Dissertations / Theses on the topic 'CHEMICAL TECHNIQUE'
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Wang, Chuangnan. "Ultrasonic technique for chemical process control." Thesis, University of Strathclyde, 2014. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=24442.
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Ultrasound has found application in chemical processing control using both low power, high frequency monitoring techniques and high power, low frequency process enhancement approaches. In many cases, standard ultrasonic systems are retrofitted to a process and while these produce efficiency improvements, the design of bespoke systems may offer more potential. In particular, this Thesis has considered two techniques used in the biomedical field; harmonic imaging and high intensity focused ultrasound (HIFU) and has translated these into ultrasonic transducers for use in an industrial process control system. Traditional ultrasound monitoring techniques are based on operation in the linear domain and are used to monitor chemical processes by measurement of material acoustic velocity, attenuation or based on spectral analysis. Both active and passive methods have been reported for application in this industrial sector. One issue is the presence of multiple reflections in the received ultrasonic signal which can mask the signals of interest from the load medium. This Thesis has considered a new ultrasonic monitoring approach using a combination of both linear and nonlinear spectral components. This was applied to high-throughput products and a dual frequency transducer designed and fabricated to acquire the ultrasonic backscattered signals in both the fundamental and second harmonic frequency regimes. The additional information provided by the harmonic device enabled discrimination between shampoo and conditioner products with the same density, but different molecular weights. HIFU transducer array designs are then considered for high power, low frequency chemical process enhancement applications. Typical applications of high power ultrasound use single or multiple discrete transducers to insonify a process. These are effective, but inflexible in the delivery of the ultrasonic field. The application of a HIFU array would provide control of the high power focal region in the load medium, which offer advantages to industry. Two transducer array approaches have been considered in this Thesis based on piezoelectric composite configurations. Three HIFU arrays based on the 1-3 piezocomposite have been fabricated to operate between 200-400kHz and fully characterised to evaluate their high power performance. A second transducer configuration was based on a novel 2-2 piezocomposite with a 2 layer stacked configuration. Simulation of this transducer design illustrated its potential for high power applications, although a number of fabrication issues resulted in the manufactured array not operating at full capacity. Importantly, the transducer configurations developed in this Thesis are shown to induce cavitation through the standard aluminium foil test.
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Loehn, Clayton William. "Investigation of the monazite chemical dating technique." Diss., Virginia Tech, 2011. http://hdl.handle.net/10919/27688.
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In order to evaluate the electron microprobe (EMP) method for chemical dating of monazite, we chemically analyzed selected suites of monazite grains that were previously dated by standard U/Pb isotopic methods at three laboratories each equipped with a sensitive high resolution ion microprobe (SHRIMP). Representing diverse igneous and metamorphic lithologies, these grains yielded conventional isotopic ages ranging in age from Neoarchean to Devonian. Chemical dating was performed at Virginia Tech using a Cameca SX-50 EMP in which the analytical routines and settings were specifically optimized for monazite geochronology, including correction of analytical peaks for all major spectral interferences and correction of peak intensities for local background emission. Placement of cross-grain analytical traverses was based on backscattered electron (BSE) images together with wavelength-dispersive (WD) generated X-ray maps for Y, Th, U, and Ca, which revealed the internal compositional complexity of each grain. Shorter EMP traverses were selected adjacent to each SHRIMP pit in order to provide the best possible comparison of ages obtained by the two dating methods. Synthesis protocol for key elemental measurements (Y, Th, U, and Pb) was developed utilizing the 1Ï elemental errors associated with individual analyses, providing an objective approach for data synthesis. Analytical dates were either accepted or excluded based on analytical and spatial justifications. Isotopic dating techniques utilize three independent age calculations, provided the sample is old enough to have accumulated sufficient 207Pb (i.e., â ¥~1000 Ma). Similarly, the chemical dating method can utilize two independent age calculations (i.e., Th/Pb and U/Pb) and a U-Th-Pbtotal centroid age in Th/Pb vs. U/Pb space, verified independently against the calculated Th* or U* CHIME ages. Across the entire 2,200 m.y. age range represented by the sample set, the chemical ages calculated from the EMP data chemical ages are internally consistent (within 2Ï error) with the previously measured SHRIMP isotopic ages, except in one case where bulk mixing of discrete age domains within an ablation pit led to an isotopically discordant apparent age. Overall, this study illustrates that EMP chemical dating (1) represents both an accurate and precise primary method for dating monazite from igneous and polymetamorphic terrains; (2) provides superior spatial resolution for obtaining meaningful ages from small and/or irregular domains of discrete age that may be irresolvable or misinterpreted by other dating techniques that sample larger volumes; and (3) illuminates the geological meaning of isotopically discordant monazite ages obtained using conventional methods with lower spatial resolution (e.g., SHRIMP).Ph. D.
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Hsu, Ching-Ming. "High resolution SIMS analysis using a chemical bevelling technique." Thesis, Imperial College London, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.243823.
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Zenaitis, Michael G. (Michael Guy). "Antibiotic production using the self-cycling fermentation technique." Thesis, McGill University, 1993. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=68061.
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The self-cycling fermentation (SCF) technique was used to grow three species of the genus Streptomyces which have been described as producing antibiotics. Application of this technique led to reproducible growth patterns for filamentous organisms. Control of the system using the CO$ sb2$ concentration in the off-gas was achieved under conditions which prevented monitoring of the dissolved oxygen. It was also possible to use the SCF system with either defined or complex media.Production of tetracycline by S. aureofaciens was obtained on an iron-deficient medium. The production rate was as high as 0.272 g tetracycline/g sucrose/h. This was comparable with that reported for tetracycline in the patent literature. Growth patterns of the SCF when tetracycline was present in the fermenter were erratic, demonstrating the negative effect of the antibiotic on the growth of the producer organism. Further growth in a secondary fermenter system resulted in additional production over a period of about fifteen hours. In these experiments, tetracycline exhibited characteristics of a siderophore.
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Wentworth, Stephen. "Citric acid production using the self-cycling fermentation technique." Thesis, McGill University, 1993. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=68057.
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Self-cycling fermentation is a new technique used to cultivate synchronous populations of cells. This work used the technique in the production of citric acid from a strain of Candida lipolytica. Application of this technique resulted in extremely stable, reproducible patterns of growth and induced a high level of cell synchrony. Synchrony was maintained even throughout long periods of extended nutrient starvation. Thus, self-cycling fermentations can be operated with cycle times significantly longer than the doubling time of the microorganism. Use of this technique led to a full order of magnitude increase in the specific biomass production rate compared to literature values. This biomass was found to be suitable for the production of citric acid in a second stage reactor. Although this preliminary work with the second stage reactor was not optimized, the specific citric acid production rate obtained was comparable to rates found in the literature.
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Truter, Lara. "Development of a zeolite washcoating technique for microchannel reactors." Master's thesis, University of Cape Town, 2011. http://hdl.handle.net/11427/10855.
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Microreactor technology is becoming an increasingly active research field in terms of chemical reaction engineering and process intensification. An important feature of microreactor technology is the requirement of a catalyst layer.
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Vadhwana, V. A. "A model simplification technique for computer flowsheeting." Thesis, London South Bank University, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.382822.
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Arayarat, Pornthip. "Refractory products based on the pore reduced cement technique." Thesis, University of Aberdeen, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.245256.
