+publisher:"The Ohio State University" +contributor:("Tomasko, David")

The Ohio State University

1. Gong, Yiwen. Toward Better Understandings of Unconventional Reservoirs - Rock Mechanical Properties and Hydraulic Fracture Perspectives.

Degree: PhD, Chemical Engineering, 2020, The Ohio State University

URL: http://rave.ohiolink.edu/etdc/view?acc_num=osu1605633687308252

► The advancements of hydraulic fracturing techniques ensure the improved fracture surface areas that are open to fluids flow. The induced microcracks accelerate the fluid communications… (more)

▼ The advancements of hydraulic fracturing techniques ensure the improved fracture surface areas that are open to fluids flow. The induced microcracks accelerate the fluid communications between fractures and the fracture adjacent rock matrix at fracture surface. In brittle rocks, the generated fracture network puzzles engineers since the induced hydraulic fractures and activated pre-existing fractures challenge the stimulated reservoir volume (SRV) characterizations. Furthermore, the necessary engineered justifications of each stage due to lateral heterogeneity of the reservoir and the stress shadow effect (in-situ stress increase along the wellbore) even introduce another level of complexity of the effective fracture drainage complexity. Simultaneous fracture growth becomes difficult, resulting in variations of fracture half lengths, within a stage, and among stages. The failure planes of the rock, from mode I, mode II and the combination of them, are not smooth and parallel; instead, they are usually associated with certain surface roughness and non-planar morphology, which in turn inhibit the ideal Poiseuille flow in the fracture. As a result, the fundamental studies of non-planar and rough complex fracture paths to the proppant transport are essentially inevitable.To gain better understanding of the fracture network and the geomechanical aspects that form the complex fracture network, the objective of this work is firstly to quantitatively measure the rock damage from the induced microcracks at the adjacent matrix of the hydraulic fracture; we will then investigate the rock geomechanical properties which essentially dominant the fracture generation using machine learning approaches with cross-disciplinary data sources, including well logs, petrophysical properties, and rock microstructures information. Lastly, we will probe proppant transport characteristics in bifurcated fracture system. To achieve the aforementioned adjectives, this dissertation is structured into two major parts: the microstructure diagnosis of fractured tight rocks and geomechanical rock property estimations beyond the traditional approach as the first part and the proppant transport considering the induced microfracture/bifurcated fractures as the second part. To be more specific, the microstructure analysis is achieved by SEM image analysis while the geomechanical study is conducted optimizing the data usage from machine learning techniques. The second major part is to build the complex fracture network modeling by including non-planarity, and secondary fractures and tertiary fractures in the computational fluid dynamics modeling frame (Eulerian-Eulerian) in the field scale as well as computational fluid dynamics – discrete element method coupling frame (Eulerian- Lagrangian) in the flow-unit scale, respectively. The proppant transport loss passing the bifurcated fractures are evaluated. Advisors/Committee Members: El-Monier, Ilham (Advisor), Tomasko, David (Committee Co-Chair).

Subjects/Keywords: Chemical Engineering; Petroleum Engineering; Proppant transport; machine learning; rock geomechanical properties; CFD; CFD-DEM

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APA (6^th Edition):

Gong, Y. (2020). Toward Better Understandings of Unconventional Reservoirs - Rock Mechanical Properties and Hydraulic Fracture Perspectives. (Doctoral Dissertation). The Ohio State University. Retrieved from http://rave.ohiolink.edu/etdc/view?acc_num=osu1605633687308252

Chicago Manual of Style (16^th Edition):

Gong, Yiwen. “Toward Better Understandings of Unconventional Reservoirs - Rock Mechanical Properties and Hydraulic Fracture Perspectives.” 2020. Doctoral Dissertation, The Ohio State University. Accessed April 12, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=osu1605633687308252.

MLA Handbook (7^th Edition):

Gong, Yiwen. “Toward Better Understandings of Unconventional Reservoirs - Rock Mechanical Properties and Hydraulic Fracture Perspectives.” 2020. Web. 12 Apr 2021.

Vancouver:

Gong Y. Toward Better Understandings of Unconventional Reservoirs - Rock Mechanical Properties and Hydraulic Fracture Perspectives. [Internet] [Doctoral dissertation]. The Ohio State University; 2020. [cited 2021 Apr 12]. Available from: http://rave.ohiolink.edu/etdc/view?acc_num=osu1605633687308252.

Council of Science Editors:

Gong Y. Toward Better Understandings of Unconventional Reservoirs - Rock Mechanical Properties and Hydraulic Fracture Perspectives. [Doctoral Dissertation]. The Ohio State University; 2020. Available from: http://rave.ohiolink.edu/etdc/view?acc_num=osu1605633687308252

The Ohio State University

2. patankar, sumant s. Role of Confinement on the Properties of Ethane and Ethane-CO2 Mixtures in Mesoporous Silica.

