Dissertations / Theses: 'Petroleum technology Chemical engineering Chemistry'

1

Heath, David John. "Characterisation of waxy gas-condensates by high temperature capillary gas chromatography and oxidative degradation." Thesis, University of Plymouth, 1995. http://hdl.handle.net/10026.1/460.

Full text

Abstract:

High molecular weight (HMW) hydrocarbons (defined herein as C35+ compounds) are difficult to characterise by conventional analytical methods. Very few studies have reported precise and reproducible quantification of such compounds in fossil fuels. Nonetheless, such components have important effects on the physical and biological fate of fossil fuels in the geosphere. For example, the phase behaviour of waxy gas condensates is significantly affected by the varying proportions of HMW compounds. Similarly HMW compounds are amongst the most resistant petroleum components to biodegradation. The current study reports the development of reproducible quantitative high temperature capillary gas chromatography (HTCGC) methods for studying both these aspects of the chemistry of HMW hydrocarbons. In addition those hydrocarbons which remain unresolved when analysed by gas chromatography (so called unresolved complex mixtures UCMs) are also studied. UCMs may account for a large portion of the hydrocarbons in many fossil fuels yet very little is known about their composition. Knowledge of these compounds may be important in enhancing the prediction of phase behaviour. Oxidative degradation and GC-MS is used to elucidate the types of structures present within the UCM. The concentrations of C3S4h. ydrocarbons in two unusually waxy gas condensates from high temperature wells in the North Sea were determined by HTCGC. The whole C, 5+ fraction comprised about 20% of the total hydrocarbons and consisted of compounds with carbon numbers extending up to and beyond Coo. By paying particular attention to sample dissolution and injection, good reproducibility and precision were obtained. For example, for authentic n-C, to n-C60 alkanes a relative standard deviation of under 5% for manual injection, linear response factors (1.01 Cm to 0.99 C6), and a linear calibration for 5 ng to 25 ng on-column were found. Limits of detection are reported for the first time for HMW n-alkanes. The limits were found to be as low as 0.8 ng for Cto to 1.87 ng for C60. Tristearin is proposed as a suitable HTCGC internal standard for quantification since the FID response factor (1.1) was close to that of the HMW n-alkanes and response was linear. Importantly, when co-injected with the two waxy North Sea condensates, tristearin was adequately separated from the closest eluting alkanes, n-C59 and n-C60 under normal operating conditions. Qualitative characterisation of the HMW compounds in the waxy gas condensates and in synthetic wax blends (polywax 1000) using HTCGC-EI MS and HTCGC-CI MS produced molecular ions or pseudo molecular ions for n-alkanes up to n- C6o. The spectra of some HMW compounds contained fragment ions characteristic of branched compounds but detailed characterisation was very limited. This study has also shown, for the first time, the significance of the unresolved complex mixture in gas condensatesU. CM hydrocarbonsa ccountedf or over 20% of the total hydrocarbons in a waxy North sea condensateT. he condensatew as first distilled and the distillate UCMs isolated. Thesew ere found to be between 64 to 97 % unresolved after molecular sieving (5A) and urea adduction. The UCMs were oxidised using CrO3/AcOHw hich produced5 -12% C02, and 55-83% dichloromethane-solublep roducts. Thus 65-94% of the original UCMs were accounted for as oxidation products. The remainder were thought to be water soluble acids which could not be determined in the presence of the AcOH reagent. Of the recovered oxidised products, 27- 81 % were resolved and these comprised mainly n-monocarboxylic acids (19-48 %). The average chain length was found to be C12 indicating the average length of alkyl groups. Branched acids, ketones, ketoacids, ndicarboxylic acids, branched dicarboxylic acids, lactones, isoprenoid acids, alkylcyclohexane carboxylic acids and toluic acids accounted for the majority of the remaining resolved products. The distillate UCMs all showed variations in amountso f productsb ut not in composition. Retro-structurala nalysis suggestedth at the UCM in the gasc ondensatew as mainly aliphatic and branched.T he numbero f isomerso f simple brancheda lkaneso ver the UCM molecular weight range (determined by cryoscopy) was calculated to be over 15000. Overall, oxidation provided structural information for about half of the UCM. HTCGC was also used to measure the biodegradability of HMW alkanes in a waxy Indonesian oil. Traditional alkane isolation techniques (TLC and CC) discriminated against HMW compounds above C40 whereas adsorption onto alumina in a warm cyclohexane slurry provided an aliphatic fraction still rich in HMW compounds and suitable as a biodegradation substrate. A waxy Indonesian oil was subjected to 136 day biodegradation by Pseudomonas fluorescens. Extraction efficiencies of over 90 % (RSD <5 %) were obtained for n-alkanes up to C6o using continuous liquid-liquid extraction. Over 80 % of the oil aliphatic fraction was degraded within 14 days. After 136 days only 14% of the original aliphatic fraction remained, yet surprisingly no decreases in the concentrations of compounds above C45 were observed. However, the use of a rapid screening biodegradation method proved conclusively that Pseudomonasfluorescens was capable of utilising n-alkanes up to C60 once the bacteria had acclimated to the HMW alkanes. This is the first report of bacterial utilisation of an n-alkane as large as C.

APA, Harvard, Vancouver, ISO, and other styles

2

Balagurunathan, Jayakishan. "Investigation of Ignition Delay Times of Conventional (JP-8) and Synthetic (S-8) Jet Fuels: A Shock Tube Study." University of Dayton / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1330351552.

Full text

APA, Harvard, Vancouver, ISO, and other styles

3

Ishola, A. "Advanced safety methodology for risk management of petroleum refinery operations." Thesis, Liverpool John Moores University, 2018. http://researchonline.ljmu.ac.uk/7984/.

Full text

Abstract:

Petroleum refineries are important facilities for refining petroleum products that provide the primary source of energy for domestic and industrial consumption globally. Petroleum refinery operations provide significant contribution to global economic growth. Petroleum refineries are complex, multifaceted systems that perform multiple phase operations characterized by a high level of risk. Evidence based major accidents that have occurred within the last three decades in the petroleum refineries, around the world, indicates losses estimated in billions of US dollars. Many of these accidents are catastrophes, which have led to the disruption of petroleum refinery operations. These accidents have resulted in production loss, asset damage, environmental damage, fatalities and injuries. However, the foremost issue analysed in literatures in relation to major accidents in petroleum refineries, is the lack of robust risk assessment and resourceful risk management approaches to identify and assess major accident risks, in order to prevent or mitigate them from escalating to an accident. Thus, it is exceptionally critical to readdress the issue of petroleum refinery risk management with the development of a more dependable, adaptable and holistic risk modelling framework for major accident risks investigation. In this thesis, a proactive framework for advanced risk management to analyse and mitigate the disruption risks of petroleum refinery operations is presented. In this research, various risk elements and their attributes that can interact to cause the disruption of PRPU operations were identified and analysed, in order to determine their criticality levels. This thesis shows that the convergent effect of the interactions between the risk elements and their attributes can lead to the disruption of petroleum refinery operations. In the scheme of the study, Fuzzy Linguistic Preference Relation (FLPR), Fuzzy Evidential Reasoning (FER) and Fuzzy Bayesian Network (FBN) methodologies were proposed and implemented to evaluate the criticality of the risk elements and their attributes and to analyse the risk level of PRPU operations. Also, AHP-fuzzy VIKOR methodology was utilised for decision modelling to determine the optimal strategy for the risk management of the most significant risk elements’ attributes that can interact to cause the disruption of PRPU operations. The methodologies proposed and implemented in this research can be utilised in the petroleum refining industry, to analyse complex risk scenarios where there is incomplete information concerning risk events or where the probability of risk events is uncertain. The result of the analysis conducted in this research to determine the risk level of petroleum refinery operations can be utilised by risk assessors and decision makers as a threshold value for decision making in order to mitigate the disruption risk of PRPU operations. The decision strategies formulated in this thesis based on robust literature review and expert contributions, contributes to knowledge in terms of the risk management of petroleum refinery operations. The result of the evaluation and ranking of the risk elements and their attributes can provide salient risk information to duty holders and decision makers to improve their perceptions, in order to prioritise resources for risk management of the most critical attributes of the risk elements. Overall, the methodologies applied in this thesis, can be tailored to be utilised as a quantitative risk assessment tool, by risk managers and decision analysts in the petroleum refining industry for enhancement risk assessment processes where available information can sometimes be vague or incomplete for risk analysis.