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The present study was aimed at an investigation of the use of the pore reduced cement (PRC) technique on the fabrication and properties of calcium aluminate-based refractories. Physical and chemical performances were compared with those of conventionally prepared (unpressed) refractory castables. The influence of firing on two types of calcium aluminate cements; (Ciment Fondu and Secar 80), mixed with aggregates such as firebrick and alpha-alumina, were observed. Most of the pressed samples based on Ciment Fondu cracked and melted during firing to 1250oC. Pressed samples based on Secar 80, however, tended to crack less with increased tabular alumina content. An appropriate weight proportion of tabular alumina and Secar 80 was found to be 70 to 30. The physical properties of Secar 80 blended with (i) tabular aluminas (20-μm and 250-μm) only and (ii) round (RMA325) and 250-μm tabular alumina were investigated before and after firing to 1350oC. Pressed tabular alumina mixes containing various percentages of aggregate showed very little change in bulk density (3000 kg/m3) and flexural strength (23 MPa), but after firing, flexural strengths increased considerably as the fine tabular alumina content increased (up to 50 MPa). Microstructural evidence indicated that the interlocking structure occurring from the crystallisation of hexagonal plates of calcium hexaluminate including partial sintering of fine alumina grains could be the origin of the increased strength on firing. Although unpressed samples show similar structures, they are more porous. On firing, unpressed samples tended to expand (0.43 to 0.64%) less than pressed samples (1.32 to 1.71%) because the phase transformation from CA2 to CA6 occurred which in pressed samples leads to expansion whereas in unpressed products, expansion is accommodated within available porosity. Abrasion resistance increases as strength increases. Fracture toughness increases with the coarse tabular alumina content increases. Similar improvements in bulk density and flexural strength are observed when round alumina (~ 44μm) and tabular alumina (250-μm) are blended. The thermal shock resistance of pressed samples was also found to be better than for unpressed samples as shown by the higher relative strength after the test. The chemical durability of unpressed and pressed samples based on the slag test was investigated. Pressed samples resist slag penetration better than the unpressed samples because of the smaller pores and reduced pores connectivity. Otherwise, chemical interaction between cement and slag was similar. In conclusion, refractory products based on the PRC technique have shown considerable improvements in both physical and chemical performance, especially green strengths which are substantially higher than for conventional castables, making them less susceptible to handling damage prior to service, i.e. during transport and installation.
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Wener, Evan. "The biomechanics of ascending aortic aneurysms: The effect of measurement technique." Thesis, McGill University, 2013. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=117062.
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An ascending aortic aneurysm is a pathologic enlargement of the ascending portion of the aorta. Comorbidities of dilation include aortic valve disease and connective tissue disorders. If the ascending aorta exceeds a threshold diameter, open heart surgery is recommended. This is a traumatic procedure and the recovery is demanding. As our population ages and with improved technologies to diagnose the disease, the number of cases will increase every year. Understanding the mechanics of ascending aortic tissue will help cardiac surgeons make timely decisions on when to intervene. There are many ways to characterize the mechanical properties of aortic tissue. In this study, we used biaxial and uniaxial tensile testing with an optical tracking system to record the Green-Lagrangian (Green strain) strain. Engineering and true stiffness values were calculated and compared along with patient characteristics. Aortas were classified by valve type as healthy, tricuspid, bicuspid type 1 and bicuspid type 2. The results show that diseased tissue does behave differently than healthy tissue indicating that a local remodeling does occurs to the aortic wall. There are also differences in the mechanics between the types of diseased valves suggesting that valve type also affects the way the aortic wall responds to the disturbed hemodynamic environment. Correlations between stiffness and patient characteristics show that no matter which experimented technique or method of stiffness calculation is used, relationships are generally conserved. The only difference is the magnitude of the elastic modulus. The conclusions drawn from the data would not change whether biaxial or uniaxial experiments were performed. However when comparing engineering and true stiffness, only 7/12 covariances were similar and therefore the conclusions are inconsistent.Un anévrisme de l'aorte ascendante est un agrandissement pathologique de l'aorte ascendante. Les comorbidités de dilatation incluent les maladies de la valve aortique et du tissu conjonctif. Si l'aorte ascendante dépasse un diamètre seuil, la chirurgie à cœur ouvert est recommandée. Il s'agit d'une procédure traumatique et la récupération est exigeante. Comme notre population vieillit et que les technologies pour diagnostiquer la maladie se sont beaucoup améliorées, le nombre de cas décelé va augmenter chaque année. Comprendre les mécanismes du tissu aortique ascendant aidera les chirurgiens cardiaques à prendre les bonnes décisions au bon moment. Il y a plusieurs façons de caractériser les propriétés mécaniques du tissu aortique. Dans cette étude, nous avons utilisé les essais de traction biaxiale et uniaxiale avec un système de suivi optique pour enregistrer la souche Green-Lagrange (souche verte). Valeurs de rigidité d'ingénierie et de vrai ont été calculées et comparées avec les caractéristiques des patients. Les aortes ont été classées en 4 types de valves : bonne santé, tricuspides, bicuspides de type 1 et bicuspides de type 2. Les résultats montrent que les tissus malades sont différents des tissus en bonne santé qui indiquent qu'un remodelage local se produit sur la paroi aortique. Il existe aussi des différences dans le mécanisme des différents types de valvules qui suggèrent que le type de valve affecte également la façon dont la paroi aortique répond à l'environnement perturbé hémodynamique. Les corrélations entre les caractéristiques de rigidité et le patient nous montrent que quelque-soit la technique ou la méthode de calcul utilisée pour la rigidité, les relations sont généralement conservées. La seule différence est la grandeur du module d'élasticité. Les conclusions tirées de ces données ne changeraient pas, peu importe le type d'expérimentation effectué; biaxiale ou uniaxiale. Cependant, lorsque l'on compare la rigidité d'ingénierie et de vrai, seulement 7 covariances sur 12 sont similaires et les conclusions sont contradictoires.
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Tontiwachwuthikul, Paitoon. "New pilot plant technique for designing gas absorbers with chemical reactions." Thesis, University of British Columbia, 1990. http://hdl.handle.net/2429/32182.
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Gas absorption with chemical reaction is an important unit operation in the chemical and petroleum industries for the selective removal of components from industrial gas streams. Apart from choosing absorption media, the most difficult problems facing the design engineer are the sizing and performance prediction of the absorption tower due to the scarcity of fundamental design data, especially when novel absorption media and/or packings are used.
The solubility of carbon dioxide in 2 and 3 M solutions of 2-amino-2-methyl-1-propanol (AMP), which is a newly introduced absorbent, was determined at 20, 40, 60 and 80 °C and for CO₂ partial pressures ranging from approximately 1 to 100 kPa. The results were interpreted with a modified Kent-Eisenberg model which predicted the present and previous experimental results well. The absorption capacities of AMP and monoethanolamine (MEA) solutions were also compared.
Detailed concentration and temperature measurements were reported for the absorption of carbon dioxide from air into NaOH, MEA and AMP solutions. A full-length absorber (0.1 m ID, packed with 12.7 mm Berl Saddles up to heights of 6.55 m) was used. It was operated in countercurrent mode and at 30 to 75 % flooding velocities which are typical for gas
absorber operations. The following ranges of operating conditions were employed: superficial gas flow rate 11.1 to 14.8 mol/m² s; superficial liquid flow rate 9.5 to 13.5 m³/m² h; feed CO₂ concentration 11.5 to 19.8 %; total absorbent concentration 1.2 to 3.8 kmol/m³; liquid feed temperature 14 to 20 °C; total pressure 103 kPa. The measurements for the CO₂-NaOH and CO₂-MEA systems were compared with predictions from a previously developed mathematical model. Generally good agreement was obtained except at high CO₂ loadings of MEA solutions. Compared with MEA, AMP was found to have superior CO₂ absorption capacities and inferior mass transfer rates.
