You searched for subject:(Nucleation).
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University of California – Riverside
1.
Fang, Zijun.
Earthquake Nucleation on Geometrically Complex Faults.
Degree: Mechanical Engineering, 2009, University of California – Riverside
URL: http://www.escholarship.org/uc/item/47v4c0sm 
► We have employed numerical approaches to study earthquake nucleation on geometrically complex faults governed by either slip-dependent friction or rate- and state- dependent friction. The…
(more)
▼ We have employed numerical approaches to study earthquake nucleation on geometrically complex faults governed by either slip-dependent friction or rate- and state- dependent friction. The interactions of fault friction, complex fault geometry and remote slow stressing from plate tectonics are investigated. In particular, we focus on characterizing three important physical aspects of an earthquake: the occurrence time, hypocenter location and earthquake source dimensions. Using a slip dependent friction law, we have investigated earthquake nucleation on both thrust and normal dip-slip faults with changes in dip (bends) at depth. Our results show that earthquakes tend to nucleate at shallower depth on thrust faults as compared to those on normal faults with the same geometry. Nucleation time increases significantly as the fault plane are bent more severe for both thrust and normal faults. Using the rate- and state-dependent friction, we studied nucleation on two parallel planar faults with step-over features. We focus on investigating how nucleation is affected by the offset between the two faults. We found that for faults with compressional step-overs, earthquakes tend to nucleate the end of the overlapping zone when the offset is small, but generally nucleate further away from the overlapping end as the offset becomes larger. For faults with extensional step-overs, nucleation always occurs near the overlapping end for all the offsets considered. Our studies provide better understanding of the effects of fault geometry on earthquake nucleation and form a basis for the study of nucleation on large scale geometrically complex fault systems such as fault systems in Southern California. Our results may also provide realistic earthquake source conditions for rupture dynamics studies which at present largely employ ad hoc source conditions.
Subjects/Keywords: Engineering, Mechanical; Geophysics; Earthquake; Fault Geometry; Nucleation; Nucleation location; Nucleation size; Nucleation time
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APA (6th Edition):
Fang, Z. (2009). Earthquake Nucleation on Geometrically Complex Faults. (Thesis). University of California – Riverside. Retrieved from http://www.escholarship.org/uc/item/47v4c0sm
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Fang, Zijun. “Earthquake Nucleation on Geometrically Complex Faults.” 2009. Thesis, University of California – Riverside. Accessed February 27, 2021.
http://www.escholarship.org/uc/item/47v4c0sm.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Fang, Zijun. “Earthquake Nucleation on Geometrically Complex Faults.” 2009. Web. 27 Feb 2021.
Vancouver:
Fang Z. Earthquake Nucleation on Geometrically Complex Faults. [Internet] [Thesis]. University of California – Riverside; 2009. [cited 2021 Feb 27].
Available from: http://www.escholarship.org/uc/item/47v4c0sm.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Fang Z. Earthquake Nucleation on Geometrically Complex Faults. [Thesis]. University of California – Riverside; 2009. Available from: http://www.escholarship.org/uc/item/47v4c0sm
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Delft University of Technology
2.
Van de Graaf, J. (author); Soare, A. (author); Kramer, H.J.M. (author).
Sonocrystallization, Nucleation of ammonium sulfate and alfa-lactose monohydrate due to ultrasonic irradiation.
Degree: 2011, Delft University of Technology
URL: http://resolver.tudelft.nl/uuid:d5a55e22-66c2-4d6d-a07d-fcc18752e12b
Experiments were conducted to investigate the nucleation of ammonium sulfate and alfa-lactose monohydrate under ultrasonic irradiation
Intensified Reaction & Separation Systems
Process and Energy
Mechanical, Maritime and Materials Engineering
Advisors/Committee Members: Soare, A. (mentor).Subjects/Keywords: Sonocrystallization; lactose; nucleation
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APA (6th Edition):
Van de Graaf, J. (author); Soare, A. (author); Kramer, H. J. M. (. (2011). Sonocrystallization, Nucleation of ammonium sulfate and alfa-lactose monohydrate due to ultrasonic irradiation. (Masters Thesis). Delft University of Technology. Retrieved from http://resolver.tudelft.nl/uuid:d5a55e22-66c2-4d6d-a07d-fcc18752e12b
Chicago Manual of Style (16th Edition):
Van de Graaf, J. (author); Soare, A. (author); Kramer, H J M (author). “Sonocrystallization, Nucleation of ammonium sulfate and alfa-lactose monohydrate due to ultrasonic irradiation.” 2011. Masters Thesis, Delft University of Technology. Accessed February 27, 2021.
http://resolver.tudelft.nl/uuid:d5a55e22-66c2-4d6d-a07d-fcc18752e12b.
MLA Handbook (7th Edition):
Van de Graaf, J. (author); Soare, A. (author); Kramer, H J M (author). “Sonocrystallization, Nucleation of ammonium sulfate and alfa-lactose monohydrate due to ultrasonic irradiation.” 2011. Web. 27 Feb 2021.
Vancouver:
Van de Graaf, J. (author); Soare, A. (author); Kramer HJM(. Sonocrystallization, Nucleation of ammonium sulfate and alfa-lactose monohydrate due to ultrasonic irradiation. [Internet] [Masters thesis]. Delft University of Technology; 2011. [cited 2021 Feb 27].
Available from: http://resolver.tudelft.nl/uuid:d5a55e22-66c2-4d6d-a07d-fcc18752e12b.
Council of Science Editors:
Van de Graaf, J. (author); Soare, A. (author); Kramer HJM(. Sonocrystallization, Nucleation of ammonium sulfate and alfa-lactose monohydrate due to ultrasonic irradiation. [Masters Thesis]. Delft University of Technology; 2011. Available from: http://resolver.tudelft.nl/uuid:d5a55e22-66c2-4d6d-a07d-fcc18752e12b
University of Florida
3.
Singh, Shantanu.
Computational Investigation of Buoyancy Effect on Temperature Field over an Axisymmetric Microheater.
Degree: MS, Mechanical Engineering - Mechanical and Aerospace Engineering, 2017, University of Florida
URL: https://ufdc.ufl.edu/UFE0051624
► Steady state, laminar, external natural convection flow over a horizontal, circular, isothermal microheater is studied for Rayleigh number range up to 100 at Prandtl number…
(more)
▼ Steady state, laminar, external natural convection flow over a horizontal, circular, isothermal microheater is studied for Rayleigh number range up to 100 at Prandtl number of 1,5 and 10. Momentum and energy equations are solved using a finite-difference scheme for the fluid region over the heater. For the case of pure conduction; influence of domain size is studied and finite difference results are validated with the exact solution. Dependence of results on grid size is studied both for the case of pure conduction and convective flow. For conduction, grid dependency of results is checked against exact solution; whereas, for convective flow, Richardson extrapolation is used to check the results against extrapolated values. Finally, a correlation for dimensionless fluid temperature near the heater is developed as a function of dimensionless axial and radial coordinates, and Rayleigh number (Theta (Z, R, Ra)). Least square regression fit is implemented to get the correlation. The correlation is a 4th order unified polynomial valid for Rayleigh number from 0 to 100. Three correlations are developed for Prandtl number of 1,5 and 10. It is observed that the flow near the centerline of heater does not follow boundary layer type behavior; whereas, it follows boundary layer type behavior on moving away from the centerline. ( en )
Advisors/Committee Members: MEI,RENWEI (committee chair), SCHEFFE,JONATHAN (committee member).
Subjects/Keywords: axisymmetric – microheater – nucleation
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APA (6th Edition):
Singh, S. (2017). Computational Investigation of Buoyancy Effect on Temperature Field over an Axisymmetric Microheater. (Masters Thesis). University of Florida. Retrieved from https://ufdc.ufl.edu/UFE0051624
Chicago Manual of Style (16th Edition):
Singh, Shantanu. “Computational Investigation of Buoyancy Effect on Temperature Field over an Axisymmetric Microheater.” 2017. Masters Thesis, University of Florida. Accessed February 27, 2021.
https://ufdc.ufl.edu/UFE0051624.
MLA Handbook (7th Edition):
Singh, Shantanu. “Computational Investigation of Buoyancy Effect on Temperature Field over an Axisymmetric Microheater.” 2017. Web. 27 Feb 2021.
Vancouver:
Singh S. Computational Investigation of Buoyancy Effect on Temperature Field over an Axisymmetric Microheater. [Internet] [Masters thesis]. University of Florida; 2017. [cited 2021 Feb 27].
Available from: https://ufdc.ufl.edu/UFE0051624.
Council of Science Editors:
Singh S. Computational Investigation of Buoyancy Effect on Temperature Field over an Axisymmetric Microheater. [Masters Thesis]. University of Florida; 2017. Available from: https://ufdc.ufl.edu/UFE0051624
University of New Mexico
4.
Benavidez, Angelica.
The Nucleation and Growth of Nanoparticles for Heterogeneous Catalysis.
Degree: Chemical and Biological Engineering, 2015, University of New Mexico
URL: http://hdl.handle.net/1928/27761
► These studies investigate the nucleation and growth of nanoparticles and how their interaction with a support affects their reactivity as a heterogeneous catalyst. As capabilities…
(more)
▼ These studies investigate the
nucleation and growth of nanoparticles and how their interaction with a support affects their reactivity as a heterogeneous catalyst. As capabilities in both synthesis methods and characterization methods advance, the use of nanoparticles and sub-nanometer species are more commonly used. These small particles introduce new factors that can cause differences in reactivity. Various catalyst synthesis methods are employed to deposit mono-dispersed particles on different oxide and carbon supports. Electron microscopy is used to study nanoparticle sintering and the careful tracking of individual particles gives insight into growth mechanisms. X-ray absorption spectroscopy measurements are used to characterize catalysts and elucidate the reasons for a support effect in both hydrogenation and oxidations reactions. This investigation aims to produce a more active catalyst by exploring different aspects that play a role in reactivity and selectivity. Understanding the growth mechanisms that commonly to lead deactivation gets us one step closer to creating a sinter resistant catalyst. These studies also show that changing a catalyst support can increase its activity. The exploration of the fundamentals of nanoparticle structure and interaction with its surroundings leads to a more efficient catalyst.
Advisors/Committee Members: Datye, Abhaya, Loehman, Ronald, Karim, Ayman, Challa, Sivakumar.
Subjects/Keywords: heterogeneous catalysis; nucleation
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APA (6th Edition):
Benavidez, A. (2015). The Nucleation and Growth of Nanoparticles for Heterogeneous Catalysis. (Doctoral Dissertation). University of New Mexico. Retrieved from http://hdl.handle.net/1928/27761
Chicago Manual of Style (16th Edition):
Benavidez, Angelica. “The Nucleation and Growth of Nanoparticles for Heterogeneous Catalysis.” 2015. Doctoral Dissertation, University of New Mexico. Accessed February 27, 2021.
http://hdl.handle.net/1928/27761.
MLA Handbook (7th Edition):
Benavidez, Angelica. “The Nucleation and Growth of Nanoparticles for Heterogeneous Catalysis.” 2015. Web. 27 Feb 2021.
Vancouver:
Benavidez A. The Nucleation and Growth of Nanoparticles for Heterogeneous Catalysis. [Internet] [Doctoral dissertation]. University of New Mexico; 2015. [cited 2021 Feb 27].
Available from: http://hdl.handle.net/1928/27761.
Council of Science Editors:
Benavidez A. The Nucleation and Growth of Nanoparticles for Heterogeneous Catalysis. [Doctoral Dissertation]. University of New Mexico; 2015. Available from: http://hdl.handle.net/1928/27761
University of Limerick
5.
Devereux, Michael.
Bubble formation in selected industrial problems.
Degree: 2011, University of Limerick
URL: http://hdl.handle.net/10344/1959
► peer-reviewed
Foam and bubbles are ubiquitous in industry and nature. They have a wide range of applications but are also an undesirable product of certain…
(more)
▼ peer-reviewed
Foam and bubbles are ubiquitous in industry and nature. They have a wide range of applications but are also an undesirable product of certain processes. This thesis considers two individual industrial problems with the common phenomenon of bubble and foam formation.
Bubble nucleation is a phenomenon observed in many different physical situations from decompression sickness to champagne effervescence. It is of vital importance to the formation of a creamy head that is
distinctive to stout beers. I present experimental work that demonstrates
that cellulose fibres can be used to initiate stout beers and could serve
as an alternative to widget technology. I derive mathematical models for
the various gas pocket geometries I observed in cellulose fibres that produce
bubbles when submerged in stout beer. These models are solved and compared to experimental results where possible to give the first quantitative evaluation of the current models of bubble nucleation.
I present the work done to model a novel design for accurate volume measurement of milk. The new design proposes a modification of the air elimination vessel used in current milk pumping systems to increase
accuracy by preventing air bubbles being pumped with milk. We consider the operation of the entire system to pump milk, the flow of milk inside the air elimination vessel, the entrainment of air bubbles into a pool of
milk and the drainage of foam.