APA, Harvard, Vancouver, ISO, and other styles

4

Ali, Abdualbaset Ahmed. "Altering Wax Appearance Temperature Using Shear and Pressure." University of Toledo / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1575992511410478.

Full text

APA, Harvard, Vancouver, ISO, and other styles

5

Lütkenhaus, Davidson. "Engineering understanding of cleaning : effect of chemistry and mechanical forces on soil removal." Thesis, University of Birmingham, 2017. http://etheses.bham.ac.uk//id/eprint/7929/.

Full text

Abstract:

The cleaning of food-based soils is highly relevant in domestic and industrial environments due to the costs associated with these operations as well as the significant consumption of time, water, and energy. Understanding the relationship between chemical and mechanical forces required to clean a surface is a critical step towards optimizing these processes. A complex twophase polymerized grease was developed and characterized with respect to its morphology, component distribution, and chemical composition. A thorough evaluation and physicochemical characterization of the cleaning process of this complex soil from a hard substrate was performed at two different length scales. Results showed that surfactants are more effective at weakening the cohesive interactions within the soil matrix and less effective in removing the adhesive bonds at the soil-substrate interface. A statistical model for cleaning efficiency was developed which described cleaning as a function of chemical and mechanical contributions. The effect of the chemistry on hydration and final cleaning performance was investigated through a definitive model screening and correlated to the tribological forces involved in the process. The model was shown to be applicable to several industrially relevant surfactant systems and revealed that hydration is the main factor driving cleaning of this two-phase soil.

APA, Harvard, Vancouver, ISO, and other styles

6

Gillespie, Noel Edward. "Energy retrofit of an oil refinery using pinch technology." Master's thesis, University of Cape Town, 1989. http://hdl.handle.net/11427/23166.

Full text

APA, Harvard, Vancouver, ISO, and other styles

7

Mammen, John Joe. "Retrofit of heat exchanger networks of a petroleum refinery crude unit (CDU) using pinch analysis." Thesis, Cape Peninsula University of Technology, 2014. http://hdl.handle.net/20.500.11838/860.

Full text

Abstract:

Thesis submitted in fulfilment of the requirements for the degree of Master of Technology: Chemical Engineering, In the Faculty of Engineering, Cape Peninsula University of Technology 2014
Energy efficiency has become an important feature in the design of process plants due to the rising cost of energy and the more stringent environmental regulations being implemented worldwide. In South Africa as in other African countries, most of the chemical plants were built during the era of cheap energy with little emphasis placed on energy efficiency due to the abundance of cheap utility sources such as coal and crude oil. In most of these plants, there exists significant potential for substantial process heat recovery by conceptual integration of the plant’s heat exchangers. Pinch Technology (PT) has been demonstrated to be a simple and very effective technique for heat integration and process optimization. This study applies the PT approach to retrofit the heat exchangers network of the Crude Distillation Unit (CDU), of a complex petroleum refinery with the aim to reduce utilities requirement and the associated gaseous pollutants emission. This objective is accomplished by firstly conducting an energy audit of the unit to scope for potential energy saving. The existing Heat Exchanger Network (HEN) was re-designed using the remaining problem analysis (RPA) to achieve improved process energy recovery while making maximum use of the existing exchangers. The aim is to maintain the existing plant topology as much as possible. This network was later relaxed trading heat recovery with number of heat transfer unit so as to optimize the capital cost. These were implemented in AspenPlus v7.2 environment. The cost implications of the retrofitted and evolved networks including the capital and operating costs were determined on a 5 years payback time basis. The Problem Table (PT) analysis revealed that the minimum utilities requirements are 75 MW and 55 MW for the hot and cold utilities respectively. Compared to the existing utilities requirements of 103 MW for hot utility and 83 MW for cold utility, this represent a potential savings of about 26 % and 33 % savings for the hot and cold utilities respectively. The target utilities usage in the re-designed network after applying Remaining Problem Analysis (RPA) was found to be 55 MW for the cold utility and 75 MW for hot utility. The relaxed HEN required a cold utility of 62.5 MW and hot utility of 81 MW. From the total cost estimation, it was found that, although an energy saving of 34% can be achieved by the re-designed network before relaxation, the capital cost, US$ 1670000 is significantly higher than for the existing network (about US$ 980000). The final relaxed network gave an energy saving of 34% and with total cost of US$ 1100000. It was recommended from the study after cost comparisons of the four different networks (the original network, the MER network, the relaxed network and a grass-root design) that the best network for the retrofit purpose was the relaxed HEN, because there is no major shift in deviation from the topology of the original network. From the analysis it was found that a 34% saving in energy cost could be achieved from this retrofit. The Total Annual Cost (TAC) for this network gives credence to the fact that this retrofit which applied the rules of pinch analysis can bring about real saving in energy usage.

APA, Harvard, Vancouver, ISO, and other styles

8

McKinley, Stephen Peter. "Physical chemical processes and environmental impacts associated with home composting." Thesis, University of Southampton, 2008. https://eprints.soton.ac.uk/73701/.

Full text

Abstract:

This thesis reports on experimental and modelling work carried out in order to make quantitative estimates on the environmental impacts of home composting. The focus of the work was climate relevant gaseous emissions, and developing and utilising a methodology for quantifying them. Experiments using 220L open bottomed home compost bins, alongside purpose built 200L composting reactors with airflow control were performed. A variety of composting conditions were tested, using different compositions of garden and kitchen wastes. The experiments were monitored for headspace gas composition, including CO2, O2, NH3, N2O, CH4 and volatile organic compounds, as well as temperature, humidity, moisture and solids losses and pH. From the CO2 emission rates calculated from the reactor experiments, theoretical analysis and modelling and airflow pathway tests on home compost bins, it was concluded that molecular diffusion, rather than bulk convective flow, is the dominant gas transfer mechanism from home compost bins. There were no detected emissions of N2O but emissions of NH3 up to 16 g/T feed. Only a few cases of CH4 emission were detected, typically in the first 2-3 days following a feed addition, with the highest single concentration measured at 86 ppm within the headspace. The total anthropogenic greenhouse gas emissions from home composting were estimated as between 3 and 12 Kg CO2E/Tw with almost 90% coming from the lifecycle of the compost bin. This compares with between 20 and 56 Kg CO2E/Tw from centralised facilities, at least more than double that for home composting. Total anthropogenic CO2-equivalent emissions from home composting in the UK in 2008 were estimated to be in the region of 7 thousand tonnes CO2E.

APA, Harvard, Vancouver, ISO, and other styles

9

Parrilla, Gutierrez Juan Manuel. "Investigating automated chemical evolution of oil-in-water droplets." Thesis, University of Glasgow, 2016. http://theses.gla.ac.uk/7744/.

Full text

Abstract:

One of the main unresolved questions in science is how non-living matter became alive in a process known as abiognesis, which aims to explain how from a primordial soup scenario containing simple molecules, by following a ``bottom up'' approach, complex biomolecules emerged forming the first living system, known as a protocell. A protocell is defined by the interplay of three sub-systems which are considered requirements for life: information molecules, metabolism, and compartmentalization. This thesis investigates the role of compartmentalization during the emergence of life, and how simple membrane aggregates could evolve into entities that were able to develop ``life-like'' behaviours, and in particular how such evolution could happen without the presence of information molecules. Our ultimate objective is to create an autonomous evolvable system, and in order tp do so we will try to engineer life following a ``top-down'' approach, where an initial platform capable of evolving chemistry will be constructed, but the chemistry being dependent on the robotic adjunct, and how then this platform can be de-constructed in iterative operations until it is fully disconnected from the evolvable system, the system then being inherently autonomous. The first project of this thesis describes how the initial platform was designed and built. The platform was based on the model of a standard liquid handling robot, with the main difference with respect to other similar robots being that we used a 3D-printer in order to prototype the robot and build its main equipment, like a liquid dispensing system, tool movement mechanism, and washing procedures. The robot was able to mix different components and create populations of droplets in a Petri dish filled with aqueous phase. The Petri dish was then observed by a camera, which analysed the behaviours described by the droplets and fed this information back to the robot. Using this loop, the robot was then able to implement an evolutionary algorithm, where populations of droplets were evolved towards defined life-like behaviours. The second project of this thesis aimed to remove as many mechanical parts as possible from the robot while keeping the evolvable chemistry intact. In order to do so, we encapsulated the functionalities of the previous liquid handling robot into a single monolithic 3D-printed device. This device was able to mix different components, generate populations of droplets in an aqueous phase, and was also equipped with a camera in order to analyse the experiments. Moreover, because the full fabrication process of the devices happened in a 3D-printer, we were also able to alter its experimental arena by adding different obstacles where to evolve the droplets, enabling us to study how environmental changes can shape evolution. By doing so, we were able to embody evolutionary characteristics into our device, removing constraints from the physical platform, and taking one step forward to a possible autonomous evolvable system.