A new procedure, called the Pilot Plant Technique (PPT), for designing gas absorbers with chemical reactions has been developed. The PPT is primarily intended for designing absorbers for which fundamental design information is lacking. It is based on the premise that full-length absorption columns can be sized by making a minimum number of tests using a small-scale pilot plant. Two special features of the PPT are (i) the details of hydrodynamic parameters (i.e. mass transfer coefficients, effective interfacial area and liquid hold-up) and the physico-chemical information of the system (e.g. reaction mechanism, reaction rate constants) need not be known and (ii) complex calculations are avoided.
Using the PPT to size the height or to predict the performance of a given full-length absorber, the specific absorption rate, which is the essential information, can be measured directly using the pilot plant model (PPM) column if both columns have the same hydrodynamic conditions. This can be achieved by using the same type and size of packing in the PPM and the full-length columns and ensuring that the end and wall effects are negligible. The PPM column must also be operated at the same superficial fluid velocities as those of the full-length column. The specific absorption rate was then obtained from the gradient of the fluid composition profile along the PPM column. The validity of the PPT was demonstrated by determining the height and predicting the performance of the full-length column in which carbon dioxide was absorbed from air by aqueous solutions of NaOH and AMP at various operating conditions; good agreement was obtained.Applied Science, Faculty of
Chemical and Biological Engineering, Department of
Graduate
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Schueler, Robert M. "Terahertz Spectroscopic Breath Analysis as a Viable Analytical Chemical Sensing Technique." Wright State University / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=wright1464170300.
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Gifford, James Hart. "Optimization of the automated spray layer-by-layer technique for thin film deposition." Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/59883.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 2010.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 82-83).
The operational parameters of the automated Spray-LbL technique for thin film deposition have been investigated in order to-identify their effects on film thickness and roughness. We use the automated Spray-LbL system developed at MIT by the Hammond lab to build 25 bilayer films of poly (ally amine hydrochloride) (PAH) and poly (acrylic acid) (PAA). Each of the 10 operational parameters of this system are explored individually to isolate each parameter's effect on film thickness and roughness. The parameter effects are analyzed for apparent trends to determine the parameters best suited for adjusting film thickness and roughness. The optimal parameters for thickness adjustment are polyelectrolyte solution concentration, polyelectrolyte spray time, spraying distance, air pressure and polyelectrolyte charge density. These parameters are independent of the type of species used to construct the film, and thus the trends should apply to any species used to construct thin films. The effect of each of the 10 operational parameters is examined in detail. While researching the parameter effects, polyelectrolyte interdiffusion in the films was observed. This interdiffusion is investigated using both the conventional dipped LbL and Spray-LbL deposition techniques. Interdiffusion is shown to be dependent on 3 factors, the charge density of the polyelectrolytes, the molecular weight of the polyelectrolytes, and the contact time between the polyelectrolyte solutions and the surface of the film. Interdiffusion is observed when the PAH is partially charged, the polyelectrolytes chains have a low molecular weight, and the contact time is sufficiently long enough to allow for interdiffusion. The significantly reduced contact time during the automated Spray-LbL process not only speeds up the film deposition time, but also significantly hinders the interdiffusion of PAH resulting in much thinner films than what is possible from dipping. Finally, the uniformity of the films produced using the automated Spray-LbL system is investigated. Films deposited on substrates greater than 1 in diameter area exhibit more than 20% variance in thickness. Adjustments were made to the setup of the system in an effort to expand this area of film thickness uniformity. However, it is determined that the design of this automated Spray-LbL system limits the film uniformity to an area of 1 in diameter.
by James Hart Gifford.
S.M.
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Бересток, Таїсія Олександрівна, Таисия Александровна Бересток, Taisiia Oleksandrivna Berestok, Денис Ігорович Курбатов, Денис Игоревич Курбатов, Denys Ihorovych Kurbatov, Надія Миколаївна Опанасюк, et al. "Structural Properties of ZnO Thin Films Obtained by Chemical Bath Deposition Technique." Thesis, Sumy State University, 2012. http://essuir.sumdu.edu.ua/handle/123456789/35076.
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Zinc oxide thin films have been deposited onto glass substrate from zinc sulfate, ammonia and thiourea
aqueous solution by chemical bath deposition. In the work this were specified solution preparation procedure
and optimized the composition of the solution and content of component in it. X-ray difraction and
high-resolution scanning electron microscopy were used to characterize structure formation of obtaining
ZnO films. As a result of investigation was determined the effect of time deposition on the structural and
substructural properties such as lattice parameters, texture quality, coherent scattering domain size.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/35076
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Liu, Cong. "New technique for radiolabelling tracer with 64CU for positron emission particles tracking (PEPT) experiments." Master's thesis, University of Cape Town, 2015. http://hdl.handle.net/11427/13709.
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Positron emission particle tracking (PEPT) is a non-invasive technique for studying the flow of particulate systems within industrial equipment. The technique tracks a tracer particle labelled with a positron emitting radionuclide moving within the field-of-view of a positron emission tomography (PET) scanner. Two important components of the technique are a PET camera and PEPT tracers, which are particle tracers labelled with a positron emitting radionuclide. Currently, the majority of PEPT tracers are made with 68Ga or 18F. However, the relatively short half-life of these two radionuclides limits the application of PEPT to a maximum of 3 hours of experimental time. 64Cu is a potential candidate for PEPT tracer fabrication due to its relatively long half-life (12.7 h) which could extend the experimental running time of PEPT experiments to two uninterrupted days. The objective of the research described in this thesis was to develop a technique for radiolabelling tracers with 64Cu, and to test their efficacy in PEPT experiment. The work was conducted at Radionuclide Production Department, iThemba LABS near Cape Town, where high purity 64Cu was obtained by a two stages separation method using ion exchange chromatography.
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Sidwall, Shaun. "The industrial application of a multiple technique paper dryer simulation /." Thesis, McGill University, 1999. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=21325.
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Drying Doctor, a multiple technique simulator of the paper drying process, has been developed at the Pulp and Paper Research Centre, McGill University. This thesis examines the different approaches to the modeling of this process, provides a rigorous validation of the simulation program and demonstrates its utility with four containerboard machines of Norampac Inc.Several features differentiate this simulator from others. When heavy grades of paper are produced or when high intensity drying processes are used even with thin sheets, substantial thickness direction gradients of moisture content and temperature develop across the sheet, demonstrating the necessity of a fully microscale model such as employed by Drying Doctor.
Using industrial and laboratory data for a variety of paper grades and drying processes, 31 uncalibrated simulations for machine speed showed a standard deviation of only 3.4% from known speeds. Through simulation of modified operating conditions such as steam pressure, spoiler bars, pocket air conditions and addition of the high intensity drying process, Yankee air impingement dryers, substantial production rate increases for the industrial partner's papermachines through use of the Drying Doctor simulator were shown possible.
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Brown, Frank Reber. "Analytical applications of flow injection analysis." Diss., The University of Arizona, 1987. http://hdl.handle.net/10150/184254.
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The rate of oxidation of copper metal to copper (I) by copper (II) in the presence of organic ligands has been determined for a variety of ligands using a flow injection analysis system to sample the reaction. The results obtained using the FIA sampling method compare favorably with those obtained in eariler work when allyl alcohol was used as the ligand. The mechanism proposed in that earlier work has been shown to be a general mechanism for the oxidation of copper metal in the presence of complexing ligands. It was found that some ligands increase the rate of the reaction beyond the ability of conventional FIA to sample many data points before the reaction reaches equilibrium. A method has been developed that allows for more rapid sampling of the reaction mixture by the FIA system, resulting in overlapping FIA peaks. These overlapping peaks can then be deconvolved by an iterative curve fitting/digital subtraction technique in which each peak in the FIA output is fitted to a model function and subtracted from the output, thus removing its effect on the peak height of subsequent peaks. The iodination of acetylacetone in acidic solution was also studied by the fast injection FIA technique. Iodine was generated coulometrically in the solution containing acetylacetone and hydrochloric acid. By this method, the keto-enol equilibrium constant of acetylacetone was determined over a range of pH's. They ranged from 2.3 x 10⁻⁵ at a pH of 2.63 to 1.8 x 10⁻⁴ at a pH of 4.03. It was also found that the reaction was first order with respect to the acetylacetone concentration.