Advisors/Committee Members: Lee, William T..
Subjects/Keywords: bubble nucleation; industry
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APA (6th Edition):
Devereux, M. (2011). Bubble formation in selected industrial problems. (Thesis). University of Limerick. Retrieved from http://hdl.handle.net/10344/1959
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Devereux, Michael. “Bubble formation in selected industrial problems.” 2011. Thesis, University of Limerick. Accessed February 27, 2021.
http://hdl.handle.net/10344/1959.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Devereux, Michael. “Bubble formation in selected industrial problems.” 2011. Web. 27 Feb 2021.
Vancouver:
Devereux M. Bubble formation in selected industrial problems. [Internet] [Thesis]. University of Limerick; 2011. [cited 2021 Feb 27].
Available from: http://hdl.handle.net/10344/1959.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Devereux M. Bubble formation in selected industrial problems. [Thesis]. University of Limerick; 2011. Available from: http://hdl.handle.net/10344/1959
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Wright State University
6.
Gurav, Ankita B.
Investigating Heterogeneous Nucleation of Barite using
Hydrothermal Atomic Force Microscopy and Optical
Microscopy.
Degree: MS, Chemistry, 2020, Wright State University
URL: http://rave.ohiolink.edu/etdc/view?acc_num=wright1610403323603442
► In order to develop a better understanding heterogeneous nucleation of barite, barite precipitation was studied under varying experimental parameters. Hydrothermal atomic force microscopy (HAFM) and…
(more)
▼ In order to develop a better understanding
heterogeneous
nucleation of barite, barite precipitation was
studied under varying experimental parameters. Hydrothermal atomic
force microscopy (HAFM) and optical microscopy were used to
investigate the effect of change in temperature, supersaturation
and varying ratios of ions on heterogeneous
nucleation of barite.
In the experiments conducted at higher temperatures, the particles
thus nucleated were found to display characteristic hexagonal and
rhomboidal shapes. In comparing results of particle densities among
different ion ratios, there is evidence suggesting that barium to
sulfate ratio plays a role of promoter. Wherein, the ratios with
higher [Ba2+] concentration were found to show more
nucleation
occurring. Although, the HAFM cell was used for experimentation,
optical microscopy turned out to be a more effective method for
analysis of samples.
Advisors/Committee Members: Higgins, Steven (Advisor).
Subjects/Keywords: Chemistry; Heterogeneous nucleation; Barite; Non-classical nucleation; nucleation
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APA (6th Edition):
Gurav, A. B. (2020). Investigating Heterogeneous Nucleation of Barite using
Hydrothermal Atomic Force Microscopy and Optical
Microscopy. (Masters Thesis). Wright State University. Retrieved from http://rave.ohiolink.edu/etdc/view?acc_num=wright1610403323603442
Chicago Manual of Style (16th Edition):
Gurav, Ankita B. “Investigating Heterogeneous Nucleation of Barite using
Hydrothermal Atomic Force Microscopy and Optical
Microscopy.” 2020. Masters Thesis, Wright State University. Accessed February 27, 2021.
http://rave.ohiolink.edu/etdc/view?acc_num=wright1610403323603442.
MLA Handbook (7th Edition):
Gurav, Ankita B. “Investigating Heterogeneous Nucleation of Barite using
Hydrothermal Atomic Force Microscopy and Optical
Microscopy.” 2020. Web. 27 Feb 2021.
Vancouver:
Gurav AB. Investigating Heterogeneous Nucleation of Barite using
Hydrothermal Atomic Force Microscopy and Optical
Microscopy. [Internet] [Masters thesis]. Wright State University; 2020. [cited 2021 Feb 27].
Available from: http://rave.ohiolink.edu/etdc/view?acc_num=wright1610403323603442.
Council of Science Editors:
Gurav AB. Investigating Heterogeneous Nucleation of Barite using
Hydrothermal Atomic Force Microscopy and Optical
Microscopy. [Masters Thesis]. Wright State University; 2020. Available from: http://rave.ohiolink.edu/etdc/view?acc_num=wright1610403323603442
San Jose State University
7.
Mar, Brendan Douglas.
Laboratory Studies of Water Ice Nucleation and Growth at Conditions Relevant to Martian Cloud Formation.
Degree: MS, Chemistry, 2011, San Jose State University
URL: https://doi.org/10.31979/etd.qccd-q3tv
;
https://scholarworks.sjsu.edu/etd_theses/4062
► Water vapor in the martian atmosphere, while significantly less abundant than on Earth, is still present in sufficient quantities to form clouds, and these…
(more)
▼ Water vapor in the martian atmosphere, while significantly less abundant than on Earth, is still present in sufficient quantities to form clouds, and these clouds play a crucial role in the martian climate. It is therefore critical that any attempt to model the martian atmosphere include a robust handling of the formation and growth of these clouds. Presented here are the results of laboratory studies at simulated martian temperature and water vapor partial pressure (150-185 K and 1.0 · 10-6 - 1.0 · 10-4 Torr) designed to probe the behavior of two parameters critical for modeling the life cycle of a martian cloud. The first of these parameters is the critical saturation ratio (Scrit), which is a measure of the threshold of water vapor pressure required in the system to facilitate formation of cloud particles of the necessary size to initiate cloud growth. Scrit was measured as a function of temperature and nucleation substrate, with silica and sulfate-functionalized polystyrene microspheres being the substrates tested. Of these two substrates, the latter was found to be the stronger nucleator, with nucleation efficiency higher than any previously tested substrates except smectite clay. The second parameter was the condensation coefficient, α, which is the ratio of the measured ice growth rate to the maximum growth rate at the corresponding experimental pressure, given by the collision frequency. For the above range of conditions, alpha; can be represented as a function of temperature offset from the solid-vapor phase boundary as α(ΔT) = 1 − e<super>0.1884ΔT</super>.
Subjects/Keywords: Clouds; Ice; Mars; Nucleation; Water
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APA (6th Edition):
Mar, B. D. (2011). Laboratory Studies of Water Ice Nucleation and Growth at Conditions Relevant to Martian Cloud Formation. (Masters Thesis). San Jose State University. Retrieved from https://doi.org/10.31979/etd.qccd-q3tv ; https://scholarworks.sjsu.edu/etd_theses/4062
Chicago Manual of Style (16th Edition):
Mar, Brendan Douglas. “Laboratory Studies of Water Ice Nucleation and Growth at Conditions Relevant to Martian Cloud Formation.” 2011. Masters Thesis, San Jose State University. Accessed February 27, 2021.
https://doi.org/10.31979/etd.qccd-q3tv ; https://scholarworks.sjsu.edu/etd_theses/4062.
MLA Handbook (7th Edition):
Mar, Brendan Douglas. “Laboratory Studies of Water Ice Nucleation and Growth at Conditions Relevant to Martian Cloud Formation.” 2011. Web. 27 Feb 2021.
Vancouver:
Mar BD. Laboratory Studies of Water Ice Nucleation and Growth at Conditions Relevant to Martian Cloud Formation. [Internet] [Masters thesis]. San Jose State University; 2011. [cited 2021 Feb 27].
Available from: https://doi.org/10.31979/etd.qccd-q3tv ; https://scholarworks.sjsu.edu/etd_theses/4062.
Council of Science Editors:
Mar BD. Laboratory Studies of Water Ice Nucleation and Growth at Conditions Relevant to Martian Cloud Formation. [Masters Thesis]. San Jose State University; 2011. Available from: https://doi.org/10.31979/etd.qccd-q3tv ; https://scholarworks.sjsu.edu/etd_theses/4062
University of Alberta
8.
Jones, Caren E.
Early Vegetation Community Development and Dispersal in
Upland Boreal Forest Reclamation.
Degree: MS, Department of Renewable Resources, 2016, University of Alberta
URL: https://era.library.ualberta.ca/files/cx346d4485
► Re-establishment of appropriate vegetation communities is an important aspect of successful forest reclamation as they contribute to various ecosystem functions. In my research I explore…
(more)
▼ Re-establishment of appropriate vegetation communities
is an important aspect of successful forest reclamation as they
contribute to various ecosystem functions. In my research I explore
how different coversoil materials (salvaged forest floor (FFM) and
peat material), their placement depths, and underlying subsoil
materials influence the early colonizing vegetation on an upland
boreal forest reclamation site. Further, I investigated what
effects the selection of tree species and their planting densities
have on vegetation community development. As salvaged FFM contains
propagules common of upland forests, it provided much higher
richness and cover than when peat material was used as a coversoil.
While material placement depth had little impact on vegetation, the
type of subsoil material did play a role when placed beneath the
coversoils, particularly with high phosphorous availability
resulting in increased plant cover and species richness. Selection
of tree species had little effect on the vegetation within the
timeframe measured as seedlings were likely too small. Planting
density had an impact early on with reduced vegetation cover in
high density plots where seeding growth was high (in FFM). In a
second study, I explored whether FFM islands would act as a nucleus
for dispersal of forest vegetation throughout reclaimed landscapes.
Vegetation egress and seed rain from the islands into adjacent peat
material were examined to assess the dispersal mechanisms
contributing to the egress. By the fourth growing season, species
associated with FFM comprised a higher proportion of the vegetation
cover than species associated with the receiving peat material up
to 20m away from the island border. Although overall cover was low
compared to in FFM areas, herbaceous, graminoid, and shrub species
associated with the FFM were all present in the peat. Wind
dispersed species were able to disperse further into the
surrounding peat material than species which utilized other
dispersal methods. Despite seeds successfully dispersing from FFM
areas, poor seed bed conditions in the peat limited seed retention
and germination. However, dispersal into peat with vegetative
reproductive structures appears promising as a result of the
material’s high nitrate concentrations and water holding
capacity.
Subjects/Keywords: Reclamation; Applied Nucleation; Boreal Forest
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Manager
APA (6th Edition):
Jones, C. E. (2016). Early Vegetation Community Development and Dispersal in
Upland Boreal Forest Reclamation. (Masters Thesis). University of Alberta. Retrieved from https://era.library.ualberta.ca/files/cx346d4485
Chicago Manual of Style (16th Edition):
Jones, Caren E. “Early Vegetation Community Development and Dispersal in
Upland Boreal Forest Reclamation.” 2016. Masters Thesis, University of Alberta. Accessed February 27, 2021.
https://era.library.ualberta.ca/files/cx346d4485.
MLA Handbook (7th Edition):
Jones, Caren E. “Early Vegetation Community Development and Dispersal in
Upland Boreal Forest Reclamation.” 2016. Web. 27 Feb 2021.
Vancouver:
Jones CE. Early Vegetation Community Development and Dispersal in
Upland Boreal Forest Reclamation. [Internet] [Masters thesis]. University of Alberta; 2016. [cited 2021 Feb 27].
Available from: https://era.library.ualberta.ca/files/cx346d4485.
Council of Science Editors:
Jones CE. Early Vegetation Community Development and Dispersal in
Upland Boreal Forest Reclamation. [Masters Thesis]. University of Alberta; 2016. Available from: https://era.library.ualberta.ca/files/cx346d4485
University of Toronto
9.
Jun, Yun-seok.
Comparison of Nucleation and Growth at Paired Urban and Rural Locations.
Degree: 2011, University of Toronto
URL: http://hdl.handle.net/1807/30646
► The number and size distributions of particles between 10 and 400 nm were measured in Toronto and rural Egbert during May 2007 to May 2008…
(more)
▼ The number and size distributions of particles between 10 and 400 nm were measured in Toronto and rural Egbert during May 2007 to May 2008 to compare nucleation and growth at paired urban and rural locations. Particle formation and growth were observed in Egbert more frequently than in Toronto, and simultaneous events occurred on 34 out of 368 days. In contrast, formation and growth rates were both higher in Toronto. Further, a linear regression analysis suggested that compounds contributing to nucleation and growth processes were different in Toronto and Egbert. Vehicular emissions seemed to suppress particle formation in downtown Toronto. Nucleation also appeared to be suppressed by long-range transported pollutants originating from industrial regions in southwestern Ontario and northern Ohio in the United States. A Nucleation Indicator (NI) was developed by combining relevant parameters, and it was found to provide a reasonable measure of the probability of nucleation events occurring.
MAST
Advisors/Committee Members: Evans, Greg J., Chemical Engineering and Applied Chemistry.
Subjects/Keywords: atmosphere; formation; particle; nucleation; 0725
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Manager
APA (6th Edition):
Jun, Y. (2011). Comparison of Nucleation and Growth at Paired Urban and Rural Locations. (Masters Thesis). University of Toronto. Retrieved from http://hdl.handle.net/1807/30646
Chicago Manual of Style (16th Edition):
Jun, Yun-seok. “Comparison of Nucleation and Growth at Paired Urban and Rural Locations.” 2011. Masters Thesis, University of Toronto. Accessed February 27, 2021.
http://hdl.handle.net/1807/30646.
MLA Handbook (7th Edition):
Jun, Yun-seok. “Comparison of Nucleation and Growth at Paired Urban and Rural Locations.” 2011. Web. 27 Feb 2021.