APA, Harvard, Vancouver, ISO, and other styles

10

Emami, Fatemesadat. "Thermodynamically Consistent Interatomic Potentials for Silica to Design Specifically Binding Peptides: Role of Surface Chemistry, PH, and Amino Acid Sequence." University of Akron / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=akron1366597654.

Full text

APA, Harvard, Vancouver, ISO, and other styles

11

Wright, Kimberley Elizabeth. "Engineering of a specific binding site for protein labelling with luminescent lanthanide coated nanoparticles : a study of protein labelling and nanoparticle-peptide interactions." Thesis, University of Birmingham, 2015. http://etheses.bham.ac.uk//id/eprint/5576/.

Full text

Abstract:

The work presented in this thesis investigates the use of new luminescent lanthanide complexes, both free and bound to the surface of gold nanoparticles, for protein labelling. Lanthanide complexes were shown to maintain their luminescence properties when conjugated to proteins and one complex also demonstrated participation in Förster resonance energy transfer when conjugated to a protein in an appropriate system. Furthermore, it was found that bovine serum albumin can act as a vehicle to transport luminescent lanthanide complexes into two human cell lines. Lanthanide complexes were then used to coat 13 nm gold nanoparticles for protein labelling within cells. The aim was to find a peptide sequence to preferentially bind to gold nanoparticles which could be expressed as part of a protein of interest, acting as a binding site within the cell. The interaction of peptides with gold nanoparticles was examined using several methods and, of the sequences tested, CCPGCC was found to have the highest affinity for the nanoparticles. This peptide was expressed in HeLa cells as part of green fluorescent protein. Co-localisation of the nanoparticles with the protein in cells could not be established through fluorescence microscopy, however, cell lysis revealed green fluorescence protein associated with nanoparticle aggregate.

APA, Harvard, Vancouver, ISO, and other styles

12

Vanerek, Alois. "Filler retention in papermaking by polymeric and microparticulate retention aid systems." Thesis, McGill University, 2004. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=85655.

Full text

Abstract:

Mineral pigments are added to paper with the aim of improving its optical and printing properties. The colloidal behavior of calcium carbonate filler shows a dependence on the quality of water used in suspensions, presence of dissolved and colloidal substances and type of polymer used as a retention aid. The role of the retention aids is to attach colloidal particles, such as fines and mineral pigments, to pulp fibers before or during the paper is made. Two very different single-component retention aids were utilized in calcium carbonate fillers destabilization and deposition on fibers. Cationic polyethylenimine destabilized or facilitated deposition of the filler on fibers by a charge neutralization mechanism while cationic polyacrylamide flocculated or deposited the filler on fibers via a bridging mechanism.
In the presence of anionic dissolved and colloidal substances, the amount of cationic polyacrylamide had to be increased in order to achieve the same degree of pigment flocculation. The reason for the increase was due to the fact that the cationic polyacrylamide formed a polyelectrolyte complex with the anionic substances, namely sulfonated kraft lignin. The reaction between cationic polyacrylamide and lignin was found to be nearly stoichiometric. Low molecular weight cationic polyacrylamide formed mostly colloidal complexes while high molecular weight cationic polyacrylamide formed predominantly coacervate complexes; this was mainly due to differences in characteristic times of lignin association with the cationic polyacrylamide, clustering of polyacrylamide molecules and reconformation of polymer chains.
The performance of two-component retention aid systems consisting of a cationic polyacrylamide and anionic microparticles were evaluated by deposition of calcium carbonate filler on pulp fibers. Kaolin clay and bentonite were used to heteroflocculate polyacrylamide-covered surfaces of the fibers and pigment. Due to their inability to delaminate, kaolin clay and acid-treated montmorillonite showed no effect of calcium carbonate filler deposition. After cation exchange with sodium-rich solutions, which caused the montmorillonite to delaminate, the montmorillonite flocculation efficiency considerably improved. Kaolin clay neither delaminated after the cation exchange nor improved calcium carbonate deposition. Bentonite was found to completely delaminate when using polyacrylamide-treated fibers. When added to a suspension of fibers, filler and cationic polyacrylamide, bentonite was found to be in a form of stacks containing on average four platelets.
An alternative way to paper filling with pigment was tested on stationary sheets and on slow and fast Fourdrinier pilot paper machines. Using a secondary headbox on the pilot paper machines, a high degree of loading (above 30%) could be achieved using positive clay or calcium carbonate fillers. However, the fillers lowered the paper strength as they interfered with the fiber-fiber bonding in a similar fashion found in conventionally filled papers.

APA, Harvard, Vancouver, ISO, and other styles

13

Zhai, Yuxin. "Spectroscopic Studies of Adsorbed CO₂ on Polyamines and Photo-generated Electrons in Photocatalytic Synthesis." University of Akron / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=akron1538145926835136.

Full text

APA, Harvard, Vancouver, ISO, and other styles

14

Espert, Ana. "Srategies for improving mechanical properties of polypropylene/cellulose composites." Doctoral thesis, KTH, Fibre and Polymer Technology, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-179.

Full text

Abstract:

The interest for polypropylene/cellulose composites has experienced a great increase in different applications such as car interiors and construction materials. Cellulose fibres are inexpensive, renewable, biodegradable, they present lower density and their mechanical properties can be compared to those of inorganic fillers. However, several factors must be considered when designing polypropylene/cellulose composites: the poor compatibility between the hydrophilic fibres and the hydrophobic thermoplastic matrix leads to a weak interface, which has to be improved by coupling agents; the hydrophilic nature of the fibres makes them very sensitive towards water absorption, which also leads to a loss of properties and swelling with subsequent dimensional instability; the reduced thermal stability of cellulose fibres leads to degradation of the fibres at thermoplastic processing temperatures producing odours in the final material; and finally the properties of composites are greatly influenced by the structure, size and quality of the fibres.

Pulp fibres modified by different methods in order to enhance the compatibility fibre-matrix, were tested. Modified fibres led to improved mechanical properties and thermal behaviour when used in composites with recycled polypropylene.

Four different types of natural fibres were used as reinforcement in two different polypropylene types: virgin and recycled polypropylene. The mechanical properties of the composites were mostly dependent on the fibre loading and slightly dependent on the type of fibre. Moreover, water absorption kinetics was studied by the Fickian diffusion theory. After absorption, a remarkable loss of properties was observed.

Hydrolysed cellulose fibres showed a greater enhancing effect on polypropylene than non-hydrolysed cellulose fibres. This is attributed to the greater mechanical properties of reduced cellulose structures.

The effect of using cellulose fibres in PP/clay nanocomposites was also studied. The interaction between the clay particles and the cellulose fibres and the combined effect of both reinforcements were believed to be the main reasons for the enhancing properties.

APA, Harvard, Vancouver, ISO, and other styles

15

Espert, Ana. "Strategies for improving mechanical properties of polypropylene/cellulose composites." Doctoral thesis, Stockholm : Fiber- och polymerteknologi, KTH, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-179.

Full text

APA, Harvard, Vancouver, ISO, and other styles

16

Taylor, Michael. "To F-SIMS/XPS chemical depth profiling of synthetic polymer hydrogels." Thesis, University of Nottingham, 2017. http://eprints.nottingham.ac.uk/38755/.