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Grobler, Thelma. "Two-dimensional gas chromatography : a novel technique for iron low temperature Fischer-Tropsch selectivity studies." Master's thesis, University of Cape Town, 2008. http://hdl.handle.net/11427/5327.
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Includes abstract.Includes bibliographical references (leaves 158-178).
Fischer-Tropsch synthesis is a process that catalytically converts hydrogen and carbon monoxide into a large variety of hydrocarbons and oxygenated products. Over the years many researchers have attempted to describe the full product spectrum (ranging from C1 to C100+) but due to the complexity of the product and shortcomings of certain analytical techniques (or equipment) most researchers were only able to construct product distributions from extrapolations of data recorded from analysis of the C1 to C5 fraction of the Fischer-Tropsch product. With recent advances in analytical technology and the development of comprehensive two-dimensional gas chromatography (GCxGC) it may now be possible to analyze the complex Fischer-Tropsch products in a relatively short time while delivering good separation of even minor compounds such as oxygenates and branched compounds. The aim of this study was to investigate if two-dimensional gas chromatography (GCxGC) really results in improved separation and identification of compounds in the complex Fischer-Tropsch product spectrum and will lead to a more complete product distribution especially of the minor compounds such as branched hydrocarbons, ketones, aldehydes and acids. For this study GCxGC equipment, supplied by Zoex Corporation, was connected to a micro slurry phase reactor system to provide for both on-line gas analysis as well as off-line product analysis. GCxGC methods were developed to analyze the hot tail gas and oil products from Fischer-Tropsch synthesis. Thereafter a test sample (C6 to C30 oil product from Fischer- Tropsch synthesis process) was injected several times into both the GCxGC and 1D GC systems. The purpose of this was to compare the detection ability and accuracy of the two instruments.
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Halsall-Whitney, Hayley. "The development and application of a multi-objective optimization technique for chemical processes and controller design." Thesis, University of Ottawa (Canada), 2004. http://hdl.handle.net/10393/26649.
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In recent years, the development and application of multi-objective optimization techniques have received increasing attention in the literature. Recent innovations in the fields of systems science, artificial intelligence, and operations research have led to the development of rigorous multi-objective optimization techniques to address the problem of optimizing complex processes in the presence of multiple conflicting objectives.
This thesis is a collection of three papers that focuses on the development and application of a multi-objective optimization strategy for selecting optimum operating conditions for the production of gluconic acid and for determining optimum tuning parameters for PID controllers. The optimization strategy developed is performed in two steps: the approximation of the set of feasible solutions called the Pareto domain using the Dual Population Evolutionary Algorithm and the classification of the domain using the Net Flow Method, which incorporates information on the process provided by an expert. This strategy has been proven to be robust in determining the optimal solution after studying twelve standard test cases, which have been used frequently in the literature, and two engineering problems. In addition, the Pareto domain per se provides very useful information on the quality of the optimal zone.
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Matthew, Brendan Mason. "Chemical probe technique for the detection of oxidized halogen species in aqueous solution /." For electronic version search Digital dissertations database. Restricted to UC campuses. Access is free to UC campus dissertations, 2002. http://uclibs.org/PID/11984.
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Naidoo, Qiling Ying. "Multicomponent catalysts for methanol electro-oxidation processes synthesized using organometallic chemical vapourde position technique." Thesis, University of the Western Cape, 2011. http://etd.uwc.ac.za/index.php?module=etd&action=viewtitle&id=gen8Srv25Nme4_7491_1320654024.
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In this study, the OMCVD method is demonstrated as a powerful, fast, economic and environmental friendly method to produce a set of PGMelectrocatalysts with different supports, metal content and metal alloys in one step and without the multiple processing stages of impregnation, washing, drying, calcinationsand activation.
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Vuppu, Anil Kumar. "Study of carbon dioxide corrosion of carbon steel pipes in multiphase systems." Ohio : Ohio University, 1994. http://www.ohiolink.edu/etd/view.cgi?ohiou1179862088.
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Horne, Abigail M. "Development of a non-destructive fluorescence technique for analysis of contact lens deposition levels." Thesis, Aston University, 1994. http://publications.aston.ac.uk/9687/.
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The primary objective of this research has been to determine the potential of fluorescence spectroscopy as a method for analysis of surface deposition on contact lenses. In order to achieve this it was first necessary to ascertain whether fluorescence analysis would be able to detect and distinguish between protein and lipid deposited on a lens surface. In conjunction with this it was important to determine the specific excitation wavelengths at which these deposited species were detected with the greatest sensitivity. Experimental observations showed that an excitation wavelength of 360nm would detect lipid deposited on a lens surface, and an excitation wavelength of 280nm would detect and distinguish between protein and lipid deposited on a contact lens. It was also very important to determine whether clean unspoilt lenses showed significant levels of fluorescence themselves. Fluorescence spectra recorded from a variety of unworn contact lenses at excitation wavelengths of 360nm and 280nm indicated that most contact lens materials do not fluoresce themselves to any great extent. Following these initial experiments various clinically and laboratory based studies were performed using fluorescence spectroscopy as a method of analysing contact lens deposition levels. The clinically based studies enabled analysis of contact lenses with known wear backgrounds to be rapidly and individually analysed following discontinuation of wear. Deposition levels in the early stages of lens wear were determined for various lens materials.
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DINI, FRANCESCA. "Chemical sensors based on image detectors." Doctoral thesis, Università degli Studi di Roma "Tor Vergata", 2010. http://hdl.handle.net/2108/1242.
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I sistemi olfattivi artificiali, in analogia con l’olfatto biologico, sono costituiti da array di sensori chimici parzialmente selettivi. Tuttavia, alcune importanti caratteristiche dei sistemi olfattivi biologici, come l’elevato numero di recettori, la convergenza dei neuroni nei glomeruli ed il ruolo attivo della mucosa devono ancora essere implementati i sistemi artificiali per incrementarne le similitudini.
Una tecniche di trasduzione semplice e diretta per sensori chimici è basata sulla modifica delle proprietà ottiche come l’assorbanza e la luminescenza. Tra i vari dispositivi disponibili per la misura di tali proprietà, la tecnica CSPT (Computer Screen Photo-assisted Technique), basata su un sensore di immagine, permette la misura simultanea delle proprietà ottiche di un enorme numero di sensori. Il CSPT fornisce un metodo per lo sviluppo di sistemi sensoriali per i quali la similitudine tra natura e tecnologia può essere potenziata.
In questa tesi sono state proposte alcune strategie innovative per la realizzazione del materiale sensibile per sensori ottici, con lo scopo di migliorarne le prestazioni nella rilevazione dei composti volatili. Usualmente, il film sensibile è costituito da molecole otticamente sensibili, le quali modificano il proprio spettro di assorbimento in risposta all’interazione con gli analiti, e da una matrice polimerica inerte e gas-permeabile che favorisce l’esposizione delle molecole sensibili ai vapori. Nel corso di questa tesi, l’attenzione si è rivolta ad entrambi i componenti del film sensibile, con lo scopo di controllare e migliorare proprietà quali la sensibilità e la selettività.
