Dissertations / Theses on the topic 'Chemical sensitivity analysi'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 26 dissertations / theses for your research on the topic 'Chemical sensitivity analysi.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
Khan, Kamil Ahmad. "Sensitivity analysis for nonsmooth dynamic systems." Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/98156.
Full textCataloged from PDF version of thesis.
Includes bibliographical references (pages 369-377).
Nonsmoothness in dynamic process models can hinder conventional methods for simulation, sensitivity analysis, and optimization, and can be introduced, for example, by transitions in flow regime or thermodynamic phase, or through discrete changes in the operating mode of a process. While dedicated numerical methods exist for nonsmooth problems, these methods require generalized derivative information that can be difficult to furnish. This thesis presents some of the first automatable methods for computing these generalized derivatives. Firstly, Nesterov's lexicographic derivatives are shown to be elements of the plenary hull of Clarke's generalized Jacobian whenever they exist. Lexicographic derivatives thus provide useful local sensitivity information for use in numerical methods for nonsmooth problems. A vector forward mode of automatic differentiation is developed and implemented to evaluate lexicographic derivatives for finite compositions of simple lexicographically smooth functions, including the standard arithmetic operations, trigonometric functions, exp / log, piecewise differentiable functions such as the absolute-value function, and other nonsmooth functions such as the Euclidean norm. This method is accurate, automatable, and computationally inexpensive. Next, given a parametric ordinary differential equation (ODE) with a lexicographically smooth right-hand side function, parametric lexicographic derivatives of a solution trajectory are described in terms of the unique solution of a certain auxiliary ODE. A numerical method is developed and implemented to solve this auxiliary ODE, when the right-hand side function for the original ODE is a composition of absolute-value functions and analytic functions. Computationally tractable sufficient conditions are also presented for differentiability of the original ODE solution with respect to system parameters. Sufficient conditions are developed under which local inverse and implicit functions are lexicographically smooth. These conditions are combined with the results above to describe parametric lexicographic derivatives for certain hybrid discrete/ continuous systems, including some systems whose discrete mode trajectories change when parameters are perturbed. Lastly, to eliminate a particular source of nonsmoothness, a variant of McCormick's convex relaxation scheme is developed and implemented for use in global optimization methods. This variant produces twice-continuously differentiable convex underestimators for composite functions, while retaining the advantageous computational properties of McCormick's original scheme. Gradients are readily computed for these underestimators using automatic differentiation.
by Kamil Ahmad Khan.
Ph. D.
Guinand, Ernique A. (Ernique Alberto) 1970. "Optimization and network sensitivity analysis for process retrofitting." Thesis, Massachusetts Institute of Technology, 2001. http://hdl.handle.net/1721.1/8744.
Full text"February 2001."
Includes bibliographical references.
Retrofitting is the redesign of an operating chemical plant to find new configurations and optimal operating conditions. In the chemical industry, 60% of new capital investments in plants and equipment are retrofitting projects, while only 10% goes to building new plants. Investment in retrofitting amounted to $26 billion in 2000. Despite the importance of retrofitting, there are few methodologies for finding improved economic and environmental performance for continuous processes. This work proposes a systematic framework for the understanding of retrofitting of continuous chemical processes and develops a new methodology to support decision making in solving this problem. Successful retrofitting solutions derive from a balance of operational experience in the plant and the rigor of mathematical analysis. This balance is accomplished by proposing tools and algorithms that in the problem formulation, the analysis of the flowsheet, the synthesis of retrofitting options and the final decision, allow the decision maker to handle the complexity of the problem and focus on the truly critical aspects of the flowsheet. The proposed methodology structures the problem by defining a broad range of retrofitting objectives and alternatives. The initial step is the formulation of retrofitting as an optimization problem. This includes defining retrofitting goals and translating them into objective functions. A parameter optimization of the base case design determines the incentives and constraints for retrofitting. The analysis continues through a network optimization analogy. The representation of the flowsheet as a multicommodity network allows the use of a graph based algorithm to determine the cycles in the process and apply flow decomposition by techniques developed in this study. Flow decomposition determines the path and cycles by which commodities (chemicals) flow through the network. The focus on chemicals and their paths rather than unit operations avoids the distinction of process subsystems providing an integrated view of the flowsheet. The objective function is evaluated in terms of path and cycle flows. Using graphical and mathematical programming (sensitivity analysis) approaches, the synthesis stage identifies retrofitting opportunities that increase the favorable and limit the unfavorable paths and cycles. Once a set of appropriate retrofitting alternatives is identified. the decision stage proceeds through a systematic construction of the superstructure and the corresponding MINLP model. The procedure takes into account the implicit logic of the retrofit alternatives to reduce the space of decision variables. The methodology is completed with a framework to implement the outer approximation algorithm taking into account the characteristics of the retrofitting problem. Case studies illustrate the benefits of the different stages of the proposed retrofitting methodology: efficient solution algorithms, systematic ways to analyze and generate alternative plant configurations and ease in finding optimal designs and investment decisions. The new methodology is compatible with existing flowsheet simulation tools and optimization packages and can easily be applied to a wide range of practical problems.