Full text

Abstract:

Over the last decade the beneficial properties of hydrogels as artificial cell culture supports have been extensively investigated. Certain synthetic hydrogels have been proposed to be similar in composition and structure to the native extracellular matrix of the stem cell niche, their in vivo cell habitat, which is a powerful component in controlling stem cell fate. The stem cell differentiation pathway taken is influenced by many factors. When culturing cells within or upon hydrogels the choice can be strongly dependent on the underlying 3D hydrogel chemistry which strongly influences hydrogel-cell interactions. The interrelationship between hydrogel chemistry and that of biomolecules in controlling cellular response ideally requires analysis methods to characterise the chemistry without labels and normally in 3D. Time-of-flight secondary ion mass spectrometry (ToF SIMS) has the potential to be utilised for through thickness characterisation of hydrogels. The frozen-hydrated sample format is well suited to minimise changes associated with dehydration or the complication of chemical ‘fixation’. There is however significant challenges associated with this sample format. Frost formation occurs on cold samples in the ambient atmosphere affecting the quality of chemical information acquired from depth profiling frozen hydrogel samples. We develop a simple method to remove this frost by blowing with gas prior to entry into the instrument which is shown to produce remarkably good profiles on a poly(2-hydroxyethyl methacrylate) (pHEMA) hydrogel film where a model protein, lysozyme, is incorporated to demonstrated how biomolecule distribution within hydrogels can be determined. A comparison of lysozyme incorporation is made between the situation where the protein is present in the polymer dip coating solution and lysozyme is a component of the incubation medium. It is shown that protonated water clusters H(H2O)n+ where n=5-11 that are indicative of ice are detected through the entire thickness of the pHEMA and the lysozyme distribution through the pHEMA hydrogel films can be determined using the intensity of characteristic fragment secondary ions. Quantitative TOF-SIMS analysis is highly desirable in biomaterial analysis as the amount and type of molecule in the material analysed may be determined. This has significant interest in hydrogel chemical analysis as cellular development on or within hydrogels may be highly influenced by the concentration and type of soluble molecule. Unfortunately, the matrix effect in SIMS changes the measured signal intensity of the analyte, preventing accurate quantitation. For this reason, we apply X-Ray Photoelectron Spectroscopy (XPS) on the equivalent samples as the ToF-SIMS in an attempt to correlate molecular ion yields to exact elemental concentrations. Similarly to ToF-SIMS the frozen-hydrated format in XPS is however still relatively unexplored. We apply the developed preparatory procedure in 3D XPS analysis of pHEMA/lysozyme hydrogel films in a hydrated state. We show that this format is suitable for alternative high vacuum analysis techniques. Furthermore, we show that lysozyme ingression and concentration can be determined through XPS. This work describes the first example of the characterisation of a hydrogel by ToF-SIMS and XPS in a frozen hydrated format, characterising hydrogels in a format most reflecting its native hydrated state at culture conditions. The described procedure allows for the mapping of biomolecules in a label free manner in 3D, furthermore allowing quantitative determination of biomolecule concentrations in hydrogels.

APA, Harvard, Vancouver, ISO, and other styles

17

Jordan, Alex Michael. "FIBER-COMPOSITE IN SITU FABRICATION: MULTILAYER COEXTRUSION AS AN ENABLING TECHNOLOGY." Case Western Reserve University School of Graduate Studies / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=case1467832877.

Full text

APA, Harvard, Vancouver, ISO, and other styles

18

Shah, Amjad. "Experimental optimization of the CAPRI process." Thesis, University of Birmingham, 2011. http://etheses.bham.ac.uk//id/eprint/3015/.

Full text

Abstract:

An experimental study was carried out concerning the optimization of catalyst type, operating conditions, addition of water and hydrogen for use in the THAI-CAPRI process and is reported. Three feeds namely, THAI field oil, Combustion Cell Oil (CCO) and n-decane were used in the presence of catalyst or an inert medium for comparison. Experiments were carried out using micro-reactors containing 5 g catalyst under different temperatures, pressures and gas environments. It was found that there was a trade-off in operation temperature between upgrading performance and catalyst lifetime. At higher temperatures of 500 °C led to an average of 6.1 °API upgrading , however, the catalyst lifetime was limited to 1.5 hours. Operation at 420 °C was found to be a suitable compromise, with upgrading limited up to 3 °API, with catalyst lifetime extended to 77.5 hours. From the results of the current study it can be said that by careful control of the temperature and oil flow rate in the in-situ CAPRI process, additional upgrading compared with the THAI process alone may be effected, resulting in a more valuable produced oil, which is easier to transport and could be further processed into distillates.

APA, Harvard, Vancouver, ISO, and other styles

19

Hasan, Farhan. "Conductive resists for nanofabrication on insulating substrates." Thesis, University of Birmingham, 2017. http://etheses.bham.ac.uk//id/eprint/7858/.

Full text

Abstract:

The purpose of this work is to support ongoing miniaturization of III-V microelectronic devices, which present a unique combination of economic and technical challenges. As miniaturization has proceeded photolithography has been able to meet required 20 nm feature sizes through the use of increasingly complex optical engineering techniques. However, this is not economically viable for low volume fabrication. The most promising low-volume technique here electron beam lithography (EBL). However, on insulating substrates, (e.g. for III-V devices), charging during EBL leads to pattern distortion and resolution is limited. Whilst charge mitigation strategies exist, they introduce process complexity, and resolution limits. A new approach using aconductive triphenylene electron beam resisthas been investigated. Triphenylenes form well-ordered hexagonal columnar discotic liquid crystals that show fast hole mobility (e.g. 10⁻³ cm²V⁻¹s⁻¹) along columns. The triphenylene based chemically amplified resist investigated here has a conductivity of ~10⁻⁶ S/m at room temperature. It has demonstrated high sensitivity in EBL, requiring a patterning dose of ~14 μC/cm² on silicon and ~10 μC/cm² on fused silica substrates at 50 keV exposure. The resist has demonstrated high-resolution patterning including 20 nm half pitch lines on silicon, and 55 nm isolated lines on glass at 30 keV exposure.

APA, Harvard, Vancouver, ISO, and other styles

20

de, Sá Ribeiro Albina Maria. "Studies of gas-liquid flow in bends." Thesis, University of Birmingham, 1994. http://etheses.bham.ac.uk//id/eprint/5069/.

Full text

Abstract:

The present investigation is concerned primarily with air-water flow in a horizontal 0.032 m ID tube, and the influence of a 90° horizontal bend on the flow characteristics. Visualisation studies using high speed still photography and cine film, and entrainment and drop size measurements were conducted before and after the bend. Entrained mass fluxes were determined from film flow measurements carried out using the film removal technique, while the drop size distributions were measured with a laser diffraction technique. During these measurements the pressure in the test section was held between 1.0-1.4 bar, and at ambient temperature. Prior to the horizontal flow study, drop size and film flow rates were measured for vertical air-water flow in a 0.01026 m ID tube. This extended the work of Jepson (1992) who reported the effect of gas density and surface tension on film flow rate, drop size and deposition mass transfer coefficient. Modifications to the equipment described by Jepson (1992) allowed an extension of the measurements to higher flow conditions. The visualisation study was taken across flow conditions that include stratified, annular and pseudo-slug flow regimes. Still photographs show the presence of air bubbles entrained in the liquid film, and the creation of liquid drops at the crest of roll waves. Drops were seen to be entrained from the liquid film by both bag break-up and ligament break-up mechanisms. At the bend, the phenomenon of film inversion was seen to occur. Also, a secondary flow existing in the gas phase at the bend can be responsible for a swirl movement observed in the liquid film, in which at the upper part of the tube the liquid was pulled from the outer wall of the bend to the top of the tube in an anti-clockwise, cork screwing fashion. In the lower half, the liquid film was drawn from the outer wall towards the bottom of the tube in a clockwise motion. From the cine films, information on drop velocity was also extracted. This showed the axial drop velocity to be constant over the time frame of analysis. No significant correlation was found between the drop size and the axial drop velocity. The entrainment results in the horizontal tube showed that for stratified/annular conditions the entrained liquid mass flux increases with liquid flow rate (for a fixed gas flow rate), and in some instances plateau conditions were reached. However, for the pseudo-slug regime the level of entrainment falls considerably. For the whole range of flow conditions studied, the entrained liquid mass flux increases with superficial gas velocity, except for GL = 10 kg/m 2 s where the amount of entrainment is constant. The reduction in entrained liquid mass flux after the bend above certain flow conditions, is caused by drops depositing on the outside wall of the bend. For the flow conditions under study, the Sauter mean diameter varies between 60-110 um. Gas velocity has a strong influence on drop size, ie, the higher the gas velocity the smaller the drop size. The effect of liquid flow rate is somewhat more complex. At the lower liquid flow rates, drop size seems to be controlled by the entrainment mechanisms, while at the higher liquid flows drop coalescence has a dominant effect. The influence of the 90° bend on the drop size distribution was to increase the diameter of the drops. Both the entrained liquid mass flux and drop size were found to be lower for horizontal annular flow than in vertical flow, for the same flow conditions and tube diameter. The measurements carried out for air-water flow in the vertical 0.01026 m ID tube, showed the entrained mass flux to increase with both gas and liquid flow rates. For the flow conditions analysed, the Sauter mean diameter varies between 26-45 um. Drop size was seen to be influenced by gas and liquid flow rates, following similar trends to those observed during the horizontal study.

