1
|
Martin-Alarcon L, Govedarica A, Ewoldt RH, Bryant SL, Jay GD, Schmidt TA, Trifkovic M. Scale-Dependent Rheology of Synovial Fluid Lubricating Macromolecules. Small 2023:e2306207. [PMID: 38161247 DOI: 10.1002/smll.202306207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2023] [Revised: 11/20/2023] [Indexed: 01/03/2024]
Abstract
Synovial fluid (SF) is the complex biofluid that facilitates the exceptional lubrication of articular cartilage in joints. Its primary lubricating macromolecules, the linear polysaccharide hyaluronic acid (HA) and the mucin-like glycoprotein proteoglycan 4 (PRG4 or lubricin), interact synergistically to reduce boundary friction. However, the precise manner in which these molecules influence the rheological properties of SF remains unclear. This study aimed to elucidate this by employing confocal microscopy and multiscale rheometry to examine the microstructure and rheology of solutions containing recombinant human PRG4 (rhPRG4) and HA. Contrary to previous assumptions of an extensive HA-rhPRG4 network, it is discovered that rhPRG4 primarily forms stiff, gel-like aggregates. The properties of these aggregates, including their size and stiffness, are found to be influenced by the viscoelastic characteristics of the surrounding HA matrix. Consequently, the rheology of this system is not governed by a single length scale, but instead responds as a disordered, hierarchical network with solid-like rhPRG4 aggregates distributed throughout the continuous HA phase. These findings provide new insights into the biomechanical function of PRG4 in cartilage lubrication and may have implications in the development of HA-based therapies for joint diseases like osteoarthritis.
Collapse
Affiliation(s)
- Leonardo Martin-Alarcon
- Biomedical Engineering Graduate Program, University of Calgary, Calgary, AB, T2N 1N4, Canada
| | - Aleksandra Govedarica
- Department of Chemical and Petroleum Engineering, University of Calgary, Calgary, AB, T2N 1N4, Canada
| | - Randy H Ewoldt
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Steven L Bryant
- Department of Chemical and Petroleum Engineering, University of Calgary, Calgary, AB, T2N 1N4, Canada
| | - Gregory D Jay
- Department of Emergency Medicine - Warren Alpert Medical School & School of Engineering, Brown University, Providence, RI, 02912, USA
| | - Tannin A Schmidt
- Biomedical Engineering Department, University of Connecticut Health Center, Farmington, CT, 06030, USA
| | - Milana Trifkovic
- Department of Chemical and Petroleum Engineering, University of Calgary, Calgary, AB, T2N 1N4, Canada
| |
Collapse
|
2
|
Varamesh A, Abraham BD, Wang H, Berton P, Zhao H, Gourlay K, Minhas G, Lu Q, Bryant SL, Hu J. Multifunctional fully biobased aerogels for water remediation: Applications for dye and heavy metal adsorption and oil/water separation. J Hazard Mater 2023; 457:131824. [PMID: 37327610 DOI: 10.1016/j.jhazmat.2023.131824] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 05/16/2023] [Accepted: 06/08/2023] [Indexed: 06/18/2023]
Abstract
Water ecosystem contamination from industrial pollutants is an emerging threat to both humans and native species, making it a point of global concern. In this work, fully biobased aerogels (FBAs) were developed by using low-cost cellulose filament (CF), chitosan (CS), citric acid (CA), and a simple and scalable approach, for water remediation applications. The FBAs displayed superior mechanical properties (up to ∼65 kPa m3 kg-1 specific Young's modulus and ∼111 kJ/m3 energy absorption) due to CA acting as a covalent crosslinker in addition to the natural hydrogen bonding and electrostatic interactions between CF and CS. The addition of CS and CA increased the variety of functional groups (carboxylic acid, hydroxyl and amines) on the materials' surface, resulting in super-high dye and heavy metal adsorption capacities (619 mg/g and 206 mg/g for methylene blue and copper, respectively). Further modification of FBAs with a simple approach using methyltrimethoxysilane endowed aerogel oleophilic and hydrophobic properties. The developed FBAs showed a fast performance in water and oil/organic solvents separation with more than 96% efficiency. Besides, the FBA sorbents could be regenerated and reused for multiple cycles without any significant impact on their performance. Moreover, thanks to the presence of amine groups by addition of CS, FBAs also displayed antibacterial properties by preventing the growth of Escherichia coli on their surface. This work demonstrates the preparation of FBAs from abundant, sustainable, and inexpensive natural resources for applications in wastewater purification.
Collapse
Affiliation(s)
- Amir Varamesh
- Department of Chemical and Petroleum Engineering, University of Calgary, Calgary T2N 1N4, Canada
| | - Brett David Abraham
- Department of Biomedical Engineering, University of Calgary, Calgary T2N 1N4, Canada; Pharmaceutical Production Research Facility, University of Calgary, Calgary T2N 1N4, Canada
| | - Hui Wang
- Department of Chemical and Petroleum Engineering, University of Calgary, Calgary T2N 1N4, Canada
| | - Paula Berton
- Department of Chemical and Petroleum Engineering, University of Calgary, Calgary T2N 1N4, Canada
| | - Heng Zhao
- Department of Chemical and Petroleum Engineering, University of Calgary, Calgary T2N 1N4, Canada
| | - Keith Gourlay
- Performance BioFilaments, 700 West Pender Street, Vancouver V6C 1G8, Canada
| | - Gurminder Minhas
- Performance BioFilaments, 700 West Pender Street, Vancouver V6C 1G8, Canada
| | - Qingye Lu
- Department of Chemical and Petroleum Engineering, University of Calgary, Calgary T2N 1N4, Canada
| | - Steven L Bryant
- Department of Chemical and Petroleum Engineering, University of Calgary, Calgary T2N 1N4, Canada.
| | - Jinguang Hu
- Department of Chemical and Petroleum Engineering, University of Calgary, Calgary T2N 1N4, Canada.
| |
Collapse
|
3
|
Gholinezhad S, Kantzas A, Bryant SL. Control of interfacial instabilities through variable injection rate in a radial Hele-Shaw cell: A nonlinear approach for late-time analysis. Phys Rev E 2023; 107:065108. [PMID: 37464653 DOI: 10.1103/physreve.107.065108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Accepted: 05/26/2023] [Indexed: 07/20/2023]
Abstract
In this paper, the nonlinear behavior of immiscible viscous fingering in a circular Hele-Shaw cell under the action of different time-dependent injection flow rate schemes is assessed numerically. Unlike previous studies which addressed the infinite viscosity ratio (inviscid-viscous flow), the problem is tackled by paying special attention to flows with finite viscosity ratio (viscous flow) in which the viscosity of the displacing and the displaced fluids can have any arbitrary value. Systematic numerical simulations based on a complex-variable formulation of Cauchy-Green barycentric coordinates are performed at different mobility ratios and capillary numbers with a focus on the late-time fully nonlinear regime. Additionally, numerical optimization is used to obtain the optimal flow rate schedule through a second-order weakly nonlinear stability analysis in contrast to previous studies in which the optimal flow rate was obtained entirely based on linear stability analysis. It is demonstrated that, irrespective of the values of the mobility ratio and/or the capillary number, for patterns whose constant injection counterpart exhibits linear flow regime, the curvature-driven relaxation time is comparable with the operational time of the time-dependent injection flow rate controlling schemes, and most of the controlling schemes work very well and suppress the fingering phenomenon remarkably with the maximum recovery improvement of 15%. As the nonlinearity of the system increases, the schemes may still perform well, but their effectiveness is more pronounced in patterns with less nonlinearity in their constant injection counterpart than those with higher nonlinearity. As the nonlinearity increases, the curvature-driven relaxation time becomes longer than the operational time of the schemes, leading to a reduction in their effectiveness. Additionally, it is shown that employment of the second-order weakly nonlinear stability analysis to formulate the objective function does not result in any remarkable variation in the obtained optimal flow rate schedule.