Vancouver:
Jun Y. Comparison of Nucleation and Growth at Paired Urban and Rural Locations. [Internet] [Masters thesis]. University of Toronto; 2011. [cited 2021 Feb 27].
Available from: http://hdl.handle.net/1807/30646.
Council of Science Editors:
Jun Y. Comparison of Nucleation and Growth at Paired Urban and Rural Locations. [Masters Thesis]. University of Toronto; 2011. Available from: http://hdl.handle.net/1807/30646
Indian Institute of Science
10.
Bommineni, Praveen Kumar.
Molecular Simulation Studies of Competing Pathways in Crystal Nucleation.
Degree: PhD, Engineering, 2018, Indian Institute of Science
URL: http://etd.iisc.ac.in/handle/2005/4033
► Microscopic nature of nuclei and extremely fast nucleation events makes it difficult to study nucleation experimentally. Route to nucleation can be effected by different parameters…
(more)
▼ Microscopic nature of nuclei and extremely fast
nucleation events makes it difficult to study
nucleation experimentally. Route to
nucleation can be effected by different parameters such as thermodynamic conditions, uid phase composition and surface heterogeneity etc. The focus of this thesis is on investigating competing pathways of crystal
nucleation in variety of systems. In this thesis, we use molecular simulations to study crystal
nucleation in model systems. These model systems mimic real systems such as colloidal systems and globular pro-teins very closely. Advances in computational power and rare event sampling methods help us in better understanding of underlying mechanism involved in
nucleation phenomena.
Proteins are hard to crystallize and high quality of protein crystals desired for their structural determination. One way to promote protein crystallization is heterogeneously using substrates. In our study, we focus on the effect of nano-wrinkled surfaces on
nucleation of model globular proteins such as lysozyme. We computed free-energy barriers for homogeneous
nucleation and heterogeneous
nucleation of proteins on at and wrinkled surfaces. The study reveals that, the enhancement of
nucleation in presence of wrinkled surface is closely related to the two step
nucleation process seen during protein crystallization. There is an enhancement of protein concentration near trough of the wrinkled surface which aid in
nucleation. However, the high curvature at the trough acts as a deterrent to crystal nucleus formation. Hence, signi cant lowering of the free energy barrier is seen only if the increase in the protein concentration at the trough is very high.
Co-crystals also known as substituionally ordered solid compounds forms when two or more different compounds combine in a stoichiometric ratio. We investigate the effect of fluid phase composition on homogeneous
nucleation of AB2 co-crystal. In this work we made a comparative study between
nucleation of met stable AB2 solid and pure A solid with FCC structure. Our simulation results show that the
nucleation of AB2 solid is favoured even under conditions where the pure A solid is more stable. This is primarily due to similarity in the composition of fluid-phase and the AB2 type solid which in turn leads to much lower interfacial tension between the crystal nucleus and the fluid phase.
Interfacial free energy is a fundamental thermodynamic quantity determines the rate of formation of nuclei from fluid phase. It also determines the barrier for formation of nuclei. In binary mixtures, interfacial free energy has a strong dependence on fluid composition. We presented a simple method to compute the effeect of fluid phase composition on interfacial free energy of binary hard sphere mixtures. In this method interfacial free energy is calculated by numerically integrating Gibbs adsorption isotherm. Surface excess quantities are computed from simulation and phase equilibrium data. Our calculations indicates interfacial free energies for binary mixtures are higher…
Advisors/Committee Members: Punnathanam, Sudeep N (advisor).
Subjects/Keywords: Crystal Nucleation; Classical Nucleation Theory; Homogeneous Crystal Nucleation; Crystal Nuclei; Hard Sphere Model; Protein Crystal Nucleation; Chemical Engineering
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APA (6th Edition):
Bommineni, P. K. (2018). Molecular Simulation Studies of Competing Pathways in Crystal Nucleation. (Doctoral Dissertation). Indian Institute of Science. Retrieved from http://etd.iisc.ac.in/handle/2005/4033
Chicago Manual of Style (16th Edition):
Bommineni, Praveen Kumar. “Molecular Simulation Studies of Competing Pathways in Crystal Nucleation.” 2018. Doctoral Dissertation, Indian Institute of Science. Accessed February 27, 2021.
http://etd.iisc.ac.in/handle/2005/4033.
MLA Handbook (7th Edition):
Bommineni, Praveen Kumar. “Molecular Simulation Studies of Competing Pathways in Crystal Nucleation.” 2018. Web. 27 Feb 2021.
Vancouver:
Bommineni PK. Molecular Simulation Studies of Competing Pathways in Crystal Nucleation. [Internet] [Doctoral dissertation]. Indian Institute of Science; 2018. [cited 2021 Feb 27].
Available from: http://etd.iisc.ac.in/handle/2005/4033.
Council of Science Editors:
Bommineni PK. Molecular Simulation Studies of Competing Pathways in Crystal Nucleation. [Doctoral Dissertation]. Indian Institute of Science; 2018. Available from: http://etd.iisc.ac.in/handle/2005/4033
University of Wollongong
11.
Griesser, Stefan.
In-situ study of the influence of alloying elements on the kinetics and mechanism of the peritectic phase transition in steel.
Degree: PhD, Faculty of Engineering and Information Sciences, 2013, University of Wollongong
URL: 0902
AUTOMOTIVE
ENGINEERING,
0912
MATERIALS
ENGINEERING
;
https://ro.uow.edu.au/theses/3911
► This thesis covers a wide range of phenomena that are related to the peritectic phase transition in iron alloys: the primary solidification of the…
(more)
▼ This thesis covers a wide range of phenomena that are related to the peritectic phase transition in iron alloys: the primary solidification of the pro-peritectic solid phase, the nucleation of the peritectic phase at the parent liquid/solid interface and the rate and mechanism of the peritectic reaction as well as the subsequent peritectic transformation. A holistic approach was followed in order to not only investigate and characterize these different aspects individually, but rather to better understand the interconnection between these seemingly diverse phenomena in addition to gaining a more comprehensive understanding of this industrially important phase transition.
Subjects/Keywords: peritectic; solidification; nucleation; steel
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APA (6th Edition):
Griesser, S. (2013). In-situ study of the influence of alloying elements on the kinetics and mechanism of the peritectic phase transition in steel. (Doctoral Dissertation). University of Wollongong. Retrieved from 0902 AUTOMOTIVE ENGINEERING, 0912 MATERIALS ENGINEERING ; https://ro.uow.edu.au/theses/3911
Chicago Manual of Style (16th Edition):
Griesser, Stefan. “In-situ study of the influence of alloying elements on the kinetics and mechanism of the peritectic phase transition in steel.” 2013. Doctoral Dissertation, University of Wollongong. Accessed February 27, 2021.
0902 AUTOMOTIVE ENGINEERING, 0912 MATERIALS ENGINEERING ; https://ro.uow.edu.au/theses/3911.
MLA Handbook (7th Edition):
Griesser, Stefan. “In-situ study of the influence of alloying elements on the kinetics and mechanism of the peritectic phase transition in steel.” 2013. Web. 27 Feb 2021.
Vancouver:
Griesser S. In-situ study of the influence of alloying elements on the kinetics and mechanism of the peritectic phase transition in steel. [Internet] [Doctoral dissertation]. University of Wollongong; 2013. [cited 2021 Feb 27].
Available from: 0902 AUTOMOTIVE ENGINEERING, 0912 MATERIALS ENGINEERING ; https://ro.uow.edu.au/theses/3911.
Council of Science Editors:
Griesser S. In-situ study of the influence of alloying elements on the kinetics and mechanism of the peritectic phase transition in steel. [Doctoral Dissertation]. University of Wollongong; 2013. Available from: 0902 AUTOMOTIVE ENGINEERING, 0912 MATERIALS ENGINEERING ; https://ro.uow.edu.au/theses/3911
Oregon State University
12.
Snelling, Hilda Jane.
Production efficiency of different silver iodide ice-forming nuclei generators.
Degree: MS, Physics, 1963, Oregon State University
URL: http://hdl.handle.net/1957/48760
► Tests compared the production efficiencies of the following three silver iodide ice-forming nuclei generators: one burning charcoal soaked in a 2% silver iodide acetone solution,…
(more)
▼ Tests compared the production efficiencies of the following three
silver iodide ice-forming nuclei generators: one burning charcoal
soaked in a 2% silver iodide acetone solution, one in which a jet of
propane gas atomized a 2% silver iodide acetone solution, and one in
which a jet of compressed air atomized this same solution.
An optical pyrometer measured the generator operating temperatures.
The United States Weather Bureau Bigg-Warner Type Ice Nuclei
Counter provided counts of the number of effective ice nuclei produced
by the generators at different temperatures. The tests occurred at
these three temperatures of the ice nuclei counter, -12°C, -15°C, and
-20°C.
The number of active nuclei produced per second of operation and
the number of active nuclei produced per gram of silver iodide used
determined the efficiency of the generator. In all cases tested the
acetone air generator had higher efficiency than either the charcoal
generator or the propane generator. Both the acetone air generator
and the propane generator had equal efficiency at the two operating
temperatures tested.
Advisors/Committee Members: Decker, Fred W. (advisor).
Subjects/Keywords: Atmospheric nucleation
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APA (6th Edition):
Snelling, H. J. (1963). Production efficiency of different silver iodide ice-forming nuclei generators. (Masters Thesis). Oregon State University. Retrieved from http://hdl.handle.net/1957/48760
Chicago Manual of Style (16th Edition):
Snelling, Hilda Jane. “Production efficiency of different silver iodide ice-forming nuclei generators.” 1963. Masters Thesis, Oregon State University. Accessed February 27, 2021.
http://hdl.handle.net/1957/48760.
MLA Handbook (7th Edition):
Snelling, Hilda Jane. “Production efficiency of different silver iodide ice-forming nuclei generators.” 1963. Web. 27 Feb 2021.
Vancouver:
Snelling HJ. Production efficiency of different silver iodide ice-forming nuclei generators. [Internet] [Masters thesis]. Oregon State University; 1963. [cited 2021 Feb 27].
Available from: http://hdl.handle.net/1957/48760.
Council of Science Editors:
Snelling HJ. Production efficiency of different silver iodide ice-forming nuclei generators. [Masters Thesis]. Oregon State University; 1963. Available from: http://hdl.handle.net/1957/48760
Colorado State University
13.
McCluskey, Christina S.
Characteristics of atmospheric ice nucleating particles associated with biomass burning in the US: prescribed burns and wildfires.
Degree: MS(M.S.), Atmospheric Science, 2013, Colorado State University
URL: http://hdl.handle.net/10217/81044
► Insufficient knowledge regarding the sources and number concentrations of atmospheric ice nucleating particles (INP) leads to large uncertainties in understanding the interaction of aerosols with…
(more)
▼ Insufficient knowledge regarding the sources and number concentrations of atmospheric ice nucleating particles (INP) leads to large uncertainties in understanding the interaction of aerosols with cloud processes, such as cloud life time and precipitation rates. An increasingly important source of aerosol in the United States is biomass burning, particularly in the form of prescribed burns and wildfires in the southeastern and western U.S., respectively. Prior field and laboratory observations have suggested that biomass burning can be a source of INP. However, emissions from biomass burning are complex, varying with combustion efficiency, fuel type, plume age and dilution. Thus, this potentially important source of INP is poorly characterized. This study utilizes measurements of INP from a diverse set of biomass burning events to better understand INP associated with biomass burning in the U.S. Prescribed burns in Georgia and Colorado, two Colorado wildfires and two laboratory burns were monitored for INP number concentrations (nINP) using the Colorado State University continuous-flow diffusion chamber (CFDC) to activate INP in the condensation/immersion freezing
nucleation mode. Additional measurements included total particle number concentrations, number concentrations of particles with diameters larger than 500 nm, aerosol mass concentrations, carbon monoxide concentrations and chemically-speciated bulk aerosol filter samples. Additionally, activated INP were collected onto TEM grids downstream of the CFDC, isolating INP for single particle chemical and morphological analyses. These fires varied by fuel type, including wiregrass, longleaf pine and ponderosa pine, and also varied by combustion efficiency, ranging from highly flaming to a mixture of flaming and smoldering. Additionally, plume histories were different between the fires including aged plumes from the wildfires and freshly emitted smoke from the prescribed and laboratory burns. The relationship between nINP and total particle number concentrations, evident within prescribed burning plumes, was degraded within aged smoke plumes from the wildfires, limiting the utility of this relationship for comparing laboratory and field data. Larger particles, represented by n500nm, are less vulnerable to plume processing and have previously been evaluated for their relation to nINP. Our measurements indicated that for a given n500nm, nINP associated with the wildfires were nearly an order of magnitude higher than nINP found in prescribed fire emissions. That is, nINP represented a much larger fraction of n500nm in wildfires as compared with prescribed fires. Further, an existing parameterization for "global" nINP that relates INP abundance to n500nm largely under-predicted and over-predicted nINP emitted from wildfires and prescribed burns, respectively. Reasons for the differences between INP characteristics in these emissions were explored, including variations in combustion efficiency, fuel type, transport time and environmental conditions. Combustion…
Advisors/Committee Members: Kreidenweis, Sonia (advisor), DeMott, Paul (advisor), Pierce, Jeffery (committee member), Volckens, John (committee member).