Degree: PhD, Chemical Engineering, 2016, The Ohio State University

URL: http://rave.ohiolink.edu/etdc/view?acc_num=osu1471541134

► Hydrocarbon fluids distributed all around the world in subterranean reservoirs form a significant source of energy. These fluids are found in the fractures and pores… (more)

Subjects/Keywords: Chemical Engineering

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APA (6^th Edition):

patankar, s. s. (2016). Role of Confinement on the Properties of Ethane and Ethane-CO2 Mixtures in Mesoporous Silica. (Doctoral Dissertation). The Ohio State University. Retrieved from http://rave.ohiolink.edu/etdc/view?acc_num=osu1471541134

Chicago Manual of Style (16^th Edition):

patankar, sumant s. “Role of Confinement on the Properties of Ethane and Ethane-CO2 Mixtures in Mesoporous Silica.” 2016. Doctoral Dissertation, The Ohio State University. Accessed April 12, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=osu1471541134.

MLA Handbook (7^th Edition):

patankar, sumant s. “Role of Confinement on the Properties of Ethane and Ethane-CO2 Mixtures in Mesoporous Silica.” 2016. Web. 12 Apr 2021.

Vancouver:

patankar ss. Role of Confinement on the Properties of Ethane and Ethane-CO2 Mixtures in Mesoporous Silica. [Internet] [Doctoral dissertation]. The Ohio State University; 2016. [cited 2021 Apr 12]. Available from: http://rave.ohiolink.edu/etdc/view?acc_num=osu1471541134.

Council of Science Editors:

patankar ss. Role of Confinement on the Properties of Ethane and Ethane-CO2 Mixtures in Mesoporous Silica. [Doctoral Dissertation]. The Ohio State University; 2016. Available from: http://rave.ohiolink.edu/etdc/view?acc_num=osu1471541134

The Ohio State University

3. Munj, Hrishikesh. CO2 ASSISTED PROCESSING OF BIOCOMPATIBLE ELECTROSPUN POLYMER BLENDS.

Degree: PhD, Chemical and Biomolecular Engineering, 2014, The Ohio State University

URL: http://rave.ohiolink.edu/etdc/view?acc_num=osu1400693315

► Current biomedical applications are focused towards solving more challenging problems with sustainable and economic solutions. Drug delivery systems, tissue engineered scaffolds and diagnostic devices are… (more)

▼ Current biomedical applications are focused towards solving more challenging problems with sustainable and economic solutions. Drug delivery systems, tissue engineered scaffolds and diagnostic devices are major areas of biomedical systems which require more efficient and benign fabrication and processing. Design of above mentioned systems involves three key components; biomaterial selection, structure and nutrient supply. Various factors such as, biocompatibility, degradation, toxicity, mechanical properties, need to be considered before biomaterial selection for specific application. Polymers are most widely used for biomedical applications due to their ability to tailor properties for specific requirements. Structured patterns are mandatory in most of the biomedical systems such as core-shell structure for drug delivery, porous scaffolds for tissue engineering and microchannels for microfluidics based devices. In the end, these systems demand efficient incorporation of sensitive drug and biomolecules and controlled release. Thus, designing of biomedical systems become a complex process where structure needs to be maintained for a biomaterial throughout the design process. High pressure carbon dioxide (CO2) offers a `green’s benign and inexpensive way for fabrication and impregnation of additives in the biocompatible polymers. CO2 assisted plasticization of polymers enhances diffusion of additives in the polymer matrix. However, interactions among polymer, CO2 and additives are complex and difficult to understand. Density and diffusivity of CO2 can be controlled easily by adjusting temperature and pressure. Hence extent of plasticization of polymer can be controlled. In the present study, biocompatible polymer blends were investigated from biomedical applications perspective. Electrospinning is a versatile process to prepare fibrous scaffolds. This process was applied to different binary and ternary blends to fabricate electrospun scaffolds. There scaffolds were impregnated with additives using high pressure CO2 to study release profiles. Results show electrospun polymer blends interact differently with each process step adopted in this study. Effect of dominant impregnation and release parameters were investigated to control and predict release of additives from complex electrospun scaffolds. The work presented in this dissertation aids in understanding of additive release from electrospun polymer blends with complex behavior. Advisors/Committee Members: Tomasko, David (Advisor).

Subjects/Keywords: Chemical Engineering; Polymers; Biomedical Engineering; Bio-Compatible Polymers, Electrospinning, Impregnation, Release, Diffusion, High Pressure CO2

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APA (6^th Edition):

Munj, H. (2014). CO2 ASSISTED PROCESSING OF BIOCOMPATIBLE ELECTROSPUN POLYMER BLENDS. (Doctoral Dissertation). The Ohio State University. Retrieved from http://rave.ohiolink.edu/etdc/view?acc_num=osu1400693315

Chicago Manual of Style (16^th Edition):

Munj, Hrishikesh. “CO2 ASSISTED PROCESSING OF BIOCOMPATIBLE ELECTROSPUN POLYMER BLENDS.” 2014. Doctoral Dissertation, The Ohio State University. Accessed April 12, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=osu1400693315.