APA, Harvard, Vancouver, ISO, and other styles

21

Leung, Pui-ki. "Development of a zinc-cerium redox flow battery." Thesis, University of Southampton, 2011. https://eprints.soton.ac.uk/333334/.

Full text

Abstract:

Redox flow batteries (RFBs) can be used to store energy on the large and medium scale (kW – MW), particularly in applications such as load levelling of electrical power supplies, power quality control application and facilitating renewable energy deployment. In this thesis, the development of a divided and undivided zinc-cerium redox flow battery from its fundamental chemistry in aqueous methanesulfonic acid has been described. This comprehensive investigation has focused on the selection of electrode materials, evaluation of zinc corrosion of the negative electrode, characterization of the redox flow battery and the cycling performance. Voltammetric studies of both the zinc and the cerium half-cell reactions have been carried out under various operating conditions and for electrolyte compositions. These studies suggested that the positive electrode reaction could limit the use of higher current densities. After testing a range of two- and three-dimensional positive electrode materials, only three-dimensional platinised titanium mesh and carbon felts were capable of discharge at 50 mA cm-2 with high charge ( > 70 %)and voltage ( > 60 %) efficiencies in an divided system based on the optimum electrolyte compositions obtained in the half-cell studies. In order to avoid the diffusion of protons across the membrane and to simplify the construction, an undivided, membraneless system was proposed. With specific design arrangement and carbon felt positive electrode, this system can operate at room temperature with a high energy efficiency (~ 75 %) instead of 60 oC as reported in the patented system in the literature. In order to facilitate zinc electrodeposition and prevent zinc corrosion, several electrolytic additives and corrosion inhibitors have been suggested. Further challenges and research directions are also discussed.

APA, Harvard, Vancouver, ISO, and other styles

22

Hopf, Nancy Brenna. "Polycyclic aromatic hydrocarbon (PAH) exposures in aluminum smelter and offshore workers." Cincinnati, Ohio : University of Cincinnati, 2009. http://rave.ohiolink.edu/etdc/view.cgi?acc_num=ucin1236105868.

Full text

Abstract:

Thesis (Ph.D.)--University of Cincinnati, 2009.
Advisors: Glenn Talaska PhD (Committee Chair), Paul Succop PhD (Committee Member), Mary Beth Genter PhD (Committee Member), James Mack PhD (Committee Member), Tania Carreon PhD (Committee Member). Title from electronic thesis title page (viewed April 26, 2009). Keywords: PAC; Offshore; exposure; biomonitoring; aluminium. Includes abstract. Includes bibliographical references.

APA, Harvard, Vancouver, ISO, and other styles

23

Babic, Marijan. "Role of Interfacial Chemistry on Wettability and Carbon Dioxide Corrosion of Mild Steels." Ohio University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1483543296145156.

Full text

APA, Harvard, Vancouver, ISO, and other styles

24

Lange, Eric Matthew. "Catalytic Gasification - Analysis of the Gas-Phase Kinetics." Cleveland State University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=csu1503964740983329.

Full text

APA, Harvard, Vancouver, ISO, and other styles

25

Baser, Deven Swapneshu. "Envisioning Catalytic Processes in Chemical Looping Systems: Material and Process Development." The Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1586359263610608.

Full text

APA, Harvard, Vancouver, ISO, and other styles

26

Curnick, Oliver J. "Ionomer-stabilised Pt and Pt-Ti bimetallic electrocatalysts for the proton exchange membrane fuel cell." Thesis, University of Birmingham, 2012. http://etheses.bham.ac.uk//id/eprint/3732/.

Full text

Abstract:

This work aims to address the need for more durable electrocatalysts with lower precious metal content for proton exchange membrane fuel cells (PEMFCs), through the development of novel electrocatalyst materials and preparation routes. In this work, 'Nafion-Pt/C' electrocatalysts have been derived from ionomer-stabilised Pt nanoparticles synthesised via a novel, wet-chemical route that offers unprecedented control over the formation of the Pt-ionomer interface, with a view towards maximising the utilisation of the electrocatalyst. Nafion-Pt/C electrocatalysts have been characterised using ex-situ electrochemical techniques, and single-cell PEMFC testing to determine their activity and selectivity towards the oxygen reduction reaction (ORR), and to compare their utilisation and durability with commercially-available electrocatalysts. Nafion-Pt/C catalysts with agglomerated Pt particles exhibited a twofold improvement in durability vs. commercial catalysts, whilst offering similar ORR activities. Their enhanced durability was attributed to inhibition of Pt particle growth mechanisms by a passivating layer of Nafion introduced during the synthesis of Nafion-stabilised colloidal Pt. The second part of this work investigated methods for the synthesis of bimetallic nanoparticles consisting of an early transition-metal core (Ti) enclosed in a Pt shell, expected to offer higher intrinsic activity towards oxygen reduction than Pt alone, whilst being less prone to degradation than other alloys of Pt such as Pt-Ni, Pt-Co and Pt-Fe.

APA, Harvard, Vancouver, ISO, and other styles

27

Sawatmongkhon, Boonlue. "Modelling of catalytic aftertreatment of NOx emissions using hydrocarbon as a reductant." Thesis, University of Birmingham, 2012. http://etheses.bham.ac.uk//id/eprint/3138/.

Full text

Abstract:

Hydrocarbon selective catalytic reduction (HC-SCR) is emerging as one of the most practical methods for the removal of nitrogen oxides (NOx) from light-duty-diesel engine exhaust gas. In order to further promote the chemical reactions of NOx-SCR by hydrocarbons, an understanding of the HC-SCR process at the molecular level is necessary. In the present work, a novel surface-reaction mechanism for HC-SCR is set up with emphasis on microkinetic analysis aiming to investigate the chemical behaviour during the process at a molecular level via detailed elementary reaction steps. Propane (C3H8) is chosen as the reductant of HC-SCR. The simulation is designed for a single channel of a monolith, typical for automotive catalytic converters, coated with a silver alumina catalyst (Ag/Al2O3). The complicated physical and chemical details occurring in the catalytic converter are investigated by using the numerical method of computational fluid dynamics (CFD) coupled with the mechanism. The C3H8-SCR reaction mechanism consists of 94 elementary reactions, 24 gas-phase species and 24 adsorbed surface species. The mechanism is optimised by tuning some important reaction parameters against some measurable data from experiments. The optimised mechanism then is validated with another set of experimental data. The numerical simulation shows good agreements between the modelling and the experimental data. Finally, the numerical modelling also provides information that is difficult to measure for example, gas-phase concentration distribution, temperature profiles, wall temperatures and the occupation of adsorbed species on catalyst surface. Consequently, computational modelling can be used as an effective tool to design and/or optimise the catalytic exhaust aftertreatment system.

APA, Harvard, Vancouver, ISO, and other styles

28

Logsdail, Andrew James. "Computational characterisation of gold nanocluster structures." Thesis, University of Birmingham, 2012. http://etheses.bham.ac.uk//id/eprint/3320/.

Full text

Abstract:

This thesis presents computational work on the structures, characterisation and optical properties of homogeneous gold nanoclusters, and gold-containing bimetallic nanoalloys. An introductory overview of nanoscience is followed by four results chapters in which various computational methods are applied to elucidate properties that are not fully understood; from these results areas for future development, and application, are identifed. Chapter 2 looks at structural motif preference as a function of composition and size for Au and Pd. Bimetallic (AuPd)_N particles are further studied, with thermodynamic preference found for Au_shellPd_core configurations with a monolayer Au shell. Chapter 3 discusses the development and implementation of a genetic algorithm designed to aid the determination of the structures of small nanoclusters from images taken with a scanning transmission electron microscope. The implementation of a search method proves efficient at identifying high-symmetry test clusters, and shows promise for further application to the identification of cluster structure from experimental images. Chapter 4 contains a first-principles study of Au₁₆ deposited on a graphite substrate. We introduce surface defects to see their influence on the nanocluster structure, as well as testing for potential catalytic applications. Finally, Chapter 5 looks at the optical response of monometallic and bimetallic nanoparticles. Surface plasmon resonance spectra are calculated for a variety of geometries, compositions and chemical ordering. The greatest influence on the extinction spectra is attributed to the particle shape and its environment.

