey, Calif. : Naval Postgraduate School, 2007. http://bosun.nps.edu/uhtbin/hyperion.exe/07Mar%5FBaldauf.pdf.
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Thesis (M.A. in Security Studies (Homeland Security and Defense))--Naval Postgraduate School, March 2007.Thesis Advisor(s): Thomas J. Mackin, Nadav Morag. "March 2007." Includes bibliographical references (p. 75-79). Also available in print.
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Latolla, Nehemiah Solomon. "The investigation of chemical variation in the stems and rhizomes of cissampelos capensis l. f. (menispermaceae) the Eastern Cape medicinal plant." Thesis, Nelson Mandela Metropolitan University, 2017. http://hdl.handle.net/10948/13970.
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Cissampelos capensis L. f. (Menispermaceae) commonly known as “Mayisake” (Xhosa) and “Dawidjieswortel” (Afrikaans) is the most commonly used medicinal plant of the Menispermaceae family in South Africa. The rhizomes of Cissampelos capensis are the most used part of the plant to treat illnesses. This poses a threat to the ongoing conservation of this valuable endemic species. Thus, we studied the chemical variation and subsequently the bioactivity in the stems and rhizomes of Cissampelos capensis, the Eastern Cape medicinal plant, to suggest the possible use of the stems for medicinal purposes. We studied the variation in the chemical composition in the stems and the rhizomes by employing four different extraction methods; the methanolic-, non-polar-, alkaloidal- and Total Tertiary Alkaloidal (TTA) to extract compounds from Cissampelos capensis. Employing various chromatographic techniques, HPLC, NMR and LC/MS to investigate the chemical variation and the in vitro assays for the crude materials of the stems and rhizomes of Cissampelos capensis. We successfully documented a library of the phytochemicals content in Cissampelos capensis from three different regions in the Eastern Cape. We could profile different extraction methods, with the TTA extraction delivering the best comparative profile. Employing LC/MS and HPLC we identified eleven known alkaloidal compounds in the stems and rhizomes. We also isolated a known alkaloid, pronuciferine, from the TTA extract and a crystal structure of proto-quericitol from the methanolic extract, which was isolated for the first time from Cissampelos capensis. Preliminary in vitro results suggested anti-inflammatory activity in the methanolic extracts of the stems and rhizomes, while the TTA extracts showed some cytotoxicity. Finally, through analytical HPLC analysis this study found as high as 31% similarity between the chemical variation of the stems and rhizomes, but key alkaloids were not always present, indicating more work is needed before the stems can be recommended as a replacement for the rhizomes.
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Babajide, Jelili Olalekan. "Chemical and biological investigation into some selected African indigenous medicinal plants." Thesis, University of the Western Cape, 2009. http://etd.uwc.ac.za/index.php?module=etd&action=viewtitle&id=gen8Srv25Nme4_7625_1297404173.
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African medicinal plants are commonly used throughout Africa to treat a variety of ailments including wounds and ulcers, cough and chest complaints, gingivitis, fever and gonorrhoea, indication all related to infection and inflammation. In screening several plant species from an inventory of common medicinal plants from both South and West Africa for diverse medicinal purposes, 6 plants were selected because of their interesting and useful ethnomedicinal values.
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Cantón, Padilla Jorge. "Integrated support system for planning and scheduling of batch chemical plants." Doctoral thesis, Universitat Politècnica de Catalunya, 2003. http://hdl.handle.net/10803/6434.
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La planificación de la producción en plantas de proceso discontinuo es uno de los problemas más complejos e importantes para una amplia variedad de procesos industriales. A pesar de esta importancia la planificación de la producción es habitualmente un proceso manual que puede conducir a un exceso de inventario, una utilización ineficiente del capital y aumento en costes de producción.Este problema ha sido el sujeto de un importante esfuerzo investigador en los últimos años, especialmente desde principios de los 80 hasta la actualidad, aunque la industria se ha mostrado interesada en el problema desde los años 40. Durante este tiempo se ha realizado mucha investigación al respecto, pero la naturaleza compleja de problema hace que todavía no exista una solución aceptada ampliamente en la industria.