MLA Handbook (7^th Edition):

Munj, Hrishikesh. “CO2 ASSISTED PROCESSING OF BIOCOMPATIBLE ELECTROSPUN POLYMER BLENDS.” 2014. Web. 12 Apr 2021.

Vancouver:

Munj H. CO2 ASSISTED PROCESSING OF BIOCOMPATIBLE ELECTROSPUN POLYMER BLENDS. [Internet] [Doctoral dissertation]. The Ohio State University; 2014. [cited 2021 Apr 12]. Available from: http://rave.ohiolink.edu/etdc/view?acc_num=osu1400693315.

Council of Science Editors:

Munj H. CO2 ASSISTED PROCESSING OF BIOCOMPATIBLE ELECTROSPUN POLYMER BLENDS. [Doctoral Dissertation]. The Ohio State University; 2014. Available from: http://rave.ohiolink.edu/etdc/view?acc_num=osu1400693315

4. Feng, Lu. Experimental Study of Nucleation in Polystyrene/CO2 System.

Degree: PhD, Chemical and Biomolecular Engineering, 2012, The Ohio State University

URL: http://rave.ohiolink.edu/etdc/view?acc_num=osu1330866154

► Polymer foams have many applications, e.g., being used as insulation material, sound-adsorbing material, and packaging material, due to their features and enhanced performance, compared to… (more)

▼ Polymer foams have many applications, e.g., being used as insulation material, sound-adsorbing material, and packaging material, due to their features and enhanced performance, compared to the counterpart, namely pure polymers. Therefore, both industrial and academic communities have put much effort to investigate polymer foams from exploring new applications to enhancing the performance. Although progress has been made on those paths; one challenge remains, i.e., poor control of morphology of polymer foams. In order to fully address this challenge, fundamental understanding of morphology evolution is needed.Additionally, the traditional blowing agents for polymer foams, i.e., chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs), are banned from the market according to the Montreal protocol as these chemicals cause ozone depletion. Therefore, it is necessary to find a replacement for CFCs and HCFCs as blowing agents. Among all the promising alternatives, CO2 has attracted much interest due to being environmentally benign and it's relative ease of use, compared to other candidates, e.g., water and N2. In present study, nucleation, an important stage of morphology evolution in the polymer foaming process, is experimentally studied in the polystyrene/CO2 system. Specifically, nucleation experiments are conducted on different polystyrene/CO2 systems where polystyrene has different molecular weights. Then, based on the information extracted from nucleation experiments, a scaling curve in terms of free energy barrier of nucleation is constructed for the purpose of providing insight into the connection between phase equilibrium boundaries and nucleation phenomena. The result shows that the scaling curve is practically independent of molecular weight, indicating that the same scaling curve could be applied to different polystyrene/CO2 systems where polystyrene has different molecular weights for the prediction of free energy barrier of nucleation. Further, the finding that the scaling curve is practically independent of molecular weight of polystyrene partially confirms the claim that scaling curve is practically independent of intermolecular potentials. Advisors/Committee Members: Tomasko, David (Committee Chair).

Subjects/Keywords: Chemical Engineering; Polystyrene; Carbon dioxide; nucleation; foaming; free energy barrier

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APA (6^th Edition):

Feng, L. (2012). Experimental Study of Nucleation in Polystyrene/CO2 System. (Doctoral Dissertation). The Ohio State University. Retrieved from http://rave.ohiolink.edu/etdc/view?acc_num=osu1330866154

Chicago Manual of Style (16^th Edition):

Feng, Lu. “Experimental Study of Nucleation in Polystyrene/CO2 System.” 2012. Doctoral Dissertation, The Ohio State University. Accessed April 12, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=osu1330866154.

MLA Handbook (7^th Edition):

Feng, Lu. “Experimental Study of Nucleation in Polystyrene/CO2 System.” 2012. Web. 12 Apr 2021.

Vancouver:

Feng L. Experimental Study of Nucleation in Polystyrene/CO2 System. [Internet] [Doctoral dissertation]. The Ohio State University; 2012. [cited 2021 Apr 12]. Available from: http://rave.ohiolink.edu/etdc/view?acc_num=osu1330866154.

Council of Science Editors:

Feng L. Experimental Study of Nucleation in Polystyrene/CO2 System. [Doctoral Dissertation]. The Ohio State University; 2012. Available from: http://rave.ohiolink.edu/etdc/view?acc_num=osu1330866154

The Ohio State University

5. Ellis, Jeffrey LeClair. Dense Carbon Dioxide Assisted Polymer Processing at the Nanoscale.

Degree: PhD, Chemical Engineering, 2009, The Ohio State University

URL: http://rave.ohiolink.edu/etdc/view?acc_num=osu1244033142

► Nanotechnology is continually becoming more integrated into consumer products used by the general public on a daily basis. Consumers reap the benefits of enhanced properties… (more)