Subjects/Keywords: atmospheric ice nucleation; biomass burning
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APA (6th Edition):
McCluskey, C. S. (2013). Characteristics of atmospheric ice nucleating particles associated with biomass burning in the US: prescribed burns and wildfires. (Masters Thesis). Colorado State University. Retrieved from http://hdl.handle.net/10217/81044
Chicago Manual of Style (16th Edition):
McCluskey, Christina S. “Characteristics of atmospheric ice nucleating particles associated with biomass burning in the US: prescribed burns and wildfires.” 2013. Masters Thesis, Colorado State University. Accessed February 27, 2021.
http://hdl.handle.net/10217/81044.
MLA Handbook (7th Edition):
McCluskey, Christina S. “Characteristics of atmospheric ice nucleating particles associated with biomass burning in the US: prescribed burns and wildfires.” 2013. Web. 27 Feb 2021.
Vancouver:
McCluskey CS. Characteristics of atmospheric ice nucleating particles associated with biomass burning in the US: prescribed burns and wildfires. [Internet] [Masters thesis]. Colorado State University; 2013. [cited 2021 Feb 27].
Available from: http://hdl.handle.net/10217/81044.
Council of Science Editors:
McCluskey CS. Characteristics of atmospheric ice nucleating particles associated with biomass burning in the US: prescribed burns and wildfires. [Masters Thesis]. Colorado State University; 2013. Available from: http://hdl.handle.net/10217/81044
Boston University
14.
Silva, James Brian.
The role of heterogeneity in long-range interacting systems : from nucleation to earthquake fault systems.
Degree: PhD, Physics, 2016, Boston University
URL: http://hdl.handle.net/2144/19420
► The role of heterogeneity in two long-range systems is explored with a focus on the interplay of this heterogeneity with the component system interactions. The…
(more)
▼ The role of heterogeneity in two long-range systems is explored with a focus on the interplay of this heterogeneity with the component system interactions. The first will be the heterogeneous Ising model with long-range interactions. Earthquake fault systems under long-range stress transfer with varying types of heterogeneity will be the second system of interest.
First I will review the use of the intervention method to determine the time and place of nucleation and extend its use as an indicator for spinodal nucleation. The heterogeneous Ising model with fixed magnetic sites will then be reformulated as a dilute random field Ising model. This reformulation will allow for the application of spinodal nucleation theory to the heterogeneous Ising model by correcting the spinodal field and the critical exponent sigma describing the critical behavior of clusters in spinodal nucleation theory. The applicability of this correction is shown by simulations that determine the cluster scaling of the nucleating droplets near the spinodal. Having obtained a reasonable definition of the saddle point object describing the nucleation droplet, the density profile of the nucleating droplet is measured and deviations from homogeneous spinodal nucleation are found due to the excess amount of sparseness in the nucleating droplet due to the heterogeneity.
Earthquake fault systems are then introduced and a connection is shown of two earthquake models. Heterogeneity is introduced in the form of asperities with the intent of modeling the effect of hard rocks on earthquake statistics. The asperities are observed to be a crucial element in explaining the behavior of aftershocks resulting in Omori's law. A second form of heterogeneity is introduced by coupling the Olami-Feder-Christensen model to an invasion percolation model for the purpose of modeling an earthquake fault system undergoing hydraulic fracturing. The ergodicty and event size statistics are explored in this extended model. The robustness of the event size statistics results are explored by allowing for the dissipation parameter in the Olami-Feder-Christensen model to vary.
Subjects/Keywords: Physics; Asperities; Nucleation; Earthquake faults
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APA (6th Edition):
Silva, J. B. (2016). The role of heterogeneity in long-range interacting systems : from nucleation to earthquake fault systems. (Doctoral Dissertation). Boston University. Retrieved from http://hdl.handle.net/2144/19420
Chicago Manual of Style (16th Edition):
Silva, James Brian. “The role of heterogeneity in long-range interacting systems : from nucleation to earthquake fault systems.” 2016. Doctoral Dissertation, Boston University. Accessed February 27, 2021.
http://hdl.handle.net/2144/19420.
MLA Handbook (7th Edition):
Silva, James Brian. “The role of heterogeneity in long-range interacting systems : from nucleation to earthquake fault systems.” 2016. Web. 27 Feb 2021.
Vancouver:
Silva JB. The role of heterogeneity in long-range interacting systems : from nucleation to earthquake fault systems. [Internet] [Doctoral dissertation]. Boston University; 2016. [cited 2021 Feb 27].
Available from: http://hdl.handle.net/2144/19420.
Council of Science Editors:
Silva JB. The role of heterogeneity in long-range interacting systems : from nucleation to earthquake fault systems. [Doctoral Dissertation]. Boston University; 2016. Available from: http://hdl.handle.net/2144/19420
Boston University
15.
Verma, Rashi.
A supercooled study of nucleation and symmetries.
Degree: PhD, Physics, 2018, Boston University
URL: http://hdl.handle.net/2144/34779
► Nucleation is the process by which a metastable phase decays into a stable phase. It is widely observed in nature, and is responsible for many…
(more)
▼ Nucleation is the process by which a metastable phase decays into a stable phase. It is widely observed in nature, and is responsible for many phenomena such as the formation clouds and domains in crystalline solids. The classical theory of
nucleation predicts that the objects that initiate the decay from the metastable to the stable phase are compact droplets whose interior has the structure of the stable phase. For quenches deep into the metastable phase, however, the droplets may be ramified, with a structure very different from the stable phase. This difference has profound implications for material properties, especially because predicting the onset of structure early enough is useful for manipulating and controlling
nucleation processes.
I used molecular dynamics to simulate
nucleation in Lennard-Jonesium, a model system for liquid-solid transformations. The system is quenched from a high temperature, where the liquid is stable, to a temperature where the liquid is metastable, and is allowed to nucleate via fluctuation-driven clusters referred to as critical droplets. I determined the occurrence of critical droplets by the intervention method,
but found a non-monotonic variation in droplet survival rates near the saddle point. I determined the structure of the critical droplet and found evidence for a core consisting of mostly solid-like particles with hcp symmetry and a previously unknown planar structure around it.
Using perturbative techniques, I showed that the planar particles have a significant influence on the
nucleation and growth of critical droplets. I also introduced a novel method of learning symmetries to predict the structure and appearance of precursors to the critical nucleus. My results give added evidence for the presence of spinodal
nucleation at deep quenches.
Advisors/Committee Members: Klein, William (advisor).
Subjects/Keywords: Physics; Molecular dynamics; Nucleation; Symmetries
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APA (6th Edition):
Verma, R. (2018). A supercooled study of nucleation and symmetries. (Doctoral Dissertation). Boston University. Retrieved from http://hdl.handle.net/2144/34779
Chicago Manual of Style (16th Edition):
Verma, Rashi. “A supercooled study of nucleation and symmetries.” 2018. Doctoral Dissertation, Boston University. Accessed February 27, 2021.
http://hdl.handle.net/2144/34779.
MLA Handbook (7th Edition):
Verma, Rashi. “A supercooled study of nucleation and symmetries.” 2018. Web. 27 Feb 2021.
Vancouver:
Verma R. A supercooled study of nucleation and symmetries. [Internet] [Doctoral dissertation]. Boston University; 2018. [cited 2021 Feb 27].
Available from: http://hdl.handle.net/2144/34779.
Council of Science Editors:
Verma R. A supercooled study of nucleation and symmetries. [Doctoral Dissertation]. Boston University; 2018. Available from: http://hdl.handle.net/2144/34779
Hong Kong University of Science and Technology
16.
Su, Lin ENVR.
A numerical study of dust over East Asia : the role of dust in ice nucleation within clouds and its effects on the regional weather system.
Degree: 2017, Hong Kong University of Science and Technology
URL: http://repository.ust.hk/ir/Record/1783.1-100375
;
https://doi.org/10.14711/thesis-991012564769603412
;
http://repository.ust.hk/ir/bitstream/1783.1-100375/1/th_redirect.html
► Dust particles are increasingly considered as having important effects on weather through their influence on atmospheric dynamics, radiation budget, clouds and precipitation. As a major…
(more)
▼ Dust particles are increasingly considered as having important effects on weather through their influence on atmospheric dynamics, radiation budget, clouds and precipitation. As a major dust contributor in the world, East Asian dust is considered to play a key role in determining global and regional dust variations, and impose significant effects on regional or even global weather system. This thesis presents the work on improving the numerical simulation of dust activity and its effects over East Asia in a regional modeling system. Large uncertainties exist in numerical dust emission simulations over East Asia due to errors in physical parameterizations or model configurations. The sensitivity of the Weather Research and Forecast model coupled with Chemistry module (WRF-Chem) to different dust emission schemes and soil data is investigated in this study, in order to quantify the uncertainties and look for a better configuration for stable long-term dust simulation over East Asia. Dust particles are considered as effective ice nuclei, which play an important part in ice nucleation process in the atmosphere, affecting the formation and evolution of ice and mixed-phase clouds. However, there is no effective and efficient way to evaluate this microphysical effect of dust in regional models. To fill the gap, a coupled dust-microphysics scheme is implemented into WRF-Chem, enabling the model to estimate the effect of dust in atmospheric microphysical processes, especially ice nucleation process within ice clouds and mixed-phase clouds. Further sensitivity experiments are carried out to optimize the parameters in the ice nucleation scheme. This work substantially improves the capability of WRF-Chem in simulating atmospheric ice water content, cloud cover, and cloud radiative effect enhanced by dust. Based on the work above, the full effects of dust aerosol, including direct radiative effect, cloud radiative effect, and indirect microphysics effect, on the weather system over East Asia during a typical dust-intensive period are evaluated. This is the first time that the microphysical and full effects of dust can be numerically estimated in East Asia. The comparison with comprehensive stationary and satellite-observations reveals that the model is capable of well reproducing dust emission, surface PM10 concentration during dust events. Furthermore, the model has a reasonable performance in simulating the dust-induced modification on optical properties, such as AOD and extinction coefficient over East Asia during dust events. The model yields the best performance in dust simulation with Shao’s emission scheme and USGS soil data. By comparing with satellite-observations, the GOCART-Thompson microphysics scheme is demonstrated to remarkably improve the performance of the model in simulating the atmospheric ice water content, with effect of dust taken into account in the atmospheric microphysical processes. The comparison between observational and simulated precipitation at over 50 meteorological stations over China…
Subjects/Keywords: Dust
; Environmental aspects
; Atmospheric nucleation
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APA (6th Edition):
Su, L. E. (2017). A numerical study of dust over East Asia : the role of dust in ice nucleation within clouds and its effects on the regional weather system. (Thesis). Hong Kong University of Science and Technology. Retrieved from http://repository.ust.hk/ir/Record/1783.1-100375 ; https://doi.org/10.14711/thesis-991012564769603412 ; http://repository.ust.hk/ir/bitstream/1783.1-100375/1/th_redirect.html
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Su, Lin ENVR. “A numerical study of dust over East Asia : the role of dust in ice nucleation within clouds and its effects on the regional weather system.” 2017. Thesis, Hong Kong University of Science and Technology. Accessed February 27, 2021.
http://repository.ust.hk/ir/Record/1783.1-100375 ; https://doi.org/10.14711/thesis-991012564769603412 ; http://repository.ust.hk/ir/bitstream/1783.1-100375/1/th_redirect.html.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Su, Lin ENVR. “A numerical study of dust over East Asia : the role of dust in ice nucleation within clouds and its effects on the regional weather system.” 2017. Web. 27 Feb 2021.
Vancouver:
Su LE. A numerical study of dust over East Asia : the role of dust in ice nucleation within clouds and its effects on the regional weather system. [Internet] [Thesis]. Hong Kong University of Science and Technology; 2017. [cited 2021 Feb 27].
Available from: http://repository.ust.hk/ir/Record/1783.1-100375 ; https://doi.org/10.14711/thesis-991012564769603412 ; http://repository.ust.hk/ir/bitstream/1783.1-100375/1/th_redirect.html.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Su LE. A numerical study of dust over East Asia : the role of dust in ice nucleation within clouds and its effects on the regional weather system. [Thesis]. Hong Kong University of Science and Technology; 2017. Available from: http://repository.ust.hk/ir/Record/1783.1-100375 ; https://doi.org/10.14711/thesis-991012564769603412 ; http://repository.ust.hk/ir/bitstream/1783.1-100375/1/th_redirect.html
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
University of Minnesota
17.
Murfield, Nathan James.
Modeling and simulation of homogeneous nucleation in turbulent flows: physics, methods and realizable solutions.