Esta tesis describe un entorno genérico para la planificación de la producción en plantas de proceso discontinuo. Se han desarrollado diferentes componentes: un modelo de datos, un modelo de temporización, estrategias de asignación y secuenciación y diferentes alternativas de optimización.
Uno de los aspectos más importantes del entorno presentado es su modularidad. El hecho de dividir el problema de planificación de la producción en diferentes módulos que comparten un modelo de datos común facilita la reutilización y la adaptación a escenarios industriales de las diferentes técnicas desarrolladas escogiendo la mejor alternativa para cada uno de ellos.
El modelo de información orientado a objetos que se presenta en esta tesis permite la organización sistemática de la información de planta, permitiendo una representación detallada de las restricciones presentes en la industria.Por otra parte, el modelo de temporización de operaciones (EON) desarrollado en la presente tesis es la capacidad de representar restricciones temporales complejas presentes en la industria utilizando componentes sencillos. Se ha desarrollado una metodología para generar modelos EON a partir del modelo de información utilizado incluyendo restricciones de depósitos y restricciones temporales entre operaciones. Adicionalmente, un método iterativo permite tener en cuenta otros recursos limitantes dependientes de calendario, como mano de obra, electricidad, etc.
En relación a las decisiones de nivel superior, se han desarrollado también reglas de balance de materiales, asignación y secuenciación que permiten obtener de una forma rápida y sencilla planes factibles a partir de un conjunto de demandas. Estas reglas se pueden aplicar tanto a planes de producción vacíos en situaciones de puesta en marcha de la planta, como a planes parcialmente llenos con la información de lotes que se están ejecutando en planta, lo que permite la replanificación en linea en caso de ser necesario.
También se han aplicado diferentes técnicas de optimización a fin de mejorar planes de producción. Se han probado tanto métodos heurísticos como modelización matemática.
En lo referente a los métodos heurísticos, se ha desarrollado un nuevo método de optimización (MSES) que mejora algunos aspectos referentes al algoritmo estándar de recocido simulado. Los algoritmos genéticos han sido también objeto de estudio, incorporando un algoritmo que transforma los individuos infactibles en factibles. Todos estos métodos han sido adaptados al entorno desarrollado permitiendo cambios de secuencia y asignación.
En lo que respecta a la modelización matemática, se ha desarrollado un nuevo modelo MILP basado en una extensión del EON introduciendo variables de decisión de secuencia y asignación así como restricciones asociadas a almacenamientos intermedios.
El entorno desarrollado en esta tesis ha sido aplicado a diferentes entornos industriales, proporcionando una validación de las tecnologías y modelos desarrollados. En todos los casos estudiados se han podido obtener planes de producción que cumplen con las restricciones presentes en planta, lo que permite establecer la validez de las metodologías desarrolladas para la planificación de la producción en plantas químicas de proceso discontinuo.
The scheduling of batch processes is one of the most complex and important problems faced by a wide variety of processing industries. In spite of this importance, scheduling is often a manual procedure, which leads to operation characterized by high inventories, inefficient capital utilization and increased operation costs. There are also reported complains about the lack of powerful, easy-to-use, PC based tools able to solve detailed operational problems, as well as perform high level analysis across the supply chain.
This problem has been the focus of an important amount of research work in the recent years, especially from the early 1980's to nowadays, although the industry has been interested in effective ways of solving the scheduling problem since the early 1940's. An extensive work has been done but the complex nature of the scheduling problem results on the lack of a unique solution widely accepted in the industry.
This thesis describes a global generic framework for planning and scheduling of batch chemical plants. Different components have been studied: a data model, a timing model, heuristic sequencing and assignment strategies and optimization procedures.
One of the strongest points of the framework presented is its modularity. The fact of having the different components of planning and scheduling as separate modules sharing a common data model allows an easy use and adaptation of different techniques that can help solving the scheduling and planning problem in specific cases. This modular approach has been useful when applying the techniques presented to industrial scenarios. Adaptation to specific scenarios choosing the best alternative for each one is not only possible but also easy.
The key point for achieving this is to share the common data and timing model (the EON model). The extensible object oriented data model presented in this thesis allows an organized and systematic information management dealing with the detailed representation of batch processes in the chemical industry. The main strength of the EON model is the capability of representation of complex time constraints between operations in the same schedule using simple components. EON model is presented and developed in detail. A methodology for the representation of storage constraints as time constraints as EON constraints is also presented. An iterative procedure allows also to take into account of limited resources as manpower, electricity, etc.