▼ Nanotechnology is continually becoming more integrated into consumer products used by the general public on a daily basis. Consumers reap the benefits of enhanced properties for these commercial products, and yet they are still affordable. For biomedical products, that include nanofeatures, this is not yet a reality. The materials and methods used to fabricate these products are still far too expensive. There are many inexpensive and commercially available polymers that have potential to be used in these advanced biomedical products, but the fabrication techniques still lack the simplicity required to create an inexpensive end product.Supercritical CO₂ has been used to overcome the polymeric nanofabrication barriers for high throughput production of biomedical devices. Novel CO₂-assisted low temperature polymer nanoprocessing fabrication techniques have been implemented for use in biomedical product creation. Polymer nanofabrication techniques such as bonding, imprinting, and active biomolecule immobilization were demenonstrated. Due to being CO₂-assisted techniques, these processes are intrinsically inexpensive and environmentally benign.In order to thoroughly investigate these nanofabrication techniques the interactions between CO₂ and the polymer were examined on a thermodynamic level. Thermodynamic modeling results of high pressure CO₂/polystyrene systems were used along with experimental bonding, imprinting, and immobilization results. It was found that the solubility of CO₂ in a polymer matrix and the resulting reduction of the polymer glass transition temperature (T_g) largely dictate the polymer chain mobility and therefore the polymer's processability. For instance, it was shown that the polymer bond strength of polystyrene, bonded via a CO₂-assisted technique, depended largely on the proximity of the processing conditions to the reduced T_g curve. It was also found that low aspect ratio nanofeatures could be patterned by CO₂-assisted nanoimprint lithography in polystyrene at conditions near the reduced T_g curve.These CO₂-assisted low temperature polymer processing techniques are now better understood in terms of the CO₂/polymer thermodynamic properties, thus making these, and other similar, techniques easier to control. This fundamental information can be applied to scaling-up these technologies so that inexpensive polymer biomedical products with nanofeatures can soon be commercially produced, thus benefiting the health of society. Advisors/Committee Members: Tomasko, David (Advisor).

Subjects/Keywords: Chemical Engineering; polymer processing; polystyrene; supercritical CO<; sub>; 2<; /sub>;

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APA (6^th Edition):

Ellis, J. L. (2009). Dense Carbon Dioxide Assisted Polymer Processing at the Nanoscale. (Doctoral Dissertation). The Ohio State University. Retrieved from http://rave.ohiolink.edu/etdc/view?acc_num=osu1244033142

Chicago Manual of Style (16^th Edition):

Ellis, Jeffrey LeClair. “Dense Carbon Dioxide Assisted Polymer Processing at the Nanoscale.” 2009. Doctoral Dissertation, The Ohio State University. Accessed April 12, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=osu1244033142.

MLA Handbook (7^th Edition):

Ellis, Jeffrey LeClair. “Dense Carbon Dioxide Assisted Polymer Processing at the Nanoscale.” 2009. Web. 12 Apr 2021.

Vancouver:

Ellis JL. Dense Carbon Dioxide Assisted Polymer Processing at the Nanoscale. [Internet] [Doctoral dissertation]. The Ohio State University; 2009. [cited 2021 Apr 12]. Available from: http://rave.ohiolink.edu/etdc/view?acc_num=osu1244033142.

Council of Science Editors:

Ellis JL. Dense Carbon Dioxide Assisted Polymer Processing at the Nanoscale. [Doctoral Dissertation]. The Ohio State University; 2009. Available from: http://rave.ohiolink.edu/etdc/view?acc_num=osu1244033142

The Ohio State University

6. Guo, Zhihua. Experimental Analysis of Polymer Nanocomposite Foaming Using Carbon Dioxide.

Degree: PhD, Chemical Engineering, 2008, The Ohio State University

URL: http://rave.ohiolink.edu/etdc/view?acc_num=osu1204562216

► In this research, environmentally benign carbon dioxide (CO2) was used as a physical blowing agent in the foaming of PS and PS nanocomposites due to… (more)

▼ In this research, environmentally benign carbon dioxide (CO2) was used as a physical blowing agent in the foaming of PS and PS nanocomposites due to the phase-out of chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs). CNFs (carbon nanofibers) and AC (activated carbon) were used as additive/nucleation agents in PS extrusion foaming. Both fillers showed promising application in insulation foams. The typical foaming process includes cell nucleation, cell growth, and cell stabilization. In this study, primary attention was given to the effects of the material related properties, solubility, diffusivity, and shear viscosity, on cell nucleation and cell growth. Two equations of state (EOS), Sanchez-Lacombe (S-L) EOS and perturbed chain statistical associating fluid theory (PC-SAFT), were used to model the solubility and also phase boundaries (binodal and spinodal curves). Nucleation is a very complex phenomenon in physical foam processing. Proposed scaling functions provide a possible way to calculate the energy barrier in the nucleus formation. Cell nucleation rate data were extracted from the literature and also by our experiments. The initial slope of the possible scaling function was calculated by the diffuse interface theory. A scaling function was correlated based on the calculation from experimental data. Shear viscosity of polymers and nanocomposites under high pressure CO2 were studied via unique modified high pressure Couette rheometry. The effects of nanoparticles on shear viscosity of polymer w/ and w/o CO2 were compared. The permeability coefficient, defined as the product of the solubility coefficient and diffusivity, of CO2 and water vapor in polymer nanocomposites and foams were measured near ambient temperature and pressure. The effects of nanoparticle and foam morphology on permeation were studied. To gain more insight on the early stages of the foaming process, in-situ observation of batch foaming and a quenching method were used to study foams with different cell growth times. In addition, the quantitative cell nucleation and growth rates were measured by our novel experimental setup. These cell nucleation rate data provided valuable information for modeling and theoretical correlation. Based on these experimental studies and modeling, a deeper and more comprehensive understanding of polymer and nanocomposite foaming was achieved. Advisors/Committee Members: Tomasko, David (Committee Chair), Lee, Ly (Advisor).