Ernique A. Guinand.
Ph.D.
Gomez, Jose Alberto Ph D. Massachusetts Institute of Technology. "Simulation, sensitivity analysis, and optimization of bioprocesses using dynamic flux balance analysis." Thesis, Massachusetts Institute of Technology, 2018. http://hdl.handle.net/1721.1/117325.
Full textCataloged from PDF version of thesis.
Includes bibliographical references (pages 301-312).
Microbial communities are a critical component of natural ecosystems and industrial bioprocesses. In natural ecosystems, these communities can present abrupt and surprising responses to perturbations, which can have important consequences. For example, climate change can influence drastically the composition of microbial communities in the oceans, which in turn affects the entirety of the food chain, and changes in diet can affect drastically the composition of the human gut microbiome, making it stronger or more vulnerable to infection by pathogens. In industrial bioprocesses, engineers work with these communities to obtain desirable products such as biofuels, pharmaceuticals, and alcoholic beverages, or to achieve relevant environmental objectives such as wastewater treatment or carbon capture. Mathematical models of microbial communities are critical for the study of natural ecosystems and for the design and control of bioprocesses. Good mathematical models of microbial communities allow scientists to predict how robust an ecosystem is, how perturbed ecosystems can be remediated, how sensitive an ecosystem is with respect to specific perturbations, and in what ways and how fast it would react to environmental changes. Good mathematical models allow engineers to design better bioprocesses and control them to produce high-quality products that meet tight specifications. Despite the importance of microbial communities, mathematical models describing their behavior remain simplistic and only applicable to very simple and controlled bioprocesses. Therefore, the study of natural ecosystems and the design of complex bioprocesses is very challenging. As a result, the design of bioprocesses remains experiment-based, which is slow, expensive, and labor-intensive. With high throughput experiments large datasets are generated, but without reliable mathematical models critical links between the species in the community are often missed. The design of novel bioprocesses rely on informed guesses by scientists that can only be tested experimentally. The expenses incurred by these experiments can be difficult to justify. Predictive mathematical models of microbial communities can provide insights about the possible outcomes of novel bioprocesses and guide the experimental design, resulting in cheaper and faster bioprocess development. Most mathematical models describing microbial communities do not take into account the internal structure of the microorganisms. In recent years, new knowledge of the internal structures of these microorganisms has been generated using highthroughput DNA sequencing. Flux balance analysis (FBA) is a modeling framework that incorporates this new information into mathematical models of microbial communities. With FBA, growth and exchange flux predictions are made by solving linear programs (LPs) that are constructed based on the metabolic networks of the microorganisms. FBA can be combined with the mathematical models of dynamical biosystems, resulting in dynamic FBA (DFBA) models. DFBA models are difficult to simulate, sensitivity information is challenging to obtain, and reliable strategies to solve optimization problems with DFBA models embedded are lacking. Therefore, the use of DFBA models in science and industry remains very limited. This thesis makes DFBA simulation more accessible to scientists and engineers with DFBAlab, a fast, reliable, and efficient Matlab-based DFBA simulator. This simulator is used by more than a 100 academic users to simulate various processes such as chronic wound biofilms, gas fermentation in bubble column bioreactors, and beta-carotene production in microalgae. Also, novel combinations of microbial communities in raceway ponds have been studied. The performance of algal-yeast cocultures and more complex communities for biolipids production has been