Degree: PhD, 2013, University of Minnesota
URL: http://purl.umn.edu/148853
► Numerical simulations of nanoparticle nucleation in turbulent shear flows are performed. We consider the homogeneous nucleation of dibutyl-phthalate (DBP) nanoparticles via direct numerical simulation (DNS)…
(more)
▼ Numerical simulations of nanoparticle nucleation in turbulent shear flows are performed. We consider the homogeneous nucleation of dibutyl-phthalate (DBP) nanoparticles via direct numerical simulation (DNS) and large-eddy simulation (LES). The flows consist of a high-temperature, DBP-laden stream issuing into a low-temperature, faster or slower moving, DBP-free environment. As the flows cool, via molecular and large- scale convective mixing, the DBP vapor becomes highly supersaturated and particles are formed by nucleation. This particle formation takes place in the absence of condensation or coagulation. Classical nucleation theory is used to model particle nucleation and the Navier-Stokes equations are coupled with the scalar transport equations to provide the fluid, thermal, and chemical fields.
The effects of large-scale mixing and vapor concentration on homogeneous nucleation rates are investigated via DNS in three-dimensional planar jets. The simulation results provide a demonstration of how nucleation takes place in narrow regions where molecular mixing of the two streams occurs. When maximum nucleation rates occur in conditions where the nucleation rates are sensitive to ambient conditions, islands of nucleation form. There are two possible nucleation events: initial shear layer nucleation, and later nucleation in coherent structures or eddies generated by the velocity difference between the jet and the co-flow. A scatter plot diagram of observed dilution paths in temperature versus condensable vapor concentration space where nucleation rates are superimposed is shown to be a convenient tool for analyzing nucleation events. Convection by large-scale eddies gradually spreads the range of mixing paths in this space towards higher nucleation rates. The results also show that boundary conditions, including inlet concentration and velocity ratio, have both qualitative and quantitative effects on particle nucleation. The effects of Lewis number on the homogeneous nucleation of DBP particles are also studied via DNS. Simulations at two Lewis numbers are performed to investigate the effects of molecular mixing on nucleation. These simulations are also carried out at two co-flow velocities to assess the effects of large-scale mixing. The results show that the Lewis number as well the level of large-scale mixing inherent in the flow have substantial effects on particle nucleation.
The effects of the subgrid-scale (SGS) scalar interactions on nanoparticle nucleation are investigated via a priori analysis of DNS data. To assess the effect of SGS scalar interactions on DBP particle nucleation, the temperature and mass-fractions are filtered and the resulting quantities are used to compute the nucleating particle field. Two filter widths are used to obtain varying levels of SGS interactions. Particle size distributions are computed to examine the particle fields produced. This work shows that the SGS interactions' effect on nucleation has two distinct trends. In the proximal region of the flow, the unresolved…
Subjects/Keywords: DNS; LES; Nucleation; Simulation
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APA (6th Edition):
Murfield, N. J. (2013). Modeling and simulation of homogeneous nucleation in turbulent flows: physics, methods and realizable solutions. (Doctoral Dissertation). University of Minnesota. Retrieved from http://purl.umn.edu/148853
Chicago Manual of Style (16th Edition):
Murfield, Nathan James. “Modeling and simulation of homogeneous nucleation in turbulent flows: physics, methods and realizable solutions.” 2013. Doctoral Dissertation, University of Minnesota. Accessed February 27, 2021.
http://purl.umn.edu/148853.
MLA Handbook (7th Edition):
Murfield, Nathan James. “Modeling and simulation of homogeneous nucleation in turbulent flows: physics, methods and realizable solutions.” 2013. Web. 27 Feb 2021.
Vancouver:
Murfield NJ. Modeling and simulation of homogeneous nucleation in turbulent flows: physics, methods and realizable solutions. [Internet] [Doctoral dissertation]. University of Minnesota; 2013. [cited 2021 Feb 27].
Available from: http://purl.umn.edu/148853.
Council of Science Editors:
Murfield NJ. Modeling and simulation of homogeneous nucleation in turbulent flows: physics, methods and realizable solutions. [Doctoral Dissertation]. University of Minnesota; 2013. Available from: http://purl.umn.edu/148853
University of Limerick
18.
Kuhs, Manuel.
The influence of solvent on the nucleation of mediums-sized flexible organic molecules from solution.
Degree: 2015, University of Limerick
URL: http://hdl.handle.net/10344/4800
► peer-reviewed
In this thesis the influence of solvents on crystal nucleation is probed to progress understanding of crystal nucleation from solution. Induction times of two…
(more)
▼ peer-reviewed
In this thesis the influence of solvents on crystal nucleation is probed to progress
understanding of crystal nucleation from solution.
Induction times of two solutes in different solvents and at different thermodynamic
driving forces were measured using a custom 20 mL multireactor system. To account for the
wide distribution of induction times under identical conditions, around 2,000 induction
times were collected, covering 25 combinations of solute, solvent and thermodynamic
driving force. Both the thermodynamic driving force required to achieve median induction
times of 2 hours, and the interfacial energies calculated using the Classical Nucleation
Theory, were found to decrease in the order ethanol > isopropanol > toluene > ethyl acetate
for fenoxycarb, and [n-propanol & toluene] > ethyl acetate > acetonitrile for tolbutamide.
Thus both solutes nucleate more easily in ethyl acetate than in either toluene or the alcohols.
Absolute values of interfacial energies ranged from 0.5 to 5 mJ/m2 in line with results of
similar experiments in the literature. For fenoxycarb these correlated quite well with
solvent-solute interaction enthalpies (with the exception of toluene) such that stronger
binding of the solute by the solvent corresponded to more difficult nucleation. This trend has
recently also been reported for salicylic acid and risperidone. In the case of tolbutamide the
same relationship appeared to be complicated by a second mechanism, whereby tolbutamide
assumes different solvent-dependent conformers in solution that hinder nucleation relative to
the energy barrier of rotating to the conformer found in the crystal.
While collecting induction times for fenoxycarb in isopropanol, a history of solution
effect on the nucleation rate was discovered whereby nucleation becomes more difficult
with increasing pretreatment temperature and time. Such an effect has been sporadically
reported for the past 100 years, but its cause remains unsolved. In order to quantify this
effect, the influence of solution pretreatment on the nucleation was measured by collecting
1,800 induction times spanning 17 combinations of pretreatment time and temperature. The
influence of pretreatment time and temperature on the induction time was found to follow a
first order rate reaction with an activation energy of over 260 kJ mol-1. On the basis of
modelling it has previously been suggested for this system that the molecular packing in the
crystal lattice is not the thermodynamically stable configuration at the level of simple dimers
in solution, and that solute aggregation must exist in solution due to the low solvent-tosolute
molecular ratio. It is thus hypothesized that the dissolution of crystalline material at
first leaves molecular assemblies in solution that retain features of the crystalline structure,
which facilitates subsequent nucleation. However, the longer the solution is kept at a
temperature above the saturation temperature and the higher the temperature, the more these
…
Advisors/Committee Members: Rasmuson, Åke C..
Subjects/Keywords: crystal nucleation; thermodynamics; solvents
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APA (6th Edition):
Kuhs, M. (2015). The influence of solvent on the nucleation of mediums-sized flexible organic molecules from solution. (Thesis). University of Limerick. Retrieved from http://hdl.handle.net/10344/4800
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Kuhs, Manuel. “The influence of solvent on the nucleation of mediums-sized flexible organic molecules from solution.” 2015. Thesis, University of Limerick. Accessed February 27, 2021.
http://hdl.handle.net/10344/4800.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Kuhs, Manuel. “The influence of solvent on the nucleation of mediums-sized flexible organic molecules from solution.” 2015. Web. 27 Feb 2021.
Vancouver:
Kuhs M. The influence of solvent on the nucleation of mediums-sized flexible organic molecules from solution. [Internet] [Thesis]. University of Limerick; 2015. [cited 2021 Feb 27].
Available from: http://hdl.handle.net/10344/4800.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Kuhs M. The influence of solvent on the nucleation of mediums-sized flexible organic molecules from solution. [Thesis]. University of Limerick; 2015. Available from: http://hdl.handle.net/10344/4800
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
University of Limerick
19.
Verma, Vivek.
Role of hydrogen bonding lifetime and complementarity in heterogeneous nucleation.
Degree: 2018, University of Limerick
URL: http://hdl.handle.net/10344/7597
► peer-reviewed
This work investigates the mechanism for the heterogeneous nucleation of active pharmaceutical ingredients (APIs) in the presence of different excipient heterosurfaces. By elucidating this…
(more)
▼ peer-reviewed
This work investigates the mechanism for the heterogeneous nucleation of active
pharmaceutical ingredients (APIs) in the presence of different excipient heterosurfaces. By
elucidating this mechanism for a range of API molecules, the appropriate crystallisation
conditions and heterosurfaces can be selected in silico for individual APIs to then generate
API crystals of the desired size and morphology via controlled heterogeneous crystallisation
processes, thus facilitating control over the API dissolution process.
The crystallisation of seven APIs (acetaminophen (AAP), carbamazepine (CBMZ), caffeine
(CAF), phenylbutazone (PBZ), risperidone (RIS), clozapine base (CPB) and fenofibrate (FF))
was studied in the absence and presence of the excipients α/β-lactose (α/β-lac), β-D-mannitol
(β-D-man), dextran (DEX), chitosan (CHT), carboxymethyl cellulose (CMC) and
microcrystalline cellulose (MCC), each of which acted as a heterosurface. Two of the APIs,
namely AAP and CBMZ, possess hydrogen bond donor (HBD) and hydrogen bond acceptor
(HBA) functionalities whereas the other five only possess HBA functionality. The
crystallisation experiments for all seven APIs were carried out within or at the limit of their
respective metastable zones at supersaturation ratios in the range of 1.08 to 1.50. A novel
methanol solvate of CPB was also discovered during these crystallisation experiments.
API crystallisations in the presence of a heterosurface were accompanied by a more
pronounced acceleration of the crystallisation for those APIs possessing only HBA
functionality relative to the acceleration observed for the APIs possessing HBA and HBD
functionalities. The smallest heterosurface acceleration of crystallisation was observed for
CBMZ at 1.4 times and the largest was observed for FF at 16 times. For all the APIs studied,
the interfacial energy was similar for crystallisations carried out in the presence and absence
of the heterosurface; by contrast, the pre-exponential factor was generally larger for
crystallisations carried out in the presence of the heterosurface than in its absence. Density Functional Theory (DFT) and Molecular Density calculations complemented the above
experimental study.
Thereafter, a model of heterogeneous crystallisation was developed wherein two factors were
identified. The first of these was the complementarity of hydrogen bonding between the
heterosurface and the APIs. Hence the crystallisation of APIs without HBD functionality was
accelerated more strongly than for those with HBA and HBD functionality because the
heterosurface provided the HBD functionality lacking in these APIs which allowed them to
attach or adsorb to the heterosurface and thus act as nucleation points for the API’s
crystallisation. The second factor identified was that the hydrogen bonding lifetime of the
individual API molecules or small API clusters attached to a heterosurface is much longer (up
to 1000 times) than (i) the lifetime of API-API interactions in the solution phase, or (ii)…
Advisors/Committee Members: Hodnett, Benjamin K., Hudson, Sarah P., Davern, Peter.
Subjects/Keywords: heterogeneous nucleation; pharmaceutical ingredients
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APA (6th Edition):
Verma, V. (2018). Role of hydrogen bonding lifetime and complementarity in heterogeneous nucleation. (Thesis). University of Limerick. Retrieved from http://hdl.handle.net/10344/7597
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Verma, Vivek. “Role of hydrogen bonding lifetime and complementarity in heterogeneous nucleation.” 2018. Thesis, University of Limerick. Accessed February 27, 2021.
http://hdl.handle.net/10344/7597.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Verma, Vivek. “Role of hydrogen bonding lifetime and complementarity in heterogeneous nucleation.” 2018. Web. 27 Feb 2021.
Vancouver:
Verma V. Role of hydrogen bonding lifetime and complementarity in heterogeneous nucleation. [Internet] [Thesis]. University of Limerick; 2018. [cited 2021 Feb 27].
Available from: http://hdl.handle.net/10344/7597.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Verma V. Role of hydrogen bonding lifetime and complementarity in heterogeneous nucleation. [Thesis]. University of Limerick; 2018. Available from: http://hdl.handle.net/10344/7597
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
University of Limerick
20.
Yousuf, Mustafa.
Quantitative approach between secondary nucleation and mixing hydrodynamics in solution crystallization system: process development and scale-up.