Subjects/Keywords: Chemical Engineering; Polymers; polymer; nanocomposite; foam; carbon dioxide; solubility; nucleation; cell growth; permeation; rheology

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APA (6^th Edition):

Guo, Z. (2008). Experimental Analysis of Polymer Nanocomposite Foaming Using Carbon Dioxide. (Doctoral Dissertation). The Ohio State University. Retrieved from http://rave.ohiolink.edu/etdc/view?acc_num=osu1204562216

Chicago Manual of Style (16^th Edition):

Guo, Zhihua. “Experimental Analysis of Polymer Nanocomposite Foaming Using Carbon Dioxide.” 2008. Doctoral Dissertation, The Ohio State University. Accessed April 12, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=osu1204562216.

MLA Handbook (7^th Edition):

Guo, Zhihua. “Experimental Analysis of Polymer Nanocomposite Foaming Using Carbon Dioxide.” 2008. Web. 12 Apr 2021.

Vancouver:

Guo Z. Experimental Analysis of Polymer Nanocomposite Foaming Using Carbon Dioxide. [Internet] [Doctoral dissertation]. The Ohio State University; 2008. [cited 2021 Apr 12]. Available from: http://rave.ohiolink.edu/etdc/view?acc_num=osu1204562216.

Council of Science Editors:

Guo Z. Experimental Analysis of Polymer Nanocomposite Foaming Using Carbon Dioxide. [Doctoral Dissertation]. The Ohio State University; 2008. Available from: http://rave.ohiolink.edu/etdc/view?acc_num=osu1204562216

The Ohio State University

7. Wingert, Maxwell. Carbon dioxide foaming and High-pressure rheology of polystyrene and polystyrene/organoclay nanocomposites.

Degree: PhD, Chemical Engineering, 2007, The Ohio State University

URL: http://rave.ohiolink.edu/etdc/view?acc_num=osu1167770881

► The polymer foam industry is slowly implementing carbon dioxide (CO2) as a low-cost, safe, and environmentally friendly blowing agent alternative to fluorocarbons and hydrocarbons. Progress… (more)

▼ The polymer foam industry is slowly implementing carbon dioxide (CO2) as a low-cost, safe, and environmentally friendly blowing agent alternative to fluorocarbons and hydrocarbons. Progress is slow due to several obstacles, ranging from low blowing agent solubility to a lack of quantitative understanding of the influence of carbon dioxide on viscosity. A crucial property in foam extrusion is viscosity. Several research groups have published viscosity data of polymer melts under high pressure, using a variety of techniques. However, few studies assist in designing polymer processing equipment because most do not contain predictive scaling (e.g., WLF-analogous scaling factors) to apply to different operating conditions. A new high-pressure rotational rheometer has been applied to polystyrene and carbon dioxide at five concentrations. It provides direct measurement of the zero shear viscosity of the polymer under a high pressure diluent. The method allows many viscosity measurements to be performed on a single sample. Scaling factors are applied to the data and the WLF-Chow equation is found to describe the results when the appropriate parameter is selected. Due to an interest in using organoclay nanoparticles for foaming, the viscosity of the polystyrene-nanoclay-CO2 system is studied using the couette rheometer and an extruder slit die. At high shear rates (10 to 100 s-1), the viscosity of polystyrene-nanoclay-CO2 unexpectedly possesses a lower viscosity than polystyrene-CO2 at the same concentration. At low shear rates (10-3 to 1 s-1), this effect is not observed. It is suspected that interfacial slip is occurred at the interface at high shear rates. Polymer additives allow tuning of bubble morphology without changing operating conditions. In this study, either a second polymer or nanoparticles are studied. Poly (methyl methacrylate) (PMMA) has the ability to drastically reduce cell size of polystyrene (PS) foams. It is believed that heterogeneous nucleation occurs at the interface of PS/PMMA, but that the bubbles are able to grow out of both phases simultaneously. Advisors/Committee Members: Tomasko, David (Advisor).