Dispatching-like rules have been developed for the calculation of the material balances, the unit assignment and the batch sequencing. The strength of this approach is based in the easy implementation and adaptation to a batch oriented framework. These rules can be applied to empty schedules or to schedules that already contain frozen batches, which represents the actual situation in the plant. This last aspect allows the use of this kind of rules when performing on-line scheduling.
Different optimization techniques have been used in this thesis to solve the scheduling approach presented. Stochastic and mathematical methods have been used and tested.
Regarding to the stochastic methods, a new optimization algorithm (MSES) has been introduced that improves the performance of the SA standard algorithm. A modified GA algorithm has also been proposed that transforms the infeasible sequences commonly generated into feasible ones. All the stochastic methods used were adapted to batch processing structures involving batch sequencing and rule driven unit assignment.
Regarding to the mathematical approach, the mathematical formulation presented in the EON timing model has been extended by introducing sequence and assignment variables as well as storage constraints.
The framework developed in this thesis has been successfully applied to different industrial scenarios that are shown. The proposed solutions have been able to represent all the complexity of the test cases studied providing a powerful tool for planning and scheduling of the different plants.
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Journet, Christophe Emile. "Computer aids for the safe design and operation of chemical plants." Thesis, University of Bath, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.332791.
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MagalhÃes, Islay Lima. "Contribution to the knowledge of Chemical Northeast plants : Caesalpinia ferrea (Leguminosae)." Universidade Federal do CearÃ, 2014. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=13738.
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CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel SuperiorEste trabalho descreve a investigaÃÃo fitoquÃmica da espÃcie vegetal Caesalpinia ferrea (Leguminosae), conhecida como âjucÃâ e usada popularmente no nordeste do Brasil como antirreumÃtico, antimicrobiano e entre outros usos. Os extratos de C. ferrea atravÃs da cromatografia em coluna tendo como fase estacionÃria gel de sÃlica e Sephadex LH-20 levaram ao isolamento de quatro substancias do tipo polifenÃis {Ãcido gÃlico (Ãcido-3,4,5-tri-hidrÃxi-benzÃico), Ãcido elÃgico (4,4â,5,5â,6,6â-hexahidroxidifÃnico-2,6,2â,6â-dilactona), amentoflavona (8-[5-(5,7-dihidroxi-4-oxo-cromeno-2-il)-2-hidroxi-fenil]-5,7-dihidroxi-2-(4-hidroxifenil) cromeno-4-one) e resveratrol (trans-3,5,4â-trihidroxiestilbeno)}; uma mistura constituÃda de um esterÃide {β-sitosterol (24-etilcolest-5-en-3β-ol) e de dois Ãcidos graxos [Ãcido palmÃtico (n-hexadecanÃico) e esteÃrico (n-octadecanÃico)]}; uma outra mistura constituÃda dos triterpenos [Lupeol (Lup-20(29)-en-3β-ol) e β-amirina (olean-12-en-3β-ol), do esterÃide 24-metilenocicloartanol (3β-9,19-Ciclolanostan-3-ol-24-metileno) e do Ãlcool lignocÃrico (n-tetracosonol). A caracterizaÃÃo dos compostos envolveu o uso das tÃcnicas de RMN 1H e 13C (1D e 2D), IV, CG-EM-IE e CLAE-EM-IES. Os extratos brutos das vagens e algumas de suas fraÃÃes foram submetidos a testes de atividades antiacetilcolinesterase e antioxidante com resultados promissores. O bi-flavonÃide, a fitoalexina e os constituintes das misturas mencionadas sÃo relatados pela primeira vez na literatura em C. ferrea.