Degree: 2019, University of Limerick
URL: http://hdl.handle.net/10344/8492
► peer-reviewed
Crystallization via secondary nucleation allows the selective crystallization of a particular crystalline form which can lead to a more consistent crystalline product in terms…
(more)
▼ peer-reviewed
Crystallization via secondary nucleation allows the selective crystallization of a particular crystalline form which can lead to a more consistent crystalline product in terms of particle size distribution (PSD). Scaling up a crystallization process often results in significant changes to crystal size distribution (CSD), purity and morphology, which are key factors of product quality and has implications for downstream operations. The development of robust crystallization processes in which these parameters can be controlled requires a clear mechanistic understanding of nucleation. The convenient method to investigate this behavior is to determine the secondary nucleation threshold (SNT) of a crystallization system, which was found to be very sensitive to process variables such as mixing. Secondary nucleation and its qualitative relationship with agitation rate was a typical criterion used in the past. However, in the present work, a novel approach was established in which particle imaging velocimetry (PIV), a non-intrusive measurement technique, was used to quantify the mixing hydrodynamics with the cooling crystallization kinetics, as a function of fluid turbulent shear stress (TSS). All the crystallization experiments were performed in a solution crystallization of paracetamol in propan-2-ol solvent using a large single seed crystal of paracetamol which was held stationary in the agitating solution. Based on the experimental evidence, crystal nuclei breeding has been proposed as the mechanism of secondary nucleation in which pre-nucleated clusters from the solution nucleated at the interface of the seed crystal. These crystallites were weakly bound to the surface and readily sheared off by the fluid shear, which led to secondary nucleation. At a given scale, with the increased agitation rate, the SNT and product mean particle size were observed to decrease due to increased TSS. The increased TSS enhanced the rate of crystallites detachment from the seed surface, which facilitated the rate of secondary nucleation, and hence a decrease in SNT. From the results, secondary nucleation due to nuclei breeding was found to have a quantitative link with TSS which resulted in SNT to be independent of the scale under the influence of a constant TSS. This, in turn, leads to the production of a consistent PSD, independent of the scale. Moreover, the investigations revealed that using nuclei breeding approach in secondary nucleation, a controlled and uniform (narrow) PSD can be obtained in a given crystallization process through quantitative hydrodynamics. The novel approach established in the present work offers a potential for a more precise model in the process development and scale-up since nucleation is the direct consequence of nuclei breeding in which the fluid shear stress is the driving factor.
Advisors/Committee Members: Frawley, Patrick J..
Subjects/Keywords: crystallization; nucleation; crystalline form
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APA (6th Edition):
Yousuf, M. (2019). Quantitative approach between secondary nucleation and mixing hydrodynamics in solution crystallization system: process development and scale-up. (Thesis). University of Limerick. Retrieved from http://hdl.handle.net/10344/8492
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Yousuf, Mustafa. “Quantitative approach between secondary nucleation and mixing hydrodynamics in solution crystallization system: process development and scale-up.” 2019. Thesis, University of Limerick. Accessed February 27, 2021.
http://hdl.handle.net/10344/8492.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Yousuf, Mustafa. “Quantitative approach between secondary nucleation and mixing hydrodynamics in solution crystallization system: process development and scale-up.” 2019. Web. 27 Feb 2021.
Vancouver:
Yousuf M. Quantitative approach between secondary nucleation and mixing hydrodynamics in solution crystallization system: process development and scale-up. [Internet] [Thesis]. University of Limerick; 2019. [cited 2021 Feb 27].
Available from: http://hdl.handle.net/10344/8492.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Yousuf M. Quantitative approach between secondary nucleation and mixing hydrodynamics in solution crystallization system: process development and scale-up. [Thesis]. University of Limerick; 2019. Available from: http://hdl.handle.net/10344/8492
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Georgia Tech
21.
Chandramowlishwaran, Pavithra.
Prion nucleation and propagation by mammalian amyloidogenic proteins in yeast.
Degree: PhD, Biology, 2018, Georgia Tech
URL: http://hdl.handle.net/1853/61159
► Cross-β fibrous protein polymers or “amyloids” are associated with a variety of human and animal diseases, including Alzheimer’s disease (AD), Parkinson’s disease (PD), and Huntington’s…
(more)
▼ Cross-β fibrous protein polymers or “amyloids” are associated with a variety of human and animal diseases, including Alzheimer’s disease (AD), Parkinson’s disease (PD), and Huntington’s disease (HD) and are suspected to possess transmissible (prion) properties. However, the molecular mechanisms of amyloid formation and propagation are difficult to investigate in vivo due to complexity of the human organism. While evolutionarily distant from humans, yeast cells carry transmissible amyloids (yeast prions) that can be detected phenotypically. The objectives of the work presented in this dissertation were to understand the molecular mechanisms of initial prion
nucleation and propagation by mammalian proteins in yeast. Our model employed chimeric constructs, containing the mammalian amyloidogenic proteins (or domains) fused to various fragments of the yeast prion protein Sup35. Phenotypic and biochemical detection assays, previously developed for the Sup35 prion, enabled us to detect prion
nucleation and propagation by mammalian proteins. We have demonstrated that several non-Q/N rich, mammalian amyloidogenic proteins, nucleated a prion in yeast in the absence of pre-existing prions. Sequence alterations antagonizing or enhancing amyloidogenicity of human Aβ (associated with AD) and mouse PrP (associated with prion diseases) respectively antagonized or enhanced
nucleation of a yeast prion by these proteins. Mutational dissection of Aβ identified sequences and chemicals that influence initial amyloid
nucleation. We have also shown that Aβ and microtubule-associated binding protein tau that is also associated with AD, could propagate a prion state on their own or after transfection with in vitro generated amyloid seeds, in yeast. Aβ- and tau-based chimeric constructs formed distinct variants (“strains”) in the yeast cell. Our data show that prion properties of mammalian proteins detected in the yeast assays correspond with those found in mammals or in vitro, thus making yeast a powerful model for deciphering molecular foundations of amyloid/prion diseases.
Advisors/Committee Members: Chernoff, Yury (advisor), Lobachev, Kirill (committee member), Lieberman, Raquel (committee member), Storici, Francesca (committee member), Conticello, Vincent (committee member).
Subjects/Keywords: Nucleation; Propagation; Amyloid; Yeast; Prion
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APA (6th Edition):
Chandramowlishwaran, P. (2018). Prion nucleation and propagation by mammalian amyloidogenic proteins in yeast. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/61159
Chicago Manual of Style (16th Edition):
Chandramowlishwaran, Pavithra. “Prion nucleation and propagation by mammalian amyloidogenic proteins in yeast.” 2018. Doctoral Dissertation, Georgia Tech. Accessed February 27, 2021.
http://hdl.handle.net/1853/61159.
MLA Handbook (7th Edition):
Chandramowlishwaran, Pavithra. “Prion nucleation and propagation by mammalian amyloidogenic proteins in yeast.” 2018. Web. 27 Feb 2021.
Vancouver:
Chandramowlishwaran P. Prion nucleation and propagation by mammalian amyloidogenic proteins in yeast. [Internet] [Doctoral dissertation]. Georgia Tech; 2018. [cited 2021 Feb 27].
Available from: http://hdl.handle.net/1853/61159.
Council of Science Editors:
Chandramowlishwaran P. Prion nucleation and propagation by mammalian amyloidogenic proteins in yeast. [Doctoral Dissertation]. Georgia Tech; 2018. Available from: http://hdl.handle.net/1853/61159
University of Texas – Austin
22.
Ghahremaninezhad Mianji, Ali.
On the role of microstructure in ductile failure.
Degree: PhD, Engineering Mechanics, 2011, University of Texas – Austin
URL: http://hdl.handle.net/2152/ETD-UT-2011-08-3804
► Failure in structural materials occurs initially by localization of deformation, and subsequently through a process of nucleation, growth and coalescence of voids. Predicting material failure…
(more)
▼ Failure in structural materials occurs initially by localization of deformation, and subsequently through a process of
nucleation, growth and coalescence of voids. Predicting material failure requires a careful investigation of the different stages of damage evolution at the multiple scales. The main objective of this thesis is to explore the evolution of damage and to correlate this with the deformation of the material at the continuum and microstructural levels. This is accomplished through macroscopic measurements of strain evolution using digital image correlation and microscale measurements of strain and damage using optical and scanning electron microscopy.
Three materials with different microstructure were examined. In oxygen-free, high-conductivity copper, a high-purity material without appreciable second phase particles, strain levels in the order of three were observed in the material without any trace of damage. Failure was observed to be triggered by plastic instability in the form of shear bands and the emergence of a prismatic cavity that grows in a self-similar fashion by an alternating slip mechanism. In Al 6061-T6, a material with a dispersion of second phase particles at a volume fraction of about 0.01,
nucleation of damage does not appear until plastic strain levels of 0.5 to 1.0. Once damage in the form of particle fracture or decohesion at the interface initiates, subsequent failure follows by the void
nucleation, growth and coalescence; but, dominated by the fluctuations in the distribution of second phase particles, final separation occurs in a highly localized layer of material on the order of the grain size, corresponding to a small increase in the overall strain. In nodular cast iron, a material with an initial porosity of about 0.10, growth of voids was observed initially, but this was terminated by a transition of the deformation into a localized region.
Phenomenological models based on strain-to-failure and micromechanical models based on a mechanistic description of the microscale deformation are evaluated in light of the above examination of failure in these three classes of materials.
Advisors/Committee Members: Ravi-Chandar, K. (advisor), Mear, Mark E. (committee member), Liechti, Kenneth M. (committee member), Huang, Rui (committee member), Benzerga, Amine (committee member).
Subjects/Keywords: Microstructure; Nucleation; Localization; Slip; Grain
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APA (6th Edition):
Ghahremaninezhad Mianji, A. (2011). On the role of microstructure in ductile failure. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/ETD-UT-2011-08-3804
Chicago Manual of Style (16th Edition):
Ghahremaninezhad Mianji, Ali. “On the role of microstructure in ductile failure.” 2011. Doctoral Dissertation, University of Texas – Austin. Accessed February 27, 2021.
http://hdl.handle.net/2152/ETD-UT-2011-08-3804.
MLA Handbook (7th Edition):
Ghahremaninezhad Mianji, Ali. “On the role of microstructure in ductile failure.” 2011. Web. 27 Feb 2021.
Vancouver:
Ghahremaninezhad Mianji A. On the role of microstructure in ductile failure. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2011. [cited 2021 Feb 27].
Available from: http://hdl.handle.net/2152/ETD-UT-2011-08-3804.
Council of Science Editors:
Ghahremaninezhad Mianji A. On the role of microstructure in ductile failure. [Doctoral Dissertation]. University of Texas – Austin; 2011. Available from: http://hdl.handle.net/2152/ETD-UT-2011-08-3804
University of New South Wales
23.
Rzechowicz, Miles Edward.
The Influence of Water Properties on Water Treatment Processes.
Degree: Physical, 2011, University of New South Wales
URL: http://handle.unsw.edu.au/1959.4/51373
;
https://unsworks.unsw.edu.au/fapi/datastream/unsworks:10055/SOURCE01?view=true
► The potential for cavitation within reverse osmosis (RO) membranes was investigated by studying the effects of feed water degassing on RO desalination. Initial experiments, conducted…
(more)
▼ The potential for cavitation within reverse osmosis (RO) membranes was investigated by studying the effects of feed water degassing on RO desalination. Initial experiments, conducted using a laboratory-scale RO desalinator, and a range of NaCl feed solutions, showed a permeate flux increase of 3-5%, on average, upon feed solution degassing. These positive results led to the design and construction, with commercial support, of an industrial pilot-scale RO desalination system. Industrially prepared seawater feed was used, and operating conditions were chosen to reproduce, as closely as possible, those of industrial seawater RO installations. Upon pressure release by restricted flow, from 10-60bar to ambient pressure, cavitation was always observed when dissolved gases were present, but never with a degassed feed. Several RO membranes were found to be slightly hydrophobic, some with considerable surface heterogeneity, which supported the view that cavitation may occur within RO membranes. However, no permeate flux enhancement was observed with the pilot system, at degassing level of about 99%, for feed pressures in the range 38-55bar. In a study of osmotic distillation, it was found that the water flux, from pure water to NaCl solutions at various concentrations, correlated almost perfectly with the variation in solution vapour pressure with salt concentration. This process may be useful for the direct experimental measurement of osmotic pressures, and the determination of partial molar volumes of water in aqueous solutions. Simple asymmetric glass filter membranes were fabricated by fusing successive layers of different sized Ballotini beads. The filters were found to have predictable size-exclusion properties and good back-flushing tolerance. The simple fabrication process required only cheap, common resources. The filters proved capable of filtering a highly fouling suspension of organic waste in water, and recovered their initial flow rate upon back-flushing. Several studies were also conducted into some of the physical properties of water. High degassing levels were achieved by a simple boiling method. Degassed water was found to resist freezing, and supercool much more than atmospherically equilibrated water. The oxidation-reduction potential of water did not vary significantly upon degassing. The potential for feed water degassing for improved electrodialysis desalination was also investigated.
Advisors/Committee Members: Pashley, Richard, Physical, Environmental & Mathematical Sciences, Australian Defence Force Academy, UNSW, Woodward, Cliff, Physical, Environmental & Mathematical Sciences, Australian Defence Force Academy, UNSW.