Subjects/Keywords: Engineering, Chemical; nanoclay; organoclay; viscosity; carbon dioxide; co2; polystyrene; ps; couette rheometer; foaming; supercritical fluids

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APA (6^th Edition):

Wingert, M. (2007). Carbon dioxide foaming and High-pressure rheology of polystyrene and polystyrene/organoclay nanocomposites. (Doctoral Dissertation). The Ohio State University. Retrieved from http://rave.ohiolink.edu/etdc/view?acc_num=osu1167770881

Chicago Manual of Style (16^th Edition):

Wingert, Maxwell. “Carbon dioxide foaming and High-pressure rheology of polystyrene and polystyrene/organoclay nanocomposites.” 2007. Doctoral Dissertation, The Ohio State University. Accessed April 12, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=osu1167770881.

MLA Handbook (7^th Edition):

Wingert, Maxwell. “Carbon dioxide foaming and High-pressure rheology of polystyrene and polystyrene/organoclay nanocomposites.” 2007. Web. 12 Apr 2021.

Vancouver:

Wingert M. Carbon dioxide foaming and High-pressure rheology of polystyrene and polystyrene/organoclay nanocomposites. [Internet] [Doctoral dissertation]. The Ohio State University; 2007. [cited 2021 Apr 12]. Available from: http://rave.ohiolink.edu/etdc/view?acc_num=osu1167770881.

Council of Science Editors:

Wingert M. Carbon dioxide foaming and High-pressure rheology of polystyrene and polystyrene/organoclay nanocomposites. [Doctoral Dissertation]. The Ohio State University; 2007. Available from: http://rave.ohiolink.edu/etdc/view?acc_num=osu1167770881

The Ohio State University

8. Liu, Dehua. Thermodynamic and glass transition behavior in CO₂-Polymer systems emphasizing the surface region.

Degree: PhD, Chemical Engineering, 2006, The Ohio State University

URL: http://rave.ohiolink.edu/etdc/view?acc_num=osu1149020480

► Application of carbon dioxide in polymer processing is a very attractive and innovative research area, driven by its significant impacts on environmental concerns, scientific and… (more)

▼ Application of carbon dioxide in polymer processing is a very attractive and innovative research area, driven by its significant impacts on environmental concerns, scientific and technological advancement and challenge. In this work, the interaction between CO₂ and polymer, including both bulk phase and thin film, has been addressed and modeled in order to guide the product and process development with the aid of CO₂2. An Axisymmetric Drop Shape Analysis (ADSA) method was developed to determine the CO₂-induced polymer dilation over a wide range of temperature and pressure. The experimental CO₂ sorption, polymer swelling and glass transition temperature (Tg) depression, have been successfully integrated with a single model, i.e., Sanchez-Lacombe Equation of State (SLEOS). Moreover, the benefits of CO₂ were demonstrated in the manufacturing of drug/polymer composite by reducing the operation temperature up to 35°C. Meanwhile, the anomalous polymer surface property, particularly Tg, was revealed in the development of CO₂-assisted polymer interfacial bonding technique. It is believed that the polymer surface has a lower Tg relative to its regular bulk value. An Atomic Force Microscopy (AFM)–based visualization method was developed to explore this surface phenomenon. The results demonstrated that CO₂ is able to further enhance the chain mobility near the surface region and allow the surface manipulation at lower temperatures. It has been hypothesized that shifts in the glass transition temperature in a polymer thin film or near a polymer surface is the result of liquid-like layer in that special region. We report here the first attempt to confirm this liquid-like layer theoretically by applying an inhomogeneous fluid theory combined with a chain molecule equation of state. Calculated entropy gradients in the surface region of a polymer reveal a liquid-like layer on the order of 1 nm at temperatures below the bulk Tg. This simple model provides a robust starting point for exploring the relation between experimentally observed anomalous properties and the inhomogeneities present near the surface. Advisors/Committee Members: Tomasko, David (Advisor).

Subjects/Keywords: Engineering, Chemical; Carbon dioxide; Polymer; Glass transition temperature(Tg); Swelling; Sanchez-Lacombe Equation of State; Surface Tg; Entropy density model

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APA (6^th Edition):

Liu, D. (2006). Thermodynamic and glass transition behavior in CO₂-Polymer systems emphasizing the surface region. (Doctoral Dissertation). The Ohio State University. Retrieved from http://rave.ohiolink.edu/etdc/view?acc_num=osu1149020480

Chicago Manual of Style (16^th Edition):

Liu, Dehua. “Thermodynamic and glass transition behavior in CO₂-Polymer systems emphasizing the surface region.” 2006. Doctoral Dissertation, The Ohio State University. Accessed April 12, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=osu1149020480.

MLA Handbook (7^th Edition):

Liu, Dehua. “Thermodynamic and glass transition behavior in CO₂-Polymer systems emphasizing the surface region.” 2006. Web. 12 Apr 2021.