This work describe the phytochemical investigation of pods and stems of specie Caesalpinia ferrea (Leguminosae) known as âjucÃâ. Popularly, this plant is used as antirheumatic, antimicrobial and among other uses. The hexane and ethanol extracts to pods and stems of C. ferrea were submitted to column chromatography having silica gel and Sephadex LH-20 as stationary phase that led to the isolation of four compounds of the type polyphenol: {gallic acid (3,4,5-trihydroxy-benzoic acid), ellagic acid (4,4', 5,5', 6,6'-hexahydroxydifÃnico-2,6,2',6'-dilactone), amentoflavone (8-[5-(5,7-dihydroxy-4-oxo-chromene-2-yl)-2-hydroxyphenyl]-5,7-dihydroxy-2-(4-hydroxyphenyl)) chromen-4-one and resveratrol (trans-3,5,4â trihydroxystilbene)}; a mixture consisting of a steroid {-sitosterol(24-etilcolest-5-en-3-ol) and two fatty acids [palmitic acid (nhexadecanoic) and stearic acid (n-octadecanoic acid)]}; another mixture consisting of the triterpenes [Lupeol (Lup-20(29)-en-3-ol) and -amyrin (olean-12-en-3-ol), steroid 24-metilenocicloartanol (3-9,19 Ciclolanostan-3-ol-24-methylene) and lignoceric alcohol (n-tetracosonol). The characterization of the chemical components involved the use 1H and 13C NMR (1D and 2D), IR, GC-MS-EI e HPLC-MS-ESI. The extracts of pods and some of its fractions were submitted in test of the antioxidant activities and antiacetylcholinesterase with promising results. The bi-flavonoid, phytoalexin and components of mixtures mentioned are first reported in the literature to C. ferrea.
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Hudelson, Timothy J. "Environmental, Chemical, and Genetic Reduction of Ethylene Sensitivity in Crop Plants." DigitalCommons@USU, 2006. https://digitalcommons.usu.edu/etd/6710.
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Ethylene is an endogenously synthesized plant hormone that dissipates quickly in field conditions and seldom exceeds five nmol mol-1. Ethylene can accumulate to 1000 times this level in closed environments. The best-known effects of ethylene are its impacts on fruit ripening and senescence, yet ethylene influences growth and development throughout the plant life cycle. At low, continuous concentrations (20 to 50 nmol mol-1), ethylene reduces yield of many plants. Clean-air treatment during critical stages of floral development, silver thiosulfate (STS), and 1-methylcyclopropene (1- MCP) may delay flower senescence and reduce the detrimental effects of ethylene on peas and tomatoes grown in continuous ethylene. There is evidence of species differences in ethylene sensitivity, but limited information on cultivar differences. To address these issues, ethylene sensitivity of two dwarf tomato cultivars, Micro-Tom and Micro-Tina, and one dwarf pea cultivar, Earligreen, was examined. Ethylene by temperature interactions were examined in tomatoes at 0, 20, and 40 nmol mol-1 ethylene and 22 and 28°C. Three-day-long clean-air treatments were applied to tomatoes from germination through fruit set to identify the most ethylene-sensitive stage of floral development. The actions and toxicities of STS and 1-MCP were compared. Ethylene sensitivities of the two closely related dwarf tomato cultivars were examined. At 22°C, the 20 and 40 nmol mol-1 red fruit yields were 51 and 11 % of control. At 28°C, yields were 37 and 4% of control. Vegetative growth at 20 and 40 nmol mol-1 was 96 and 91 % of control, at both temperatures. Three-day-long clean-air treatments from days 22 to 33 (axillary flower opening) improved fruit set and final yield. Floral bud abortion in elevated ethylene occurred primarily at or before microsporogenesis. Floral bud initiation and vegetative development were not significantly affected. Tomato plants grown in continuous 70 nmol mol-1 ethylene conditions retained only 3% of the total number of floral buds initiated. STS-treated plants retained 50 to 54% of their floral buds. Leaf area of plants subjected to 100 nmol mol-1 ethylene was 26% of control, and plants subjected to 200 nmol mol-1 ethylene were 21 % of control. When plants were treated daily for 10 hours with 35 nmol mol-1 l-MCP, leaf area improved to 81 and 64% of control. Manipulating temperature had neither a statistically nor a biologically significant effect on ethylene sensitivity. Ethylene reduced yield primarily by arresting floral bud development and causing early floral bud senescence. Both STS and 1-MCP looked promising for improving yield in high ethylene environments, but concentrations and durations of application need to be further refined. Yield of Micro-Tom was significantly less sensitive to ethylene than Micro-Tina. These results indicate that solving ethylene sensitivity issues in controlled environments may be accommodated by cultivar choice as well as timely control of environmental ethylene, chemical inhibitors, and genetic manipulation.
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Rigitano, R. L. O. "Physio-chemical factors affecting translocation and distribution of xenobiotics in plants." Thesis, Imperial College London, 1985. http://hdl.handle.net/10044/1/37834.
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Kwasny, Richard S. "Hazard assessment strategies for reduction reactions." Thesis, London South Bank University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.298377.
Full textAbstract:
Reduction reactions involving heterogeneous catalytic hydrogenations, complex metal hydrides, and to lesser degree hydrogen-transfer reactions, are regularly scaled-up in pilot plants. Unfortunately, thermal runaway incidents involving reduction reactions do occur, despite best efforts to prevent them through the application of a chemical reaction hazard assessment strategy. A review of the literature, plant incidents, thermochemical and calorimetric techniques, identified the requirements for a unique assessment strategy for reduction reactions. The preference was to safeguard the plant using preventive measures first which were supported by adequate protective measures. The basis of safety was defined by, the boiling point of the reaction mass, the process temperature and the adiabatic temperature rise for the desired and/or adverse reactions including other kinetic data, e. g., "time to maximum rate". A number of instrumental and thermochemical procedures were adopted for the hazard identification portion of the strategy. The DSC capillary and ampoule techniques were used for substrate thermal decomposition and air oxidation determinations including reaction solution thermal stability studies. An estimation technique (Yoshida) used DSC exothermic data to predict a substrate's susceptibility of being shock sensitive and/or explosion propagating. An evolved gas mass flow detector was coupled to a reaction calorimeter to determine the maximum off-gas rate. A modified stirred ARC for hydrogenations and a stirred-micro-calorimeter for the quantification of the adverse reaction were developed. Adiabatic determinations for quantification of the adverse reaction were variable. The heat losses were unacceptable for a controlled hydrogenation in a modified stirred ARC. Results for the stirred-micro-calorimeter were satisfactory. However, adverse reactions for hydride decompositions and "shot additions" yielded adequate calorimetric results. A series of controlled experiments by reaction calorimeter coupled with an insitu FTIR, characterised the thermochemistry, reaction kinetics, mass transfer coefficient and reaction mechanism for the desired and inhibited hydrogenations. A customised What-If? /Checklist process hazard analysis technique was developed for reduction reactions and two worked examples are presented. A hazard assessment strategy with appropriate hazard identification procedures was developed. Eight case studies (three hydrogenations, three hydride reductions and two hydrogen-transfer reactions) were used as examples to validate the reduction assessment strategy and hazard identification procedures.
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Parmar, Jayesh C. "A method for computer-aided hazard identification of process plants." Thesis, Loughborough University, 1986. https://dspace.lboro.ac.uk/2134/7279.
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Silue, Mamadou. "Numerical modelling of non-linear chemical reactions in power plant plumes." Thesis, Brunel University, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.299115.
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Bailey, D. A. "Chemical Height Control of Florists' Hydrangeas." College of Agriculture, University of Arizona (Tucson, AZ), 1988. http://hdl.handle.net/10150/215854.
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XE-1019 (2 foliar sprays of 10, 2Q or 30 mg-liter⁻¹) was applied to plants of Hydrangea macrophylla Ser. 'Rose Supreme' during greenhouse forcing. Doses applied resulted in excessive reductions in shoot elongation and inflorescence diameters and delayed anthesis. Shoot growth was reduced with increasing XE-1019 concentration. Shoot length was reduced 46 %; stem dry weight was reduced 31 %; leaf area per shoot was reduced 44 %; inflorescence height was cut by 45 %; and inflorescence mass was reduced 48% with the 30 mg-liter⁻¹ XE-1019 treatment. Specific leaf weight increased with increased XE -1019 concentration (192% increase with the 30 mg-liter⁻¹ treatment) resulting in thicker leaves at anthesis. XE-1019 is an effective height control agent for florists' hydrangeas, and shows significant activity at very low (less than 0.2 mg a.i. per plant) doses.
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Broomhead, A. J. "Chemical and biochemical studies of tumour inhibitory aryl tetralin lignans." Thesis, University of Nottingham, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.235376.
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