Subjects/Keywords: Cavitation; Reverse Osmosis; Degassing; Nucleation
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APA (6th Edition):
Rzechowicz, M. E. (2011). The Influence of Water Properties on Water Treatment Processes. (Doctoral Dissertation). University of New South Wales. Retrieved from http://handle.unsw.edu.au/1959.4/51373 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:10055/SOURCE01?view=true
Chicago Manual of Style (16th Edition):
Rzechowicz, Miles Edward. “The Influence of Water Properties on Water Treatment Processes.” 2011. Doctoral Dissertation, University of New South Wales. Accessed February 27, 2021.
http://handle.unsw.edu.au/1959.4/51373 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:10055/SOURCE01?view=true.
MLA Handbook (7th Edition):
Rzechowicz, Miles Edward. “The Influence of Water Properties on Water Treatment Processes.” 2011. Web. 27 Feb 2021.
Vancouver:
Rzechowicz ME. The Influence of Water Properties on Water Treatment Processes. [Internet] [Doctoral dissertation]. University of New South Wales; 2011. [cited 2021 Feb 27].
Available from: http://handle.unsw.edu.au/1959.4/51373 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:10055/SOURCE01?view=true.
Council of Science Editors:
Rzechowicz ME. The Influence of Water Properties on Water Treatment Processes. [Doctoral Dissertation]. University of New South Wales; 2011. Available from: http://handle.unsw.edu.au/1959.4/51373 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:10055/SOURCE01?view=true
University of Utah
24.
Jacobson, Liam Christopher.
Molecular mechanisms of nucleation and growth of clathrate hydrates.
Degree: PhD, Chemistry, 2011, University of Utah
URL: http://content.lib.utah.edu/cdm/singleitem/collection/etd3/id/176/rec/1632
► Clathrate hydrates are a crystalline phase of water in which the hydrogen bond network forms polyhedral cages that can trap nonhydrogen bonding molecules such as…
(more)
▼ Clathrate hydrates are a crystalline phase of water in which the hydrogen bond network forms polyhedral cages that can trap nonhydrogen bonding molecules such as methane and carbon dioxide. Methane clathrate hydrates occur naturally on the ocean floor and are so abundant that it is estimated they contain more energy than the rest of the world’s hydrocarbon reserves combined. As a result, methods to promote and inhibit the formation of clathrates are highly sought after. However, a detailed understanding of the microscopic mechanism of clathrate nucleation remains elusive. Experimental techniques are unable to resolve the structure of clathrate nuclei. Simulations provide an alternative, but nucleation is a stochastic event and the computational cost to observe nucleation events can be prohibitive. In this work we studied the mechanism of clathrate hydrate nucleation with molecular simulations using an efficient coarse-grained model mW that represents water as a single site that is encouraged to form “hydrogen-bonded” configurations without the use of hydrogen atoms. The coarse-grained model allows the observation of many more nucleation events than is possible with atomistic models. Using the coarse-grained water model and guest potentials, we studied the nucleation of clathrate hydrates at supercooled conditions. The nucleation mechanism we observed is a multistep mechanism with an amorphous intermediate that we call “the blob.” The first step in the nucleation is the densification of guest molecules in solution to form long-lived solvent-separated configurations. These persist in solution and give rise to the formation and dissolution of individual cages. Once “the blob” is large enough, it eventually forms persistent polyhedral cages. The critical nucleus is defined by the solvent-separated guest molecules and polyhedral water cages. The clathrate at this point is amorphous and lacks the symmetry of the crystalline clathrate, but is made of the same building blocks. We find that an amorphous clathrate seed is able to nucleate the formation of crystalline clathrates. We develop order parameters for the densification of guest molecules in solution, the identification of polyhedral cages, and the crystallinity of the clathrate phase. These order parameters will be useful for describing the reaction coordinate of clathrate nucleation at low driving force.
Subjects/Keywords: Amorphous; Clathrates; Coarse-grained; Hydrates; Multistep nucleation; Nucleation
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APA (6th Edition):
Jacobson, L. C. (2011). Molecular mechanisms of nucleation and growth of clathrate hydrates. (Doctoral Dissertation). University of Utah. Retrieved from http://content.lib.utah.edu/cdm/singleitem/collection/etd3/id/176/rec/1632
Chicago Manual of Style (16th Edition):
Jacobson, Liam Christopher. “Molecular mechanisms of nucleation and growth of clathrate hydrates.” 2011. Doctoral Dissertation, University of Utah. Accessed February 27, 2021.
http://content.lib.utah.edu/cdm/singleitem/collection/etd3/id/176/rec/1632.
MLA Handbook (7th Edition):
Jacobson, Liam Christopher. “Molecular mechanisms of nucleation and growth of clathrate hydrates.” 2011. Web. 27 Feb 2021.
Vancouver:
Jacobson LC. Molecular mechanisms of nucleation and growth of clathrate hydrates. [Internet] [Doctoral dissertation]. University of Utah; 2011. [cited 2021 Feb 27].
Available from: http://content.lib.utah.edu/cdm/singleitem/collection/etd3/id/176/rec/1632.
Council of Science Editors:
Jacobson LC. Molecular mechanisms of nucleation and growth of clathrate hydrates. [Doctoral Dissertation]. University of Utah; 2011. Available from: http://content.lib.utah.edu/cdm/singleitem/collection/etd3/id/176/rec/1632
25.
Burkhart, Eryn Therese.
Investigation of the Seismic Nucleation Phase of Large Earthquakes Using Broadband Teleseismic Data.
Degree: 2014, University of California – eScholarship, University of California
URL: http://www.escholarship.org/uc/item/0dx0d94s
► The dynamic motion of an earthquake begins abruptly, but is often initiated by a short interval of weak motion called the seismic nucleation phase (SNP).…
(more)
▼ The dynamic motion of an earthquake begins abruptly, but is often initiated by a short interval of weak motion called the seismic nucleation phase (SNP). Ellsworth and Beroza [1995, 1996] concluded that the SNP was detectable in near-source records of 48 earthquakes with moment magnitude (Mw), ranging from 1.1 to 8.1. They found that the SNP accounted for approximately 0.5% of the total moment and 1/6 of the duration of the earthquake. Ji et al [2010] investigated the SNP of 19 earthquakes with Mw greater than 8.0 using teleseismic broadband data. This study concluded that roughly half of the earthquakes had detectable SNPs, inconsistent with the findings of Ellsworth and Beroza [1995]. Here 69 earthquakes of Mw 7.5-8.0 from 1994 to 2011 are further examined. The SNP is clearly detectable using teleseismic data in 32 events, with 35 events showing no nucleation phase, and 2 events had insufficient data to perform stacking, consistent with the previous analysis. Our study also reveals that the percentage of the SNP events is correlated with the focal mechanism and hypocenter depths. Strike-slip earthquakes are more likely to exhibit a clear SNP than normal or thrust earthquakes. Eleven of 14 strike-slip earthquakes (78.6%) have detectable NSPs. In contrast, only 16 of 40 (40%) thrust earthquakes have detectable SNPs. This percentage also became smaller for deep events (33% for events with hypocenter depth>250 km). To understand why certain thrust earthquakes have a visible SNP, we examined the sediment thickness, age, and angle of the subducting plate of all thrust earthquakes in the study. We found that thrust events with shallow (<50 km) hypocenters with thick seafloor sediments (>600 m) on the subducting plate tend to have clear SNPs. If the SNP can be better understood in the future, it may help seismologists better understand the rupture dynamics of large earthquakes. Potential applications of this work could attempt to predict the magnitude of an earthquake seconds before it begins by measuring the SNP, vastly improving earthquake Early Warning Systems for populated areas.
Subjects/Keywords: Geophysics; earthquake; earthquake nucleation; large earthquake; seismic nucleation phase; seismology; SNP
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APA (6th Edition):
Burkhart, E. T. (2014). Investigation of the Seismic Nucleation Phase of Large Earthquakes Using Broadband Teleseismic Data. (Thesis). University of California – eScholarship, University of California. Retrieved from http://www.escholarship.org/uc/item/0dx0d94s
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Burkhart, Eryn Therese. “Investigation of the Seismic Nucleation Phase of Large Earthquakes Using Broadband Teleseismic Data.” 2014. Thesis, University of California – eScholarship, University of California. Accessed February 27, 2021.
http://www.escholarship.org/uc/item/0dx0d94s.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Burkhart, Eryn Therese. “Investigation of the Seismic Nucleation Phase of Large Earthquakes Using Broadband Teleseismic Data.” 2014. Web. 27 Feb 2021.
Vancouver:
Burkhart ET. Investigation of the Seismic Nucleation Phase of Large Earthquakes Using Broadband Teleseismic Data. [Internet] [Thesis]. University of California – eScholarship, University of California; 2014. [cited 2021 Feb 27].
Available from: http://www.escholarship.org/uc/item/0dx0d94s.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Burkhart ET. Investigation of the Seismic Nucleation Phase of Large Earthquakes Using Broadband Teleseismic Data. [Thesis]. University of California – eScholarship, University of California; 2014. Available from: http://www.escholarship.org/uc/item/0dx0d94s
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
University of Edinburgh
26.
Mackenzie, Alasdair Morgan.
Investigating nucleation control in batch and flow using non-photochemical laser-induced nucleation.
Degree: PhD, 2017, University of Edinburgh
URL: http://hdl.handle.net/1842/31458
► The practical application of non-photochemical laser-induced nucleation (NPLIN) to continuous flow was investigated. Supersaturated aqueous solutions were screened with a 5 ns pulsed laser (532…
(more)
▼ The practical application of non-photochemical laser-induced nucleation (NPLIN) to continuous flow was investigated. Supersaturated aqueous solutions were screened with a 5 ns pulsed laser (532 nm 44 MW cm-2) for NPLIN activity. Upon irradiation succinic acid nucleated at S20 = 4.3 and adipic acid at S20 = 2.0 - 3.0. NPLIN activity is reported for the first time in nicotinic acid (S20 = 2.6 - 3.0). No overall pattern was observed of chemical structure on NPLIN activity. From inorganic compounds similarly screened, ammonium chloride (S20 = 1.04 - 1.20) was identified as most suitable for further tests. It was shown to have an increase of NPLIN crystals with higher supersaturation from 13 at S = 1.038 to 252 at S = 1.135. A quadratic increase in number of crystals with increased laser power. The effects of NPLIN upon ammonium chloride are diminished upon filtration through a 0.2 μm poly (ether sulfone) filter, reducing the number of crystals from 350 to 10 per 70 mJ pulse (25 MW cm-2). The use of NPLIN in continuous flow was demonstrated from the first time. A S23 = 1.1 solution of aqueous ammonium chloride in flow produced crystals when irradiated by 10 pulses s-1 of a 1064 nm 6 ns laser. When the laser was stopped, crystals were no longer produced and the system returned to flowing supersaturated solution. Lab scale apparatus for continuous NPLIN experiments was developed. A design involving a re-dissolution step and loop flow was constructed for both laminar and slug-flow regimes. Nucleation of ammonium chloride (S = 1.1) was demonstrated in both systems. Repeatable NPLIN experiments were hindered by spontaneous nucleation. Spontaneous nucleation in flow was observed around areas where supersaturated solution passed from one component to another. Spontaneous nucleation was also observed upon cooling (25 to 10 °C). Filtration was observed to both suppress NPLIN and spontaneous nucleation in flow.
Subjects/Keywords: 548; Crystallisation; homogeneous nucleation; NPLIN; non-photochemical laser-induced nucleation
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APA (6th Edition):
Mackenzie, A. M. (2017). Investigating nucleation control in batch and flow using non-photochemical laser-induced nucleation. (Doctoral Dissertation). University of Edinburgh. Retrieved from http://hdl.handle.net/1842/31458
Chicago Manual of Style (16th Edition):
Mackenzie, Alasdair Morgan. “Investigating nucleation control in batch and flow using non-photochemical laser-induced nucleation.” 2017. Doctoral Dissertation, University of Edinburgh. Accessed February 27, 2021.
http://hdl.handle.net/1842/31458.
MLA Handbook (7th Edition):
Mackenzie, Alasdair Morgan. “Investigating nucleation control in batch and flow using non-photochemical laser-induced nucleation.” 2017. Web. 27 Feb 2021.
Vancouver:
Mackenzie AM. Investigating nucleation control in batch and flow using non-photochemical laser-induced nucleation. [Internet] [Doctoral dissertation]. University of Edinburgh; 2017. [cited 2021 Feb 27].
Available from: http://hdl.handle.net/1842/31458.
Council of Science Editors:
Mackenzie AM. Investigating nucleation control in batch and flow using non-photochemical laser-induced nucleation. [Doctoral Dissertation]. University of Edinburgh; 2017. Available from: http://hdl.handle.net/1842/31458
University of Texas – Austin
27.
Carpenter, Katherine Patricia.
Influence of surface chemistry and electric fields on the nucleation of ice and hydrates.
Degree: PhD, Mechanical Engineering, 2016, University of Texas – Austin
URL: http://hdl.handle.net/2152/68268
► Understanding and controlling the formation of ice and hydrates has important energy-related applications including ice mitigation, methane harvesting from hydrates, and desalination by freezing. This…
(more)
▼ Understanding and controlling the formation of ice and hydrates has important energy-related applications including ice mitigation, methane harvesting from hydrates, and desalination by freezing. This dissertation describes multiple studies to explore the role of surface chemistry and electric fields on the
nucleation of ice and hydrates.
The first part of this dissertation describes a study on saltwater ice formation. A majority of the available literature on ice mitigation concerns freshwater icing, unlike this study. This work quantifies the influence of surface chemistry and texture on saltwater ice formation. Two kinds of experiments are conducted as part of this effort. The first set of experiments quantifies the influence of surface chemistry on ice
nucleation of various saltwater solutions. It is noted that a large number of individual experiments were conducted, which makes the present results statistically meaningful, unlike most previous studies. The second set of experiments studies the dynamics associated with impact of saltwater droplets on supercooled superhydrophobic surfaces. It is seen that the saltwater droplets retract more than freshwater droplets (after impact). The greater bounciness of saltwater droplets is a result of slower ice
nucleation propagation kinetics. These experiments indicate that superhydrophobic surfaces will offer greater resistance to impact icing with saltwater than pure water and can remain useful at temperatures as low as -40 °C.
The second part of the dissertation includes a detailed study of electrofreezing, i.e., the electrically induced
nucleation of ice from supercooled water. This work studies ice
nucleation in electrowetted water droplets, wherein there is no electric field inside the droplet resting on a dielectric layer. Instead, there is an interfacial electric field and charge buildup at the solid-liquid interface. Through carefully planned experiments, the influence of electric fields and electric currents on the freezing temperature elevation is quantified. The results facilitate an in-depth understanding of various mechanisms underlying electrofreezing. Firstly, interfacial electric fields alone can significantly elevate freezing temperatures by more than 15 °C in the absence of current flow. Secondly, electrofreezing-induced temperature elevation saturates at high electric field strengths. Thirdly, the polarity of the interfacial charge does not significantly influence electrofreezing. Finally, current flow can further elevate the
nucleation temperature by providing additional triggers for
nucleation events. Overall, both the electric field and the electric current influence electrofreezing; however, the physical mechanisms are very different.
The third part of the dissertation studies a novel concept to induce rapid formation of hydrates. The long induction times (hours to days) associated with hydrate
nucleation is a significant barrier to many hydrate-based applications. The present work shows that electro-
nucleation can promote rapid hydrate…
Advisors/Committee Members: Bahadur, Vaibhav (advisor), Bogard, David (committee member), Espinoza, David N (committee member), Ezekoye, Ofodike (committee member), Shi, Li (committee member).
Subjects/Keywords: Phase change; Ice formation; Ice nucleation; Electrofreezing; Electro-nucleation; Saltwater; Hydrates
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APA (6th Edition):
Carpenter, K. P. (2016). Influence of surface chemistry and electric fields on the nucleation of ice and hydrates. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/68268
Chicago Manual of Style (16th Edition):
Carpenter, Katherine Patricia. “Influence of surface chemistry and electric fields on the nucleation of ice and hydrates.” 2016. Doctoral Dissertation, University of Texas – Austin. Accessed February 27, 2021.
http://hdl.handle.net/2152/68268.
MLA Handbook (7th Edition):
Carpenter, Katherine Patricia. “Influence of surface chemistry and electric fields on the nucleation of ice and hydrates.” 2016. Web. 27 Feb 2021.
Vancouver:
Carpenter KP. Influence of surface chemistry and electric fields on the nucleation of ice and hydrates. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2016. [cited 2021 Feb 27].
Available from: http://hdl.handle.net/2152/68268.
Council of Science Editors:
Carpenter KP. Influence of surface chemistry and electric fields on the nucleation of ice and hydrates. [Doctoral Dissertation]. University of Texas – Austin; 2016. Available from: http://hdl.handle.net/2152/68268
Colorado School of Mines
28.
Dabney, Matthew S.
Laser nucleated grain growth in hydrogenated amorphous silicon films.
Degree: PhD, Metallurgical and Materials Engineering, 2013, Colorado School of Mines
URL: http://hdl.handle.net/11124/78806
► Large grained film crystal silicon has been pursued for decades in hopes of replacing expensive wafer devices with lower cost film products with comparable electronic…
(more)
▼ Large grained film crystal silicon has been pursued for decades in hopes of replacing expensive wafer devices with lower cost film products with comparable electronic properties. The focus of these pursuits has been on directly producing thicker (>1um) films with bulk crystallization treatments. The recent development of a low cost, thin film compatible epi-thickening process of thin film template layers has opened up new possibilities for utilizing different methods of producing film crystal silicon. The focus of this research was an understanding of the
nucleation and growth process sufficient to develop a "thin"(<1um) seed layer on an inexpensive (glass) substrate that replicates a large grained c-Si surface, thus presenting a template surface for the subsequent epitaxial growth of a "thick"(~10um) c-Si film. By combining laser
nucleation and solid phase crystallization of a-Si:H films with different film hydrogen content (CH), the
nucleation and crystallization processes were explored. The laser fluence necessary for
nucleation through direct crystallization were explored for 100nm a-Si:H films with different film H content (CH). The affect of film H content and sub-crystallization threshold laser fluence were investigated by X-ray diffraction (XRD) measurements during in situ thermal annealing at 600°C of films with different CH treated with an array of fluences. The laser-treated films showed a reduced incubation time (t0) for crystallization compared to as-grown films, with the largest incubation time reduction exhibited for samples with higher film H and higher laser fluences. The grain sizes of HWCVD a-Si:H films which had been exposed to sub-threshold laser prior to thermal annealing were measured with electron backscattering diffraction (EBSD) and compared to unexposed films. For large area laser processed and thermally annealed films which exhibited a reduced to, the EBSD grain sizes were unchanged as compared to those for the same film which were annealed directly from the as grown state. The trends in EBSD grain size with in situ XRD crystallization time tc are consistent with theoretical predictions obtained from the classical model of
nucleation and grain growth. An optical method was developed as a new and simple method to investigate crystallite
nucleation and growth in stepwise, thermally annealed PECVD and HWCVD a-Si:H films. By confining film thicknesses to the range 500-4000Å, optical microscopy in the reflection mode was used to readily detect crystallites in the thermally annealed a-Si:H lattice. Measurements of the crystallite density versus annealing time for identically prepared films of different thicknesses demonstrated crystallite
nucleation rates smaller for thinner films, suggesting homogeneous
nucleation, in agreement with previous results. The effect of film stress on crystallite
nucleation was investigated in 0.11µm thick, thermally annealed hydrogenated amorphous silicon films. The
nucleation rate was significantly suppressed around scratches, cleaved film edges, and laser ablated…
Advisors/Committee Members: Ginley, D. S. (David S.) (advisor), Collins, Reuben T. (advisor), Ohno, Timothy R. (committee member), Packard, Corinne E. (committee member), Herring, Andrew M. (committee member), Gennett, Thomas (committee member), Kazmerski, Lawrence L. (committee member).
Subjects/Keywords: film; laser; nucleation; silicon; Nucleation; Silicon; Thin films; Photovoltaic power generation
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APA (6th Edition):
Dabney, M. S. (2013). Laser nucleated grain growth in hydrogenated amorphous silicon films. (Doctoral Dissertation). Colorado School of Mines. Retrieved from http://hdl.handle.net/11124/78806
Chicago Manual of Style (16th Edition):
Dabney, Matthew S. “Laser nucleated grain growth in hydrogenated amorphous silicon films.” 2013. Doctoral Dissertation, Colorado School of Mines. Accessed February 27, 2021.
http://hdl.handle.net/11124/78806.
MLA Handbook (7th Edition):
Dabney, Matthew S. “Laser nucleated grain growth in hydrogenated amorphous silicon films.” 2013. Web. 27 Feb 2021.
Vancouver:
Dabney MS. Laser nucleated grain growth in hydrogenated amorphous silicon films. [Internet] [Doctoral dissertation]. Colorado School of Mines; 2013. [cited 2021 Feb 27].
Available from: http://hdl.handle.net/11124/78806.
Council of Science Editors:
Dabney MS. Laser nucleated grain growth in hydrogenated amorphous silicon films. [Doctoral Dissertation]. Colorado School of Mines; 2013. Available from: http://hdl.handle.net/11124/78806
NSYSU
29.
Liu, Ting-yu.
A Study of the Formation of Intermetallic Compounds and Interface Structures of Pt and Sn.
Degree: Master, Materials and Optoelectronic Science, 2014, NSYSU
URL: http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0803114-153338
► The purpose of this research is to study the early stage reaction between Pt and Sn. Pt substrate was immersed into molten Sn for 1,…
(more)
▼ The purpose of this research is to study the early stage reaction between Pt and Sn. Pt substrate was immersed into molten Sn for 1, 2 and 10 seconds and the cross-section specimens was cut by focused-ion beam.
The results were analyzed by X-ray diffraction, and transmission electron microscopy (TEM) to study the microstructure, and the type, shape and the growth conditions of intermetallic compounds (IMCs). the possible orientation relationships between Pt and IMCs are analyzed.
TEM results showed that PtSn4 was on the surface of the specimens reflowed for 1 s and 2 s, and had a shape of square plate. However, a thin layer, 10 -20 nm, of PtSn was observed next to Pt substrate. There is no orientation relationships among Pt, PtSn and PtSn4. It is clear that both PtSn and PtSn4 are formed in the first second.
The formation of PtSn and PtSn4 was analyzed by heterogeneous
nucleation theory, including the free energies of formation, and their interfacial energies with respect to Pt and molten Sn.
Advisors/Committee Members: H. L. Huang (chair), Liu-wen Chang (chair), Der- shin Gan (committee member), P. Shen (chair).
Subjects/Keywords: heterogeneous nucleation; Immersion plating; PtSn4; PtSn
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APA (6th Edition):
Liu, T. (2014). A Study of the Formation of Intermetallic Compounds and Interface Structures of Pt and Sn. (Thesis). NSYSU. Retrieved from http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0803114-153338
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Liu, Ting-yu. “A Study of the Formation of Intermetallic Compounds and Interface Structures of Pt and Sn.” 2014. Thesis, NSYSU. Accessed February 27, 2021.
http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0803114-153338.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Liu, Ting-yu. “A Study of the Formation of Intermetallic Compounds and Interface Structures of Pt and Sn.” 2014. Web. 27 Feb 2021.
Vancouver:
Liu T. A Study of the Formation of Intermetallic Compounds and Interface Structures of Pt and Sn. [Internet] [Thesis]. NSYSU; 2014. [cited 2021 Feb 27].
Available from: http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0803114-153338.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Liu T. A Study of the Formation of Intermetallic Compounds and Interface Structures of Pt and Sn. [Thesis]. NSYSU; 2014. Available from: http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0803114-153338
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
NSYSU
30.
Huang, Chang-Chen.
Nucleation on a water-ice advancing interface.
Degree: Master, Mechanical Engineering, 2003, NSYSU
URL: http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0704103-094139
► Heterogeneous nucleation of bubbles on an advancing solidification front during freezing of water containing a dissolved gas has been experimentally and analytically studied. The formation…
(more)
▼ Heterogeneous
nucleation of bubbles on an advancing solidification front during freezing of water containing a dissolved gas has been experimentally and analytically studied. The formation of bubbles resulting from supersaturation of liquids is commonly encountered in different fields such as heat transfer, manufacturing, and bioscience.
In this work, sizes of nucleating bubbles and concentration profiles of dissolved oxygen and carbon dioxide gases in water ahead of the solidification front have been measured. From successful comparisons between the measured and predicted critical radii of nucleating bubbles and distributions of dissolved gas content, phenomena of heterogeneous
nucleation in a binary weak solution during the freezing process are quantitatively confirmed.
The results show that an increase in gas content at the solidification front in the liquid decreases the free energy barrier and critical radii of bubbles that are formed on the solidification front. In the early stage of solidification, sizes of the critical radii decrease and the number of nucleating bubbles increase. As solidification rates decrease later, content of the dissolved gas in the liquid on the advancing interface decreases and the critical radii of nucleating bubbles increase.
Advisors/Committee Members: F.B Hsiao (chair), Jiin-Yuh Jang (chair), Peng-Sheng Wei (committee member), Han-Taw Chen (chair).
Subjects/Keywords: solidification; bubble; nucleation
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APA (6th Edition):
Huang, C. (2003). Nucleation on a water-ice advancing interface. (Thesis). NSYSU. Retrieved from http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0704103-094139
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Huang, Chang-Chen. “Nucleation on a water-ice advancing interface.” 2003. Thesis, NSYSU. Accessed February 27, 2021.
http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0704103-094139.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Huang, Chang-Chen. “Nucleation on a water-ice advancing interface.” 2003. Web. 27 Feb 2021.
Vancouver:
Huang C. Nucleation on a water-ice advancing interface. [Internet] [Thesis]. NSYSU; 2003. [cited 2021 Feb 27].
Available from: http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0704103-094139.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Huang C. Nucleation on a water-ice advancing interface. [Thesis]. NSYSU; 2003. Available from: http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0704103-094139
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
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Open Access Theses and Dissertations