Vancouver:

Liu D. Thermodynamic and glass transition behavior in CO₂-Polymer systems emphasizing the surface region. [Internet] [Doctoral dissertation]. The Ohio State University; 2006. [cited 2021 Apr 12]. Available from: http://rave.ohiolink.edu/etdc/view?acc_num=osu1149020480.

Council of Science Editors:

Liu D. Thermodynamic and glass transition behavior in CO₂-Polymer systems emphasizing the surface region. [Doctoral Dissertation]. The Ohio State University; 2006. Available from: http://rave.ohiolink.edu/etdc/view?acc_num=osu1149020480

The Ohio State University

9. Gao, Weihong. Adsorption of supercritical carbon dioxide on microporous adsorbents: experiment and simulation.

Degree: PhD, Chemical Engineering, 2005, The Ohio State University

URL: http://rave.ohiolink.edu/etdc/view?acc_num=osu1114617964

► Supercritical carbon dioxide is an efficient solvent for adsorption separations because it can potentially be used as both the carrier solvent for adsorption and the… (more)

Subjects/Keywords: zeolite; SUPERCRITICAL; excess adsorption; pore; adsorption of CO2

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APA (6^th Edition):

Gao, W. (2005). Adsorption of supercritical carbon dioxide on microporous adsorbents: experiment and simulation. (Doctoral Dissertation). The Ohio State University. Retrieved from http://rave.ohiolink.edu/etdc/view?acc_num=osu1114617964

Chicago Manual of Style (16^th Edition):

Gao, Weihong. “Adsorption of supercritical carbon dioxide on microporous adsorbents: experiment and simulation.” 2005. Doctoral Dissertation, The Ohio State University. Accessed April 12, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=osu1114617964.

MLA Handbook (7^th Edition):

Gao, Weihong. “Adsorption of supercritical carbon dioxide on microporous adsorbents: experiment and simulation.” 2005. Web. 12 Apr 2021.

Vancouver:

Gao W. Adsorption of supercritical carbon dioxide on microporous adsorbents: experiment and simulation. [Internet] [Doctoral dissertation]. The Ohio State University; 2005. [cited 2021 Apr 12]. Available from: http://rave.ohiolink.edu/etdc/view?acc_num=osu1114617964.

Council of Science Editors:

Gao W. Adsorption of supercritical carbon dioxide on microporous adsorbents: experiment and simulation. [Doctoral Dissertation]. The Ohio State University; 2005. Available from: http://rave.ohiolink.edu/etdc/view?acc_num=osu1114617964

The Ohio State University

10. Clogston, Jeffrey. Applications of the lepidic cubic phase: from controlled release and uptake to in meso crystallization of membrane proteins.

Degree: PhD, Chemical Engineering, 2005, The Ohio State University

URL: http://rave.ohiolink.edu/etdc/view?acc_num=osu1117564268

► The lipidic cubic phase consists of a pair of interpenetrating but non-contacting aqueous channels separated by a single, highly curved continuous lipid bilayer. Because of… (more)

▼ The lipidic cubic phase consists of a pair of interpenetrating but non-contacting aqueous channels separated by a single, highly curved continuous lipid bilayer. Because of its unique microstructure and dual nature (hydrophobic/hydrophilic character), the cubic phase finds use in controlled release and uptake. With a view to exploiting these features in combination with small molecule and proteinaceous drugs, a systematic approach aimed at understanding how the transport properties of the cubic phases are controlled by phase identity and microstructure (aqueous channel size) and by the physical and chemical properties of the drug itself (molecular size, shape) was taken. Furthermore, tailored release was demonstrated by adjusting electrostatic interaction strength and by His-tag displacement. Additional control was demonstrated by alkylating a water-soluble additive in such a manner that it interacted with the lipid bilayer. The results show that by varying the alkyl chain length, the release from the cubic phase can be controlled/prolonged in a systematic manner. While the previous study examined diffusion within the water channels, the study was extended to include lipid-soluble additives. For this purpose, the diffusion of three hydrophobic additives ranging in size from a small molecule (354 g/mol) to a huge multisubunit membrane protein (~129 kDa) in the lipid bilayer was quantified. This made use of commercial quartz tubing (microcuvettes), which allowed for the measurement of small sample volumes (1-5 uL). The results compare well with those obtained using more complicated techniques. Finally, the possibility of exploiting the "sponge-like" properties of the cubic phase in wastewater remediation was investigated. For this purpose, Myverol 18-99K, a relatively inexpensive commercial and biocompatible material, was used as the source lipid. Accordingly, the uptake of phenol, a wastewater contaminant of note, into pre-formed cubic phase prepared from Myverol has been quantified. This was compared to uptake by "neat" or pure Myverol, by a colloidal dispersion of the Myverol-based cubic phase referred to as cubosomes and by activated carbon. Advisors/Committee Members: Tomasko, David (Advisor).