APA, Harvard, Vancouver, ISO, and other styles

29

Yang, Xiangxin. "Sol-gel synthesized nanomaterials for environmental applications." Diss., Manhattan, Kan. : Kansas State University, 2008. http://hdl.handle.net/2097/884.

Full text

APA, Harvard, Vancouver, ISO, and other styles

30

Kondaveeti, Rajiv. "Impact of Halogenated Aliphatic and Aromatic Additives on Soot and Polycyclic Aromatic Hydrocarbons -- An Ethylene-air Laminar Co-flow Diffusion Flame Study." University of Dayton / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1343786258.

Full text

APA, Harvard, Vancouver, ISO, and other styles

31

Melin, Tim. "Morphology of electrodeposited Na on Al electrodes." Thesis, Uppsala universitet, Strukturkemi, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-390801.

Full text

Abstract:

The demand for alternative secondary batteries to lithium-ion batteries (LIBs) grows. Sodium-ion batteries (SIBs) have been studied for many years and could replace LIBsfor some application. Metallic anodes for both LIBs and SIBs are interesting due totheir high energy densities. Several aspects such as reactivity, stability and depositionmorphology must be properly addressed before metallic Na could be considered apossible anode material. This study aims to evaluate deposition of Na on Alelectrodes using fundamental electrochemical theories. Na deposition was studiedusing pouch cells and sodium triflate (NaOTf) in dimethyl glycol ether (diglyme) aselectrolyte. Galvanostatic deposition using different current densities, electrolyteconcentrations and potential pulses prior to galvanostatic deposition were tested. Theelectrochemical methods used in this study were galvanostatic deposition andchronoamperometry. The morphology of deposited Na was analyzed with ex-situscanning electron microscopy (SEM). A decrease of the size of deposited Na islandswas observed for both increasing current density and decreasing electrolyteconcentration. Fluctuations and poor stability in the deposition potential wereobtained when decreasing the electrolyte concentration under 0.5 M and also whenincreasing the current density over 1 mA cm-2. The most homogeneous depositionwas obtained with a 1030 ms potential pulse amplitude (-3 V vs. Na+/Na) prior togalvanostatic deposition (1 mA cm-2, 0.5 mAh cm-2) using 0.1 M NaOTf in diglyme aselectrolyte. Reproducibility was a major issue in this study and further investigation ofseveral parameters is needed.

APA, Harvard, Vancouver, ISO, and other styles

32

Nyflött, Åsa. "Development of an Image Processing Tool for Fluorescence Microscopy Analysis of Paper Chemistry." Thesis, Karlstads universitet, Fakulteten för teknik- och naturvetenskap, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-6990.

Full text

Abstract:

Paper making today is, to some extent, based on empirical knowledge. It is wellknown that fines, pH, charge and ion strength affect the manufacture of paper. One way of extending knowledge of the mechanisms of paper chemistry is to follow the trajectories of fines and additives in the paper suspension to gather information as to the manner in which they react. Four tracking algorithms adapted to the needs of this particular problem were implemented in order to track particles effciently. The tracking algorithms include two variants of the well-known "Lucas-Kanade algorithm" and template matching techniques based on cross-correlation and least squares matching. Although these techniques are similar in principle, the actual tracking can nevertheless differ; the Lucas-Kanade algorithms were found to be more invariant to noise, whereas the cross-correlation and least squares methods are more rapid to execute in Matlab. The tracking methods have been evaluated using a simulator to generate image sequences of synthetic particles moving according to Brownian motion. Tracking has also been evaluated on microscope images of real latex particles where the results have been compared to manual tracking. Tracking of both the simulated particles and the latex particles resulted in similar results when compared to known position and manual tracking, respectively.
Tillverkning av papper är till en viss del baserad på empirisk kunskap. Välkänt är att finmaterial, pH värde, laddning och jonstyrka påverkar de papperskemiska mekanismerna och därmed flertalet pappersegenskaper vid tillverkning av papper. En möjlighet att utveckla kunskaperna inom papperskemiska mekanismerar att studera finmaterial och additiv i en pappers suspension for att samla in informationom reaktionsmekanismer. Fyra trackningalgoritmer ar vidareutvecklade i syftet att möjliggöra studier kring papperskemiska mekanismer. Trackningalgoritmerna inkluderar två varianter av den välkända "Lucas-Kanade" algoritm och två template-baserade metoder: korskorrelation och minsta kvadratmetoden. Samtliga metoder bygger på samma princip, men trots detta kan resultaten från trackningen skilja mellan metoderna. Lucas-Kanade algoritmerna är mer oberoende av brus medan korskorrelationen och minsta kvadratmetoden exekveras snabbare i Matlab. Trackning metoderna utvärderades med hjälp av en simulator som genererar bildsekvenser av syntetiska partiklar med en Brownsk rörelse. Trackningen har även använts på mikroskopibilder av rörelsebanor på verkliga suspenderade latex partiklar, varvid trackningresultatet har jämförts med manuell trackning. De genererade bildsekvensernapa de simulerade partiklarna har kända rörelsebanor som är jämförbara med rörelsebanor for latex partiklarna.

APA, Harvard, Vancouver, ISO, and other styles

33

Patel, Ankit Arvind. "Novel P-(SBMA) Grafted Glass Fiber Filters and Glass Slides for Oil-Water Separation and Underwater Self-Cleaning Applications." University of Akron / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=akron1353362655.

Full text

APA, Harvard, Vancouver, ISO, and other styles

34

Isaacs, Justin Douglas. "Development and Commercialization of an Ozone Generator for the Oxidation of Mercury in Flue Gasses." Case Western Reserve University School of Graduate Studies / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=case1367332511.

Full text

APA, Harvard, Vancouver, ISO, and other styles

35

Sander, Zachary Hugo. "Heat Transfer, Fluid Dynamics, and Autoxidation Studies in the Jet Fuel Thermal Oxidation Tester (JFTOT)." University of Dayton / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1355367856.

Full text

APA, Harvard, Vancouver, ISO, and other styles

36

Bourquin, Yannyk Parulian Julian. "Shaping surface waves for diagnostics." Thesis, University of Glasgow, 2012. http://theses.gla.ac.uk/4167/.

Full text

Abstract:

Infectious diseases continue to kill millions of people every year and are a significant burden on the socio-economic development of developing countries. After many years of international policy aimed at containing diseases, it has recently become an explicit aim to move towards elimination of infectious diseases. However, if this is to occur, it will be necessary to have highly eficacious diagnostic tools to ensure infected individuals are identified and treated. However, the diagnosis of infectious diseases in the developed and developing world requires the full integration of complex assays in easy-to-use platforms with robust analytical performances at low cost. Many relevant bioanalytical technologies have been developed for use in laboratories and clinics, including the current gold standard for the diagnosis of tuberculosis and malaria. The miniaturization and integration of complex functions into lab-on-a-chip (LOC)technologies using microfluidics have only had limited success in translating diagnosis assays out of a centralized laboratory to point-of-care (POC) settings, because they still remain constrained due to chip interconnection and they are either not likely to go out of research laboratories or are not appropriate for low resource settings. In this thesis, a new microfluidic platform was developed that reduced the dependency of the diagnostic procedure on large laboratory instruments providing simplicity of use, enabling the patient sample to be processed and diagnosed on a low cost, disposable biochip. Surface acoustic wave (SAW) devices, which are commonly used in mobile phone technologies, were adapted to provide controlled microfluidic functions by shaping the SAW using particular designs of electrodes and phononic structures. The control of lateral positioning of the SAW was demonstrated using a slanted finger interdigitated transducer (IDT) in a frequency tuneable manner allowing microfluidic functions such as mixing, moving and merging, sequentially performed using a single IDT both on the substrate and on a disposable chip. Alternatively, phononic bandgaps were designed to break the symmetry of the SAW in a tuneable manner and gradient index phononic crystals (GRIN-PC) lenses were designed to focus the SAW and successfully increased the amplitude of the wave by a factor 3 while the focal position could be tuned with the frequency. The potential of these techniques was demonstrated by controlling the amplitude and direction of water jet towers by the use of a phononic horn structure that allowed the enhancement of energy at defined positions and by propelling and directing a macrometer scale object in water using a slanted IDT. As proof of concepts of diagnostic devices for the developing world, an immunoassay for tuberculosis using only mobile phone technologies (SAW, light-emitting diode(LED) and complementary metaloxidesemiconductor (CMOS) camera) was demonstrated with a limit of detection of 1 pM, which is the limit required in an interferon-release assay. This limit of detection was only achievable because of the ability of SAW to increase the mixing and to reduce the non-specific binding. Furthermore, a method to enrich malaria infected cells, based on SAW and isopycnic gradient, was also demonstrated and showed an enrichment up to 100x in the equivalent of a fingerprick of blood in 3 seconds. This technique will allow to reduce the limit of detection of the current gold standard. This platform not only opens a clear road toward POC diagnostics due to its size, cost, versatility and ease in integration, but has also the potential to provide useful tools in laboratory settings for large scale, high throughput technologies.