Per agire sul primo aspetto, le molecole sensibili, è stato proposto l’uso di aggregati di molecole in materiale nano-strutturato per incrementare le prestazioni. E’ stato dimostrato che nano-aggregati di porfirine di forma tubulare conferiscono un’aumentata sensibilità al film sensibile rispetto ai singoli costituenti. Per quanto riguarda il secondo aspetto, la matrice polimerica, è stato dapprima studiato l’effetto di differenti polimeri nei quali è stato disperso un unico indicatore colorimetrico. Si è dimostrato che un array di diversi polimeri può essere utilizzato per discriminare tra vari composti volatili grazie al differente partizionamento che contribuisce alla discriminazione degli analiti. Anche la diffusione del gas attraverso una fase polimerica è cruciale nelle tecniche di chimica analitica, così come nella mucosa dell’epitelio olfattivo biologico. Pertanto, si è studiata la diffusione di diversi gas e vapori attraverso uno strato uniforme di polimero funzionalizzato con una singola porfirina. In tal modo è stato possibile separare e discriminare i composti volatili, introducendo le proprietà della mucosa biologica in un sistema olfattivo artificiale. È auspicabile che tale approccio “bio-mimetico” possa essere introdotto nello sviluppo di nuovi sensori chimici. Infine, tali osservazioni sperimentali sono state combinate per sviluppare una piattaforma di olfatto artificiale caratterizzata da ulteriori proprietà dell’olfatto biologico, tra cui l’elevato numero di recettori, la convergenza nello strato glomerulare e l’insorgere di pattern spazio-temporali nella risposta dei sensori.Artificial sensor systems, similarly to biological olfaction, are conceived as arrays of partially selective chemical sensors. Significant issues of natural olfaction such as the large number of olfactory neurons, the convergence of receptors on a glomerular layer, and the active role of the olfactory mucosa still needs to be implemented to further increase the similitude between natural and artificial systems. Straightforward techniques for chemical sensing are those based on the modification of optical properties such as absorbance and luminescence. Among the devices available to measure the optical features, the Computer Screen Photo-Assisted Technique (CSPT), being based on an image detector, allows the simultaneous measurement of optical properties of large ensembles of individual sensors. The CSPT provides a tool to develop sensing systems where the resemblance between nature and technology may be enhanced. In this thesis novel strategies for the design of sensing materials for optical sensors are proposed to improve the detection capabilities of image sensors. A sensing layer usually consists of an optically responsive molecule, that changes its absorption spectrum in response to analytes, and an inert and gas permeable polymeric support that allows a more efficient exposure of the sensing molecule to vapours. Herein, the attention was focused on both the standard components of a sensing layer with the aim to control features such as sensitivity and selectivity. On the one hand, nano-structured arrangements were investigated to enhance the performances of sensing molecules. A tubular self assembled formation of two different porphyrins was demonstrated to produce an enhancement of performances with respect to the individual units. On the other hand, the effect of matrices made of different polymers to disperse a single indicator was investigated. An array of several polymers containing the same dye was demonstrated to discriminate among a variety of vapours, revealing that the different partitioning of polymers contributes to the analytes recognition. Also the behaviour of gas through a polymeric phase is a fundamental pillar in analytical chemistry, as well as in the biological olfactory mucosa. The diffusion of vapours in uniformly distributed layers of porphyrin-functionalized polymers was studied. This platform is able to separate and detect volatile compounds introducing the olfactory mucosa properties in an artificial sensor system. This bio-mimetic approach is then wished to prompt the development of novel principles to be incorporated in optical sensors. All these findings were combined in order to design an artificial olfaction platform characterized by further biological olfaction features such as a large number of receptors, the convergence into a glomerular layer and the emergence of a spatio-temporal response patterns.
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Raman, Vijay Immanuel Palmese Giuseppe R. "Design of nanoporous polymer networks using a reactive encapsulation of solvent (RES) technique /." Philadelphia, Pa. : Drexel University, 2005. http://dspace.library.drexel.edu/handle/1860/554.
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Hope, Campbell Bruce. "The development of a water soluble photochromic dye tracing technique and its application to horizontal two-phase flows." Thesis, Imperial College London, 1990. http://hdl.handle.net/10044/1/7502.
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Paramguru, Kamrakali. "Growth of carbon nanotubes on anodized titanium oxide templates by catalytic chemical vapor deposition technique." abstract and full text PDF (free order & download UNR users only), 2005. http://0-gateway.proquest.com.innopac.library.unr.edu/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1433346.
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Ingersoll, Justin E. "A regularization technique for the analysis of photographic data used in chemical release wind measurements." Connect to this title online, 2008. http://etd.lib.clemson.edu/documents/1219854940/.
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Heeb, Thomas Gregory. "Examination of turbulent mixing with multiple second order chemical reactions by the statistical analysis technique /." The Ohio State University, 1986. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487267024995615.
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Baker, Matthew J. "CFD simulation of flow through packed beds using the finite volume technique." Thesis, University of Exeter, 2011. http://hdl.handle.net/10036/3396.
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When a disordered packed bed, or any heterogeneous media is studied using computational fluid dynamics, the tortuous task of generating a domain and creating a workable mesh presents a challenging issue to Engineers and Scientists. In this Thesis these challenges are addressed in the form of three studies in which both traditional and novel techniques are used to generate packed beds of spheres and cylinders for analysis using computational fluid dynamics, more specifically, the finite volume method. The first study uses a Monte-Carlo method to generate random particle locations for use with a traditional CADbased meshing approach. Computational studies are performed and compared in detail with experimental equivalent beds. In the second study, where there is a need for actual, physical beds to be studied, magnetic-resonance-imaging is used coupled with a novel approach known as image based meshing. In parallel experimental studies are performed on the experimental bed and compared with computational data. In the third study, to overcome fidelity issues with the previous approaches, a physical packed bed is manufactured which is 100% geometrically faithful to its computational counterpart to provide a direct comparison. All three computational studies have shown promising results in comparison with the experimental data described in this Thesis, with the data of Reichelt (1972) and the semi-empirical correlation of Eisfeld & Schnitzlein (2001). All experiments and computational models were carried out by the author unless otherwise stated.
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Meysami, Seyyed Shayan. "Development of an aerosol-CVD technique for the production of CNTs with integrated online control." Thesis, University of Oxford, 2013. http://ora.ox.ac.uk/objects/uuid:73ccdd97-2325-4ff0-84dc-6abe0a2e4288.
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This dissertation summarises the study of different aspects of the aerosol-assisted chemical vapour deposition (AACVD) technique for the production of multi-wall carbon nanotubes (MWCNTs). Upscaling the synthesis while retaining the quality of MWCNTs has been a prime objective throughout the work. A key aspect of this work was the study of different growth parameters and their influence on the homogeneity of the products across the reactor. The effect of the precursor composition on the yield and quality of MWCNTs were also investigated. It was shown that the synthesis rate can be significantly (60 – 80 %) increased by tuning the composition of the precursor. Moreover, by optimising the synthesis recipe and using a larger reactor, the synthesis rate and efficiency of the precursor were increased fivefold (up to 14 g/hr) and twice (up to 88 %) respectively. Large area (up to 90 cm2), mm-thick carpets of MWCNTs which were both free-standing and on substrate were produced. The carpets could withstand normal handlings without tearing apart, making them suitable for macroscopic characterisations and applications. By in-situ qualitative and quantitative gas analysis of the atmosphere of the reactor, the thermocatalytic cracking behaviour of 25 precursors was investigated and a mechanism for successive formation of different hydrocarbon fragments inside the reactor was proposed. A number of dedicated gas analysis methods and apparatuses such as a probe for zone-by-zone gas analysis of reactor and a heated chamber for preparation of standard gas analysis samples were developed to explore some of the least investigated aspects of the thermocatalytic cracking of precursors. Mapping the reactor revealed that some single-wall and double-wall carbon nanotubes (SWCNTs and DWCNTs) were also produced near the exhaust of the reactor. The SWCNTs were partly covered by fullerene-like species and resembled different forms of carbon nanobuds. In addition, the effect of the electron beam on the interaction of the SWCNTs and the fullerene-like species was studied in situ using high-resolution transmission electron microscopy (HRTEM).
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Vakos, Helen T. "Applications of the in vacuo chemical modification technique to the study of protein structure and function." Thesis, University of Ottawa (Canada), 2001. http://hdl.handle.net/10393/6179.
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Sensitive NMR methods have been developed for analyzing N- and C-termini in protein structure for investigating protein purity, identity, and homogeneity. The in vacuo chemical modification procedure allows for the incorporation of isotopically labeled reagents (13C, 14C, 2H, 3H) into protein with a high degree of reaction specificity in a cost-effective manner, since there is no competing reaction with water and only microlitre quantities are required to derivatize milligram quantities of lyophilized protein. Reaction in vacuo at 75°C with 13C-iodomethane results in the preferential 13C-trimethylation of alpha-amino groups in proteins lyophilized from aqueous solutions at pH (LpH) 6 to 7. In vacuo trimethylation of alpha-amino groups and analysis by 13C-NMR spectroscopy provides a new approach for determining the number and types of N-terminal amino acid residues and for verifying the presence of a free or blocked amino-terminus in a protein preparation. Reaction of lyophilized proteins in vacuo at 75°C with 13C-iodomethane at LpH values between 3 and 4 effects the preferential esterification of carboxyl groups, and is in accord with the pH memory effect. The extent of reaction increases with an increase in amount of deprotonated carboxyl groups at higher LpH values, but trimethylation of amino groups is the predominant reaction at LpH values greater than 4 or 5. In contrast, the novel in vacuo esterification reaction (75°C) of lyophilized proteins (LpH 3) with gaseous 13C-methanol/HCl or 13C-ethanol/HCl results in the exclusive, rapid, and extensive formation of alpha-, gamma- and delta-carboxyl 13C-methyl or 13C-ethyl ester derivatives with no protein degradation, which could be distinguished by the distinct chemical shifts of their resonances. Reaction in vacuo with 14C- or 3H-enriched iodomethane results in a higher incorporation of specific radioactivity into lyophilized proteins than can be achieved in aqueous environments. The chemical tag can serve as a probe of structure and function in tracer studies for proteins that are not enzymes. Trace-radiolabeled proteins (e.g., 14C-methylated Bacillus thuringiensis (Bt) insecticidal toxin, 14C-methylated insulin) show a high specific activity, and retain bioactivity (e.g., 14C-methylated Bt toxin). In a separate study, pure bovine and porcine cholesterol esterase (CE) and human milk bile salt-activated lipase are obtained using a cholate-derivatized affinity column and a taurocholate concentration gradient in the eluent, which is critical to the success of the method. Taurocholate induces dimerization of bovine CE in SIDS as observed by SDS-PAGE. Studies of the bile salt-modulated stereoselectivity of CE-catalyzed hydrolysis of alpha-tocopheryl acetates show that, in competitive experiments, the diastereoselectivity of CE depends on the bile salt used, which is relevant if the bile salt-modulated effect on CE-catalyzed reactions is to be exploited in organic syntheses. (Abstract shortened by UMI.)
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Holavanhalli, Jayatirtha. "Growth and characterization of ZnSe on GaAs and Si substrates using organic chemical vapour deposition technique." Thesis, McGill University, 1989. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=55608.
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Noor, Samsul Bahari Mohd. "Development of an optimal adaptive control technique for distillation and chemical processes based on analytical models." Thesis, University of Sheffield, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.267118.
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Amoah, Enoch. "Modification of Chemical Vapor-Deposited Carbon Electrodes with Electrocatalytic Metal Nanoparticles through a Soft Nitriding Technique." Digital Commons @ East Tennessee State University, 2019. https://dc.etsu.edu/etd/3616.
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Metal nanoparticles have been widely used for many catalytic and electrocatalytic applications due to their larger surface area-to-volume ratios and higher densities of active sites compared to bulk materials. This has resulted in much interest in understanding the electrocatalytic behavior of metal nanoparticles with respect to their structure. However, most research on this topic has employed collections of nanoparticles. Due to difficulties in controlling and characterizing particle loading and interparticle distance in nanoparticle ensembles, single nanoparticles studies have recently become a topic of great interest. In this study, a soft nitriding technique was applied to chemical vapor-deposited carbon ultramicroelectrodes (UMEs) in order to immobilize ligand-free AuNPs onto the carbon substrate. The feasibility of this method is geared toward studying the properties of single AuNPs immobilized onto carbon nanoelectrodes. The ligand-free AuNPs immobilized onto the nitrided carbon UMEs were highly electrocatalytic toward methanol oxidation.
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Dalgic, Meric. "Solutions Of The Equations Of Change By The Averaging Technique." Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/12609525/index.pdf.
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Area averaging is one of the techniques used to solve problems encountered in the transport of momentum, heat, and mass. The application of this technique simplifies the mathematical solution of the problem. However, it necessitates expressing the local value of the dependent variable and/or its derivative(s) on the system boundaries in terms of the averaged variable. In this study, these expressions are obtained by the two-point Hermite expansion and this approximate method is applied to some specific problems, such as, unsteady flow in a concentric annulus, unequal cooling of a long slab, unsteady conduction in a cylindrical rod with internal heat generation, diffusion of a solute into a slab from limited volume of a well-mixed solution, convective mass transport between two parallel plates with a wall reaction, convective mass transport in a cylindrical tube with a wall reaction, and unsteady conduction in a two -layer composite slab. Comparison of the analytical and approximate solutions is shown to be in good agreement for a wide range of dimensionless parameters characterizing each system.
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Swiderski, Konrad. "Quantitative investigation of reaction kinetics and mechanisms in ionic liquids using laser flash photolysis technique." Thesis, University of the West of Scotland, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.544371.
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Dival, Lucas. "The development of an in-field rapid derivatisation technique for the analysis of chemical warfare agent degradants." Thesis, Dival, Lucas (2018) The development of an in-field rapid derivatisation technique for the analysis of chemical warfare agent degradants. Masters by Coursework thesis, Murdoch University, 2018. https://researchrepository.murdoch.edu.au/id/eprint/41362/.
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The degradation of various toxic nerve agents in the environment has been documented throughout literature to result in the formation of methylphosphonic acid. The detection of this compound is used as an indication of previous use or production of such nerve agents, however for this detection to be possible methylphosphonic acid must first undergo derivatisation. This process, at its current stage, can be time consuming. To validate the need for alternative, faster methods, this literature review shall investigate the degradation of various nerve agents and current derivatisation processes. It was evident from the findings attained that a process in which derivatisation of methylphosphonic acid could be achieved quickly would be of great interest to forensic specialists.
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Ramakrishnan, Praveen. "Processing of fluoro alumino-silicate glass-ceramics by Field Assisted Sintering Technology and honeycomb extrusion technique." Thesis, University of Birmingham, 2016. http://etheses.bham.ac.uk//id/eprint/6579/.