Subjects/Keywords: Engineering, Chemical; diffusion coefficients; lipidic cubic phase; drug delivery; monoolein

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Clogston, J. (2005). Applications of the lepidic cubic phase: from controlled release and uptake to in meso crystallization of membrane proteins. (Doctoral Dissertation). The Ohio State University. Retrieved from http://rave.ohiolink.edu/etdc/view?acc_num=osu1117564268

Chicago Manual of Style (16^th Edition):

Clogston, Jeffrey. “Applications of the lepidic cubic phase: from controlled release and uptake to in meso crystallization of membrane proteins.” 2005. Doctoral Dissertation, The Ohio State University. Accessed April 12, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=osu1117564268.

MLA Handbook (7^th Edition):

Clogston, Jeffrey. “Applications of the lepidic cubic phase: from controlled release and uptake to in meso crystallization of membrane proteins.” 2005. Web. 12 Apr 2021.

Vancouver:

Clogston J. Applications of the lepidic cubic phase: from controlled release and uptake to in meso crystallization of membrane proteins. [Internet] [Doctoral dissertation]. The Ohio State University; 2005. [cited 2021 Apr 12]. Available from: http://rave.ohiolink.edu/etdc/view?acc_num=osu1117564268.

Council of Science Editors:

Clogston J. Applications of the lepidic cubic phase: from controlled release and uptake to in meso crystallization of membrane proteins. [Doctoral Dissertation]. The Ohio State University; 2005. Available from: http://rave.ohiolink.edu/etdc/view?acc_num=osu1117564268

The Ohio State University

11. Hongbo, Li. The effect of interfacial tension in CO₂ assisted polymer processing.

Degree: PhD, Chemical Engineering, 2004, The Ohio State University

URL: http://rave.ohiolink.edu/etdc/view?acc_num=osu1087479703

► Supercritical CO₂ is a promising solvent for application in polymer blending and foaming. The addition of small amounts of compressed gases to polymer phases results… (more)

▼ Supercritical CO₂ is a promising solvent for application in polymer blending and foaming. The addition of small amounts of compressed gases to polymer phases results in substantial and sometimes dramatic changes in the physical properties that dictate processing. Interfacial tension is a key parameter in determining the bubble nucleation and growth rates, as well as droplet break up in blending. However very limited data on this property is available in the literature for CO₂-polymer systems. A novel technique is presented to determine the interfacial tension for the polymer melts and high pressure CO₂ systems by analysis on the axisymmetric pendant drop shape profile, which can simultaneously yield the density, swelling and interfacial tension results. The method avoids the “capillary effect” and the “necking effect” and provides good axisymmetry of the pendant drop, which makes it a suitable method for measuring the interfacial tension for polymer melts under high pressure CO₂ conditions. The interfacial tension between polymer melt (PS, PP, PLGA, PMMA) and high pressure CO₂, and the interfacial tension between polymer melt pairs (PS/PP) saturated with high pressure CO ₂ were studied using the pendant drop method in a high pressure, temperature view cell. CO ₂ was found to significantly depress the interfacial tension in the pressure range studied. The linear gradient theory combining with the Sanchez-Lacombe Equation of State was applied in predicting the surface tension or interfacial tensions for polymer melts under high pressure CO₂ conditions, which correctly predicts the depression of interfacial tension by high pressure CO₂ and yields reasonable agreement with experimental data. The role of CO₂ in enhancing the polymer blending process was carried out based on the Capillary Number, which is the most important parameter governing the drop breakage and coalescence in the blending process and thus the morphology of the blends. A highly simplified population balance model was applied to calculate the morphology evolution by only considering the droplet breakup during the mixing. The calculated results agree with the experimental data relatively well. Based on the model, the effect of CO₂ on the morphology evolution was also discussed. Advisors/Committee Members: Tomasko, David (Advisor).

Subjects/Keywords: Engineering, Chemical; Interfacial tension; CO<; sub>; 2<; /sub>;

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Hongbo, L. (2004). The effect of interfacial tension in CO₂ assisted polymer processing. (Doctoral Dissertation). The Ohio State University. Retrieved from http://rave.ohiolink.edu/etdc/view?acc_num=osu1087479703

Chicago Manual of Style (16^th Edition):

Hongbo, Li. “The effect of interfacial tension in CO₂ assisted polymer processing.” 2004. Doctoral Dissertation, The Ohio State University. Accessed April 12, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=osu1087479703.

MLA Handbook (7^th Edition):

Hongbo, Li. “The effect of interfacial tension in CO₂ assisted polymer processing.” 2004. Web. 12 Apr 2021.

Vancouver:

Hongbo L. The effect of interfacial tension in CO₂ assisted polymer processing. [Internet] [Doctoral dissertation]. The Ohio State University; 2004. [cited 2021 Apr 12]. Available from: http://rave.ohiolink.edu/etdc/view?acc_num=osu1087479703.

Council of Science Editors:

Hongbo L. The effect of interfacial tension in CO₂ assisted polymer processing. [Doctoral Dissertation]. The Ohio State University; 2004. Available from: http://rave.ohiolink.edu/etdc/view?acc_num=osu1087479703

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