APA, Harvard, Vancouver, ISO, and other styles

37

Olszewski, Amy L. "Synthesis, Biological Functionalization, and Integration ofCarbon Nanotubes for Bio-Sensing Textiles." Youngstown State University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ysu1369854838.

Full text

APA, Harvard, Vancouver, ISO, and other styles

38

Silva, Mojica Ernesto. "Polymer-silica Hybrids for Separation of CO2 and Catalysis of Organic Reactions." University of Akron / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=akron1398439043.

Full text

APA, Harvard, Vancouver, ISO, and other styles

39

Gonzalez-Pena, Omar Israel. "Mass Transport Enhancement in Copper Electrodeposition due to Gas Co-Evolution." Case Western Reserve University School of Graduate Studies / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=case1439826379.

Full text

APA, Harvard, Vancouver, ISO, and other styles

40

Furlong, Brian Keith. "Selective hydrogenation of 1,3-butadiene in 1-butene over alumina supported palladium and palladium/copper catalysts." Thesis, 1994. http://hdl.handle.net/1911/13832.

Full text

Abstract:

Copper addition to palladium increases both activity and selectivity in the selective hydrogenation of 1,3-butadiene to n-butenes. The bimetal catalyst (Cu/Pd:2/1(atomic)) hydrogenates the diene to virtually 100% conversion without significant n-butene isomerization or butane formation. While at moderate conversions monometallic palladium is quite selective for n-butene production, 1-butene is quickly isomerized and saturated at higher conversions resulting from butadiene's inability to monopolize the active surface at lower partial pressures. Copper also promotes higher trans-2-butene selectivity and modifies the rate dependence on 1,3-butadiene from zero to negative order. These results suggest a donor "ligand" effect in which copper changes the palladium's electronic character. The apparent activation energy for 1,3-butadiene hydrogenation over palladium is 14.9 $\pm$ 0.2 kcal/mol.

APA, Harvard, Vancouver, ISO, and other styles

41

Routray, Kamalakanta. "Catalysis science of bulk mixed metal oxides." 2009. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3354755.

Full text

APA, Harvard, Vancouver, ISO, and other styles

42

Friedfeld, Stephen. "The temperature and ionic strength dependence of the solubility product constant of ferrous phosphonate." Thesis, 1997. http://hdl.handle.net/1911/17085.

Full text

Abstract:

The formation of ferrous phosphonate precipitate and its dissolution were monitored in a batch experiment for a range of temperatures and ionic strengths. The precipitate was found to be Fe$\sb{2.5}$HNTMP, where NTMP is a phosphonate compound. Using a complexation and speciation model, concentrations of free iron and phosphonate were calculated, from which the solubility product constant was derived for each temperature and ionic strength. The temperature (K) and ionic strength (M) dependence of the negative logarithm of the ferrous phosphonate solubility product constant $(pK\sb{\rm sp})$ was thus determined:$$pK\sb{\rm sp} = 39.54 - 6.14\sqrt{IS}+2.18IS - 1315/T.$$Simulated calculations using actual field data to compare iron and calcium phosphonates predicted ferrous salts to form in all instances and calcium salts to form occasionally. Further, a relationship was established whereby the concentration of free iron in a calcium-iron-phosphonate system can be predicted.

APA, Harvard, Vancouver, ISO, and other styles

43

Sun, Xiaoxuan. "Electrodeposition and Electroless Deposition of Copper in Interconnect Technology and Biotechnology Related Applications." Thesis, 2015. https://doi.org/10.7916/D83X8634.

Full text

Abstract:

Electroless copper deposition is a promising alternative technique for interconnect fabrication because it may be difficult for electrodeposition to fill features that are 10 nm and smaller. An electroless copper bath of low toxicity and mild operating conditions with dimethylamine borane (DMAB) as reducing agent was examined. The results were interpreted within the framework of mixed potential theory, and a strong catalytic effect of the presence of the anodic reaction to the cathodic reaction was observed, possibly due to a significant pH decrease near the electrode that impacts the chelation of cupric ions. It was also found that the nucleus density not only depends on the type of substrates, but is also controllable by pH, temperature and the addition of PEG. Whether electroless deposition will be implemented in manufacturing is dependent on continued improvements in electrodeposition, and organic additives play a major role in efficacy. Development of advanced additives continues, and two lab scale tools that facilitate additive studies are designed and implemented. A membrane-separated cell was developed to effectively differentiate additive aging on the cathode side and anode side. Additive behavior in the cell was characterized by cyclic voltammetric stripping (CVS), and a significant aging effect of bis (3-sulfopropyl) disulfide (SPS) on the cathode side was observed. The rate of aging increases at higher acid level and lower current density, yet decreases in the presence of PEG. Complex wafer plating tools have been developed for use in manufacturing to guarantee a high uniformity of copper electrodeposition. Wafer size tools were “scaled down” for lab use by introduction of a simple insulating shield system for coupon size plating studies to avoid poor current distribution. By numerical simulation, sensitivities of parameters were systematically studied, with which the optimum shield design was made. The design reduced the spatial variation in current density from 18% to only 3%. Copper deposition can be applied to other applications, and naturally constraints on processing can be very different. For example, for biosensor applications, copper deposition can be a signal amplification method of binding to engineered phages. Chapter 5 demonstrates the use of electroless copper deposition to image phage with both high sensitivity and low operational time and cost. A correlation between copper quantity and phage concentration was established, with a limit of detection in ppt level. A pre-concentration device can be utilized to detect phage of lower concentrations without significantly increasing the time for detection. In another example, copper deposition may be used in an integrated process to produce a biofuel. Here, the process is akin to copper electrowinning processes albeit with modified electrolytes. A design of the electrowinning cell was built in-house and showed product yield capability and scalability to serve the bioreactor. Lower cell potentials were demonstrated by utilizing novel mixed metal oxides anodes. Copper deposit adhesion depended on electrolyte composition, and this impacts bioreactor performance. The current efficiency during electrowinning is between 70% and 90% depending on electrolyte composition.

APA, Harvard, Vancouver, ISO, and other styles

44

Pontes, Maria Margarida Pereira de Medeiros. "Surface coating and curing technologies: Linking chemistry to applications." Dissertação, 2020. https://hdl.handle.net/10216/132766.

Full text

APA, Harvard, Vancouver, ISO, and other styles

45

Pontes, Maria Margarida Pereira de Medeiros. "Surface coating and curing technologies: Linking chemistry to applications." Master's thesis, 2020. https://hdl.handle.net/10216/132766.

Full text

APA, Harvard, Vancouver, ISO, and other styles

46

Ramluckan, Krishan. "The evaluation of liquid hydrocarbon contamination of soil around petrochemical tank farms at a Durban refinery." Thesis, 2004. http://hdl.handle.net/10321/162.

Full text

Abstract:

Thesis (M.Tech.: Chemistry) -Dept. of Chemistry, Durban Institute of Technology, 2004 xxiv, 349 leaves : ill. ; 31 cm
The primary objective of this study was to determine the levels of liquid hydrocarbon contamination present in the soil within the SAPREF refinery. The secondary objective arising from this was the development of a gas chromatographic (GC) method using a fifty metre PONA (Paraffin, Olefin, Naphthalene and Aromatic) capillary column and the split injection technique, for the analysis. Toluene was the solvent selected, with the Standard method for the BÜCHI extraction system, to extract the hydrocarbons present in the soil samples taken at the five different tank farm sites in the refinery. The main purpose of the analysis and evaluation was to enable the refinery to establish environmental control measures to reduce the contamination of the soil in the area.

APA, Harvard, Vancouver, ISO, and other styles

47

Rathilal, Sudesh. "Modelling of a vibrating-plate extraction column." Thesis, 2010. http://hdl.handle.net/10413/3706.