evaluated, gaining relevant insights that will soon be tested experimentally. These combinations could enable the production of lipids-rich biomass in locations far away from power plants and other concentrated CO 2 sources by utilizing lignocellulosic waste instead. Following reliable DFBA simulation, the mathematical theory required for sensitivity analysis of DFBA models, which happen to be nonsmooth, was developed. Methods to compute generalized derivative information for special compositions of functions, hierarchical LPs, and DFBA models were generated. Significant numerical challenges appeared during the sensitivity computation of DFBA models, some of which were resolved. Despite the challenges, sensitivity information for DFBA models was used to solve for the steady-state of a high-fidelity model of a bubble column bioreactor using nonsmooth equation-solving algorithms. Finally, local optimization strategies for different classes of problems with DFBA models embedded were generated. The classes of problems considered include parameter estimation and optimal batch, continuous steady-state, and continuous cyclic steady-state process design. These strategies were illustrated using toy metabolic networks as well as genome-scale metabolic networks. These optimization problems demonstrate the superior performance of optimizers when reliable sensitivity information is used, as opposed to approximate information obtained from finite differences. Future work includes the development of global optimization strategies, as well as increasing the robustness of the computation of sensitivities of DFBA models. Nevertheless, the application of DFBA models of microbial communities for the study of natural ecosystems and bioprocess design and control is closer to reality.
by Jose Alberto Gomez.
Ph. D.
Gou, Tianyi. "Computational Tools for Chemical Data Assimilation with CMAQ." Thesis, Virginia Tech, 2010. http://hdl.handle.net/10919/31017.
Full textMaster of Science
Wilkins, Anna Katharina. "Sensitivity analysis of oscillating dynamical systems with applications to the mammalian circadian clock." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/42944.
Full textThis electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Includes bibliographical references (p. 227-234).
The work presented in this thesis consists of two major parts. In Chapter 2, the theory for sensitivity analysis of oscillatory systems is developed and discussed. Several contributions are made, in particular in the precise definition of phase sensitivities and in the generalization of the theory to all types of autonomous oscillators. All methods rely on the solution of a boundary value problem, which identifies the periodic orbit. The choice of initial condition on the limit cycle has important consequences for phase sensitivity analysis, and its influence is quantified and discussed in detail. The results are exact and efficient to compute compared to existing partial methods. The theory is then applied to different models of the mammalian circadian clock system in the following chapters. First, different types of sensitivities in a pair of smaller models are analyzed. The models have slightly different architectures, with one having an additional negative feedback loop compared to the other. The differences in their behavior with respect to phases, the period and amplitude are discussed in the context of their network architecture. It is found that, contrary to previous assumptions in the literature, the additional negative feedback loop makes the model less "flexible" in at least one sense that was studied here. The theory was also applied to larger, more detailed models of the mammalian circadian clock, based on the original model of Forger and Peskin. Between the original model's publication in 2003 and the present time, several key advances were made in understanding the mechanistic detail of the mammalian circadian clock, and at least one additional clock gene was identified. These advances are incorporated in an extended model, which is then studied using sensitivity analysis. Period sensitivity analysis is performed first and it was found that only one negative feedback loop dominates the setting of the period.
(cont.) This was an interesting one-to-one correlation between one topological feature of the network and a single metric of network performance. This led to the question of whether the network architecture is modular, in the sense that each of the several feedback loops might be responsible for a separate network function. A function of particular interest is the ability to separately track "dawn" and "dusk", which is reported to be present in the circadian clock. The ability of the mammalian circadian clock to modify different relative phases --defined by different molecular events -- independently of the period was analyzed. If the model can maintain a perceived day -- defined by the time difference between two phases -- of different lengths, it can be argued that the model can track dawn and dusk separately. This capability is found in all mammalian clock models that were studied in this work, and furthermore, that a network-wide effort is needed to do so. Unlike in the case of the period sensitivities, relative phase sensitivities are distributed throughout several feedback loops. Interestingly, a small number of "key parameters" could be identified in the detailed models that consistently play important roles in the setting of period, amplitude and phases. It appears that most circadian clock features are under shared control by local parameters and by the more global "key parameters". Lastly, it is shown that sensitivity analysis, in particular period sensitivity analysis, can be very useful in parameter estimation for oscillatory systems biology models. In an approach termed "feature-based parameter fitting", the model's parameter values are selected based on their impact on the "features" of an oscillation (period, phases, amplitudes) rather than concentration data points. It is discussed how this approach changes the cost function during the parameter estimation optimization, and when it can be beneficial.
(cont.) A minimal model system from circadian biology, the Goodwin oscillator, is taken as an example. Overall, in this thesis it is shown that the contributions made to the theoretical understanding of sensitivities in oscillatory systems are relevant and useful in trying to answer questions that are currently open in circadian biology. In some cases, the theory could indicate exactly which experiments or detailed mechanistic studies are needed in order to perform meaningful mathematical analysis of the system as a whole. It is shown that, provided the biologically relevant quantities are analyzed, a network-wide understanding of the interplay between network function and topology can be gained and differences in performance between models of different size or topology can be quantified.
by Anna Katharina Wilkins.
Ph.D.
Chen, Lu. "Computational Study of Turbulent Combustion Systems and Global Reactor Networks." Diss., Virginia Tech, 2017. http://hdl.handle.net/10919/78804.
Full textPh. D.
Holland, Troy Michael. "A Comprehensive Coal Conversion Model Extended to Oxy-Coal Conditions." BYU ScholarsArchive, 2017. https://scholarsarchive.byu.edu/etd/6525.
Full textGOMES, MARCELO da S. "Determinacao de elementos metalicos em sedimentos da Baia do Almirantado, Ilha Rei George, Penisula Antartica." reponame:Repositório Institucional do IPEN, 1999. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10762.
Full textMade available in DSpace on 2014-10-09T13:58:06Z (GMT). No. of bitstreams: 1 06649.pdf: 21672592 bytes, checksum: ce3be21667c4c3939460ddeff380f31c (MD5)
Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
Poduri, Shripriya Darshini. "THEORETICAL MODELING AND ANALYSIS OF AMMONIA GAS SENSING PROPERTIES OF VERTICALLY ALIGNED MULTIWALLED CARBON NANOTUBE RESISTIVE SENSORS AND ENHANCING THEIR SENSITIVITY." UKnowledge, 2010. http://uknowledge.uky.edu/gradschool_theses/51.
Full textGriffiths, Michael Lee. "Multivariate calibration for ICP-AES." Thesis, University of Plymouth, 2001. http://hdl.handle.net/10026.1/1942.
Full textSingh, Kumaresh. "Efficient Computational Tools for Variational Data Assimilation and Information Content Estimation." Diss., Virginia Tech, 2010. http://hdl.handle.net/10919/39125.
Full textPh. D.
Waddick, Caitlin Janson. "Healthy residential developments: reducing pollutant exposures for vulnerable populations with multiple chemical sensitivities." Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/37270.
Full textAdotey, Bless. "MATHEMATICAL MODELING OF CLOSTRIDIUM THERMOCELLUM’S METABOLIC RESPONSES TO ENVIRONMENTAL PERTURBATION." UKnowledge, 2011. http://uknowledge.uky.edu/bae_etds/1.
Full textGhosh, Saikat. "Model Development and Validation of Pesticide Volatilization from Soil and Crop Surfaces Post Spraying during Agricultural Practices." Ohio University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1588610082125279.
Full textSong, Shin Miin, and shinmiin@singnet com sg. "Comprehensive two-dimensional gas chromatography (GCxGC ) for drug analysis." RMIT University. Applied Sciences, 2006. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20080627.114511.
Full textParrish, Douglas K. "Application of solid phase microextraction with gas chromatography-mass spectrometry as a rapid, reliable, and safe method for field sampling and analysis of chemical warfare agent precursors /." Download the dissertation in PDF, 2005. http://www.lrc.usuhs.mil/dissertations/pdf/Parrish2005.pdf.
Full textХамза, Омар Адел Хамза. "Вибір параметрів силової установки із системою утилізації попутного нафтового газу." Thesis, НТУ "ХПІ", 2017. http://repository.kpi.kharkov.ua/handle/KhPI-Press/29868.
Full textThesis for the degree of candidate of technical sciences by specialty 05.05.03 - engines and power units. - National Technical University "Kharkiv Polytechnic Institute". - Kharkiv, 2017. The thesis is devoted to the choice of the scheme and parameters of the power plant for utilization of associated petroleum gas. The paper analyzes the possibility of using various power plants for utilization of associated petroleum gas. The schemes of power units using gas turbine and gas piston internal combustion engines to generate power electricity have been developed by using associated petroleum gas in oil refinery. The anergy-exergy method was used to analys the effectiveness of the proposed schemes. An economic analysis of the feasibility of constructing power generating capacities that will consume the associated oil gas with an analysis of sensitivity for such parameters as a change in the price of electricity and the impact of high ambient temperatures has been carried out. If the ambient temperature is changed from +15 to + 45 ° C, the amount of energy generated for Project A will be reduced by 26%, for Project B - by 10.9%. It is determined that despite the high cost of Project B ($ 2,843,009.55) against Project A ($ 1964,434.69), the payback period is: for Project A - 6 years, 1 month; For Project B - 3 years, 8 months. The expediency of using the piston-internal ICE as part of the power generating unit is substantiated.
Hamzah, Omar Adel Hamzah. "Parameter selection the powerplant with recovery system Off-gas in the refinery." Thesis, NTU "KhPI", 2017. http://repository.kpi.kharkov.ua/handle/KhPI-Press/29869.
Full textДисертація на здобуття наукового ступеня кандидата технічних наук за спеціальністю 05.05.03 «Двигуни та енергетичні установки» (14 – Електрична інженерія). – Національний технічний університет «Харківський політехнічний інститут», Харків, 2017. Дисертаційна робота присвячена актуальному питанню - вибору схеми та параметрів силової енергетичної установки для утилізації попутного нафтового газу. Проблема спалювання попутних газів постійно підіймається на міжнародних конференціях зі збереження навколишнього середовища які проходять під егідою ООН та Всесвітнього банку. Зокрема, на Всесвітній конференції з клімату в Парижі (COP21) у 2015 році, була висунута та підтримана глобальна ініціатива з викорінення практики спалювання попутного газу в нафтовій промисловості. В усьому світі її підтримали 45 нафтових компаній, урядів та інших сторін завдяки яким викиди CO2 можуть скоротитись на 100 мільйонів тонн на рік. Прийнята програма “Zero Routine Flaring by 2030” передбачає покінчити з практикою спалювання супутнього нафтового газу до 2030 року. Цю ініціативу підтримала і держава Ірак, яка на 2015 рік займала друге місце у світі зі спалювання попутних газів у факелах. Попутний нафтовий газ складає 2% від виходу продуктів нафтопереробного підприємства в Іраку. Враховуючи кількість нафтопереробних підприємств та їх потужності, щоденно, при його спалюванні у факелах, втрачається велика кількість енергії та відбувається значне забруднення навколишньої території не тільки хімічними викидами а і теплотою яка виділяється при згорянні попутного нафтового газу. У роботі використано комплексний підхід до вибору схеми та параметрів силової енергетичної установки для утилізації попутного нафтового газу. Розглянуто можливі варіанти утилізації супутнього нафтового газу. Серед варіантів взято енергетичну установку на базі газотурбінного двигуна та установку на базі газотурбінного двигуна який діє сумісно з поршневим двигуном. Поставлене питання розглянуто з точки зору енерго-ексергетичного балансу установки та отримання найкращих техніко-економічних показників з урахуванням кліматичних особливостей регіону держави Ірак. Розглянуто особливості фізико-хімічного складу супутнього нафтового газу на нафтопереробному заводі держави Ірак, зокрема проведено визначення метанового числа, за методикою фірми Caterpillar. Метанове число газового палива впливає на вибір поршневої енергетичної установки. Значний вплив на вибір схеми установки з утилізації супутнього нафтового газу оказують температурні особливості регіону. Для їх урахування визначено середню температуру для регіону. Проведені теплові розрахунки дозволили проаналізувати вплив температури навколишнього середовища на показники енергетичних установок та провести економічне обґрунтування обрання найкращої схеми установки. Виконання енерго-ексергетичного балансу для запропонованих схем енергогенеруючих установок дозволило підтвердити значне зменшення теплового забруднення навколишнього середовища та вказати на найбільш привабливу з цієї точки зору схему. Економічні розрахунки дозволили визначити термін окупності запропонованих проектів установок та довести економічну доцільність їх побудови. Визначено найбільш економічно привабливий проект. Проведено аналіз економічних ризиків чутливості до зміни ціни електроенергії та до зміни температури навколишнього середовища. Подібні розрахунки аналізу чутливості проведено для заводів з двома енергетичними установками. На основі проведеного аналізу, на замовлення Іракської сторони, було розроблено основу бізнес проекту для енергогенеруючих потужностей на базі енергетичних утилізаційних установок. Виконання результатів дослідження дозволить не тільки отримати необхідну електричну енергію, яку можна використовувати не тільки на підприємстві, а і покращити стан навколишнього середовища у відповідності до міжнародних домовленостей. Результати дисертаційного дослідження будуть використані при будівництві нових енергоблоків на нафтопереробних заводах Іраку згідно листа від Міністерства промисловості і природних ресурсів.
Hanning-Lee, Mark Adrian. "A study of atom and radical kinetics." Thesis, University of Oxford, 1990. http://ora.ox.ac.uk/objects/uuid:89cabe5d-7cc8-43b3-8c2a-686563ff1b3f.
Full textSkinner, Michael A. "Hapsite® gas chromatograph-mass spectrometer (GC/MS) variability assessment /." Download the thesis in PDF, 2005. http://www.lrc.usuhs.mil/dissertations/pdf/Skinner2005.pdf.
Full textSANTOPOLO, LUISA. "Chromate resistance and biofilm development in Pseudomonas alcaliphila 34: molecular bases." Doctoral thesis, 2013. http://hdl.handle.net/2158/803671.
Full textNiranjan, S. C. "Sensitivity analysis of a mechanistic growth model of Escherichia coli." Thesis, 1991. http://hdl.handle.net/1911/16521.
Full textRao, Sirigudi Rahul. "Biomass to ethanol process simulation, validation and sensitivity analysis of a gasifier and a bioreactor /." 2005. http://digital.library.okstate.edu/etd/umi-okstate-1527.pdf.
Full textPavlovich, James Gilbert. "Ion pairing of nucleotides with surfactants for enhanced sensitivity in liquid matrix assisted secondary ion mass spectrometry." Thesis, 1993. http://hdl.handle.net/1957/36760.
Full textGraduation date: 1994
Gower, Stephanie Karen. "A Computer-Based Decision Tool for Prioritizing the Reduction of Airborne Chemical Emissions from Canadian Oil Refineries Using Estimated Health Impacts." Thesis, 2007. http://hdl.handle.net/10012/2758.
Full textMcCanna, David. "Development of Sensitive In Vitro Assays to Assess the Ocular Toxicity Potential of Chemicals and Ophthalmic Products." Thesis, 2009. http://hdl.handle.net/10012/4338.
Full text