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Field Assisted Sintering Technique (FAST) was used for the crystallisation of ionomer glasses and the production of the relevant glass ceramics. Extrusion was also used as an alternative processing method to produce honeycomb glass ceramics derived from similar glass compositions. Apatite-mullite glass ceramics derived from the general glass composition 4.5SiO\(_2\)-3A1\(_2\)O\(_3\)- 1.5P\(_2\)O\(_5\)-(5-x)CaO-xCaF\(_2\) can be produced by a lost wax method. However, Field Assisted Sintering Technique and Honeycomb Extrusion Technique are never used before and this present work presents the first data on the use of both of the above mentioned techniques. Calcium (Ca), Strontium (Sr) and Magnisium (Mg) containing glass powder compositions were produced and processed by FAST and Extrusion technique. X-ray diffraction of the materials produced by FAST showed the formation of a fluorapatite, mulite and a minor A1PO\(_4\) phase for the calcium glass. Sr-fluorapatite and Sr-aluminium silicate were formed in Sr glass and mullite and wagnerite were formed in Mg glasses. All the crystal phases formed were in good agreement with previous conventional crystallization studies. The FAST sintered glass ceramic properties were improved when compared with conventional sintering. In extrusion technique, the rheological properties were studied using Benow/Bridgwater model for paste parameters. Honeycomb extrusion pressure drop was also studied using a model developed by Blackburn and Bohm. In this study, we used waste glass to model the binder rehology of glass powder and modelled binder rheology in the apatite mullite glass. The measured paste parameters were in good agreement when compared with the experimental results. The produced honeycomb structure was sintered conventionally using a furnace. Microstructural studies and X-ray diffraction were carried out. The results of this studies show a well-defined porous structure and formation of crystal phases similar to the phases observed during conventional sintering.
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De, Silva Kandaudage Channa R. "Effect of Manufacturing Technique on Electrochemical Response of a Sulfur Tolerant Planar Solid Oxide Fuel Cell Anode." Ohio University / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1225992967.
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Spencer, Matthew Todd. "New approaches for the chemical and physical characterization of aerosols using a single particle mass spectrometry based technique." Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2007. http://wwwlib.umi.com/cr/ucsd/fullcit?p3264603.
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Thesis (Ph. D.)--University of California, San Diego, 2007.Title from first page of PDF file (viewed August 2, 2007). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references.
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Choi, Changhoon. "Kinetic study of copper chemistry in chemical mechanical polishing (CMP) by an in-situ real time measurement technique." [Ames, Iowa : Iowa State University], 2008.
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Boateng, Douglas. "Re-configuring an international pharma-chemical customer services policy through the Delphi technique and process mapping : executive summary." Thesis, University of Warwick, 1997. http://wrap.warwick.ac.uk/34706/.
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As part of the organisation's strategy to improve its manufacturing logistics and supply chain management operations, they sponsored me on a Doctoral Program to research into the concept of customer service within the international Pharma-chemical and Pharmaceutical manufacturing industry. The research was structured in such a way that it formed part of my day to day manufacturing logistics assignments on and off site. The ideas cultured through the research have resulted in unprecedented improvements in both material an information flows on and off site. In particular, the systematic solicitation of our customer views through the Delphi technique has enabled the firm to gain a better understanding of its customer needs. Today, customer service performance as defined by our Pharmaceutical customers averages 98%. Nor is this all, for the continuous critiquing of various process steps through the virtuous circle of continuous improvement has enabled the organisation to improve the overall process lead times for two products by approximately 35%. With these improvements, all customers (internal or external) get what they want on time, in full and at the right quality. By gaining a better understanding of our customer and supplier needs, through timely information flows, the manufacturing strategy for two products have moved from make-to-stock to make to order. To date, over £1/2m savings have been realised by virtue of the fact that no raw material or finished product inventory is held for these two finished products. At the back end of Pharmaceutical supply chains, the survey on sourcing patterns within the industry showed that Pharma-chemical manufacturing was still concentrated among the major Pharmaceutical organisations. In fact, the study showed that Pharmaceutical organisations with sales of less than £900m outsourced their bulk Pharmaceutical needs whereas those having sales in excess of the stated amount used a combination of internal and external sources to satisfy their bulk Pharmaceutical needs. At the front end of Pharmaceutical supply chains, the survey highlighted the fragmented nature of the industry with over 60% having sales of less than £500m. This fording supports the view held today that the industry is heavily fragmented with more consolidation likely. The improvements to date have in fact exceeded what was expected. The gaining of approval to manufacture another product can be partly attributed to the continuous improvement efforts and accomplishments. With senior management's support, each individual and teams on site are continuously questioning their processes and seeking ways to reduce or eliminate the associated non value adding activities.
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Blanco-Cuaresma, Sergi. "Test de la technique de marquage chimique avec des amas ouverts." Thesis, Bordeaux, 2014. http://www.theses.fr/2014BORD0079/document.
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Contexte. Les étoiles naissent ensemble dans des nuages moléculaires géants. Si nous faisons l’hypothèse qu’ils étaient à l’origine chimiquement homogènes et bien mélangés, nous nous attendrions à ce que les étoiles issues d’un même nuage aient la même composition chimique. La plupart des groupes d’étoiles sont perturbés lors de leur évolution dans la galaxie et l’information dynamique est perdue. Ainsi la seule possibilité que nous ayons de reconstruire l’histoire de la formation stellaire est d’analyser les abondances chimiques que l’on observe aujourd’hui.But. La technique de marquage chimique a pour but de retrouver les amas d’étoiles dissociés en se basant uniquement sur leur composition chimique. Nous évaluons la viabilité de cette technique pour retrouver les étoiles qui sont nées dans un même amas mais qui ne sont plus gravitationnellement liées.Méthodes. Nous avons créé une librairie de spectres stellaires de haute qualité afin de faciliter l’évaluation des analyses spectrales. Nous avons développé notre propre outil d’analyse spectrale, nommée iSpec, capable d’homogénéiser les spectres stellaires venant de tous types d’instruments et de dériver les paramètres atmosphériques et les abondances chimiques. Finalement, nous avons compilé des spectres stellaires d’étoiles de 32 amas ouverts, nous avons dérivé de façon homogène les paramètres atmosphériques et les abondances de 17 espèces, et nous avons utilisé des algorithmes d’apprentissage automatique pour grouper les étoiles en se basant sur leur composition chimique.Résultats. Nous avons trouvé que les étoiles à des étapes d’évolution différentes ont des motifs chimiques distincts qui peuvent être dus à des effets NLTE,de diffusion atomique, de mélange et de corrélation à partir des déterminations de paramètres atmosphériques. Quand nous séparons les étoiles suivant leur stade d’évolution, nous observons qu’il y a un important degré de recouvrement dans la détermination des signatures chimiques des amas ouverts. Ceci rend difficile de retrouver les groupes d’étoiles nées ensemble en utilisant la technique de marquage chimiqueContext. Stars are born together from giant molecular clouds and, if weassume that they were chemically homogeneous and well-mixed, we expect them toshare the same chemical composition.Most of the stellar aggregates are disrupted while orbiting the Galaxy and thedynamic information is lost, thus the only possibility to reconstruct the stellarformation history is to analyze the chemical abundances that we observe today.Aims. The chemical tagging technique aims to recover disrupted stellarclusters based merely on their chemical composition. We evaluate the viability of thistechnique to recover conatal stars that are not gravitationally bound anymore.Methods. We built a high-quality stellar spectra library to facilitate theassessment of spectral analyses. We developed our own spectral analysisframework, named iSpec, capable of homogeneizing stellar spectra and derivingatmospheric parameters/chemical abundances. Finally, we compiled stellar spectrafrom 32 Open Clusters, homogeneously derived atmospheric parameters and 17abundance species, and applied machine learning algorithms to group the starsbased on their chemical composition. This approach allows us to evaluate theviability of the chemical tagging technique.Results. We found that stars in different evolutionary stages havedistinguished chemical patterns may be due to NLTE effects, atomic diffusion, mixingand correlations from atmospheric parameter determinations. When separating starsper evolutionary stage, we observed a high degree of overlapping among OpenCluster’s chemical signatures, making it difficult to recover conatal aggregates byapplying the chemical tagging technique
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Dao, Trinh. "DEVELOPPEMENT DE LA TECHNIQUE MICROSCOPIE ELECTROCHIMIQUE A BALAYAGE EN MODE COURANT ALTERNATIF : MECHANISMES ET CINETIQUES REACTIONNELS." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2011. http://tel.archives-ouvertes.fr/tel-00807617.
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Les techniques électrochimiques locales comme la microscopie électrochimique à balayage (SECM) permettent, au moyen d'une ultramicroélectrode utilisée comme sonde locale, de caractériser la topographie ou la réactivité locale de la surface d'un substrat. Cependant, il faut noter que la SECM a largement été utilisée dans des conditions stationnaires. L'objectif de ce travail a été de développer la technique SECM en mode courant alternatif (ac-SECM) tant d'un point de vue expérimental que théorique. Le mode ac- SECM a tout d'abord été utilisé pour caractériser un processus électrochimique simple (le ferri/ferrocyanure en solution aqueuse) afin de calibrer la contribution spécifique du transport de matière entre la sonde et le substrat et les processus se déroulant au niveau du substrat. Dans une seconde étape, cette nouvelle approche a été utilisée pour la caractérisation des processus d'adsorption lors de la réaction de dégagement d'hydrogène (HER) dans une solution d'acide sulfurique. Il a été montré que cette technique permet l'analyse quantitative des processus d'adsorption, et les mesures de la capacité différentielle en fonctionde la fréquence ont pu ête obtenus. La constante de temps pour la relaxation de l'hydrogène adsorbé est d'environ 2 Hz, et l'analyse du diagramme de Nyquist permet une évaluation directe de la charge impliquée. En outre, la comparaison des impédances électrochimique traditionnelles et des résultats de ac-SECM obtenus simultanément permet la caractérisation des processus qui se produisent à la surface et en solution.
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Stevanovic, Svetlana. "Investigation of the chemical and physical basis of oxidative stress generated by particulate matter using the profluorescent probe technique." Thesis, Queensland University of Technology, 2013. https://eprints.qut.edu.au/62029/1/Svetlana_Stevanovic_Thesis.pdf.
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Following the growing need for adoption of alternative fuels, this project aimed at getting more information on the oxidative potential of biodiesel particulate matter. Within this scope, the physical and chemical characteristics of biodiesel PM were analysed which lead to identification of reactive organic fractions. An in-house developed proflurescent nitroxide probe was used. This project further developed in-depth understanding of the chemical mechanisms following the detection of the oxidative potential of PM. This knowledge made a significant contribution to our understanding of processes behind negative health effects of pollution and enabled us to further develop new techniques to monitor it.
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Boue-Bigne, Fabienne. "Development and application of a calibration technique for laser ablation-ICP-MS." Thesis, Loughborough University, 2000. https://dspace.lboro.ac.uk/2134/12892.
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Laser Ablation - Inductively Coupled Plasma - Mass Spectrometry (LA-ICP-MS) is a powerful analytical technique for the direct elemental analysis of solid samples, with spatial resolution down to a few microns However, calibration remains the limiting factor in obtaining quantitative analysis by LA-ICP-MS for a wide range of sample types. No universal method exists as yet and the ones that are currently used tend to employ matrix-matched solid standards Matrix-matched solid standards are not available for many types of sample, such as polymers, biological materials, fluid inclusions, etc The need for a universal method of calibration that involves standards that are easy to prepare and suitable for any type of sample is required. Additional to matrix-matching, internal standards are widely used in LA-ICP-MS for quantitative analyses The internal standard compensates for the different ablation yields from the sample and the standard and for the laser shot to shot variation. Given that the use of an internal standard is required to obtain reliable results, the need for matrix-matching might be regarded as questionable This project has focused on the development and application of a new method of calibration for LA-ICP-MS. It involves the use of aqueous standards whose absorption characteristics are modified by the addition of a chromophore to the solution. Additives were selected for ablation with KrF excimer, and Nd.YAG lasers The influence of the additive concentration on the ablation yield was investigated for different laser energies. Response curves were obtained showing that as the additive concentration was increased, less energy was required to ablate the modified standard solutions efficiently. A general procedure was then defined for the preparation and use of the modified standard solutions for a given sample. The new method of calibration was used for the quantitative analysis of different sample types· low density polyethylene (LDPE), polyketone (PK), polyethylene thin film as well as gels contained in the thin film, and stainless steel. Investigations were carried out on the mechanism of ablation of the modified standard solutions. It appeared that the ablation proceeded by a three-step process leading ultimately to nebulisation of the bulk liquid.
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Xie, Qingqing. "Study on mass transfer and turbulence in large pipe flow using limiting current density technique." Ohio University / OhioLINK, 1997. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1184606447.
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Michel, Anna Pauline Miranda. "Laboratory evaluation of laser-induced breakdown spectroscopy (LIBS) as a new in situ chemical sensing technique for the deep ocean." Cambridge, Mass. : Woods Hole, Mass. : Massachusetts Institute of Technology ; Woods Hole Oceanographic Institution, 2007. http://hdl.handle.net/1912/1957.
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Thesis (Ph. D.)--Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2007.Title from Web page (viewed on Mar. 24, 2008). "September 2007." Includes bibliographical references.
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Williams, Eva Christabel. "Smart Packaging: A Novel Technique For Localized Drug Delivery For Ovarian Cancer." Scholar Commons, 2012. http://scholarcommons.usf.edu/etd/4257.
Full textAbstract:
Localized drug delivery is emerging as an effective technique due to its ability to administer therapeutic concentrations and controlled release of drugs to cancer sites in the body. It also prevents the contact of harsh chemotherapy drugs to healthy regions in the body that otherwise would become exposed to current treatments.
This study reports on a model chemotherapy drug delivery system comprising non-ionic surfactant vesicles (niosomes) packaged within a temperature-sensitive chitosan network. This smart packaging, or package-within-a package system, provides two distinct advantages. First, the gel prevents circulation of the niosomes and maintains delivery in the vicinity of a tumor. Secondly, the chitosan network protects the niosomes against fluctuations in tonicity, which affects delivery rates. Tonicity is the sum of the concentrations of the solutes which have the capacity to exert an osmotic force across the membrane. Release rates were monitored from both bare niosomes alone and niosome-embedded, chitosan networks. It was observed that chitosan networks prolonged delivery from 100 hours to 55 days in low ionic strength environment and pH conditions similar to a tumor site. The primary effect of chitosan is to add control on release time and dosage, and stabilize the niosomes through a high ionic strength surrounding that prevents uncontrolled bursting of the niosomes. Secondary factors include cross-link density of the chitosan network, molecular weight of the individual chitosan polymers, dye concentration within the niosomes, and the number density of niosomes packaged within the chitosan network. Each of these factors can be altered to fine-tune release rates. Release rate experiments were conducted with 5,6-carboxyfluorescein, a fluorescent dye and chemotherapeutics paclitaxel and carboplatin. In vitro studies showed a preferential affinity of the smart packaged system to ovarian carcinoma cell line OV2008 as compared to normal epithelial cell lines of Ilow and MCC3. Further, feasibility of the drug delivery system was evaluated in vivo. Toxicity studies revealed that the system was non-toxic and feasible in vivo. The final outcome of this study includes tuning of the variables mentioned above that will contribute to the development of low cost and improved methods for drug delivery with application to intracavitary ovarian cancer treatment and other types of cancer
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Li, Yingchun Verfasser], Reinhard H. H. [Akademischer Betreuer] [Neubert, Maximilian [Akademischer Betreuer] Fleischer, and Ralf [Akademischer Betreuer] Lucklum. "Surface modification technique for acoustic chemical sensor arrays based on CMUTs / Yingchun Li. Betreuer: Reinhard Neubert ; Maximilian Fleischer ; Ralf Lucklum." Halle, Saale : Universitäts- und Landesbibliothek Sachsen-Anhalt, 2011. http://d-nb.info/1025135121/34.
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