Full text

Abstract:

Liquid extraction, sometimes called solvent extraction, is the separation of the constituents of a liquid solution by contact with another insoluble liquid. It belongs to the class of countercurrent diffusional separation processes, where it ranks second in importance to distillation. There are many different types of columns that are available for liquid-liquid extraction and the reciprocating column (RPC) and vibrating plate column (VPE) are two types of mechanically aided columns. This research aims at developing a mathematical model for the prediction of NTUIHETS and the mass transfer coefficient, k-ox for the VPE based on the agitation level of the plates (af- the product of frequency and amplitude of the plate motion), the plate spacing and the flow rates which will allow for the simplification in the design of this type of column. There is a lot of research that has gone into the development of mechanically aided extraction columns but it is limited when it comes to the RPC and VPE and most of this research is devoted to the RPC. The system chosen is the acetone-toluene-water system with the acetone in toluene forming the feed that is dispersed in the column as it moves upward while the water moves as a continuous phase down the column. Experiments were conducted to evaluate the hydrodynamics of the droplets moving up the column (in terms of drop sizes, size distribution and dispersed phase holdup) and to evaluate the mass transfer that occurs (in order to evaluate NTU, HTU and k-ox) as well as the effect of mass transfer on the hydrodynamics of the system while varying the agitation levels and spacing of the plates in the column. Successful models were developed using some of the experimental data and these correlations were verified with additional data.
Thesis (Ph.D.)-University of KwaZulu-Natal, Durban, 2010.

APA, Harvard, Vancouver, ISO, and other styles

48

Harris, Roger Allen. "Monoethanolamine : suitability as an extractive solvent." Thesis, 2000. http://hdl.handle.net/10413/5454.

Full text

Abstract:

Separation processes are fundamental to all chemical engineering industries. Solvent separation, either liquid-liquid extraction or extractive distillation, is a specialised segment of separation processes. Solvents can be used either to optimise conventional distillation processes or for azeotropic systems, which can not be separated by conventional means. This work focuses on the performance of monoethanolamine (MEA) as a solvent in extractive distillation. Furthermore, the methodology of solvent evaluation is also studied. The preliminary assessment of solvent selection requires the determination of selectivity factors. The selectivity factor is defined as follows: P• = y,." . y, where y" is the activity coefficient at infinite dilution of the solute in the solvent. Subscript 1 and 2 refer to solute 1 and 2. A large selectivity factor implies enhanced separation of component 1 from 2 due to the solvent. Activity coefficients at infinite dilution were determined experimentally (gas-liquid chromatography) and predicted theoretically (UNIFAC group contribution method) for twenty-four solutes at three temperatures. Solutes used were alkanes, alkenes, alkynes, cyclo-alkanes, aromatics, ketones and alcohols. Most of this experimental work comprises data for systems which have not been measured before. Predicted and experimental values for y' were compared. For systems such as these (with polar solvents and non-polar solutes), UNIFAC results are not accurate and experimentation is vital. The experimental selectivity factors indicated tihat MEA could be an excellent solvent for hydrocarbon separation. Three binary azeotropic systems were chosen for further experimentation with MEA n-hexane (1) - benzene (2): fJ,~ = 31. Compared to other industrial solvents this is one of the largest values and MEA could serve as an excellent solvent. cyclohexane (1) - ethanol (2): fJ,~ = 148. This high value indicates an excellent solvent for this system. Acetone (1) - methanol (2): fJ,~ = 7.7. Further work involved vapour-liquid equilibrium experimentation at sub-atmospheric pressures in a dynamic recirculating stil l. The binary components with a certain amount of MEA were added to the still. The vapour and liquid mole fractions for the binary azeotropic components were measured and plotted on a solvent-free basis. The results are summarised below: n-hexane - benzene: Amount MEA added to still feed: 2%. MEA improved separability slightly. Further addition of MEA resulted in two liquid phases forming. cyclohexane - ethanol: Amount MEA added to still feed: 5% and 10%. Two liquid phases were formed for cyclohexane rich mixtures. Addition of MEA improved separability but did not remove the azeotrope. acetone - methanol: Amount MEA added to still feed : 5%, 10% and 20%. The ternary mixture remained homogenous and separability improved with addition of MEA. The binary azeotrope was eliminated. Due to the hetrogenous nature of the cyclohexane - ethanol system liquid-liquid equilibrium experimentation was performed to complete the analysis. Viable separation processes are possible for (a) cyclohexane - ethanol mixtures and for (b) acetone - methanol mixtures using MEA as the solvent. Comparison of various solvents used for the separation of acetone from methanol was possible by constructing equivolatility curves for the ternary systems. Results showed that MEA may possibly be the best solvent for this extractive distillation process. This study provides the following results and conclusions: • New thermodynamic data, important for the understanding of MEA in the field of solvent separations, was obtained. • Results show that the UNIFAC contribution method cannot be used to accurately predict polar solvent - non-polar solute y«> values. Experimentation is essential. • Selectivity factors indicate that MEA could be an excellent solvent for hydrocarbon separation. • The separation of the azeotropic cyclohexane - ethanol mixture is possible with a combination of extractive distillation and liquid-liquid extraction or simply liquid-liquid extraction using MEA as the solvent. • The separation of the azeotropic acetone methanol mixture is possible with extractive distillation using MEA as the solvent. The solvent MEA is possibly the best solvent for this separation.
Thesis (M.Sc.Eng.)-Univeristy of Natal, Durban, 2000.

APA, Harvard, Vancouver, ISO, and other styles

49

(11198013), Kevin Wee. "Creation, deconstruction, and evaluation of a biochemistry animation about the role of the actin cytoskeleton in cell motility." Thesis, 2021.

Find full text

Abstract:

External representations (ERs) used in science education are multimodal ensembles consisting of design elements to convey educational meanings to the audience. As an example of a dynamic ER, an animation presenting its content features (i.e., scientific concepts) via varying the feature’s depiction over time. A production team invited the dissertation author to inspect their creation of a biochemistry animation about the role of the actin cytoskeleton in cell motility and the animation’s implication on learning. To address this, the author developed a four-step methodology entitled the Multimodal Variation Analysis of Dynamic External Representations (MVADER) that deconstructs the animation’s content and design to inspect how each content feature is conveyed via the animation’s design elements.

This dissertation research investigated the actin animation’s educational value and the MVADER’s utility in animation evaluation. The research design was guided by descriptive case study methodology and an integrated framework consisting of the variation theory, multimodal analysis, and visual analytics. As stated above, the animation was analyzed using MVADER. The development of the actin animation and the content features the production team members intended to convey via the animation were studied by analyzing the communication records between the members, observing the team meetings, and interviewing the members individually. Furthermore, students’ learning experiences from watching the animation were examined via semi-structured interviews coupled with post- storyboarding. Moreover, the instructions of MVADER and its applications in studying the actin animation were reviewed to determine the MVADER’s usefulness as an animation evaluation tool.

Findings of this research indicate that the three educators in the production team intended the actin animation to convey forty-three content features to the undergraduate biology students. At least 50% of the student who participated in this thesis learned thirty-five of these forty-three (> 80%) features. Evidence suggests that the animation’s effectiveness to convey its features was associated with the features’ depiction time, the number of identified design elements applied to depict the features, and the features’ variation of depiction over time.

Additionally, one-third of the student participants made similar mistakes regarding two content features after watching the actin animation: the F-actin elongation and the F-actin crosslink structure in lamellipodia. The analysis reveals the animation’s potential design flaws that might have contributed to these common misconceptions. Furthermore, two disruptors to the creation process and the educational value of the actin animation were identified: the vagueness of the learning goals and the designer’s placement of the animation’s beauty over its reach to the learning goals. The vagueness of the learning goals hampered the narration scripting process. On the other hand, the designer’s prioritization of the animation’s aesthetic led to the inclusion of a “beauty shot” in the animation that caused students’ confusion.

MVADER was used to examine the content, design, and their relationships in the actin animation at multiple aspects and granularities. The result of MVADER was compared with the students’ learning outcomes from watching the animation to identify the characteristics of content’s depiction that were constructive and disruptive to learning. These findings led to several practical recommendations to teach using the actin animation and create educational ERs.

To conclude, this dissertation discloses the connections between the creation process, the content and design, and the educational implication of a biochemistry animation. It also introduces MVADER as a novel ER analysis tool to the education research and visualization communities. MVADER can be applied in various formats of static and dynamic ERs and beyond the disciplines of biology and chemistry.

APA, Harvard, Vancouver, ISO, and other styles

Dissertations / Theses on the topic 'Petroleum technology Chemical engineering Chemistry'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles