You searched for subject:(rheology).
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University of Montana
1.
Granzow, Glen David.
An Investigation of Viscosity Using Measured Velocities on Helheim Glacier.
Degree: MS, 2013, University of Montana
URL: https://scholarworks.umt.edu/etd/4184 
► Using recent measurements of the velocity of ice on the surface of Helheim Glacier, located on the south-east coast of Greenland, the variation of viscosity,…
(more)
▼ Using recent measurements of the velocity of ice on the surface of Helheim Glacier, located on the south-east coast of Greenland, the variation of viscosity, a material property of the ice, is investigated.
The investigation focuses on determining the value of a parameter in Glen's flow law, a constitutive equation widely used in numerical models of ice sheets.
Three different approaches are used:
(1) Finite differences are used in a direct approach,
(2) A finite element model is used in an approach involving an inverse problem, and
(3) Nonlinear least squares fits of the velocity are used.
The parameter focused on, the exponent in Glen's flow law, is assigned a value of three in most ice sheet models but the results presented in this thesis suggest that the behavior of ice (at least that in the fast moving portion of Helheim Glacier) might be more accurately modeled using a significantly smaller value, 1.6.
Subjects/Keywords: rheology
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APA (6th Edition):
Granzow, G. D. (2013). An Investigation of Viscosity Using Measured Velocities on Helheim Glacier. (Masters Thesis). University of Montana. Retrieved from https://scholarworks.umt.edu/etd/4184
Chicago Manual of Style (16th Edition):
Granzow, Glen David. “An Investigation of Viscosity Using Measured Velocities on Helheim Glacier.” 2013. Masters Thesis, University of Montana. Accessed March 04, 2021.
https://scholarworks.umt.edu/etd/4184.
MLA Handbook (7th Edition):
Granzow, Glen David. “An Investigation of Viscosity Using Measured Velocities on Helheim Glacier.” 2013. Web. 04 Mar 2021.
Vancouver:
Granzow GD. An Investigation of Viscosity Using Measured Velocities on Helheim Glacier. [Internet] [Masters thesis]. University of Montana; 2013. [cited 2021 Mar 04].
Available from: https://scholarworks.umt.edu/etd/4184.
Council of Science Editors:
Granzow GD. An Investigation of Viscosity Using Measured Velocities on Helheim Glacier. [Masters Thesis]. University of Montana; 2013. Available from: https://scholarworks.umt.edu/etd/4184
University of Alberta
2.
Sundararajan, Sujith.
A rheological model for composite truck ground
behavior.
Degree: MS, Department of Civil and Environmental
Engineering, 2014, University of Alberta
URL: https://era.library.ualberta.ca/files/wm117p26v
► Mining haul trucks are operated on different ground conditions subjected to adverse shock loading, creating the need to give more attention to the truck components…
(more)
▼ Mining haul trucks are operated on different ground
conditions subjected to adverse shock loading, creating the need to
give more attention to the truck components like suspension, tire,
and the operating ground. Extensive experimental research has been
done on these components at scale. In order to understand the
deformation behavior and the overall relationship between truck
components and the operating ground for a full sized truck,
mathematical equations have been derived for truck operation on
both rigid and oil sand ground surfaces. A rheological model is
also proposed here that has the ability to predict the total and
individual strain of the components. A model consisting of
suspension, tire, and ground is created using MATLAB (Simulink).
Finally, using the data obtained from the three methods, graphs are
plotted and comparisons made with previous laboratory and field
test results to validate the models and their
equations.
Subjects/Keywords: Rheology; Truck
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APA (6th Edition):
Sundararajan, S. (2014). A rheological model for composite truck ground
behavior. (Masters Thesis). University of Alberta. Retrieved from https://era.library.ualberta.ca/files/wm117p26v
Chicago Manual of Style (16th Edition):
Sundararajan, Sujith. “A rheological model for composite truck ground
behavior.” 2014. Masters Thesis, University of Alberta. Accessed March 04, 2021.
https://era.library.ualberta.ca/files/wm117p26v.
MLA Handbook (7th Edition):
Sundararajan, Sujith. “A rheological model for composite truck ground
behavior.” 2014. Web. 04 Mar 2021.
Vancouver:
Sundararajan S. A rheological model for composite truck ground
behavior. [Internet] [Masters thesis]. University of Alberta; 2014. [cited 2021 Mar 04].
Available from: https://era.library.ualberta.ca/files/wm117p26v.
Council of Science Editors:
Sundararajan S. A rheological model for composite truck ground
behavior. [Masters Thesis]. University of Alberta; 2014. Available from: https://era.library.ualberta.ca/files/wm117p26v
Cape Peninsula University of Technology
3.
Foudazi, Reza.
Models for structure-rheology of highly concentrated emulsions
.
Degree: 2009, Cape Peninsula University of Technology
URL: http://etd.cput.ac.za/handle/20.500.11838/2152
► Highly concentrated emulsions (HCE) are classified as high internal phase ratio emulsions (or simply HIPRE), and the dispersed phase droplets are ranged In a hexagonal…
(more)
▼ Highly concentrated emulsions (HCE) are classified as high internal phase ratio
emulsions (or simply HIPRE), and the dispersed phase droplets are ranged In a
hexagonal closely packed configuration. This closely packed configuration and the
profound hydrodynamic interaction between neighbouring droplets induce mechanical
interference between the droplets, thus prohibiting their free movement. Hence, while
the highly concentrated emulsions consist of very low viscosity and inelastic
components, they show gel-like behaviour with high elasticity and non-Newtonian flow
response. It has been suggested in the literature that this behaviour originated from
interfacial energy in terms of Laplace pressure. Therefore, the scaling of rheological
properties with Laplace pressure is expected, but several publications show a deviation
from this scaling behaviour. It seems that the source of deviation from this scaling is
interdroplet interaction, which can contribute to the rheological behaviour of highly
concentrated emulsions. The shear modulus of highly concentrated emulsions in the
presence of interdroplet interaction was developed in this work. The prediction of model
was verified by the data presented in the literature. It was shown that a small source of
interdroplet interaction can result in deviation from scaling of shear modulus with
Laplace pressure.
Subjects/Keywords: Emulsions;
Rheology
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APA (6th Edition):
Foudazi, R. (2009). Models for structure-rheology of highly concentrated emulsions
. (Thesis). Cape Peninsula University of Technology. Retrieved from http://etd.cput.ac.za/handle/20.500.11838/2152
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):
Foudazi, Reza. “Models for structure-rheology of highly concentrated emulsions
.” 2009. Thesis, Cape Peninsula University of Technology. Accessed March 04, 2021.
http://etd.cput.ac.za/handle/20.500.11838/2152.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Foudazi, Reza. “Models for structure-rheology of highly concentrated emulsions
.” 2009. Web. 04 Mar 2021.
Vancouver:
Foudazi R. Models for structure-rheology of highly concentrated emulsions
. [Internet] [Thesis]. Cape Peninsula University of Technology; 2009. [cited 2021 Mar 04].
Available from: http://etd.cput.ac.za/handle/20.500.11838/2152.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Foudazi R. Models for structure-rheology of highly concentrated emulsions
. [Thesis]. Cape Peninsula University of Technology; 2009. Available from: http://etd.cput.ac.za/handle/20.500.11838/2152
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
4.
Neelakantan, Ravi.
Effect of Shear Energy Input on the Rheology of
Flocculant-Dosed Kaolinite Suspensions.
Degree: MS, Department of Chemical and Materials
Engineering, 2016, University of Alberta
URL: https://era.library.ualberta.ca/files/c4b29b603z
► Thickened tailings technology is implemented in some oil sands operations in order to recycle warm process water, thereby reducing net water draw, and to reduce…
(more)
▼ Thickened tailings technology is implemented in some
oil sands operations in order to recycle warm process water,
thereby reducing net water draw, and to reduce the size of tailings
impoundment areas. The rheology of thickened tailings is complex
and time-dependent, and the underlying mechanism of rheological
degradation (J.M. Treinen and R. Cooke, HYDROTRANSPORT 18, BHR
Group, Cranfield, UK, 487-499, 2010) is not well understood. In the
present study, the time evolution of the particle size distribution
(PSD) and vane yield stress of a kaolinite dispersion mixed with
polymer flocculants is examined as a function of shear energy
input. Size distributions are obtained using the Focused Beam
Reflectance Measurement technique. The shear energy input was
quantified with the use of a large-volume, customized concentric
cylinder shearing apparatus which allowed for the testing of about
300cm3 of flocculated tailings per experiment. It was found that
decreases in vane yield stress and aggregate size were correlated
with energy input when acrylamide polymers were used as
flocculants. In particular, very large aggregates appeared to break
down to produce a significant population in the 10-100µm size range
as shear energy input was increased, which was seen in other
studies, e.g. Vaezi et al. (J. Colloid Int. Sci, 355, 96-105,
2011), who observed both size and structure (porosity) changes. A
decrease in apparent volume is the main mechanism for rheological
degradation of acrylamide flocculated thickened tailings. Lowering
the slurry pH before flocculation from 8.5 to 7.0 resulted in a
much greater equilibrium yield stress; however initial rates of
yield stress decay and floc degradation were unaffected. Dual
polymer flocculation with Magnafloc® LT27AG and HyChem HyperFloc
CD650 resulted in increased rates of decay in both rheology and
size distribution. Data obtained for non-conventional polymers
(e.g. PEO) demonstrate the potential for elastic polymer structures
to flocculate in high shear environments and the importance of
other factors (aggregate shape, zeta potential) which require
further investigation.
Subjects/Keywords: Rheology
…Normalized rheology reduction as a function of shear energy input Magnafloc® LT27AG at
pH 7 and pH… …Figure 4.13: Rheology reduction of kaolinite dispersion flocculated with A-C-A at pH 8.5 and… …and rheology reduction using 41% by mass solids paste .41
Table 3.2: Summary of paste… …permanent change. In fact, once the tailings are transported in a pipeline,
the rheology changes… …Predicting the rheology change of such complex mixtures has proven to be difficult and currently…
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APA ·
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Manager
APA (6th Edition):
Neelakantan, R. (2016). Effect of Shear Energy Input on the Rheology of
Flocculant-Dosed Kaolinite Suspensions. (Masters Thesis). University of Alberta. Retrieved from https://era.library.ualberta.ca/files/c4b29b603z
Chicago Manual of Style (16th Edition):
Neelakantan, Ravi. “Effect of Shear Energy Input on the Rheology of
Flocculant-Dosed Kaolinite Suspensions.” 2016. Masters Thesis, University of Alberta. Accessed March 04, 2021.
https://era.library.ualberta.ca/files/c4b29b603z.
MLA Handbook (7th Edition):
Neelakantan, Ravi. “Effect of Shear Energy Input on the Rheology of
Flocculant-Dosed Kaolinite Suspensions.” 2016. Web. 04 Mar 2021.
Vancouver:
Neelakantan R. Effect of Shear Energy Input on the Rheology of
Flocculant-Dosed Kaolinite Suspensions. [Internet] [Masters thesis]. University of Alberta; 2016. [cited 2021 Mar 04].
Available from: https://era.library.ualberta.ca/files/c4b29b603z.
Council of Science Editors:
Neelakantan R. Effect of Shear Energy Input on the Rheology of
Flocculant-Dosed Kaolinite Suspensions. [Masters Thesis]. University of Alberta; 2016. Available from: https://era.library.ualberta.ca/files/c4b29b603z
5.
Costanzo, Salvatore.
Development of protocols for investigating linear, branched and supramolecular polymers undergoing shear.
Degree: 2017, University of Crete (UOC); Πανεπιστήμιο Κρήτης
URL: http://hdl.handle.net/10442/hedi/40133
► The aim of the present thesis is to shed light into the nonlinear rheological behavior ofcomplex polymeric structures by means of state-of-the-art instrumentation, particularlyfocusing on…
(more)
▼ The aim of the present thesis is to shed light into the nonlinear rheological behavior ofcomplex polymeric structures by means of state-of-the-art instrumentation, particularlyfocusing on shear rheology. Strong nonlinear flows are ubiquitous in polymer process-ing, therefore their understanding is fundamental for technological applications. On theother hand, the progress in nonlinear rheology has been halted by experimental issuesassociated with flow instabilities, rendering rheometric experiments problematic. Thedevelopment of experimental tools to resolve these issues is a timely, outstanding challenge. Overcoming flow instabilities in nonlinear experimental rheology will advancethe field in different directions such as accurate modeling development, decoding molec-ular mechanisms of motion, designing macromolecular systems with desired, tunableproperties. Particularly, in relation to molecular mechanisms, knowledge of polymerdynamics in nonlinear flows is rather limited, especially in shear. In such a context,this thesis work attempts to answer two key questions: i) How can we obtain reliablemeasurements in transient shear? ii) What is the interplay of entanglements, branch-ing and associations in determining the nonlinear rheology of complex systems? It isclear that answering the first question is necessary in order to address the second one.Therefore, in the first part of this thesis we present the design and implementation of acone-partitioned-plate (CPP) geometry for ARES rheometer that allows for accurate,artifact-free measurements in nonlinear transient shear. In the second part, we applyCPP and uniaxial extensional rheometry to investigate model systems including linear,ring, Cayley-tree and dendronized polymers, in order to address the above-mentionedquestions.
Ο στόχος της παρούσας διατριβής είναι να ρίξει φως στη μή-γραμμική ρεολογική συμπεριφορά σύνθετων πολυμερικών δομών με τη χρήση προχωρημένων τεχνικών τελευταίας τεχνολογίας και με ιδιαίτερη εστίαση στην ρεολογία διάτμησης. Ισχυρά μή-γραμμικά φαινόμενα ροής είναι πανταχού παρόντα στις διαδικασίες κατεργασίας πολυμερών,επομένως η κατανόησή τους είναι θεμελιώδους σημασίας για τεχνολογικές εφαρμογές. Από την άλλη πλευρά, η πρόοδος στην μή-γραμμική ρεολογία εξαρτάται από την επίλυση σοβαρών πειραματικών προβλημάτων που σχετίζονται με αστάθειες ροής. Η ανάπτυξη πειραματικών εργαλείων για την επίλυση αυτών των ζητημάτων είναι μια εξαιρετικά χρονοβόρα και επίπονη πρόκληση. Ξεπερνώντας αστάθειες ροής στην μή-γραμμική πειραματική ρεολογία θα οδηγήσει τον τομέα σε νέες κατευθύνσεις όπως η ακριβής και ποσοτική μοντελοποίηση, η αποκωδικοποίηση των μηχανισμών κίνησης μακρομορίων, και ο σχεδιασμός μακρομοριακών συστημάτων με επιθυμητές ιδιότητες που θα δύνανται να καθοριστούν. Ιδιαίτερα, σε σχέση με τους μοριακούς μηχανισμούς, η γνώση της μή-γραμμικής ροής είναι μάλλον περιορισμένη,ειδικά στη διάτμηση. Σε αυτό το πλαίσιο, το έργο αυτής της διατριβής επιχειρεί να απαντήσει σε δύο καίρια ερωτήματα: i) πώς θα αποκτήσουμε αξιόπιστες μετρήσεις σε παροδική (χρονικά…
Subjects/Keywords: Ρεολογία; Rheology
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APA (6th Edition):
Costanzo, S. (2017). Development of protocols for investigating linear, branched and supramolecular polymers undergoing shear. (Thesis). University of Crete (UOC); Πανεπιστήμιο Κρήτης. Retrieved from http://hdl.handle.net/10442/hedi/40133
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):
Costanzo, Salvatore. “Development of protocols for investigating linear, branched and supramolecular polymers undergoing shear.” 2017. Thesis, University of Crete (UOC); Πανεπιστήμιο Κρήτης. Accessed March 04, 2021.
http://hdl.handle.net/10442/hedi/40133.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Costanzo, Salvatore. “Development of protocols for investigating linear, branched and supramolecular polymers undergoing shear.” 2017. Web. 04 Mar 2021.
Vancouver:
Costanzo S. Development of protocols for investigating linear, branched and supramolecular polymers undergoing shear. [Internet] [Thesis]. University of Crete (UOC); Πανεπιστήμιο Κρήτης; 2017. [cited 2021 Mar 04].
Available from: http://hdl.handle.net/10442/hedi/40133.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Costanzo S. Development of protocols for investigating linear, branched and supramolecular polymers undergoing shear. [Thesis]. University of Crete (UOC); Πανεπιστήμιο Κρήτης; 2017. Available from: http://hdl.handle.net/10442/hedi/40133
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
University of Florida
6.
Shaikh, Saif Asif.
Dynamics and Rheology of Concentrated Suspensions of Rigid Fibers.
Degree: PhD, Chemical Engineering, 2017, University of Florida
URL: https://ufdc.ufl.edu/UFE0051779
► A combined work of experiments and numerical simulations is proposed to investigate the dynamics and rheology of highly concentrated suspensions of non-colloidal rigid rods in…
(more)
▼ A combined work of experiments and numerical simulations is proposed to investigate the dynamics and
rheology of highly concentrated suspensions of non-colloidal rigid rods in a Newtonian fluid. Detailed measurements of the
rheology and the microstructure are made using a variety of experimental devices with different geometries and imposed flows. Standard
rheology experiments (volume-controlled
rheology), as well as a novel method of rheometry, are carried out to measure torques, particle pressures, and volume fractions at high concentration (pressure-controlled
rheology). Another experiment has been designed and constructed to study the microstructure (spatial and orientation distribution) of a suspension of rigid rods in an oscillatory parabolic flow. Though the flow is reversible in these systems, the changes in the microstructure are irreversibile in the case of concentrated suspensions due to particle interactions. The microstructure is affected by, and has an effect, on the imposed flows; this non-linear dependency includes hydrodynamic interactions. The purpose of these experiments is to gain insight into phenomena such as apparent shear-thinning at high shear rates and demixing due to shear-induced migration. ( en )
Advisors/Committee Members: BUTLER,JASON E (committee chair), CHAUHAN,ANUJ (committee member), MEI,RENWEI (committee member).
Subjects/Keywords: rheology – suspensions
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APA (6th Edition):
Shaikh, S. A. (2017). Dynamics and Rheology of Concentrated Suspensions of Rigid Fibers. (Doctoral Dissertation). University of Florida. Retrieved from https://ufdc.ufl.edu/UFE0051779
Chicago Manual of Style (16th Edition):
Shaikh, Saif Asif. “Dynamics and Rheology of Concentrated Suspensions of Rigid Fibers.” 2017. Doctoral Dissertation, University of Florida. Accessed March 04, 2021.
https://ufdc.ufl.edu/UFE0051779.
MLA Handbook (7th Edition):
Shaikh, Saif Asif. “Dynamics and Rheology of Concentrated Suspensions of Rigid Fibers.” 2017. Web. 04 Mar 2021.
Vancouver:
Shaikh SA. Dynamics and Rheology of Concentrated Suspensions of Rigid Fibers. [Internet] [Doctoral dissertation]. University of Florida; 2017. [cited 2021 Mar 04].
Available from: https://ufdc.ufl.edu/UFE0051779.
Council of Science Editors:
Shaikh SA. Dynamics and Rheology of Concentrated Suspensions of Rigid Fibers. [Doctoral Dissertation]. University of Florida; 2017. Available from: https://ufdc.ufl.edu/UFE0051779
Rutgers University
7.
Sridhar, Adithya, 1994-.
Focused laser spike dewetting as a method to probe rheology of polymer thin films.
Degree: MS, Mechanical and Aerospace Engineering, 2018, Rutgers University
URL: https://rucore.libraries.rutgers.edu/rutgers-lib/59236/
► Thin polymer films whose thickness ranges from fractions of a nanometer to several micrometers have been in high demand over the past few years in…
(more)
▼ Thin polymer films whose thickness ranges from fractions of a nanometer to several micrometers have been in high demand over the past few years in several industries. Their high surface area to volume ratio and the potential for low-cost processing with minimal material usage while fulfilling purpose requirements make them very useful. However, these films behave differently from bulk materials and majority of polymer fabrication processes involve polymer flow. Hence the study of polymer thin film
rheology becomes crucial. Bulk measurement of
rheology is well established, but it has disadvantages in that it requires a lot of material and may not capture thin film physics. Previous studies have demonstrated dewetting of thin polymer films to study film material stability and properties. This study seeks to use focused laser spike (FLaSk) dewetting as a method to probe
rheology of thin material films. The method is used to extract materials properties of three thin films – Polystyrene (PS), Poly –4–hydroxystyrene (PHS) and N, N′-Bis (3 – methylphenyl)–N, N′-diphenylbenzidine (TPD) having different glass transition temperatures
Advisors/Committee Members: Singer, Jonathan P (chair), Mazzeo, Aaron (co-chair), Malhotra, Rajiv (co-chair), School of Graduate Studies.
Subjects/Keywords: Rheology; Polymers
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APA ·
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to Zotero / EndNote / Reference
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APA (6th Edition):
Sridhar, Adithya, 1. (2018). Focused laser spike dewetting as a method to probe rheology of polymer thin films. (Masters Thesis). Rutgers University. Retrieved from https://rucore.libraries.rutgers.edu/rutgers-lib/59236/
Chicago Manual of Style (16th Edition):
Sridhar, Adithya, 1994-. “Focused laser spike dewetting as a method to probe rheology of polymer thin films.” 2018. Masters Thesis, Rutgers University. Accessed March 04, 2021.
https://rucore.libraries.rutgers.edu/rutgers-lib/59236/.
MLA Handbook (7th Edition):
Sridhar, Adithya, 1994-. “Focused laser spike dewetting as a method to probe rheology of polymer thin films.” 2018. Web. 04 Mar 2021.
Vancouver:
Sridhar, Adithya 1. Focused laser spike dewetting as a method to probe rheology of polymer thin films. [Internet] [Masters thesis]. Rutgers University; 2018. [cited 2021 Mar 04].
Available from: https://rucore.libraries.rutgers.edu/rutgers-lib/59236/.
Council of Science Editors:
Sridhar, Adithya 1. Focused laser spike dewetting as a method to probe rheology of polymer thin films. [Masters Thesis]. Rutgers University; 2018. Available from: https://rucore.libraries.rutgers.edu/rutgers-lib/59236/
Cape Peninsula University of Technology
8.
Mudeme, Sipho.
Drop formation and rupture in shearing during processing of highly concentrated emulsions
.
Degree: 2009, Cape Peninsula University of Technology
URL: http://etd.cput.ac.za/handle/20.500.11838/2164
► The purpose of emulsification process is to create numerous small droplets from a large and homogenous oil phase. The emulsion used for this study is…
(more)
▼ The purpose of emulsification process is to create numerous small droplets from a large and
homogenous oil phase. The emulsion used for this study is new thermodynamically unstable
multi-component water-in-oil (w/o) explosive type with an internal phase ratio of approximately
94% (wt), i.e. far beyond the close packing limit of spherical droplets of 74%. However, little work
has been done for this system, pertaining to the literature explaining what physical phenomena
plays a major role in the process of drop formation during highly concentrated emulsion (HGE)
manufacturing. This thesis is devoted to develop an understanding of what parameters control
drop formation and rupture during processing of highly concentrated emulsions. The material used for the study consisted of three Pibsa derivatives (MEA, IMIDE and UREA),
one mixture (MEA/SMO, 10:1) and SMO. Two concentrations were used namely 8% and 14%
and the two fuel phase material were Mosspar-H and Shell sol. The Pibsa IMIDE was carried out
in both oil phases. To carry out the study, the Hobart N50 mixer coupled with a power and
harmonic analyser to record power as a function of time was used to manufacture all samples
for the study.
Subjects/Keywords: Emulsions;
Drops;
Rheology
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APA ·
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Manager
APA (6th Edition):
Mudeme, S. (2009). Drop formation and rupture in shearing during processing of highly concentrated emulsions
. (Thesis). Cape Peninsula University of Technology. Retrieved from http://etd.cput.ac.za/handle/20.500.11838/2164
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):
Mudeme, Sipho. “Drop formation and rupture in shearing during processing of highly concentrated emulsions
.” 2009. Thesis, Cape Peninsula University of Technology. Accessed March 04, 2021.
http://etd.cput.ac.za/handle/20.500.11838/2164.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Mudeme, Sipho. “Drop formation and rupture in shearing during processing of highly concentrated emulsions
.” 2009. Web. 04 Mar 2021.
Vancouver:
Mudeme S. Drop formation and rupture in shearing during processing of highly concentrated emulsions
. [Internet] [Thesis]. Cape Peninsula University of Technology; 2009. [cited 2021 Mar 04].
Available from: http://etd.cput.ac.za/handle/20.500.11838/2164.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Mudeme S. Drop formation and rupture in shearing during processing of highly concentrated emulsions
. [Thesis]. Cape Peninsula University of Technology; 2009. Available from: http://etd.cput.ac.za/handle/20.500.11838/2164
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
University of Alberta
9.
Salehi, Mohammadreza.
Characterization of mature fine tailings in the context of
its response to chemical treatment.
Degree: MS, Department of Chemical and Materials
Engineering, 2010, University of Alberta
URL: https://era.library.ualberta.ca/files/zg64tn162
► Continuous accumulation of Mature Fine Tailings (MFT) is a major challenge to oil sands industry. To reduce the inventory of MFT through development of novel…
(more)
▼ Continuous accumulation of Mature Fine Tailings (MFT)
is a major challenge to oil sands industry. To reduce the inventory
of MFT through development of novel tailings treatment
technologies, it is essential to understand the stabilization
mechanism of fine solids in MFT. This project aims at
characterizing fine solids of MFT. A novel method is developed in
this study to understand characteristics of fine solids in MFT by
studying their response to the changes in water chemistry and
chemical treatment. Settling and rheological response of MFT to
chemical additives is determined. Combined with solids
characterization of the different layers of settled MFT, an
enhanced understanding of stabilization of fine solids in MFT is
gained. The knowledge generated through this study will provide a
scientific basis for technology development of MFT
treatment.
Subjects/Keywords: Characterization; MFT; Rheology
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Chicago ·
MLA ·
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CSE |
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APA (6th Edition):
Salehi, M. (2010). Characterization of mature fine tailings in the context of
its response to chemical treatment. (Masters Thesis). University of Alberta. Retrieved from https://era.library.ualberta.ca/files/zg64tn162
Chicago Manual of Style (16th Edition):
Salehi, Mohammadreza. “Characterization of mature fine tailings in the context of
its response to chemical treatment.” 2010. Masters Thesis, University of Alberta. Accessed March 04, 2021.
https://era.library.ualberta.ca/files/zg64tn162.
MLA Handbook (7th Edition):
Salehi, Mohammadreza. “Characterization of mature fine tailings in the context of
its response to chemical treatment.” 2010. Web. 04 Mar 2021.
Vancouver:
Salehi M. Characterization of mature fine tailings in the context of
its response to chemical treatment. [Internet] [Masters thesis]. University of Alberta; 2010. [cited 2021 Mar 04].
Available from: https://era.library.ualberta.ca/files/zg64tn162.
Council of Science Editors:
Salehi M. Characterization of mature fine tailings in the context of
its response to chemical treatment. [Masters Thesis]. University of Alberta; 2010. Available from: https://era.library.ualberta.ca/files/zg64tn162
Cornell University
10.
Athiphunamphai, Nongnuch.
Effect Of Processing Parameters On The Rheological And Physico-Chemical Properties Of Varietal Applesauce.
Degree: PhD, Food Science and Technology, 2013, Cornell University
URL: http://hdl.handle.net/1813/34325
► Applesauce is made from a blend of varieties and processed year round due to the availability of apples from cold storage and controlled atmosphere storage,…
(more)
▼ Applesauce is made from a blend of varieties and processed year round due to the availability of apples from cold storage and controlled atmosphere storage, factors that affect applesauce quality. Applesauce attributes are also affected by processing operations; thus, understanding how these factors influence the final product will help to improve applesauce quality. Our goals were to assess the effect of processing parameters on rheological, physical and chemical properties of applesauce, considering variety and ripening effects, and to optimize processing conditions to improve sauce quality. We investigated the following factors: hot and cold break process; extractor rotational speed; addition of diced apples to extractor sauce output; addition of exogenous pectin methyl esterase (PME) and calcium; and activation of endogenous PME. Samples were analyzed for rheological properties (consistency index, yield stress, USDA consistency values) and physico-chemical properties (particle size distribution, pH, soluble solids, pectin content, pectin degree of methoxylation (DM)). Results were evaluated by ANOVA and Tukey's HSD test (p ! 0.05). Best sauce quality (thicker sauce with low syneresis) was achieved when applesauce had a mean particle size ! 700 [MICRO SIGN]m, particle size distribution span " 1.75, total soluble pectin " 0.25%, and pectin DM ! 60%. Ripening or processing conditions could modify these parameters to meet targeted applesauce
rheology. Processing effects differed with variety and ripening stage. Overall, higher rotational extractor speed and addition of "50% diced apples to extractor sauce output prior to final pulping, resulted in increased sauce viscosity and decreased syneresis, due to an increase in total soluble pectin, a lower mean particle diameter and a wider particle size distribution. Exogenous PME addition caused a decrease in pectin DM, leading to higher sauce viscosity and less syneresis. When PME and Ca2+ were added, viscosity was highest but resulted in higher syneresis. Activation of endogenous PME at 5560°C for 10 min lowered the pectin DM from 83% to 60-70% but no change on applesauce
rheology was observed. By understanding how sauce physico-chemical and rheological properties are affected by variety, ripening and processing parameters, it is possible to optimize all relevant conditions to achieve better consistency and quality.
Advisors/Committee Members: Padilla-Zakour, Olga I. (chair), Schmit, Todd Michael (committee member), Moraru, Carmen I (committee member).
Subjects/Keywords: applesauce; rheology; processing
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MLA ·
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APA (6th Edition):
Athiphunamphai, N. (2013). Effect Of Processing Parameters On The Rheological And Physico-Chemical Properties Of Varietal Applesauce. (Doctoral Dissertation). Cornell University. Retrieved from http://hdl.handle.net/1813/34325
Chicago Manual of Style (16th Edition):
Athiphunamphai, Nongnuch. “Effect Of Processing Parameters On The Rheological And Physico-Chemical Properties Of Varietal Applesauce.” 2013. Doctoral Dissertation, Cornell University. Accessed March 04, 2021.
http://hdl.handle.net/1813/34325.
MLA Handbook (7th Edition):
Athiphunamphai, Nongnuch. “Effect Of Processing Parameters On The Rheological And Physico-Chemical Properties Of Varietal Applesauce.” 2013. Web. 04 Mar 2021.
Vancouver:
Athiphunamphai N. Effect Of Processing Parameters On The Rheological And Physico-Chemical Properties Of Varietal Applesauce. [Internet] [Doctoral dissertation]. Cornell University; 2013. [cited 2021 Mar 04].
Available from: http://hdl.handle.net/1813/34325.
Council of Science Editors:
Athiphunamphai N. Effect Of Processing Parameters On The Rheological And Physico-Chemical Properties Of Varietal Applesauce. [Doctoral Dissertation]. Cornell University; 2013. Available from: http://hdl.handle.net/1813/34325
University of Manchester
11.
Zhang, Yi.
Suspension Dewatering with Aggregate
Densification.
Degree: 2014, University of Manchester
URL: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:232270
► This thesis concerns design of two pieces of suspension dewatering equipment (i.e. transient batch settlers and steady state continuous gravity thickeners). In a transient batch…
(more)
▼ This thesis concerns design of two pieces of
suspension dewatering equipment (i.e. transient batch settlers and
steady state continuous gravity thickeners). In a transient batch
settler, very slow densification of aggregates within the
suspension is considered whilst the drag on the solids in the
suspension is assumed to be negligible. The interface of the
suspension is then determined by a balance between gravity and the
gradient of the compressive yield stress of the gelled suspension.
The compressive yield stress functional form in general could be
either a weakly gelled formula, or a strongly gelled formula. These
formulae differ in the way they behave for solids concentrations in
the neighbourhood of the suspension gel point. The effects of the
above two gel formulae, the evolution of the compressive yield
stress functional form over time during aggregate densification,
different initial suspension heights, and different initial feed
solids volume fractions upon the predictions of consolidated bed
structures and solids volume fractions obtained at the bottom of a
batch settler, and upon the evolution of the heights of the
suspension and the consolidated bed have been explored. A
sufficiently tall initial suspension height might lead to
insignificant increases in the solids volume fractions obtained at
the bottom of batch settlers after time-dependent aggregate
densification. The interfaces of the suspension and the
consolidation zone coincide after aggregate densification if the
gel point, which increases with time, is larger than the initial
feed solids volume fractions. Moreover, the maximum permitted
underflow solids fluxes predicted from steady state thickeners have
been investigated and compared. Pre-shearing of aggregates which
densifies aggregates to have smaller diameters upon entering the
thickener is necessary if large underflow solids fluxes and small
underflow solids volume fractions are specified. The solids volume
fraction at the top of the consolidated bed which is the densified
gel point is influenced by the extent of pre-shearing of
aggregates. An algorithm for determining this densified gel point
has also been developed. In reality, thickeners contain not just a
consolidating bed, but also a hindered settling region above it.
When the hindered settling region is considered in a thickener, the
effects of the extent of aggregate densification that has occurred
in the hindered settling region and how that impacts upon thickener
performance and sludge rheological properties have been explored in
this thesis. A new algorithm for predicting the densified gel point
obtained at the top of the consolidated bed has been developed when
the hindered settling region is present. The effects of underflow
solids volume fractions, aggregate densification rate parameters
and pre-shearing of aggregates upon the predictions of maximum
permitted underflow solids fluxes, sludge rheological properties,
and thickener performance have been explored. The predictions of
thickener performance using both the weakly and…
Advisors/Committee Members: MARTIN, ALASTAIR AD, Grassia, Paul, Martin, Alastair.
Subjects/Keywords: Suspension;
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APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Zhang, Y. (2014). Suspension Dewatering with Aggregate
Densification. (Doctoral Dissertation). University of Manchester. Retrieved from http://www.manchester.ac.uk/escholar/uk-ac-man-scw:232270
Chicago Manual of Style (16th Edition):
Zhang, Yi. “Suspension Dewatering with Aggregate
Densification.” 2014. Doctoral Dissertation, University of Manchester. Accessed March 04, 2021.
http://www.manchester.ac.uk/escholar/uk-ac-man-scw:232270.
MLA Handbook (7th Edition):
Zhang, Yi. “Suspension Dewatering with Aggregate
Densification.” 2014. Web. 04 Mar 2021.
Vancouver:
Zhang Y. Suspension Dewatering with Aggregate
Densification. [Internet] [Doctoral dissertation]. University of Manchester; 2014. [cited 2021 Mar 04].
Available from: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:232270.
Council of Science Editors:
Zhang Y. Suspension Dewatering with Aggregate
Densification. [Doctoral Dissertation]. University of Manchester; 2014. Available from: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:232270
Western Carolina University
12.
Ballew, Stephen Daniel.
Rheological characteristics of aqueous wax emulsions used
for the controlled release of pheromones as an alternative to the
use of pesticides for insect pest management.
Degree: 2011, Western Carolina University
URL: http://libres.uncg.edu/ir/listing.aspx?styp=ti&id=9011
► Most pesticides produce some risk of harm to the environment because pesticides are designed to kill or adversely affect living organisms (US EPA, 2010). It…
(more)
▼ Most pesticides produce some risk of harm to the
environment because pesticides are designed to kill or adversely
affect living organisms (US EPA, 2010). It is desirable that
alternate, safer forms of pest control be developed. One
alternative is the controlled release of pest insect sex pheromones
to produce a mating disruption effect (Ahmed et al., 1993;
Atterholt, 1996). Aqueous paraffin wax emulsions have shown much
promise as formulations for this controlled release when applied to
tree bark or foliage (Atterholt et al., 1996; Rice et al., 1997;
Atterholt et al., 1998; Atterholt et al., 1999; Meissner et al.,
2000; de Lame, 2003). Soy wax has recently become of interest in
pheromone formulations because it is renewable, biodegradable,
commercially available, and acceptable for organic farming (Behle,
2008). Emulsions exhibit complex flow behavior which can be studied
using rheometry (Macosko, 1994; Mezger, 2006). Rheometry refers to
experimental techniques to determine the fundamental relationships
between force and deformation in materials (Macosko, 1994). The
rheological properties of emulsions are very important for
production, storage, and application of these formulations (Mezger,
2006). In this project the flow and viscoelastic properties of
aqueous 30% paraffin wax and soy wax emulsions were investigated
using three different emulsifiers: sorbitan monostearate (Span
60®), triethanolamine (TEA) stearate, and a 50%-50% mixture of
both. Span 60® has already been used to make effective emulsions
for the controlled release of pheromones, and it is food safe
(Atterholt et al., 1996; Rice et al., 1997; Atterholt et al., 1998;
Atterholt et al., 1999; Meissner et al., 2000; de Lame, 2003). TEA
stearate is widely used to make nontoxic wax emulsions in the
cosmetics industry (Wilkinson, 1940). The investigations were
carried out in both the rotational and oscillatory modes of a
parallel-plate rheometer. The flow curves at three different
temperatures (15 °C, 25 °C and 35 °C) of each emulsion were fitted
with the Herschel-Bulkley model with the yield points determined
using the one tangent method. The resulting equations can predict
flow behavior at different conditions (Mezger, 2006). The emulsions
were also tested using a temperature sweep at low shear from 15 °C
to 50 °C to investigate temperature dependent changes. The
viscoelastic properties were investigated using oscillatory shear
tests and expressed in terms of elastic modulus and loss modulus.
This gives information about time-dependant behavior like storage
and the elastic character of the formulations which were found to
be weak gels (Mezger, 2006). The Span 60® emulsions displayed faux
shear-thickening behavior due to droplet subdivision while the
other emulsions generally displayed shear-thinning behavior. Each
emulsion approaches an infinite shear viscosity. The yield points
and other flow parameters for the emulsions varied with
temperature, depending on the formulation in question. All soy wax
emulsions showed an increase in viscosity between 45 °C…
Advisors/Committee Members: Cynthia Atterholt (advisor).
Subjects/Keywords: Pheromones; Emulsions; Rheology
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APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Ballew, S. D. (2011). Rheological characteristics of aqueous wax emulsions used
for the controlled release of pheromones as an alternative to the
use of pesticides for insect pest management. (Masters Thesis). Western Carolina University. Retrieved from http://libres.uncg.edu/ir/listing.aspx?styp=ti&id=9011
Chicago Manual of Style (16th Edition):
Ballew, Stephen Daniel. “Rheological characteristics of aqueous wax emulsions used
for the controlled release of pheromones as an alternative to the
use of pesticides for insect pest management.” 2011. Masters Thesis, Western Carolina University. Accessed March 04, 2021.
http://libres.uncg.edu/ir/listing.aspx?styp=ti&id=9011.
MLA Handbook (7th Edition):
Ballew, Stephen Daniel. “Rheological characteristics of aqueous wax emulsions used
for the controlled release of pheromones as an alternative to the
use of pesticides for insect pest management.” 2011. Web. 04 Mar 2021.
Vancouver:
Ballew SD. Rheological characteristics of aqueous wax emulsions used
for the controlled release of pheromones as an alternative to the
use of pesticides for insect pest management. [Internet] [Masters thesis]. Western Carolina University; 2011. [cited 2021 Mar 04].
Available from: http://libres.uncg.edu/ir/listing.aspx?styp=ti&id=9011.
Council of Science Editors:
Ballew SD. Rheological characteristics of aqueous wax emulsions used
for the controlled release of pheromones as an alternative to the
use of pesticides for insect pest management. [Masters Thesis]. Western Carolina University; 2011. Available from: http://libres.uncg.edu/ir/listing.aspx?styp=ti&id=9011
Queens University
13.
Zhang, Ying.
Polyolefin Formulations for Improved Foaming: Effects of Molecular Structure and Material Properties
.
Degree: Chemical Engineering, 2013, Queens University
URL: http://hdl.handle.net/1974/7777
► The morphology and mechanical properties of foams made out of ethylene-α-olefin copolymers (EC) having well-characterized rheological properties were investigated. The polymers differed in the amount…
(more)
▼ The morphology and mechanical properties of foams made out of ethylene-α-olefin copolymers (EC) having well-characterized rheological properties were investigated. The polymers differed in the amount of comonomer contained, type of comonomer and molecular weight, resulting in variable thermal properties and different rheological responses under shear and extensional flow. All of the octene-based copolymers with comparable rheological properties had similar foam morphology. However grades with low extensional viscosity and low crystallization points resulted in poor foams. Increasing density resulted in a higher secant modulus of the foamed samples. To further investigate the effects of material properties, trimethylolpropane trimethacrylate (TMPTMA) and triallyl trimesate (TAM) coagents were used to generate a series of PP derivatives through radical mediated melt state reactive modification. Coagent modification resulted in pronounced effects in the molecular weights and viscosities of the derivatives. However, evidence of long-chain branching (LCB) was only present in TAM modified PPs. Significant increases in the crystallization temperature, heat of fusion and crystallization rate were attributed to the formation of nanoparticles, which resulted in a heterogeneous nucleation effect, both for crystallization and foaming. Generally lower viscosities, coupled by strain hardening, enhanced nucleation and increased crystallization temperatures induced by the nanoparticles resulted in foams with higher expansion ratios and smaller cells, due to higher rates of cell growth, coupled with suppressed coalescence. Nanocomposites based on isotactic PP and nanosilica (SiO2) were prepared using a co-rotating twin-screw extruder (TSE) in order to investigate foaming on a larger scale. High shear stress, sufficient residence time, and high fill ratio in the melting section of the screw were the most important factors in achieving good nanosilica dispersion. Well-dispersed surface-modified hydrophobic SiO2 particles were effective nucleating agents for foaming, when used at loadings below 1 phr.
Subjects/Keywords: Rheology
;
Polyolefin
;
Foaming
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APA ·
Chicago ·
MLA ·
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Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Zhang, Y. (2013). Polyolefin Formulations for Improved Foaming: Effects of Molecular Structure and Material Properties
. (Thesis). Queens University. Retrieved from http://hdl.handle.net/1974/7777
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):
Zhang, Ying. “Polyolefin Formulations for Improved Foaming: Effects of Molecular Structure and Material Properties
.” 2013. Thesis, Queens University. Accessed March 04, 2021.
http://hdl.handle.net/1974/7777.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Zhang, Ying. “Polyolefin Formulations for Improved Foaming: Effects of Molecular Structure and Material Properties
.” 2013. Web. 04 Mar 2021.
Vancouver:
Zhang Y. Polyolefin Formulations for Improved Foaming: Effects of Molecular Structure and Material Properties
. [Internet] [Thesis]. Queens University; 2013. [cited 2021 Mar 04].
Available from: http://hdl.handle.net/1974/7777.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Zhang Y. Polyolefin Formulations for Improved Foaming: Effects of Molecular Structure and Material Properties
. [Thesis]. Queens University; 2013. Available from: http://hdl.handle.net/1974/7777
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
California State University – Sacramento
14.
Cavanaugh, Jeff; Castaneda, Francisco; Jensen, Mikkel Herholdt.
Computational driving and analysis of microrheological instruments and data.
Degree: 2019, California State University – Sacramento
URL: http://hdl.handle.net/10211.3/214254
► During the Summer of 2019, my group and I set out to set up and test instruments for a new Soft Condensed Matter Lab. My…
(more)
▼ During the Summer of 2019, my group and I set out to set up and test instruments for a new Soft Condensed Matter Lab. My focus was on setting up and testing a set of Optical Tweezers. Our optical tweezers use a near infrared laser to trap a small silica bead for manipulation in a medium. This medium can be organic or inorganic and the goal is to characterize its viscoelastic properties. This can be helpful in studies of biofuels, biological environments, and biomedical science.
Subjects/Keywords: Rheology; Optical tweezers
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to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Cavanaugh, Jeff; Castaneda, Francisco; Jensen, M. H. (2019). Computational driving and analysis of microrheological instruments and data. (Thesis). California State University – Sacramento. Retrieved from http://hdl.handle.net/10211.3/214254
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):
Cavanaugh, Jeff; Castaneda, Francisco; Jensen, Mikkel Herholdt. “Computational driving and analysis of microrheological instruments and data.” 2019. Thesis, California State University – Sacramento. Accessed March 04, 2021.
http://hdl.handle.net/10211.3/214254.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Cavanaugh, Jeff; Castaneda, Francisco; Jensen, Mikkel Herholdt. “Computational driving and analysis of microrheological instruments and data.” 2019. Web. 04 Mar 2021.
Vancouver:
Cavanaugh, Jeff; Castaneda, Francisco; Jensen MH. Computational driving and analysis of microrheological instruments and data. [Internet] [Thesis]. California State University – Sacramento; 2019. [cited 2021 Mar 04].
Available from: http://hdl.handle.net/10211.3/214254.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Cavanaugh, Jeff; Castaneda, Francisco; Jensen MH. Computational driving and analysis of microrheological instruments and data. [Thesis]. California State University – Sacramento; 2019. Available from: http://hdl.handle.net/10211.3/214254
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Kansas State University
15.
Vosahlik, Jan.
Pumping of
concrete mixtures: rheology, lubrication layer properties and
pumping pressure assessment.
Degree: PhD, Department of Civil
Engineering, 2018, Kansas State University
URL: http://hdl.handle.net/2097/39134
► Pumping is the most utilized placement technique to deliver fresh concrete from the concrete mixer to the formwork on construction site. Compared to other available…
(more)
▼ Pumping is the most utilized placement technique to
deliver fresh concrete from the concrete mixer to the formwork on
construction site. Compared to other available placement methods,
such as bucket-and-crane or conveyor belts, pumping offers superior
placement rates while reducing the required labor cost. Despite the
fact that concrete pumping has been utilized on job sites around
the world since the early 1960s, there is still a lack of
knowledge, supported by research evidence, as to what affects
concrete pumpability and how pumping changes concrete properties
both in the plastic and hardened state.
A four-phase research
study was carried out to: (1) improve the existing methodology of
rheological characterization of the lubrication layer formed during
pumping, (2) evaluate the effect of concrete mixture constituents
and proportioning on rheological properties of concrete and the
lubrication layer, (3) asses the effect of pumping and pumping
pressure on concrete fresh properties and the air void system under
controlled conditions, and (4) to evaluate the effect of pumping on
concrete fresh properties and the air void system in the field
conditions.
In the first phase of this research program, a
correction procedure was developed evaluating 3D flow at the bottom
of the cylindrical concrete interface rheometer. Results showed
that the correction procedure can be successfully used for
characterization of lubrication layer properties, and that the
bottom of the cylinder can cause measurement error of up to 10%
depending on concrete rheological properties and the interface
rheometer geometry.
The second phase of this research program
consisted of a laboratory study to evaluate rheological properties
and properties of the lubrication layer of large variety of
concrete mixtures. Considered mixture proportion variables included
air void content, water-to-cement ratio, paste volume, fly ash
replacement ratio, fine-to-coarse aggregate ratio, aggregate shape,
use of viscosity-modifying admixture, and use of nano-clay
particles. Results indicated that the changes in rheological
properties of the lubrication due to mixture proportioning
adjustments corresponded in most cases to changes of the bulk
concrete rheological properties.
In the third phase of the study,
a full-scale controlled pumping experiment was conducted. During
the experiment, three different concrete mixtures were pumped and
both fresh and hardened properties of concrete were determined.
Additionally, the pumping circuit was equipped with a system to
monitor pumping pressures. The obtained results revealed that
concrete pumping can significantly modify concrete fresh
properties. Additionally, it was shown that changes in the fresh
properties as well as in the concrete air void system are
independent of applied concrete pressure.
Finally, the forth phase
of this research program consisted of field evaluation of concrete
pumping. Six concrete bridge project sites were visited and
concrete samples were collected before and after pumping. Analysis
results…
Advisors/Committee Members: Christopher A. Jones
Kyle A. Riding.
Subjects/Keywords: concrete;
pumping;
rheology
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APA ·
Chicago ·
MLA ·
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CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Vosahlik, J. (2018). Pumping of
concrete mixtures: rheology, lubrication layer properties and
pumping pressure assessment. (Doctoral Dissertation). Kansas State University. Retrieved from http://hdl.handle.net/2097/39134
Chicago Manual of Style (16th Edition):
Vosahlik, Jan. “Pumping of
concrete mixtures: rheology, lubrication layer properties and
pumping pressure assessment.” 2018. Doctoral Dissertation, Kansas State University. Accessed March 04, 2021.
http://hdl.handle.net/2097/39134.
MLA Handbook (7th Edition):
Vosahlik, Jan. “Pumping of
concrete mixtures: rheology, lubrication layer properties and
pumping pressure assessment.” 2018. Web. 04 Mar 2021.
Vancouver:
Vosahlik J. Pumping of
concrete mixtures: rheology, lubrication layer properties and
pumping pressure assessment. [Internet] [Doctoral dissertation]. Kansas State University; 2018. [cited 2021 Mar 04].
Available from: http://hdl.handle.net/2097/39134.
Council of Science Editors:
Vosahlik J. Pumping of
concrete mixtures: rheology, lubrication layer properties and
pumping pressure assessment. [Doctoral Dissertation]. Kansas State University; 2018. Available from: http://hdl.handle.net/2097/39134
University of Akron
16.
Liu, Gengxin.
Nonlinear Rheology of Long-Chain Branched Polymers.
Degree: PhD, Polymer Science, 2015, University of Akron
URL: http://rave.ohiolink.edu/etdc/view?acc_num=akron1436977058
► Entangled polymers show significant nonlinear rheological behaviors. Those studies on the mechanical behaviors of polymer melts and solutions not only promote our understanding on polymer…
(more)
▼ Entangled polymers show significant nonlinear
rheological behaviors. Those studies on the mechanical behaviors of
polymer melts and solutions not only promote our understanding on
polymer dynamics, but also guide the application of polymers and
establish principals to design polymeric materials. Recently
emerged interpretations on nonlinear
rheology of linear polymers
proposed by Dr. Shi-Qing Wang emphasize the network nature of
entangled polymers. This dissertation studies the nonlinear
rheology of long-chain branched (LCB) polymers. A new synthetic
method is developed and implemented to overcome the limitation of
previous methods for not being able to synthesize long enough
branches. This method can produce ultra-high molecular weight LCB
polymers with branches of identical length and uniform spacing
between branch points.Polymers with multiple long branches show
remarkable resistant to the elastic-driven decohesion comparing to
linear polymers. In startup uniaxial extension, they are
extraordinarily more stretchable. An empirical rule shows that the
failure of entangled network, as characterized by the overshoot of
engineering stress, is proportional to the square root of number of
entanglements. Polymers with LCB are also more resistant to failure
in stepwise extension (withstand a larger stretching ratio), which
would be part of film blowing process. Historically, strain
hardening stands for the upward deviation of transient extensional
viscosity comparing to zero-rate transient viscosity, which
typically shows up on branched polymers. Under the newly emerged
conceptual framework, such behavior is due to three factors:
firstly, the shrinking cross-section area leads to a factor of
extension ratio in calculating true stress and transient
extensional viscosity; secondly, the introduction of branches
suppresses the breakdown of entangled network; lastly, the
entanglement network is strengthened at sufficient high Hencky
rates during extension. Entangled polymeric liquids have so far
only shown strain softening upon startup shear, signified by stress
overshoot. However, solutions of polystyrenes with LCB exhibit
strain hardening upon startup shear at high shear rates, undergoing
non-Gaussian chain stretching and reaching finite extensibility
limit. The stronger than linear increase of the shear stress ends
with a sharp decline, forming a cusp. At intermediate shear rates,
stress overshoots always occur at the same strain, which is
explained also by the length of backbone. The LCB polymers show a
rich variety of transient responses to startup shear at different
rates and open a large window of dynamics to meet practical
applications.
Advisors/Committee Members: Wang, Shi-Qing (Advisor).
Subjects/Keywords: Polymers; rheology; polymer
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APA (6th Edition):
Liu, G. (2015). Nonlinear Rheology of Long-Chain Branched Polymers. (Doctoral Dissertation). University of Akron. Retrieved from http://rave.ohiolink.edu/etdc/view?acc_num=akron1436977058
Chicago Manual of Style (16th Edition):
Liu, Gengxin. “Nonlinear Rheology of Long-Chain Branched Polymers.” 2015. Doctoral Dissertation, University of Akron. Accessed March 04, 2021.
http://rave.ohiolink.edu/etdc/view?acc_num=akron1436977058.
MLA Handbook (7th Edition):
Liu, Gengxin. “Nonlinear Rheology of Long-Chain Branched Polymers.” 2015. Web. 04 Mar 2021.
Vancouver:
Liu G. Nonlinear Rheology of Long-Chain Branched Polymers. [Internet] [Doctoral dissertation]. University of Akron; 2015. [cited 2021 Mar 04].
Available from: http://rave.ohiolink.edu/etdc/view?acc_num=akron1436977058.
Council of Science Editors:
Liu G. Nonlinear Rheology of Long-Chain Branched Polymers. [Doctoral Dissertation]. University of Akron; 2015. Available from: http://rave.ohiolink.edu/etdc/view?acc_num=akron1436977058
Cape Peninsula University of Technology
17.
Tshilumbu, Nsenda Ngenda.
Design and development of a novel high performance emulsion explosive using nanoparticles
.
Degree: 2014, Cape Peninsula University of Technology
URL: http://etd.cput.ac.za/handle/20.500.11838/930
► This study investigated water-in-oil (W/O) super-concentrated emulsions used as pumpable explosives. The aqueous phase of the emulsions is a supersaturated nitrate salt solution (at room…
(more)
▼ This study investigated water-in-oil (W/O) super-concentrated emulsions used as pumpable explosives. The aqueous phase of the emulsions is a supersaturated nitrate salt solution (at room temperature), with a volume fraction of approximately 0.9. Instability of such emulsions arises either from crystallization of the dispersed phase in the system during ageing or under high shear conditions. Here, we report an alternative approach to stabilize this highly concentrated W/O emulsion by adding colloidal particles in combination with short amphiphilic molecules. Thus, the primary goal of this research concerned a phenomenological study of the dependence of surfactant-to-particle ratio as well as the particle hydrophobicity index on stability under high shear in the emulsification process, rheological properties and stability against initiation of crystallization of an internal phase both with ageing and under high shear with a view to optimize the time to the start of crystallization of the emulsion both with ageing and under high shear; to elucidate the mechanism of initiation of crystallization of an internal phase (homogeneous or heterogeneous) and shed light in the stabilization mechanism of the emulsion; to determine how the emulsion formulation content affect pumping characteristics as measured by characteristic rheological parameters.
A series of five fumed silica nanoparticles, each with a different hydrophobicity index (HI) in the range of 0.60 – 3, were used in the form of single types of particles as well as binary mixtures. These particles were combined with a low molecular weight conventional surfactant, Sorbitan MonoOleate (SMO), into the oil phase prior to emulsification.
It has been found that regardless of the particle hydrophobicity, fumed nanosilica alone cannot form highly concentrated W/O emulsion up to 90 vol%. Moreover, Pickering emulsions are unstable under shear conditions and thus it is difficult to make highly concentrated W/O pumpable emulsion explosives using only fumed nanosilica.
The correlation between the refinement time and SMO-to-particle ratio showed a deflection point/transitional point in the stabilization mechanism. Below the transitional point the silica content dominates over SMO. Conversely, above the transitional point the particles have little effect and the SMO dominates. A thermodynamic consideration revealed that in this region only SMO is likely to adsorb at the W/O interface and controls the emulsifying process. As
with refinement time, the correlation between the shear modulus and SMO/particle ratio shows a deflection /transitional point which, as before, mark the transition point between regions of particle or SMO domination.
Interestingly, it was found that for each HI, the initiation of crystallization is the most delayed, both on shelf life and under high shear, when the emulsion is prepared with an SMO-to-particle ratio equaling exactly the value at this transitional point. Moreover, the research demonstrated that a drastic change in mechanism of initiation of…
Subjects/Keywords: Emulsions;
Rheology;
Crystallization;
Nanoparticles
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APA (6th Edition):
Tshilumbu, N. N. (2014). Design and development of a novel high performance emulsion explosive using nanoparticles
. (Thesis). Cape Peninsula University of Technology. Retrieved from http://etd.cput.ac.za/handle/20.500.11838/930
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):
Tshilumbu, Nsenda Ngenda. “Design and development of a novel high performance emulsion explosive using nanoparticles
.” 2014. Thesis, Cape Peninsula University of Technology. Accessed March 04, 2021.
http://etd.cput.ac.za/handle/20.500.11838/930.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Tshilumbu, Nsenda Ngenda. “Design and development of a novel high performance emulsion explosive using nanoparticles
.” 2014. Web. 04 Mar 2021.
Vancouver:
Tshilumbu NN. Design and development of a novel high performance emulsion explosive using nanoparticles
. [Internet] [Thesis]. Cape Peninsula University of Technology; 2014. [cited 2021 Mar 04].
Available from: http://etd.cput.ac.za/handle/20.500.11838/930.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Tshilumbu NN. Design and development of a novel high performance emulsion explosive using nanoparticles
. [Thesis]. Cape Peninsula University of Technology; 2014. Available from: http://etd.cput.ac.za/handle/20.500.11838/930
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Cape Peninsula University of Technology
18.
Yakhoub, Hamat Abderrahmane.
Effect of high shearing on the rheological/structural properties of highly concentrated w/o emulsions
.
Degree: 2009, Cape Peninsula University of Technology
URL: http://etd.cput.ac.za/handle/20.500.11838/2163
► Emulsion explosives are classified as highly concentrated water-in-oil emulsions with high droplet volume fraction that exceeding the close packing limit of spherical droplets. These emulsions…
(more)
▼ Emulsion explosives are classified as highly concentrated water-in-oil emulsions with high
droplet volume fraction that exceeding the close packing limit of spherical droplets. These
emulsions are commonly used as re-pumpable materials. Thus, the shearing action resulting
from the transportation process of these materials has a tremendous impact on their
structures and functionality and might reduce the shelf-life and performance of the products.
Therefore the main goal of this research was to investigate the stability of highly
concentrated water-in-oil emulsion under shearing using a newly designed piston-pumping
instrument.
The results of measurement included the droplet size distribution, microscopic observation,
flow and viscoelastic properties of the materials. Neither crystallisation nor other
destabilisation phenomena such as coalescence, partial coalescence, or phase inversion
occurred during the shearing process of these emulsions, regardless of their formulation
content. It was found that the high shearing action within this research experimental window
induced droplet refinement. The changes in droplet size distribution were achieved by multipass
flow through a small orifice set as outlet of the piston-chamber pumping instrument,
and intensive shearing provided the shift of the droplet sizes to the smaller-size side of the
distribution. Their distributions were wider and of Gaussian type. Two models were proposed
and used to fit the refinement evolution and the width of distributions respectively.
Subjects/Keywords: Emulsions;
Rheology;
Drops;
Shear flow
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APA (6th Edition):
Yakhoub, H. A. (2009). Effect of high shearing on the rheological/structural properties of highly concentrated w/o emulsions
. (Thesis). Cape Peninsula University of Technology. Retrieved from http://etd.cput.ac.za/handle/20.500.11838/2163
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):
Yakhoub, Hamat Abderrahmane. “Effect of high shearing on the rheological/structural properties of highly concentrated w/o emulsions
.” 2009. Thesis, Cape Peninsula University of Technology. Accessed March 04, 2021.
http://etd.cput.ac.za/handle/20.500.11838/2163.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Yakhoub, Hamat Abderrahmane. “Effect of high shearing on the rheological/structural properties of highly concentrated w/o emulsions
.” 2009. Web. 04 Mar 2021.
Vancouver:
Yakhoub HA. Effect of high shearing on the rheological/structural properties of highly concentrated w/o emulsions
. [Internet] [Thesis]. Cape Peninsula University of Technology; 2009. [cited 2021 Mar 04].
Available from: http://etd.cput.ac.za/handle/20.500.11838/2163.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Yakhoub HA. Effect of high shearing on the rheological/structural properties of highly concentrated w/o emulsions
. [Thesis]. Cape Peninsula University of Technology; 2009. Available from: http://etd.cput.ac.za/handle/20.500.11838/2163
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Ryerson University
19.
Sammour, Moustafa M.
Rheology, fresh and hardened properties of self-consolidating concrete utilizing metal and PVA polymer fibers.
Degree: 2008, Ryerson University
URL: https://digital.library.ryerson.ca/islandora/object/RULA%3A472
► Fiber reinforced self-consolidating concrete (FRSCC) has a tremendous potential to be used in construction industry as it combines the advantagees of both self-consolidating concrete (SCC)…
(more)
▼ Fiber reinforced self-consolidating concrete (FRSCC) has a tremendous potential to be used in construction industry as it combines the advantagees of both self-consolidating concrete (SCC) and fiber reinforced concrete (FRC). 18 concrete mixtures were developed by incorporating differenct volumes (0 to 0.3) of polyvinyl alchohol (PVA) and metallic fibers. Fresh, rheological, mechanical and durability (in terms of chloride penetration resistance) properties of all FRSCC mixtures were evaluated. The influences of fiber types/size/ dosages and fiber combination (used in hybrid mixes) on fresh (slump flow, L-box passing ability, V-funnel flow time and segregation index), rheological (plastic viscosity and yield stress) and hardened (fracture energy and compressive/flexural/splitting tensile strength) properties were critically analyzed to examine the relationships among various properties as well as to suggest suitable FRSCC mixtures. The fibers (especially metallic ones) wre more effective in increasing the fracture energy of FRSCC than compressive/splitting tensile/flexural strength. A fracture energy gain of about 730% was observed (which is substantial) compared to 10% of compressive strength, 39% of splitting tensil strength and 124% of flexural strength. The improved strength and fracture energy of FRSCC mixtures can significantly reduce the amount of tensile reinforcement and subsantially increase the energy absorbing capacity of concrete structures.
Advisors/Committee Members: Lachemi, Mohamed (Thesis advisor), Hossain, Anwar (Thesis advisor), Ryerson University (Degree grantor).
Subjects/Keywords: Rheology; Polymers
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Manager
APA (6th Edition):
Sammour, M. M. (2008). Rheology, fresh and hardened properties of self-consolidating concrete utilizing metal and PVA polymer fibers. (Thesis). Ryerson University. Retrieved from https://digital.library.ryerson.ca/islandora/object/RULA%3A472
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):
Sammour, Moustafa M. “Rheology, fresh and hardened properties of self-consolidating concrete utilizing metal and PVA polymer fibers.” 2008. Thesis, Ryerson University. Accessed March 04, 2021.
https://digital.library.ryerson.ca/islandora/object/RULA%3A472.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Sammour, Moustafa M. “Rheology, fresh and hardened properties of self-consolidating concrete utilizing metal and PVA polymer fibers.” 2008. Web. 04 Mar 2021.
Vancouver:
Sammour MM. Rheology, fresh and hardened properties of self-consolidating concrete utilizing metal and PVA polymer fibers. [Internet] [Thesis]. Ryerson University; 2008. [cited 2021 Mar 04].
Available from: https://digital.library.ryerson.ca/islandora/object/RULA%3A472.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Sammour MM. Rheology, fresh and hardened properties of self-consolidating concrete utilizing metal and PVA polymer fibers. [Thesis]. Ryerson University; 2008. Available from: https://digital.library.ryerson.ca/islandora/object/RULA%3A472
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
University of Alberta
20.
Zhao, Yi.
Petrophysical properties of bitumen from the Upper Devonian
Grosmont reservoir, Alberta, Canada.
Degree: MS, Department of Earth and Atmospheric
Sciences, 2009, University of Alberta
URL: https://era.library.ualberta.ca/files/xk81jm35n
► The Upper Devonian Grosmont reservoir in Alberta, Canada, is the single largest carbonate bitumen reservoir in the world, with an estimated 400 billion barrels of…
(more)
▼ The Upper Devonian Grosmont reservoir in Alberta,
Canada, is the single largest carbonate bitumen reservoir in the
world, with an estimated 400 billion barrels of bitumen in place.
The Grosmont bitumen formed from light crude oil via extensive
biodegradation, which produced extremely high in-situ viscosities
of >1 million cP. Forty nine samples from fifteen wells were
selected for rheological behavior, viscosity, and biodegradation
pattern analysis. In addition, various methods of viscosity
determination were compared. Results indicate that the Grosmont
bitumen is essentially a non-Newtonian fluid at in-situ conditions,
exhibiting a distinctive shear-thinning behavior at T <
40°C. Neglecting this character will cause inaccurate viscosity
measurements. The viscosity variations in the Grosmont reservoir
are cyclic with depth and are stratigraphically controlled. The
bitumen exhibits 3 levels of biodegradation. Biodegradation
parameters from hopanes and tricyclic terpanes may potentially be
used for bitumen quality prediction.
Subjects/Keywords: Biodegradation; Viscosity; Bitumen; Grosmont; Rheology
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APA (6th Edition):
Zhao, Y. (2009). Petrophysical properties of bitumen from the Upper Devonian
Grosmont reservoir, Alberta, Canada. (Masters Thesis). University of Alberta. Retrieved from https://era.library.ualberta.ca/files/xk81jm35n
Chicago Manual of Style (16th Edition):
Zhao, Yi. “Petrophysical properties of bitumen from the Upper Devonian
Grosmont reservoir, Alberta, Canada.” 2009. Masters Thesis, University of Alberta. Accessed March 04, 2021.
https://era.library.ualberta.ca/files/xk81jm35n.
MLA Handbook (7th Edition):
Zhao, Yi. “Petrophysical properties of bitumen from the Upper Devonian
Grosmont reservoir, Alberta, Canada.” 2009. Web. 04 Mar 2021.
Vancouver:
Zhao Y. Petrophysical properties of bitumen from the Upper Devonian
Grosmont reservoir, Alberta, Canada. [Internet] [Masters thesis]. University of Alberta; 2009. [cited 2021 Mar 04].
Available from: https://era.library.ualberta.ca/files/xk81jm35n.
Council of Science Editors:
Zhao Y. Petrophysical properties of bitumen from the Upper Devonian
Grosmont reservoir, Alberta, Canada. [Masters Thesis]. University of Alberta; 2009. Available from: https://era.library.ualberta.ca/files/xk81jm35n
University of Alberta
21.
Rostami Najafabadi, Zahra.
Rheological Behaviour of Heptane-Diluted Bitumen in the
Presence of Precipitates.
Degree: MS, Department of Chemical and Materials
Engineering, 2015, University of Alberta
URL: https://era.library.ualberta.ca/files/8910jx45p
► One of the challenges that Vapor Extraction process might be conducted is the unpredictable precipitation of asphaltene from solvent-diluted bitumen that can cause process problems…
(more)
▼ One of the challenges that Vapor Extraction process
might be conducted is the unpredictable precipitation of asphaltene
from solvent-diluted bitumen that can cause process problems during
bitumen extraction in porous media. The objective of this study was
to investigate the rheological behaviour of Athabasca bitumen and
n-heptane solutions in the present of precipitates using a
rheometer and flow through porous media. Rheometry measurements
shown for solutions have the viscosity higher than 0.001 Pa·s and
less than 0.0005 Pa·s, the phase angle is around 90° out of phase
and the solutions are purely viscous; while for the solutions
having the viscosity around 0.0007 Pa·s, the phase angle is around
84° out of phase and the solution behave as a non-Newtonian liquid.
Also, the flow of heptane-bitumen solutions through a porous media
experiments shows that for bitumen-heptane solution having
viscosity around 0.0007 Pa·s, after 24 hours mixing of the
solutions, the predicted and measured friction factor did not
agreed. This disagreement might be because of both decrease the
void area between the particles due to the presence of solids and
non-Newtonian behaviour of the solution, which is in consistent
with the rheology measurement results.
Subjects/Keywords: rheology, porous media, asphaltene
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to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Rostami Najafabadi, Z. (2015). Rheological Behaviour of Heptane-Diluted Bitumen in the
Presence of Precipitates. (Masters Thesis). University of Alberta. Retrieved from https://era.library.ualberta.ca/files/8910jx45p
Chicago Manual of Style (16th Edition):
Rostami Najafabadi, Zahra. “Rheological Behaviour of Heptane-Diluted Bitumen in the
Presence of Precipitates.” 2015. Masters Thesis, University of Alberta. Accessed March 04, 2021.
https://era.library.ualberta.ca/files/8910jx45p.
MLA Handbook (7th Edition):
Rostami Najafabadi, Zahra. “Rheological Behaviour of Heptane-Diluted Bitumen in the
Presence of Precipitates.” 2015. Web. 04 Mar 2021.
Vancouver:
Rostami Najafabadi Z. Rheological Behaviour of Heptane-Diluted Bitumen in the
Presence of Precipitates. [Internet] [Masters thesis]. University of Alberta; 2015. [cited 2021 Mar 04].
Available from: https://era.library.ualberta.ca/files/8910jx45p.
Council of Science Editors:
Rostami Najafabadi Z. Rheological Behaviour of Heptane-Diluted Bitumen in the
Presence of Precipitates. [Masters Thesis]. University of Alberta; 2015. Available from: https://era.library.ualberta.ca/files/8910jx45p
Cornell University
22.
Mallavajula, Rajesh.
Structure And Rheology Of Cubic Particles In Suspensions.
Degree: PhD, Chemical Engineering, 2014, Cornell University
URL: http://hdl.handle.net/1813/37120
► It is well known that the shape of particles is an important factor that determines the fluid flow behavior of suspensions. Interactions of cubic particles…
(more)
▼ It is well known that the shape of particles is an important factor that determines the fluid flow behavior of suspensions. Interactions of cubic particles with one another and with the flow medium are unique because of their sharp edges, corners and flat surfaces. Using theory, simulations and experiments, the structure and flow properties of cube-shaped particles in suspension over a range of volume fractions is studied to understand the effect of shape on fluid structure and
rheology. At very low volume fractions, the sharp edges and corners of cubes are found to profoundly alter the velocity field around the cube.The stresslet-strain relationship for a cube is anisotropic and depends on the orientation of the cube with respect to the velocity flow field. The effective viscosity of the suspension in a simple shear flow is obtained by computing the orientationaly averaged stresslet acting on cubes. These calculations yield a universal intrinsic viscosity, [[eta]] = 3.1 for sharp cubes, which is higher than the corresponding value for spheres [[eta]] = 5/2. Using the 2D velocity flow profile around sharp corners we further find that the pressure becomes singular near the edges of the cube, which results in the increased value of stress and hence the higher viscosity when compared with spherical particles. In the presence of an external torque acting on each cube, the orientation distribution is no longer isotropic. This can be achieved by using magnetic cubes in magnetic field. The general expression for the stress in a suspension of mag- netic cubes subjected to linear velocity field in presence of an external magnetic field is calculated. We find that the intrinsic viscosity for the weakly Brownian suspension in a simple shear flow can be varied between [[eta]] = 3.25 to [[eta]] = 5.5 by changing the strength and the direction of the applied magnetic field. At low to moderate volume fractions, Brownian dynamics simulations were carried out to study the structure and flow behavior of suspensions. Simulations were performed over a wide range of volume fractions and Pe to study its rheological properties. Our equilibrium results show that cubic particles behave like spheres interacting with a soft repulsion potential function for volume fractions less than 0.25. This soft repulsion potential captures the orientationally averaged excluded volume of the cubes and produces identical probability distributions as that of for cubes at very low volume fractions. For higher volume fractions, cubic particles starts to lose their orientational freedom resulting in the deviation of equilibrium properties from that of soft spheres. We also found that suspension of cubic particles when subjected to simple shear will produce higher viscosity when compared with spherical particles in suspensions with equivalent volume. We show that the suspension
rheology in this regime can be discussed in terms of ordering and collisions among hard cubic particles. In order to gain insights from experiments, cubic particles of varying sizes (10nm…
Advisors/Committee Members: Archer, Lynden A. (chair), Koch, Donald L (committee member), Cohen, Itai (committee member).
Subjects/Keywords: Rheology; Suspensions; Brownian Dynamics
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APA (6th Edition):
Mallavajula, R. (2014). Structure And Rheology Of Cubic Particles In Suspensions. (Doctoral Dissertation). Cornell University. Retrieved from http://hdl.handle.net/1813/37120
Chicago Manual of Style (16th Edition):
Mallavajula, Rajesh. “Structure And Rheology Of Cubic Particles In Suspensions.” 2014. Doctoral Dissertation, Cornell University. Accessed March 04, 2021.
http://hdl.handle.net/1813/37120.
MLA Handbook (7th Edition):
Mallavajula, Rajesh. “Structure And Rheology Of Cubic Particles In Suspensions.” 2014. Web. 04 Mar 2021.
Vancouver:
Mallavajula R. Structure And Rheology Of Cubic Particles In Suspensions. [Internet] [Doctoral dissertation]. Cornell University; 2014. [cited 2021 Mar 04].
Available from: http://hdl.handle.net/1813/37120.
Council of Science Editors:
Mallavajula R. Structure And Rheology Of Cubic Particles In Suspensions. [Doctoral Dissertation]. Cornell University; 2014. Available from: http://hdl.handle.net/1813/37120
Texas A&M University
23.
Sanchez Telesforo, Hugo Antonio.
Rheological Behavior of an OBM Sample of the GOM under xHPHT Conditions.
Degree: MS, Petroleum Engineering, 2017, Texas A&M University
URL: http://hdl.handle.net/1969.1/165804
► The scope of this research is to study the rheological behavior of an oil based mud (OBM) sample from the Mexican side of the Gulf…
(more)
▼ The scope of this research is to study the rheological behavior of an oil based mud (OBM) sample from the Mexican side of the Gulf of Mexico (GOM) under extreme conditions of High Pressure High Temperature (HPHT). In the coming years many HPHT wells are going to be drilled in this area of the GOM. Currently Mexican Oil and Gas industry is already open to international operators because the Mexican energy reform has been approved, so it is important to study the possible drilling fluids that will be used. These fluids can be within any of these 3 tiers of HPHT classification: HPHT, ultra (uHPHT) or extreme (xHPHT).
The sample was submitted to extreme HPHT conditions, by using the state-of-the-art Model 7600 HPHT Viscometer that is capable of measuring drilling fluid properties up to 40,000 psi and 600 °F. During the laboratory tests performance, it was noticed that erroneous results were obtained by several mechanical failures. It should be noted that the spare parts take a long time to arrive-around 3 weeks. One of the failures was that the pivot of the spring assembly got inside the device, so the bob was spinning nonstop. For this reason the readings of the dial went well beyond the allowed range; another mechanical failure was that the spring of the spring assembly was loose, which did not allow us to obtain a correct reading of shear stress at high pressures and low temperatures; also the baffle does not separate the pressurizing oil from the sample, mixing these two fluids and obviously affecting the properties of the sample. This was noticed by running one test with baffle and another without it getting very similar results.
The rheological behavior of the sample showed that the viscosity is inversely proportional to temperature and directly proportional to pressure, noticing a failure point at 300 °F, because of sample degradation.
Moreover the rheogram’s curves obtained are quite similar to a second degree polynomial function, with R-squared values ranging from 0.95 to 0.99; hence an equation can be adjusted in the future by extrapolating different pressure and temperature values.
Advisors/Committee Members: Schubert, Jerome (advisor), Noynaert, Sam (committee member), Medina-Cetina, Zenon (committee member).
Subjects/Keywords: HPHT; drilling fluids; rheology
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APA (6th Edition):
Sanchez Telesforo, H. A. (2017). Rheological Behavior of an OBM Sample of the GOM under xHPHT Conditions. (Masters Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/165804
Chicago Manual of Style (16th Edition):
Sanchez Telesforo, Hugo Antonio. “Rheological Behavior of an OBM Sample of the GOM under xHPHT Conditions.” 2017. Masters Thesis, Texas A&M University. Accessed March 04, 2021.
http://hdl.handle.net/1969.1/165804.
MLA Handbook (7th Edition):
Sanchez Telesforo, Hugo Antonio. “Rheological Behavior of an OBM Sample of the GOM under xHPHT Conditions.” 2017. Web. 04 Mar 2021.
Vancouver:
Sanchez Telesforo HA. Rheological Behavior of an OBM Sample of the GOM under xHPHT Conditions. [Internet] [Masters thesis]. Texas A&M University; 2017. [cited 2021 Mar 04].
Available from: http://hdl.handle.net/1969.1/165804.
Council of Science Editors:
Sanchez Telesforo HA. Rheological Behavior of an OBM Sample of the GOM under xHPHT Conditions. [Masters Thesis]. Texas A&M University; 2017. Available from: http://hdl.handle.net/1969.1/165804
Penn State University
24.
Haines, Brian Michael.
Effective Viscosity of Dilute Bacterial Suspensions.
Degree: 2011, Penn State University
URL: https://submit-etda.libraries.psu.edu/catalog/11996
► This dissertation explores the bulk (volume averaged) properties of suspensions of microswimmers in a fluid. A microswimmer is a microscopic object that propels itself through…
(more)
▼ This dissertation explores the bulk (volume averaged) properties of
suspensions of microswimmers in a fluid. A microswimmer is a
microscopic object that propels itself through a fluid. A common
example of a microswimmer is a bacterium, such as Bacillus subtilis.
Our particular interest is the bulk rheological properties of
suspensions of bacteria – that is, studying how such a suspension
deforms under the application of an external force. In the simplest
case, the
rheology of a fluid can be described by a scalar effective
viscosity. The goal of this dissertation is to find explicit formulae
for the effective viscosity in terms of known geometric and physical parameters
characterizing bacteria and use them to explain experimental
observations. Throughout the dissertation, we consider bacterial
suspensions in the dilute limit, where bacteria are assumed to be so
far apart that interactions between them are negligible. This
simplifies calculations significantly and is the regime in which the
most striking experimental results have been observed.
We first study suspensions of self-propelled particles using a
two-dimensional (2D) Partial Differential Equation (PDE) model. A
bacterium is modeled as a disk in 2D with self-propulsion provided by a
point force in the fluid. A formula is obtained for the effective
viscosity of such suspensions in the dilute limit. This formula
includes the two terms that are found in the 2D version of Einstein's
classical result for a passive suspension of spheres. To this, our main
contribution is added, an additional term due to self-propulsion which
depends on the physical and geometric properties of the suspension.
This work demonstrates how bacterial self-propulsion can alter the
viscosity of a fluid and highlights the importance of bacterial
orientation.
Next, we present a more realistic PDE model for dilute suspensions of
swimming bacteria in a three-dimensional fluid. In this work, a
bacterium is modeled as a prolate spheroid with self-propulsion once
more provided by a point force. Furthermore, the bacterium is
subject
to a random torque in order to model tumbling (random reorientation).
This model is used to calculate the effective viscosity of the
suspension from the microscopic details of the interaction of an
elongated body with a prescribed background flow, once more in the
dilute limit. Due to a bacterium's asymmetric shape (in particular,
unlike the case of rotationally symmetric bacteria used in the first
model), interactions with generic planar background flows cause the
bacterium to preferentially align in certain directions. Due to the
random torque, the steady-state distribution of orientations is unique
for a given background flow. Under this distribution of orientations,
self-propulsion produces a reduction in the effective viscosity. For
sufficiently weak background flows, the effect of self-propulsion on
the effective viscosity dominates all other contributions, leading to
an effective viscosity of the suspension that is lower than the
viscosity of the ambient…
Advisors/Committee Members: Leonid Berlyand, Dissertation Advisor/Co-Advisor, Leonid Berlyand, Committee Chair/Co-Chair, Alberto Bressan, Committee Member, Helge Kristian Jenssen, Committee Member, Anna L Mazzucato, Committee Member, Jayanth R Banavar, Committee Member.
Subjects/Keywords: rheology; effective viscosity; bacterial suspensions
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APA (6th Edition):
Haines, B. M. (2011). Effective Viscosity of Dilute Bacterial Suspensions. (Thesis). Penn State University. Retrieved from https://submit-etda.libraries.psu.edu/catalog/11996
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):
Haines, Brian Michael. “Effective Viscosity of Dilute Bacterial Suspensions.” 2011. Thesis, Penn State University. Accessed March 04, 2021.
https://submit-etda.libraries.psu.edu/catalog/11996.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Haines, Brian Michael. “Effective Viscosity of Dilute Bacterial Suspensions.” 2011. Web. 04 Mar 2021.
Vancouver:
Haines BM. Effective Viscosity of Dilute Bacterial Suspensions. [Internet] [Thesis]. Penn State University; 2011. [cited 2021 Mar 04].
Available from: https://submit-etda.libraries.psu.edu/catalog/11996.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Haines BM. Effective Viscosity of Dilute Bacterial Suspensions. [Thesis]. Penn State University; 2011. Available from: https://submit-etda.libraries.psu.edu/catalog/11996
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Texas A&M University
25.
Peak, Charles W.
Nanoengineered Biomaterials for Cell and Therapeutic Delivery.
Degree: PhD, Biomedical Engineering, 2018, Texas A&M University
URL: http://hdl.handle.net/1969.1/173424
► Direct-write extrusion bioprinting, a form of additive manufacturing, is a useful technique to recapitulate anatomical complexity for tissue engineering applications. However, bioprinting has hit a…
(more)
▼ Direct-write extrusion bioprinting, a form of additive manufacturing, is a useful technique to recapitulate anatomical complexity for tissue engineering applications. However, bioprinting has hit a bottleneck in progress due to the lack of available bioinks with high printability, mechanical strength, and biocompatibility. Here, we report a family of hydrogel-based bioinks for extrusion bioprinting from poly (ethylene glycol) (PEG) and two-dimensional (2D) nanoparticles. PEG, a non-fouling easily modifiable polymer, combined with biocompatible Laponite XLG nanoparticles (2D nanosilicates) to obtain shear-thinning hydrogel bioinks. Electrostatic interactions between nanoparticles and hydrogen-bonding between polymer and nanoparticles govern the flow behavior and printability of bioink. The evaluation of hydrogel bioink using flow sweeps, peak holds, and dynamic oscillatory
rheology, suggest that minimum shear-thinning index of ~0.3, solution viscosities >1000 Pa·s, and 80% recovery within 30s are necessary for printing high fidelity constructs. Mechanically stiff 3D printed structures are obtained by covalently crosslinking polymeric chains using ultraviolet (UV) light. Modifications to the PEG system through inclusion of dithiothreitol linkage or combining with gelatin methacrylate are used to control matrix degradation, cell adhesion properties, and therapeutic release. We envision that PEG bioinks can be used to print complex, large-scale, cell-laden tissue constructs with high structural fidelity and mechanical stiffness for applications in custom bioprinted scaffolds and tissue engineered implants.
Advisors/Committee Members: Gaharwar, Akhilesh K (advisor), McShane, Michael J (committee member), Kaunas, Roland R (committee member), Grunlan, Jaime C (committee member).
Subjects/Keywords: Two-dimensional materials; rheology; bioprinting
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APA (6th Edition):
Peak, C. W. (2018). Nanoengineered Biomaterials for Cell and Therapeutic Delivery. (Doctoral Dissertation). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/173424
Chicago Manual of Style (16th Edition):
Peak, Charles W. “Nanoengineered Biomaterials for Cell and Therapeutic Delivery.” 2018. Doctoral Dissertation, Texas A&M University. Accessed March 04, 2021.
http://hdl.handle.net/1969.1/173424.
MLA Handbook (7th Edition):
Peak, Charles W. “Nanoengineered Biomaterials for Cell and Therapeutic Delivery.” 2018. Web. 04 Mar 2021.
Vancouver:
Peak CW. Nanoengineered Biomaterials for Cell and Therapeutic Delivery. [Internet] [Doctoral dissertation]. Texas A&M University; 2018. [cited 2021 Mar 04].
Available from: http://hdl.handle.net/1969.1/173424.
Council of Science Editors:
Peak CW. Nanoengineered Biomaterials for Cell and Therapeutic Delivery. [Doctoral Dissertation]. Texas A&M University; 2018. Available from: http://hdl.handle.net/1969.1/173424
Texas A&M University
26.
Viloria Ochoa, Marilyn.
Analysis of drilling fluid rheology and tool joint effect to reduce errors in hydraulics calculations.
Degree: PhD, Petroleum Engineering, 2006, Texas A&M University
URL: http://hdl.handle.net/1969.1/4334
► This study presents a simplified and accurate procedure for selecting the rheological model which best fits the rheological properties of a given non- Newtonian fluid…
(more)
▼ This study presents a simplified and accurate procedure for selecting the
rheological model which best fits the rheological properties of a given non-
Newtonian fluid and introduces five new approaches to correct for tool joint
losses from expansion and contraction when hydraulics is calculated. The new
approaches are enlargement and contraction (E&C), equivalent diameter (ED),
two different (2IDs), enlargement and contraction plus equivalent diameter
(E&C+ED), and enlargement and contraction plus two different IDs (E&C+2IDs).
In addition to the Newtonian model, seven major non-Newtonian rheological
models (Bingham plastic, Power law, API, Herschel-Bulkley, Unified, Robertson
and Stiff, and Casson) provide alternatives for selecting the model that most
accurately represents the shear-stress/shear-rate relationship for a given non-
Newtonian fluid.
The project assumes that the model which gives the lowest absolute average
percent error (EAAP) between the measured and calculated shear stresses is the
best one for a given non-Newtonian fluid.
The results are of great importance in achieving correct results for pressure drop
and hydraulics calculations and the results are that the API rheological model (RP 13D) provides, in general, the best prediction of rheological behavior for the
mud samples considered (EAAP=1.51), followed by the Herschel-Bulkley,
Robertson and Stiff, and Unified models. Results also show that corrections with
E&C+2IDs and API hydraulics calculation give a good approximation to
measured pump pressure with 9% of difference between measured and
calculated data.
Advisors/Committee Members: Juvkam-Wold, Hans (advisor), Shubert, Jerome (committee member), Ugaz, Victor (committee member), Valko, Peter (committee member).
Subjects/Keywords: rheology; drilling
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APA (6th Edition):
Viloria Ochoa, M. (2006). Analysis of drilling fluid rheology and tool joint effect to reduce errors in hydraulics calculations. (Doctoral Dissertation). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/4334
Chicago Manual of Style (16th Edition):
Viloria Ochoa, Marilyn. “Analysis of drilling fluid rheology and tool joint effect to reduce errors in hydraulics calculations.” 2006. Doctoral Dissertation, Texas A&M University. Accessed March 04, 2021.
http://hdl.handle.net/1969.1/4334.
MLA Handbook (7th Edition):
Viloria Ochoa, Marilyn. “Analysis of drilling fluid rheology and tool joint effect to reduce errors in hydraulics calculations.” 2006. Web. 04 Mar 2021.
Vancouver:
Viloria Ochoa M. Analysis of drilling fluid rheology and tool joint effect to reduce errors in hydraulics calculations. [Internet] [Doctoral dissertation]. Texas A&M University; 2006. [cited 2021 Mar 04].
Available from: http://hdl.handle.net/1969.1/4334.
Council of Science Editors:
Viloria Ochoa M. Analysis of drilling fluid rheology and tool joint effect to reduce errors in hydraulics calculations. [Doctoral Dissertation]. Texas A&M University; 2006. Available from: http://hdl.handle.net/1969.1/4334
Leiden University
27.
Wit, Martin de.
On Slippery Ground: The Search for Superlubricity in Macroscopic Samples and the Exploration of Graphene as a Friction Lowering Coating.
Degree: 2013, Leiden University
URL: http://hdl.handle.net/1887/66245
► During this study, a device was developed which is capable of measuring the friction coefficient between two macroscopic solid samples for different rotation angles. It…
(more)
▼ During this study, a device was developed which is capable of measuring the friction coefficient between two macroscopic solid samples for different rotation angles. It is based on an Anton Paar rheometer. It can measure torques ranging from 10 nNm up to 200 mNm, while controlling the rotation angle with a minimum resolution of 10 nrad. The normal load exerted on the samples can be controlled with mN accuracy. Measurements on HOPG and silicon dioxide have verified that the instrument works and is capable of measuring very low friction coefficients as a function of the rotation angle between the two samples. The obtained friction coefficients are in agreement with values found in literature.
Advisors/Committee Members: Frenken, Joost (advisor).
Subjects/Keywords: Friction; Graphene; Superlubricity; Rheology
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APA (6th Edition):
Wit, M. d. (2013). On Slippery Ground: The Search for Superlubricity in Macroscopic Samples and the Exploration of Graphene as a Friction Lowering Coating. (Masters Thesis). Leiden University. Retrieved from http://hdl.handle.net/1887/66245
Chicago Manual of Style (16th Edition):
Wit, Martin de. “On Slippery Ground: The Search for Superlubricity in Macroscopic Samples and the Exploration of Graphene as a Friction Lowering Coating.” 2013. Masters Thesis, Leiden University. Accessed March 04, 2021.
http://hdl.handle.net/1887/66245.
MLA Handbook (7th Edition):
Wit, Martin de. “On Slippery Ground: The Search for Superlubricity in Macroscopic Samples and the Exploration of Graphene as a Friction Lowering Coating.” 2013. Web. 04 Mar 2021.
Vancouver:
Wit Md. On Slippery Ground: The Search for Superlubricity in Macroscopic Samples and the Exploration of Graphene as a Friction Lowering Coating. [Internet] [Masters thesis]. Leiden University; 2013. [cited 2021 Mar 04].
Available from: http://hdl.handle.net/1887/66245.
Council of Science Editors:
Wit Md. On Slippery Ground: The Search for Superlubricity in Macroscopic Samples and the Exploration of Graphene as a Friction Lowering Coating. [Masters Thesis]. Leiden University; 2013. Available from: http://hdl.handle.net/1887/66245
Queens University
28.
Agrawal, Prashant.
Effect of Crumb Rubber and Warm Mix Additives on Asphalt Aging, Rheological, and Failure Properties
.
Degree: Chemistry, 2014, Queens University
URL: http://hdl.handle.net/1974/8602
► Asphalt-rubber mixtures have been shown to have useful properties with respect to distresses observed in asphalt concrete pavements. The most notable change in properties is…
(more)
▼ Asphalt-rubber mixtures have been shown to have useful properties with respect to distresses observed in asphalt concrete pavements. The most notable change in properties is a large increase in viscosity and improved low-temperature cracking resistance. Warm mix additives can lower production and compaction temperatures. Lower temperatures reduce harmful emissions and lower energy consumption, and thus provide environmental benefits and cut costs.
In this study, the effects of crumb rubber modification on various asphalts such as California Valley, Boscan, Alaska North Slope, Laguna and Cold Lake were also studied. The materials used for warm mix modification were obtained from various commercial sources. The RAF binder was produced by Imperial Oil in their Nanticoke, Ontario, refinery on Lake Erie. A second commercial PG 52-34 (hereafter denoted as NER) was obtained/sampled during the construction of a northern Ontario MTO contract.
Some regular tests such as Dynamic Shear Rheometer (DSR) and Bending Beam Rheometer (BBR), Multiple Stress Creep Recovery (MSCR) and some modified new protocols such as the extended BBR test (LS-308) and the Double-Edge Notched Tension (DENT) test (LS-299) are used to study, the effect of warm mix and a host of other additives on rheological, aging and failure properties.
A comparison in the properties of RAF and NER asphalts has also been made as RAF is good quality asphalt and NER is bad quality asphalt.
From the studies the effect of additives on chemical and physical hardening tendencies was found to be significant. The asphalt samples tested in this study showed a range of tendencies for chemical and physical hardening.
Subjects/Keywords: Crumb Rubber
;
Rheology
;
Asphalt
;
WMA
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Manager
APA (6th Edition):
Agrawal, P. (2014). Effect of Crumb Rubber and Warm Mix Additives on Asphalt Aging, Rheological, and Failure Properties
. (Thesis). Queens University. Retrieved from http://hdl.handle.net/1974/8602
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):
Agrawal, Prashant. “Effect of Crumb Rubber and Warm Mix Additives on Asphalt Aging, Rheological, and Failure Properties
.” 2014. Thesis, Queens University. Accessed March 04, 2021.
http://hdl.handle.net/1974/8602.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Agrawal, Prashant. “Effect of Crumb Rubber and Warm Mix Additives on Asphalt Aging, Rheological, and Failure Properties
.” 2014. Web. 04 Mar 2021.
Vancouver:
Agrawal P. Effect of Crumb Rubber and Warm Mix Additives on Asphalt Aging, Rheological, and Failure Properties
. [Internet] [Thesis]. Queens University; 2014. [cited 2021 Mar 04].
Available from: http://hdl.handle.net/1974/8602.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Agrawal P. Effect of Crumb Rubber and Warm Mix Additives on Asphalt Aging, Rheological, and Failure Properties
. [Thesis]. Queens University; 2014. Available from: http://hdl.handle.net/1974/8602
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
University of Toronto
29.
Wang, Edwin Shao Wen.
Slow Flow of a Viscoelastic Fluid Past a Circular Cylinder.
Degree: 2012, University of Toronto
URL: http://hdl.handle.net/1807/32289
► Flow around a cylinder is important in the motion of microorganisms found in biological viscoelastic fluids that propel themselves by flagella. Flow around a cylinder…
(more)
▼ Flow around a cylinder is important in the motion of microorganisms found in biological viscoelastic fluids that propel themselves by flagella. Flow around a cylinder experiments are difficult to perform because of the influence of the walls and ends. An approach was developed to measure the drag on a cylinder by correcting for wall and end effects. Cylinders were vertically dipped into fluids in an annular shaped tank, which was rotated to generate a flow. The force acting on a cylinder was measured using a custom force transducer. This method was used for a Newtonian fluid and two Boger fluids. The drag of the Boger fluids was several times that of an equivalent Newtonian fluid. A cavity was observed to develop behind the cylinders once the flow surpassed a critical velocity. Streakline images taken during the experiment confirmed the presence of a wake region behind the cylinders.
MAST
Advisors/Committee Members: James, David F., Mechanical and Industrial Engineering.
Subjects/Keywords: Fluid Mechanics; Rheology; 0548
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APA (6th Edition):
Wang, E. S. W. (2012). Slow Flow of a Viscoelastic Fluid Past a Circular Cylinder. (Masters Thesis). University of Toronto. Retrieved from http://hdl.handle.net/1807/32289
Chicago Manual of Style (16th Edition):
Wang, Edwin Shao Wen. “Slow Flow of a Viscoelastic Fluid Past a Circular Cylinder.” 2012. Masters Thesis, University of Toronto. Accessed March 04, 2021.
http://hdl.handle.net/1807/32289.
MLA Handbook (7th Edition):
Wang, Edwin Shao Wen. “Slow Flow of a Viscoelastic Fluid Past a Circular Cylinder.” 2012. Web. 04 Mar 2021.
Vancouver:
Wang ESW. Slow Flow of a Viscoelastic Fluid Past a Circular Cylinder. [Internet] [Masters thesis]. University of Toronto; 2012. [cited 2021 Mar 04].
Available from: http://hdl.handle.net/1807/32289.
Council of Science Editors:
Wang ESW. Slow Flow of a Viscoelastic Fluid Past a Circular Cylinder. [Masters Thesis]. University of Toronto; 2012. Available from: http://hdl.handle.net/1807/32289
Cape Peninsula University of Technology
30.
Migabo, Willy Mbasha.
The effect of gypsum phase components on the rheokinetics of cement paste
.
Degree: 2018, Cape Peninsula University of Technology
URL: http://etd.cput.ac.za/handle/20.500.11838/2763
► Rheological properties of most ordinary Portland cements are dictated by the hydration reactions that their different phases experience. Cement clinker has four main phases with…
(more)
▼ Rheological properties of most ordinary Portland cements are dictated by the hydration reactions that their different phases experience. Cement clinker has four main phases with aluminate being the most reactive. Once in contact with water, the aluminate phase reacts rapidly and generally impedes the early hydration of other cement compounds such as calcium silicates that are responsible for the strength of cement systems. Consequently, the obtained matrix is stiff without much strength. Alternatively, calcium sulphate bearing materials are added within the clinker as set regulators of the aluminate phase hydration. For this purpose, natural gypsum is moslty gound with cement clinker as a source of sufficient sulphate, thereby keeping the cement paste plastic for a certain amount of time, allowing the hydration of silicate phases that are responsible for the early and later strength. However, the heat generated within the mill during the grinding process of clinker and gypsum causes a partial dehydration of natural gypsum into hemihydrate. The final ground cement product is thus comprised of two unexpected types of calcium sulphate bearing materials in an unpredictable proportion. Due to the difference in their solubility, the hydration of the aluminate phase can variably be altered which consequently affects the rheokinetics of the cement paste. Currently, the effect of the available amount of hemihydrate and natural gypsum in the cement sulphate phase, on both the hydration and rheology of ordinary Portland cements (OPC), are not well-understood. An ordinary Portland cement clinker was sampled during the production process of CEM I under stable kiln operations at a local cement plant. This was ground without any form of calcium sulphate bearing material and the final product was considered as relatively pure cement clinker. The degree of natural gypsum degeneration was achieved by partially replacing fractions of hemihydrate with those of natural gypsum. Firstly, the individual effect of these calcium sulphate bearing materials on the hydration kinetics was studied by varying their concentrations from 2-7% within the cement system. Secondly, the effect of their mix proportions at an optimum calcium sulphate concentration on cement paste rheokinetics was investigated. This research confirmed the findings of previous investigations relative to the effect of calcium sulphate on the hydration kinetic , giving new insight on the rheokinetics of cement paste with mix proportions of various calcium bearing materials. Results showed that the reaction rates of cement systems with hemihydrate were faster than those with natural gypsum and generally tended to decrease with the increase in their concentrations. Cements with hemihydrate experiencing shorter dormant durations than those with natural gypsum, likely due to the fact that the consumption rate of calcium sulphate was higher in cement systems with hemihydrate than those with natural gypsum. Consequently, before the exhaustion of sulphate ions, cement systems with…
Subjects/Keywords: Portland cement;
Rheology;
Gypsum;
Hydration
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Manager
APA (6th Edition):
Migabo, W. M. (2018). The effect of gypsum phase components on the rheokinetics of cement paste
. (Thesis). Cape Peninsula University of Technology. Retrieved from http://etd.cput.ac.za/handle/20.500.11838/2763
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):
Migabo, Willy Mbasha. “The effect of gypsum phase components on the rheokinetics of cement paste
.” 2018. Thesis, Cape Peninsula University of Technology. Accessed March 04, 2021.
http://etd.cput.ac.za/handle/20.500.11838/2763.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Migabo, Willy Mbasha. “The effect of gypsum phase components on the rheokinetics of cement paste
.” 2018. Web. 04 Mar 2021.
Vancouver:
Migabo WM. The effect of gypsum phase components on the rheokinetics of cement paste
. [Internet] [Thesis]. Cape Peninsula University of Technology; 2018. [cited 2021 Mar 04].
Available from: http://etd.cput.ac.za/handle/20.500.11838/2763.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Migabo WM. The effect of gypsum phase components on the rheokinetics of cement paste
. [Thesis]. Cape Peninsula University of Technology; 2018. Available from: http://etd.cput.ac.za/handle/20.500.11838/2763
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
◁ [1] [2] [3] [4] [5] … [71] ▶
. 
Open Access Theses and Dissertations