Collapse
Affiliation(s)
- Sajjad Gholinezhad
- Department of Chemical and Petroleum Engineering, University of Calgary, 2500 University Drive NW, Calgary, Alberta, Canada, T2N 1N4
| | - Apostolos Kantzas
- Department of Chemical and Petroleum Engineering, University of Calgary, 2500 University Drive NW, Calgary, Alberta, Canada, T2N 1N4
- PERM Inc. TIPM Laboratory, 3-2221 41 Avenue NE, Calgary, Alberta, Canada, T2E 6P2
| | - Steven L Bryant
- Department of Chemical and Petroleum Engineering, University of Calgary, 2500 University Drive NW, Calgary, Alberta, Canada, T2N 1N4
- Canada Excellence Research Chair in Materials Engineering for Unconventional Oil Reservoirs, 750 Campus Drive NW, Calgary, Alberta, Canada, T2N 1N4
| |
Collapse
|
4
|
Ding B, Ahmadi SH, Babak P, Bryant SL, Kantzas A. On the Stability of Pickering and Classical Nanoemulsions: Theory and Experiments. Langmuir 2023; 39:6975-6991. [PMID: 37083472 DOI: 10.1021/acs.langmuir.3c00133] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Emulsification is a crucial technique for mixing immiscible liquids into droplets in various industries, such as food, cosmetics, biomedicine, agrochemistry, and petrochemistry. Quantitative analysis of the stability is pivotal before the utilization of these emulsions. Differences in X-ray attenuation for emulsion components and surface relaxation of the droplets may contribute to X-ray CT imaging and low-field NMR spectroscopy as viable techniques to quantify emulsion stability. In this study, Pickering (stabilized solely by nanoparticles) and Classical (stabilized solely by low molecular weight polymers) nanoemulsions were prepared with a high-energy method. NMR and X-ray CT were employed to constantly monitor the two types of nanoemulsions until phase separation. The creaming rates calculated from NMR match well with the results obtained from X-ray CT. Furthermore, we show that Stokes' law coupled with the classical Lifshitz-Slyozov-Wagner theory underestimates the creaming rate of the nanoemulsions compared to the experimental results from NMR and X-ray CT imaging. A new theory is proposed by fully incorporating the effects of Pickering nanoparticles, hydrocarbon types, volume fraction, size distribution, and flocculation on the droplet coarsening. The theoretical results agree well with the experimentally measured creaming rates. It reveals that the attachment of nanoparticles onto a droplet surface decreases the mass transfer for hydrocarbon molecules to move from the bulk aqueous phase into other droplets, thus slowing the Ostwald ripening. Therefore, Pickering nanoemulsions show a better stability behavior compared to Classical nanoemulsions. The impacts of hydrocarbon and emulsification energy on the stability of nanoemulsions are reported. These findings demonstrate that the stability of the nanoemulsions can be manipulated and optimized for a specific application, setting the stage for subsequent investigations of these nanodroplets.
Collapse
Affiliation(s)
- Boxin Ding
- Department of Chemical and Petroleum Engineering, University of Calgary, Calgary, AB T2N 1N4, Canada
- Reservoir Engineering Research Institute, Palo Alto, California 94301, United States
| | - Seyedeh Hannaneh Ahmadi
- Department of Chemical and Petroleum Engineering, University of Calgary, Calgary, AB T2N 1N4, Canada
| | - Petro Babak
- Department of Chemical and Petroleum Engineering, University of Calgary, Calgary, AB T2N 1N4, Canada
- Southern Alberta Institute of Technology, Calgary, AB T2M 0L4, Canada
| | - Steven L Bryant
- Department of Chemical and Petroleum Engineering, University of Calgary, Calgary, AB T2N 1N4, Canada
- Canada Excellence Research Chair in Materials Engineering for Unconventional Oil Reservoirs, Calgary, AB T2N 1N4, Canada
| | - Apostolos Kantzas
- Department of Chemical and Petroleum Engineering, University of Calgary, Calgary, AB T2N 1N4, Canada
- TIPM Laboratory, PERM Inc., Calgary, AB T2E 6P2, Canada
| |
Collapse
|
5
|
Voegtlin SP, Barnes RJ, Hubert CRJ, Larter SR, Bryant SL. Formation of biologically influenced palladium microstructures by Desulfovibrio desulfuricans and Desulfovibrio ferrophilus IS5. N Biotechnol 2022; 72:128-138. [PMID: 36396027 DOI: 10.1016/j.nbt.2022.11.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Revised: 11/04/2022] [Accepted: 11/05/2022] [Indexed: 11/16/2022]
Abstract
A range of Desulfovibrio spp. can reduce metal ions to form metallic nanoparticles that remain attached to their surfaces. The bioreduction of palladium (Pd) has been given considerable attention due to its extensive use in areas of catalysis and electronics and other technological domains. In this study we report, for the first time, evidence for Pd(II) reduction by the highly corrosive Desulfovibrio ferrophilus IS5 strain to form surface attached Pd nanoparticles, as well as rapid formation of Pd(0) coated microbial nanowires. These filaments reached up to 8 µm in length and led to the formation of a tightly bound group of interconnected cells with enhanced ability to attach to a low carbon steel surface. Moreover, when supplied with high concentrations of Pd (≥ 100 mmol Pd(II) g-1 dry cells), both Desulfovibrio desulfuricans and D. ferrophilus IS5 formed bacteria/Pd hybrid porous microstructures comprising millions of cells. These three-dimensional structures reached up to 3 mm in diameter with a dose of 1200 mmol Pd(II) g-1 dry cells. Under suitable hydrodynamic conditions during reduction, two-dimensional nanosheets of Pd metal were formed that were up to several cm in length. Lower dosing of Pd(II) for promoting rapid synthesis of metal coated nanowires and enhanced attachment of cells onto metal surfaces could improve the efficiency of various biotechnological applications such as microbial fuel cells. Formation of biologically stimulated Pd microstructures could lead to a novel way to produce metal scaffolds or nanosheets for a wide variety of applications.
Collapse
Affiliation(s)
- Stephen P Voegtlin
- Department of Chemical and Petroleum Engineering, University of Calgary, Calgary, Canada
| | - Robert J Barnes
- Department of Chemical and Petroleum Engineering, University of Calgary, Calgary, Canada; Department of Biological Sciences, University of Calgary, Calgary, Canada
| | - Casey R J Hubert
- Department of Biological Sciences, University of Calgary, Calgary, Canada
| | - Stephen R Larter
- Department of Geosciences, University of Calgary, Calgary, Canada
| | - Steven L Bryant
- Department of Chemical and Petroleum Engineering, University of Calgary, Calgary, Canada.
| |
Collapse
|
6
|
Berton P, Chen YN, Manouchehr S, Wong K, Ahmadi Z, Bryant SL, Rogers RD. Design of ionic liquids for dewatering stable solid/liquid complex slurries. AIChE J 2021. [DOI: 10.1002/aic.17494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Paula Berton
- Chemical and Petroleum Engineering Department University of Calgary Calgary Alberta Canada
- CalAgua Innovations Corp. Calgary Alberta Canada
| | - Yi N. Chen
- Chemical and Petroleum Engineering Department University of Calgary Calgary Alberta Canada
- Department of Chemical Engineering University of Waterloo Waterloo Ontario Canada
| | - Shokoufeh Manouchehr
- Chemical and Petroleum Engineering Department University of Calgary Calgary Alberta Canada
| | - Kyle Wong
- Chemical and Petroleum Engineering Department University of Calgary Calgary Alberta Canada
- Department of Chemical Engineering University of Waterloo Waterloo Ontario Canada
| | - Zohrab Ahmadi
- Chemical and Petroleum Engineering Department University of Calgary Calgary Alberta Canada
| | - Steven L. Bryant
- Chemical and Petroleum Engineering Department University of Calgary Calgary Alberta Canada
- CalAgua Innovations Corp. Calgary Alberta Canada
| | - Robin D. Rogers
- CalAgua Innovations Corp. Calgary Alberta Canada
- 525 Solutions, Inc. Tuscaloosa Alabama USA
| |
Collapse
|
7
|
Kumar S, Pandey A, Trifkovic M, Bryant SL. A facile and economical configuration for continuous generation and separation of oil in water emulsions. Sep Purif Technol 2021. [DOI: 10.1016/j.seppur.2020.117849] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
|
8
|
Sang Q, Zhao X, Abdelfatah E, Bryant SL, Dong M. Dispersibility of Poly(vinyl acetate) Modified Silica Nanoparticles in Carbon Dioxide with Several Cosolvents. Langmuir 2021; 37:655-665. [PMID: 33412854 DOI: 10.1021/acs.langmuir.0c02522] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The dispersibility and stabilization of silica nanoparticles with surface-capped poly(vinyl acetate) (PVAc) chains are examined in carbon dioxide with four different cosolvents. Three surface coverages of silica-PVAc were formed by using different weight ratios of the silica and PVAc. The dispersibilities of three silica-PVAc nanoparticles in CO2 with the four cosolvents were tested in a rotatable high-pressure variable-volume view cell. The effects of surface coverage, cosolvent type, pressure, and particle concentration on dispersion were investigated. Results show that, in the experimental pressure range (5.5 to 20 MPa), the pressure has no significant effect on the dispersion of nanoparticles, and the cosolvent is the key factor in dispersing silica-PVAc particles in CO2. 1-Butanol is an adequate cosolvent to disperse silica-PVAc in CO2 with any coverage of PVAc on the surface of the particles when the concentration of particles is smaller than 0.31 wt %. Ethanol can only improve the dispersibility of particles with a high surface coverage of PVAc when the concentration of particles is smaller than 0.14 wt %. 1-Hexanol and ethyl acetate cannot disperse the particles in CO2 with any coverage of PVAc. Molecular dynamics simulations were carried out to study the nanoparticle-CO2-cosolvent dispersions. Results suggest that 1-butanol has a good solubility in the CO2 condensed phase and can effectively absorb onto the nanoparticle surface, which help to prevent the formation of nanoparticle aggregation. The precipitation of nanoparticles in the nanoparticle/1-hexanol/CO2 and nanoparticle/ethyl acetate/CO2 systems is attributed to the relatively low solubility of CO2 in 1-hexanol and ethyl acetate. The precipitation of nanoparticles in the nanoparticle/ethanol/CO2 system is the result of less hindrance of ethanol molecules to the aggregation of nanoparticles.
Collapse
Affiliation(s)
- Qian Sang
- Key Laboratory of Unconventional Oil & Gas Development (China University of Petroleum (East China)), Ministry of Education, Qingdao 266580, P. R. China
- School of Petroleum Engineering, China University of Petroleum (East China), Qingdao 266580, P. R. China
| | - Xinyi Zhao
- Key Laboratory of Unconventional Oil & Gas Development (China University of Petroleum (East China)), Ministry of Education, Qingdao 266580, P. R. China
- School of Petroleum Engineering, China University of Petroleum (East China), Qingdao 266580, P. R. China
| | - Elsayed Abdelfatah
- Department of Chemical and Petroleum Engineering, University of Calgary, Calgary, AB T2N 1N4, Canada
| | - Steven L Bryant
- Department of Chemical and Petroleum Engineering, University of Calgary, Calgary, AB T2N 1N4, Canada
| | - Mingzhe Dong
- Department of Chemical and Petroleum Engineering, University of Calgary, Calgary, AB T2N 1N4, Canada
| |
Collapse
|
9
|
Kedzior SA, Cranmer-Smith S, Behabtu N, Kim K, Lenges C, Bryant SL, Trifkovic M. Elucidating the effect of enzymatic polymerized polysaccharide particle morphology on emulsion properties. Carbohydr Polym 2021; 251:117112. [DOI: 10.1016/j.carbpol.2020.117112] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2020] [Revised: 09/11/2020] [Accepted: 09/12/2020] [Indexed: 01/04/2023]
|
10
|
Kedzior SA, Kapadia W, Egberts P, Karan K, Trifkovic M, Bryant SL. In situ monitoring of the morphology evolution of interfacially-formed conductive nanocomposite films and their use as strain sensors. J Colloid Interface Sci 2019; 554:305-314. [PMID: 31302368 DOI: 10.1016/j.jcis.2019.07.018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 07/05/2019] [Accepted: 07/07/2019] [Indexed: 10/26/2022]
Abstract
HYPOTHESIS Understanding and monitoring the film formation of interfacially formed layered films allows for the design of conductive nanocomposite films suitable for strain sensing. EXPERIMENTS To understand the mechanism of interfacial film formation, the hexane/water interface was monitored during the evaporation process via confocal laser scanning microscopy. Scanning electron microscopy and atomic force microscopy were utilized to investigate final film morphology. Tensile testing was used to determine their mechanical properties under uniaxial strain. FINDINGS Conductive nanocomposite films were formed at the hexane/water interface. Due to their low colloidal stability in hexane, the Vulcan carbon (VC) nanoparticles settled to the hexane/water interface prior to the onset of paraffin wax precipitation. Consequently, after the evaporation of hexane a two-layer structured film was formed. The bottom (water-facing, VC-rich) layer was conductive due to the existence of a percolated network of nanoparticle aggregates, while the top (hexane facing, paraffin-rich) layer was not conductive. The films showed high sensitivity for strains between 1% and 10%. We propose that the mechanism of strain sensing is similar to that of layer-structured sensors fabricated through embedding conductive nanofillers onto flexible polymeric substrates. The advantage of the films derived by the method proposed here is their ease of fabrication as well as their low cost.
Collapse
Affiliation(s)
- Stephanie A Kedzior
- Department of Chemical and Petroleum Engineering, University of Calgary, 2500 University Drive NW, Calgary, AB T2N 1N4, Canada.
| | - Wasim Kapadia
- Department of Chemical and Petroleum Engineering, University of Calgary, 2500 University Drive NW, Calgary, AB T2N 1N4, Canada.
| | - Philip Egberts
- Department of Mechanical and Manufacturing Engineering, University of Calgary, 2500 University Drive NW, Calgary, AB T2N 1N4, Canada.
| | - Kunal Karan
- Department of Chemical and Petroleum Engineering, University of Calgary, 2500 University Drive NW, Calgary, AB T2N 1N4, Canada.
| | - Milana Trifkovic
- Department of Chemical and Petroleum Engineering, University of Calgary, 2500 University Drive NW, Calgary, AB T2N 1N4, Canada.
| | - Steven L Bryant
- Department of Chemical and Petroleum Engineering, University of Calgary, 2500 University Drive NW, Calgary, AB T2N 1N4, Canada.
| |
Collapse
|
11
|
Maaref S, Kantzas A, Bryant SL. The effect of silanization assisted nanoparticle hydrophobicity on emulsion stability through droplet size distribution analysis. Chem Eng Sci 2019. [DOI: 10.1016/j.ces.2019.02.034] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
12
|
Mohammadmoradi P, Taheri S, Bryant SL, Kantzas A. Solvent diffusion and dispersion in partially saturated porous media: An experimental and numerical pore-level study. Chem Eng Sci 2018. [DOI: 10.1016/j.ces.2018.06.072] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
13
|
Pandey A, Derakhshandeh M, Kedzior SA, Pilapil B, Shomrat N, Segal-Peretz T, Bryant SL, Trifkovic M. Role of interparticle interactions on microstructural and rheological properties of cellulose nanocrystal stabilized emulsions. J Colloid Interface Sci 2018; 532:808-818. [DOI: 10.1016/j.jcis.2018.08.044] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Revised: 08/14/2018] [Accepted: 08/16/2018] [Indexed: 11/28/2022]
|
14
|
Doroudian Rad M, Telmadarreie A, Xu L, Dong M, Bryant SL. Insight on Methane Foam Stability and Texture via Adsorption of Surfactants on Oppositely Charged Nanoparticles. Langmuir 2018; 34:14274-14285. [PMID: 30372614 DOI: 10.1021/acs.langmuir.8b01966] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We report the phase behavior of a dispersion of alumina-coated silica nanoparticles in the presence of an anionic surfactant (sodium fatty alcohol polyoxyethylene ether sulfate), and then describe the influence of surfactant/nanoparticle concentration ratio on the stability of methane foam as a potential fluid for enhanced oil recovery application. The surface tension of the methane/aqueous phase interface, surface charge, and size of the particle aggregates and amount of surfactant adsorption were characterized as a function of surfactant/nanoparticle ratio. Five adsorption stages, which are described in terms of the extent and type of the surfactant coverage on the nanoparticle surface, explain the behavior of the solution at different surfactant/nanoparticle ratios. The static foam generation experiments were conducted to monitor the variation of the foam stability and texture over the defined adsorption stages. The surface tension trends illustrate that the affinity of nanoparticles for the gas-liquid interface is strongly affected by the adsorption extent of AES molecules on the particle surface. At high surfactant/nanoparticle ratio, the adsorbed surfactant bilayer causes a high hydrophilicity of the particles that significantly pushed the particles away from the gas-liquid interface. At the most hydrophobic state of the particles which occurred at the ratio of 0.2, the foam structure collapsed quickly. The most stable foam with fine texture was found at surfactant/nanoparticle ratio less than 0.008 at which the particles are partially covered with surfactants and have smaller aggregate size. The findings provide a better understanding of the interaction between oppositely charged nanoparticle/surfactant pairs and how that interaction affects foam stability. It is demonstrated that substitution of absolute concentration by surfactant/nanoparticle ratio can truly govern the foam stability and texture. The results can be beneficial to predict the foam behavior in its numerous applications and whether interactions will be synergistic, antagonistic, or neutral.
Collapse
Affiliation(s)
- Mina Doroudian Rad
- Department of Chemical and Petroleum Engineering , University of Calgary , Calgary T2N 1N4 , Canada
| | - Ali Telmadarreie
- Department of Chemical and Petroleum Engineering , University of Calgary , Calgary T2N 1N4 , Canada
| | - Long Xu
- Department of Chemical and Petroleum Engineering , University of Calgary , Calgary T2N 1N4 , Canada
- School of Petroleum Engineering , China University of Petroleum , Qingdao 266580 , P. R. China
| | - Mingzhe Dong
- Department of Chemical and Petroleum Engineering , University of Calgary , Calgary T2N 1N4 , Canada
| | - Steven L Bryant
- Department of Chemical and Petroleum Engineering , University of Calgary , Calgary T2N 1N4 , Canada
| |
Collapse
|
15
|
Jahandideh H, Ganjeh-Anzabi P, Bryant SL, Trifkovic M. The Significance of Graphene Oxide-Polyacrylamide Interactions on the Stability and Microstructure of Oil-in-Water Emulsions. Langmuir 2018; 34:12870-12881. [PMID: 30266070 DOI: 10.1021/acs.langmuir.8b02288] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The emulsification of oil in water by nanoparticles can be facilitated by the addition of costabilizers, such as polymers and surfactants. The enhanced properties of the resulting emulsions are usually attributed to nanoparticle/costabilizer synergy; however, the mechanism of this synergistic effect and its impacts on emulsion stability and microstructure remain unclear. Here, we study the synergistic interaction of graphene oxide (GO) and a high molecular weight anionic polyacrylamide (PAM) in stabilization of paraffin oil/water emulsion systems. We show that the addition of PAM reduces the amount of GO required to stabilize an emulsion significantly. In order to probe the synergistic effect of GO and PAM, we analytically analyze the oil-free GO and GO-PAM dispersions and directly image their morphology via Cryo-TEM and atomic force microscopy (AFM). X-ray diffraction results confirm the adsorption of PAM molecules onto GO sheets resulting in the formation of ultimate GO-PAM complexes. The adsorption phenomenon is a consequence of hydrogen bonding and acid-base interactions, conceivably leading to a resilient electron-donor-acceptor complex. The microstructure of emulsions is captured with two-color fluorescent microscopy and Cryo-TEM. The acquired images display the localization of GO-PAM complexes at the interface while large amount of GO-PAM flocs coexist at the interface and in between oil droplets. Localization of such complexes and flocs at the interface is found to be responsible for their slow creaming rates compared to their GO counterparts. Mechanical properties of both dispersions and emulsions are studied by shear rheology. Rheological measurements confirm that GO-PAM complexes have a higher desorption energy from the interface resulting in higher critical shear strain of GO-PAM emulsions. The results, with insights into both structure and rheology, form a foundational understanding for integration of other polymers and nanoparticles in emulsion systems, which enables efficient design of these systems for an application of interest.
Collapse
Affiliation(s)
- Heidi Jahandideh
- Department of Chemical and Petroleum Engineering , University of Calgary , 2500 University Drive N.W. , Calgary , Canada
| | - Pejman Ganjeh-Anzabi
- Department of Chemical and Petroleum Engineering , University of Calgary , 2500 University Drive N.W. , Calgary , Canada
| | - Steven L Bryant
- Department of Chemical and Petroleum Engineering , University of Calgary , 2500 University Drive N.W. , Calgary , Canada
| | - Milana Trifkovic
- Department of Chemical and Petroleum Engineering , University of Calgary , 2500 University Drive N.W. , Calgary , Canada
| |
Collapse
|
16
|
Derakhshandeh M, Pilapil BK, Workman B, Trifkovic M, Bryant SL. Analysis of network formation and long-term stability in silica nanoparticle stabilized emulsions. Soft Matter 2018; 14:4268-4277. [PMID: 29557446 DOI: 10.1039/c7sm02457f] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Emulsions are widely used in industrial applications, including in food sciences, cosmetics, and enhanced oil recovery. For these industries, an in depth understanding of the stability and rheological properties of emulsions under both static and dynamic conditions is vital to their successful application. Presented here is a thorough assessment of a model nanoparticle (NP) stabilized dodecane-in-water emulsion as a route to improved understanding of the relationship between NP properties, microstructure and droplet-droplet interactions on the stability and rheological properties of emulsions. Emulsions are obtained here with low NP loadings without the need for added electrolyte through the use of an optimized silica NP (SNP) surface modification procedure. The prepared emulsions were characterized via optical microscopy, cryo-scanning electron microscopy (cryo-SEM), zeta potential analysis and laser scanning confocal microscopy (LSCM), enabling quantification of the emulsion droplet size, SNP interfacial coverage/morphology and surface charge. The correlation of these properties with the rheology of the emulsions is investigated through small amplitude oscillatory shear experiments which provide significant insight into the origins of the emulsions' rheological behavior and their stability. In addition, long-term stability, droplet-droplet network formation and microstructural evolution are found to be readily detectable shortly after preparation through measured progression of the emulsion's rheological properties.
Collapse
Affiliation(s)
- Maziar Derakhshandeh
- University of Calgary, Department of Chemical and Petroleum Engineering, 2500 University Dr NW Calgary, AB T2N 1N4, Canada.
| | - Brandy K Pilapil
- University of Calgary, Department of Chemical and Petroleum Engineering, 2500 University Dr NW Calgary, AB T2N 1N4, Canada.
| | - Ben Workman
- University of Calgary, Department of Chemical and Petroleum Engineering, 2500 University Dr NW Calgary, AB T2N 1N4, Canada.
| | - Milana Trifkovic
- University of Calgary, Department of Chemical and Petroleum Engineering, 2500 University Dr NW Calgary, AB T2N 1N4, Canada.
| | - Steven L Bryant
- University of Calgary, Department of Chemical and Petroleum Engineering, 2500 University Dr NW Calgary, AB T2N 1N4, Canada.
| |
Collapse
|
17
|
Sebastian HB, Mayall RM, Pilonieta RJ, Bryant SL. An Inexpensive, Single Use Carbon-Based Sensor for the Rapid and Early Detection of Hydrocarbon Leaks. ACS Sens 2017; 2:757-765. [PMID: 28723113 DOI: 10.1021/acssensors.7b00112] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A novel fabrication process for a single use, low-cost organic solvent sensor has been developed. The process is simple, and the materials are readily available. Carbon nanomaterials are self-assembled at a water/hexane interface, where the hexane phase contains dissolved paraffin wax. Upon the controlled evaporation of hexane, the paraffin wax precipitates, trapping the carbon nanoparticles at the surface in a paraffin wax backbone, realizing a carbon-nanoparticle-decorated film. The film is hydrophobic and highly electrically conductive. When exposed to hydrocarbons or a mixture of hydrocarbons, the conductive carbon network deteriorates and an increase in film resistivity is monitored. The rate of change in resistivity is proportional to the concentration and composition of organic molecules in contact with the film.
Collapse
Affiliation(s)
- H. Bri Sebastian
- University of Calgary, 2500 University Drive NW, Calgary, AB T2N
1N4, Canada
| | - Robert M. Mayall
- University of Calgary, 2500 University Drive NW, Calgary, AB T2N
1N4, Canada
| | | | - Steven L. Bryant
- University of Calgary, 2500 University Drive NW, Calgary, AB T2N
1N4, Canada
| |
Collapse
|
18
|
Sebastian HB, Bryant SL. Self-assembly of an electronically conductive network through microporous scaffolds. J Colloid Interface Sci 2017; 496:505-512. [PMID: 28259016 DOI: 10.1016/j.jcis.2017.02.042] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Accepted: 02/17/2017] [Indexed: 11/27/2022]
Abstract
Electron transfer spanning significant distances through a microporous structure was established via the self-assembly of an electronically conductive iridium oxide nanowire matrix enveloping the pore walls. Microporous formations were simulated using two scaffold materials of varying physical and chemical properties; paraffin wax beads, and agar gel. Following infiltration into the micropores, iridium nanoparticles self-assembled at the pore wall/ethanol interface. Subsequently, cyclic voltammetry was employed to electrochemically crosslink the metal, erecting an interconnected, and electronically conductive metal oxide nanowire matrix. Electrochemical and spectral characterization techniques confirmed the formation of oxide nanowire matrices encompassing lengths of at least 1.6mm, 400× distances previously achieved using iridium nanoparticles. Nanowire matrices were engaged as biofuel cell anodes, where electrons were donated to the nanowires by a glucose oxidizing enzyme.
Collapse
Affiliation(s)
- H Bri Sebastian
- University of Calgary, Department of Chemical and Petroleum Engineering, 2500 University Dr. NW, Calgary, AB T2N 1N4, Canada.
| | - Steven L Bryant
- University of Calgary, Department of Chemical and Petroleum Engineering, 2500 University Dr. NW, Calgary, AB T2N 1N4, Canada.
| |
Collapse
|
19
|
Pilapil BK, Jahandideh H, Bryant SL, Trifkovic M. Stabilization of Oil-in-Water Emulsions with Noninterfacially Adsorbed Particles. Langmuir 2016; 32:7109-7116. [PMID: 27351486 DOI: 10.1021/acs.langmuir.6b00873] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Classical (surfactant stabilized) and Pickering (particle stabilized) type emulsions have been widely studied to elucidate the mechanisms by which emulsion stabilization is achieved. In Pickering emulsions, a key defining factor is that the stabilizing particles reside at the liquid-liquid interface providing a mechanical barrier to droplet coalescence. This interfacial adsorption is achieved through the use of nanoparticles that are partially wet by both liquid phases, often through covalent surface modification of or surfactant adsorption to the nanoparticle surfaces. Herein, we demonstrate particle-induced stabilization of an oil-in-water emulsion with fully water wet nanoparticles (no interfacial adsorption) via synergistic interaction with low concentrations of surfactants. Laser scanning confocal microscopy analysis allows for unique and vital insights into the properties of these emulsions via both three-dimensional imaging and real-time monitoring of particle dynamics at the oil-water interface. Investigation of these "non-Pickering" particle stabilized emulsions suggests that the nonadsorbed particles impart stability to the emulsion primarily via entropic forces imparted by the accumulation of silica nanoparticles in the coherent phase between dispersed oil droplets.
Collapse
Affiliation(s)
- Brandy K Pilapil
- Department of Chemical and Petroleum Engineering, University of Calgary , 2500 University Dr. NW, Calgary, AB T2N 1N4, Canada
| | - Heidi Jahandideh
- Department of Chemical and Petroleum Engineering, University of Calgary , 2500 University Dr. NW, Calgary, AB T2N 1N4, Canada
| | - Steven L Bryant
- Department of Chemical and Petroleum Engineering, University of Calgary , 2500 University Dr. NW, Calgary, AB T2N 1N4, Canada
| | - Milana Trifkovic
- Department of Chemical and Petroleum Engineering, University of Calgary , 2500 University Dr. NW, Calgary, AB T2N 1N4, Canada
| |
Collapse
|
20
|
|
21
|
Yoon KY, Xue Z, Fei Y, Lee JH, Cheng V, Bagaria HG, Huh C, Bryant SL, Kong SD, Ngo VW, Rahmani AR, Ahmadian M, Ellison CJ, Johnston KP. Control of magnetite primary particle size in aqueous dispersions of nanoclusters for high magnetic susceptibilities. J Colloid Interface Sci 2016; 462:359-67. [DOI: 10.1016/j.jcis.2015.09.058] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Revised: 09/23/2015] [Accepted: 09/23/2015] [Indexed: 01/12/2023]
|
22
|
Prigiobbe V, Worthen AJ, Johnston KP, Huh C, Bryant SL. Transport of Nanoparticle-Stabilized CO $$_2$$ 2 -Foam in Porous Media. Transp Porous Media 2015. [DOI: 10.1007/s11242-015-0593-7] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
23
|
Bhandari AR, Flemings PB, Polito PJ, Cronin MB, Bryant SL. Erratum to: Anisotropy and Stress Dependence of Permeability in the Barnett Shale. Transp Porous Media 2015. [DOI: 10.1007/s11242-015-0501-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
|
24
|
Bhandari AR, Flemings PB, Polito PJ, Cronin MB, Bryant SL. Anisotropy and Stress Dependence of Permeability in the Barnett Shale. Transp Porous Media 2015. [DOI: 10.1007/s11242-015-0482-0] [Citation(s) in RCA: 138] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
25
|
Prigiobbe V, Ko S, Huh C, Bryant SL. Measuring and modeling the magnetic settling of superparamagnetic nanoparticle dispersions. J Colloid Interface Sci 2015; 447:58-67. [PMID: 25700211 DOI: 10.1016/j.jcis.2015.01.056] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Revised: 01/08/2015] [Accepted: 01/20/2015] [Indexed: 02/05/2023]
Abstract
In this paper, we present settling experiments and mathematical modeling to study the magnetic separation of superparamagnetic iron-oxide nanoparticles (SPIONs) from a brine. The experiments were performed using SPIONs suspensions of concentration between 3 and 202g/L dispersed in water and separated from the liquid under the effect of a permanent magnet. A 1D model was developed in the framework of the sedimentation theory with a conservation law for SPIONs and a mass flux function based on the Newton's law for motion in a magnetic field. The model describes both the hindering effect of suspension concentration (n) during settling due to particle collisions and the increase in settling rate due to the attraction of the SPIONs towards the magnet. The flux function was derived from the settling experiments and the numerical model validated against the analytical solution and the experimental data. Suspensions of SPIONs were of 2.8cm initial height, placed on a magnet, and monitored continuously with a digital camera. Applying a magnetic field of 0.5T of polarization, the SPION's velocity was of approximately 3·10(-5)m/s close to the magnet and decreases of two orders of magnitude across the domain. The process was characterized initially by a classical sedimentation behavior, i.e., an upper interface between the clear water and the suspension slowly moving towards the magnet and a lower interface between the sediment layer and the suspension moving away from the magnet. Subsequently, a rapid separation of nanoparticle occured suggesting a non-classical settling phenomenon induced by magnetic forces which favor particle aggregation and therefore faster settling. The rate of settling decreased with n and an optimal condition for fast separation was found for an initial n of 120g/L. The model agrees well with the measurements in the early stage of the settling, but it fails to describe the upper interface movement during the later stage, probably because of particle aggregation induced by magnetization which is not accounted for in the model.
Collapse
Affiliation(s)
- Valentina Prigiobbe
- Department of Petroleum and Geosystems Engineering, The University of Texas at Austin, 200 E. Dean Keeton St., C0300, Austin, 78712 TX, USA.
| | - Saebom Ko
- Department of Petroleum and Geosystems Engineering, The University of Texas at Austin, 200 E. Dean Keeton St., C0300, Austin, 78712 TX, USA
| | - Chun Huh
- Department of Petroleum and Geosystems Engineering, The University of Texas at Austin, 200 E. Dean Keeton St., C0300, Austin, 78712 TX, USA
| | - Steven L Bryant
- Department of Chemical and Petroleum Engineering, University of Calgary, 2500 University Dr. NW, Calgary T2N 1N4, Canada(1)
| |
Collapse
|
26
|
Dong J, Worthen AJ, Foster LM, Chen Y, Cornell KA, Bryant SL, Truskett TM, Bielawski CW, Johnston KP. Modified montmorillonite clay microparticles for stable oil-in-seawater emulsions. ACS Appl Mater Interfaces 2014; 6:11502-11513. [PMID: 24932773 DOI: 10.1021/am502187t] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Environmentally benign clay particles are of great interest for the stabilization of Pickering emulsions. Dodecane-in-synthetic seawater (SSW) emulsions formed with montmorillonite (MMT) clay microparticles modified with bis(2-hydroxyethyl)oleylamine were stable against coalescence, even at clay concentrations down to 0.1% w/v. Remarkably, as little as 0.001% w/v surfactant lowered the hydrophilicity of the clay to a sufficient level for stabilization of oil-in-SSW emulsions. The favorable effect of SSW on droplet size reduction and emulsion stability enhancement is hypothesized to be due to reduced electrostatic repulsion between adsorbed clay particles and a consequent increase in the continuous phase (an aqueous clay suspension) viscosity. Water/oil (W/O) emulsions were inverted to O/W either by decreasing the mass ratio of surfactant-to-clay (transitional inversion) or by increasing the water volume fraction (catastrophic inversion). For both types of emulsions, coalescence was minimal and the sedimentation or creaming was highly correlated with the droplet size. For catastrophic inversions, the droplet size of the emulsions was smaller in the case of the preferred curvature. Suspensions of concentrated clay in oil dispersions in the presence of surfactant were stable against settling. The mass transfer pathways during emulsification of oil containing the clay particles were analyzed on the droplet size/stability phase diagrams to provide insight for the design of dispersant systems for remediating surface and subsurface oceanic oil spills.
Collapse
Affiliation(s)
- Jiannan Dong
- McKetta Department of Chemical Engineering, ‡Department of Chemistry and Biochemistry, and §Department of Petroleum and Geosystems Engineering, The University of Texas at Austin , Austin, Texas 78712-0231, United States
| | | | | | | | | | | | | | | | | |
Collapse
|
27
|
Prigiobbe V, Bryant SL. pH-dependent transport of metal cations in porous media. Environ Sci Technol 2014; 48:3752-3759. [PMID: 24564735 DOI: 10.1021/es403695r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We study the effect of pH-dependent adsorption and hydrodynamic dispersion on cation transport through a reactive porous medium with a hydrophilic surface. We investigate how competitive adsorption between a proton and a metal (which in some situations of practical interest may also be a radionuclide) can facilitate the migration of a certain fraction of the latter. We performed laboratory experiments using a chromatographic column filled with silica beads coated with iron oxide and flooded initially with an acidic solution (pH ≈ 3) and then with an alkaline solution (pH > 7) containing either sodium, potassium, lithium, calcium, magnesium, or barium. The composition of each injected solution was chosen to represent one of two possible theoretical predictions, either a retarded shock and a fast pulse, that is, traveling at the interstitial fluid velocity, or only a retarded shock. Highly resolved breakthrough curves measured with inline ion chromatography allowed us to observe in all cases agreement with theoretical predictions, including numerous observations of a fast pulse. The fast pulse is the result of the interaction between pH-dependent adsorption and hydrodynamic dispersion and has previously been observed in systems with strontium. Here, we show the fast pulse arises also in the case of other cations allowing a generalization of the physical mechanism underlying this phenomenon and consideration of it as a new fast transport behavior. A one-dimensional reactive transport model for an incompressible fluid was developed combining surface complexation with mass conservation equations for a solute and the acidity (difference between the total proton and hydroxide concentration). In all cases, the model agrees with the measurements capturing the underlying physics of the overall transport behavior. Our results suggest that the interplay between pH-dependent adsorption and hydrodynamic dispersion can give rise to the rapid migration of metals through reactive porous media with potential effects on, for example, the performance of subsurface engineering infrastructures for pollutant containment, the mobilization of metal contaminants by brine acidified upon contact with CO2 during geologic carbon storage, and the chromatographic separation processes in industrial applications.
Collapse
Affiliation(s)
- Valentina Prigiobbe
- Department of Petroleum and Geosystems Engineering, The University of Texas at Austin , Austin, Texas 78712-1186, United States
| | | |
Collapse
|
28
|
Worthen AJ, Foster LM, Dong J, Bollinger JA, Peterman AH, Pastora LE, Bryant SL, Truskett TM, Bielawski CW, Johnston KP. Synergistic formation and stabilization of oil-in-water emulsions by a weakly interacting mixture of zwitterionic surfactant and silica nanoparticles. Langmuir 2014; 30:984-94. [PMID: 24409832 DOI: 10.1021/la404132p] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Oil-in-water emulsions were formed and stabilized at low amphiphile concentrations by combining hydrophilic nanoparticles (NPs) (i.e., bare colloidal silica) with a weakly interacting zwitterionic surfactant, caprylamidopropyl betaine, to generate a high hydrophilic-lipophilic balance. The weak interaction of the NPs with surfactant was quantified with contact angle measurements. Emulsions were characterized by static light scattering to determine the droplet size distributions, optical photography to quantify phase separation due to creaming, and both optical and electron microscopy to determine emulsion microstructure. The NPs and surfactant acted synergistically to produce finer emulsions with a greater stability to coalescence relative to the behavior with either NPs or surfactant alone. As a consequence of the weak adsorption of the highly hydrophilic surfactant on the anionic NPs along with the high critical micelle concentration, an unusually large surfactant concentration was available to adsorb at the oil-water interface and lower the interfacial tension. The synergy for emulsion formation and stabilization for the two amphiphiles was even greater in the case of a high-salinity synthetic seawater aqueous phase. Here, higher NP adsorption at the oil-water interface was caused by electrostatic screening of interactions between (1) NPs and the anionic oil-water interface and (2) between the NPs. This greater adsorption as well as partial flocculation of the NPs provided a more efficient barrier to droplet coalescence.
Collapse
Affiliation(s)
- Andrew J Worthen
- McKetta Department of Chemical Engineering, ‡Department of Chemistry and Biochemistry, and §Department of Petroleum and Geosystems Engineering, University of Texas at Austin , Austin, Texas 78712-0231, United States
| | | | | | | | | | | | | | | | | | | |
Collapse
|
29
|
|
30
|
Yoon KY, An SJ, Chen Y, Lee JH, Bryant SL, Ruoff RS, Huh C, Johnston KP. Graphene oxide nanoplatelet dispersions in concentrated NaCl and stabilization of oil/water emulsions. J Colloid Interface Sci 2013; 403:1-6. [DOI: 10.1016/j.jcis.2013.03.012] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2012] [Revised: 03/11/2013] [Accepted: 03/12/2013] [Indexed: 11/26/2022]
|
31
|
Affiliation(s)
- Andrew J. Worthen
- Dept. of Chemical Engineering; The University of Texas at Austin; Austin; TX; 78712
| | - Steven L. Bryant
- Dept. of Petroleum & Geosystems Engineering; The University of Texas at Austin; Austin; TX; 78712
| | - Chun Huh
- Dept. of Petroleum & Geosystems Engineering; The University of Texas at Austin; Austin; TX; 78712
| | - Keith P. Johnston
- Dept. of Chemical Engineering; The University of Texas at Austin; Austin; TX; 78712
| |
Collapse
|
32
|
Bagaria HG, Neilson BM, Worthen AJ, Xue Z, Yoon KY, Cheng V, Lee JH, Velagala S, Huh C, Bryant SL, Bielawski CW, Johnston KP. Adsorption of iron oxide nanoclusters stabilized with sulfonated copolymers on silica in concentrated NaCl and CaCl2 brine. J Colloid Interface Sci 2013; 398:217-26. [DOI: 10.1016/j.jcis.2013.01.056] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2012] [Accepted: 01/20/2013] [Indexed: 10/27/2022]
|
33
|
Bagaria HG, Yoon KY, Neilson BM, Cheng V, Lee JH, Worthen AJ, Xue Z, Huh C, Bryant SL, Bielawski CW, Johnston KP. Stabilization of iron oxide nanoparticles in high sodium and calcium brine at high temperatures with adsorbed sulfonated copolymers. Langmuir 2013; 29:3195-3206. [PMID: 23373590 DOI: 10.1021/la304496a] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
A series of sulfonated random and block copolymers were adsorbed on the surface of ~100 nm iron oxide (IO) nanoparticles (NPs) to provide colloidal stability in extremely concentrated brine composed of 8% wt NaCl + 2% wt CaCl2 (API brine; 1.4 M NaCl + 0.2 M CaCl2) at 90 °C. A combinatorial materials chemistry approach, which employed Ca(2+)-mediated adsorption of anionic acrylic acid-containing sulfonated polymers to preformed citrate-stabilized IO nanoclusters, enabled the investigation of a large number of polymer coatings. Initially a series of poly(2-methyl-2-acrylamidopropanesulfonate-co-acrylic acid) (poly(AMPS-co-AA)) (1:8 to 1:1 mol:mol), poly(styrenesulfonate-block-acrylic acid) (2.4:1 mol:mol), and poly(styrenesulfonate-alt-maleic acid) (3:1 mol:mol) copolymers were screened for solubility in API brine at 90 °C. The ratio of AMPS to AA groups was varied to balance the requirement of colloid dispersibility at high salinity (provided by AMPS) against the need for anchoring of the polymers to the iron oxide surface (via the AA). Steric stabilization of IO NPs coated with poly(AMPS-co-AA) (1:1 mol:mol) provided colloidal stability in API brine at room temperature and 90 °C for up to 1 month. The particles were characterized before and after coating at ambient and elevated temperatures by a variety of techniques including colloidal stability experiments, dynamic light scattering, zeta potential, and thermogravimetric analysis.
Collapse
Affiliation(s)
- Hitesh G Bagaria
- Department of Chemical Engineering, The University of Texas at Austin, Austin, Texas 78712, United States
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
34
|
Huerta NJ, Hesse MA, Bryant SL, Strazisar BR, Lopano CL. Experimental evidence for self-limiting reactive flow through a fractured cement core: implications for time-dependent wellbore leakage. Environ Sci Technol 2013; 47:269-275. [PMID: 22894832 DOI: 10.1021/es3013003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We present a set of reactive transport experiments in cement fractures. The experiments simulate coupling between flow and reaction when acidic, CO(2)-rich fluids flow along a leaky wellbore. An analog dilute acid with a pH between 2.0 and 3.15 was injected at constant rate between 0.3 and 9.4 cm/s into a fractured cement core. Pressure differential across the core and effluent pH were measured to track flow path evolution, which was analyzed with electron microscopy after injection. In many experiments reaction was restricted within relatively narrow, tortuous channels along the fracture surface. The observations are consistent with coupling between flow and dissolution/precipitation. Injected acid reacts along the fracture surface to leach calcium from cement phases. Ahead of the reaction front, high pH pore fluid mixes with calcium-rich water and induces mineral precipitation. Increases in the pressure differential for most experiments indicate that precipitation can be sufficient to restrict flow. Experimental data from this study combined with published field evidence for mineral precipitation along cemented annuli suggests that leakage of CO(2)-rich fluids along a wellbore may seal the leakage pathway if the initial aperture is small and residence time allows mobilization and precipitation of minerals along the fracture.
Collapse
Affiliation(s)
- Nicolas J Huerta
- Jackson School of Geosciences, The University of Texas at Austin, Austin, Texas 78712, United States.
| | | | | | | | | |
Collapse
|
35
|
Yoon KY, Li Z, Neilson BM, Lee W, Huh C, Bryant SL, Bielawski CW, Johnston KP. Effect of Adsorbed Amphiphilic Copolymers on the Interfacial Activity of Superparamagnetic Nanoclusters and the Emulsification of Oil in Water. Macromolecules 2012. [DOI: 10.1021/ma202511b] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
- Ki Youl Yoon
- Department of Chemical Engineering, University of Texas at Austin, Austin, Texas 78712,
United States
| | - Zicheng Li
- Department of Chemistry and Biochemistry, University of Texas at Austin, Austin, Texas 78712,
United States
| | - Bethany M. Neilson
- Department of Chemistry and Biochemistry, University of Texas at Austin, Austin, Texas 78712,
United States
| | - Wonjae Lee
- Department of Chemical Engineering, University of Texas at Austin, Austin, Texas 78712,
United States
| | - Chun Huh
- Department
of Petroleum and
Geosystems Engineering, University of Texas at Austin, Austin, Texas 78712, United States
| | - Steven L. Bryant
- Department
of Petroleum and
Geosystems Engineering, University of Texas at Austin, Austin, Texas 78712, United States
| | - Christopher W. Bielawski
- Department of Chemistry and Biochemistry, University of Texas at Austin, Austin, Texas 78712,
United States
| | - Keith P. Johnston
- Department of Chemical Engineering, University of Texas at Austin, Austin, Texas 78712,
United States
| |
Collapse
|
36
|
Yoon KY, Kotsmar C, Ingram DR, Huh C, Bryant SL, Milner TE, Johnston KP. Stabilization of superparamagnetic iron oxide nanoclusters in concentrated brine with cross-linked polymer shells. Langmuir 2011; 27:10962-10969. [PMID: 21728368 DOI: 10.1021/la2006327] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Iron oxide nanoparticles, in the form of sub-100-nm clusters, were synthesized in the presence of poly(acrylic acid) (PAA) or poly(styrene sulfonate-alt-maleic acid) (PSS-alt-MA) to provide electrosteric stabilization. The superparamagnetic nanoclusters were characterized using a superconducting quantum interference device (SQUID), transmission electron microscopy (TEM), dynamic light scattering (DLS), thermogravimetric analysis (TGA), and zeta potential measurements. To anchor the polymer shell on the nanoparticle surface, the polymer was cross-linked for a range of cross-linking densities. For nanoclusters with only 12% (w/w) PSS-alt-MA, electrosteric stabilization was sufficient even in 8 wt % NaCl. For PAA, the cross-linked polymer shell was essentially permanent and did not desorb even upon dilution of the nanoparticles for iron oxide concentrations down to 0.014 wt %. Without cross-linking, over half of the polymer desorbed from the particle surfaces. This general approach of the adsorption of polymer stabilizers onto nanoparticles followed by cross-linking may be utilized for a wide variety of cross-linkable polymers without the need to form covalent bonds between the nanoparticles and polymer stabilizer. Thus, this cross-linking approach is an efficient and inexpensive method of stabilizing nanoparticles for large-scale applications, including the electromagnetic imaging of subsurface reservoirs, even at high salinity.
Collapse
Affiliation(s)
- Ki Youl Yoon
- Department of Chemical Engineering, University of Texas at Austin, Austin, Texas 78712, USA
| | | | | | | | | | | | | |
Collapse
|
37
|
|
38
|
|
39
|
Kotsmar C, Yoon KY, Yu H, Ryoo SY, Barth J, Shao S, Prodanović M, Milner TE, Bryant SL, Huh C, Johnston KP. Stable Citrate-Coated Iron Oxide Superparamagnetic Nanoclusters at High Salinity. Ind Eng Chem Res 2010. [DOI: 10.1021/ie1010965] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- Csaba Kotsmar
- Department of Chemical Engineering, University of Texas at Austin, Austin, Texas 78712, United States, Department of Petroleum and Geosystems Engineering, University of Texas at Austin, Austin, Texas 78712, United States, Department of Biomedical Engineering, University of Texas at Austin, Austin, Texas 78712, United States, and College of Engineering, Michigan State University, East Lansing, Michigan 48825, United States
| | - Ki Youl Yoon
- Department of Chemical Engineering, University of Texas at Austin, Austin, Texas 78712, United States, Department of Petroleum and Geosystems Engineering, University of Texas at Austin, Austin, Texas 78712, United States, Department of Biomedical Engineering, University of Texas at Austin, Austin, Texas 78712, United States, and College of Engineering, Michigan State University, East Lansing, Michigan 48825, United States
| | - Haiyang Yu
- Department of Chemical Engineering, University of Texas at Austin, Austin, Texas 78712, United States, Department of Petroleum and Geosystems Engineering, University of Texas at Austin, Austin, Texas 78712, United States, Department of Biomedical Engineering, University of Texas at Austin, Austin, Texas 78712, United States, and College of Engineering, Michigan State University, East Lansing, Michigan 48825, United States
| | - Seung Yup Ryoo
- Department of Chemical Engineering, University of Texas at Austin, Austin, Texas 78712, United States, Department of Petroleum and Geosystems Engineering, University of Texas at Austin, Austin, Texas 78712, United States, Department of Biomedical Engineering, University of Texas at Austin, Austin, Texas 78712, United States, and College of Engineering, Michigan State University, East Lansing, Michigan 48825, United States
| | - Joseph Barth
- Department of Chemical Engineering, University of Texas at Austin, Austin, Texas 78712, United States, Department of Petroleum and Geosystems Engineering, University of Texas at Austin, Austin, Texas 78712, United States, Department of Biomedical Engineering, University of Texas at Austin, Austin, Texas 78712, United States, and College of Engineering, Michigan State University, East Lansing, Michigan 48825, United States
| | - Stephen Shao
- Department of Chemical Engineering, University of Texas at Austin, Austin, Texas 78712, United States, Department of Petroleum and Geosystems Engineering, University of Texas at Austin, Austin, Texas 78712, United States, Department of Biomedical Engineering, University of Texas at Austin, Austin, Texas 78712, United States, and College of Engineering, Michigan State University, East Lansing, Michigan 48825, United States
| | - Maša Prodanović
- Department of Chemical Engineering, University of Texas at Austin, Austin, Texas 78712, United States, Department of Petroleum and Geosystems Engineering, University of Texas at Austin, Austin, Texas 78712, United States, Department of Biomedical Engineering, University of Texas at Austin, Austin, Texas 78712, United States, and College of Engineering, Michigan State University, East Lansing, Michigan 48825, United States
| | - Thomas E. Milner
- Department of Chemical Engineering, University of Texas at Austin, Austin, Texas 78712, United States, Department of Petroleum and Geosystems Engineering, University of Texas at Austin, Austin, Texas 78712, United States, Department of Biomedical Engineering, University of Texas at Austin, Austin, Texas 78712, United States, and College of Engineering, Michigan State University, East Lansing, Michigan 48825, United States
| | - Steven L. Bryant
- Department of Chemical Engineering, University of Texas at Austin, Austin, Texas 78712, United States, Department of Petroleum and Geosystems Engineering, University of Texas at Austin, Austin, Texas 78712, United States, Department of Biomedical Engineering, University of Texas at Austin, Austin, Texas 78712, United States, and College of Engineering, Michigan State University, East Lansing, Michigan 48825, United States
| | - Chun Huh
- Department of Chemical Engineering, University of Texas at Austin, Austin, Texas 78712, United States, Department of Petroleum and Geosystems Engineering, University of Texas at Austin, Austin, Texas 78712, United States, Department of Biomedical Engineering, University of Texas at Austin, Austin, Texas 78712, United States, and College of Engineering, Michigan State University, East Lansing, Michigan 48825, United States
| | - Keith P. Johnston
- Department of Chemical Engineering, University of Texas at Austin, Austin, Texas 78712, United States, Department of Petroleum and Geosystems Engineering, University of Texas at Austin, Austin, Texas 78712, United States, Department of Biomedical Engineering, University of Texas at Austin, Austin, Texas 78712, United States, and College of Engineering, Michigan State University, East Lansing, Michigan 48825, United States
| |
Collapse
|
40
|
Ingram DR, Kotsmar C, Yoon KY, Shao S, Huh C, Bryant SL, Milner TE, Johnston KP. Superparamagnetic nanoclusters coated with oleic acid bilayers for stabilization of emulsions of water and oil at low concentration. J Colloid Interface Sci 2010; 351:225-32. [PMID: 20719327 DOI: 10.1016/j.jcis.2010.06.048] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2010] [Revised: 06/16/2010] [Accepted: 06/18/2010] [Indexed: 11/28/2022]
Abstract
Emulsions of water and dodecane with drop sizes down to 1 microm were stabilized with 30-100 nm interfacially active nanoclusters of sub-15 nm iron oxide primary particles at an extremely low loading of 0.14 wt.%. The nanoclusters, coated with a bilayer of oleic acid, formed stable dispersions in water at pH 7-10. The phase behavior and droplet morphologies of the emulsions of water and dodecane were tuned with pH. The oil/water emulsions at pH 9-10 were converted to middle phase emulsions at pH 6-7 and water/oil emulsions as the pH was further lowered. The magnetization per gram of Fe is similar for the nanoclusters and the primary particles, indicating the spacing between the particles is sufficient to avoid magnetic coupling. The larger volume of nanoclusters relative to the individual primary particles is beneficial for magnetomotive sensing applications including imaging of oil reservoirs, as it increases the force on the particles for a given magnetic field.
Collapse
|
41
|
|
42
|
|
43
|
Nicot JP, Oldenburg CM, Bryant SL, Hovorka SD. Pressure perturbations from geologic carbon sequestration: Area-of-review boundaries and borehole leakage driving forces. ACTA ACUST UNITED AC 2009. [DOI: 10.1016/j.egypro.2009.01.009] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
|
44
|
|
45
|
Prodanović M, Bryant SL. A level set method for determining critical curvatures for drainage and imbibition. J Colloid Interface Sci 2006; 304:442-58. [PMID: 17027812 DOI: 10.1016/j.jcis.2006.08.048] [Citation(s) in RCA: 157] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2006] [Revised: 08/20/2006] [Accepted: 08/23/2006] [Indexed: 11/22/2022]
Abstract
An accurate description of the mechanics of pore level displacement of immiscible fluids could significantly improve the predictions from pore network models of capillary pressure-saturation curves, interfacial areas and relative permeability in real porous media. If we assume quasi-static displacement, at constant pressure and surface tension, pore scale interfaces are modeled as constant mean curvature surfaces, which are not easy to calculate. Moreover, the extremely irregular geometry of natural porous media makes it difficult to evaluate surface curvature values and corresponding geometric configurations of two fluids. Finally, accounting for the topological changes of the interface, such as splitting or merging, is nontrivial. We apply the level set method for tracking and propagating interfaces in order to robustly handle topological changes and to obtain geometrically correct interfaces. We describe a simple but robust model for determining critical curvatures for throat drainage and pore imbibition. The model is set up for quasi-static displacements but it nevertheless captures both reversible and irreversible behavior (Haines jump, pore body imbibition). The pore scale grain boundary conditions are extracted from model porous media and from imaged geometries in real rocks. The method gives quantitative agreement with measurements and with other theories and computational approaches.
Collapse
Affiliation(s)
- Masa Prodanović
- Institute for Computational Engineering and Sciences, University of Texas at Austin, 1 University Station, C0200 Austin, TX 78712, USA.
| | | |
Collapse
|
46
|
|
47
|
Affiliation(s)
- Steven L. Bryant
- Center for Subsurface ModelingC0200, Texas Institute for Computational and Applied Mathematics, The University of Texas, Austin, Texas 78712, and CWI, Amsterdam, The Netherlands
| | - Clint Dawson
- Center for Subsurface ModelingC0200, Texas Institute for Computational and Applied Mathematics, The University of Texas, Austin, Texas 78712, and CWI, Amsterdam, The Netherlands
| | - Cornelius J. van Duijn
- Center for Subsurface ModelingC0200, Texas Institute for Computational and Applied Mathematics, The University of Texas, Austin, Texas 78712, and CWI, Amsterdam, The Netherlands
| |
Collapse
|
48
|
Bryant SL. Information services for primary care: the organizational culture of general practice and the information needs of partnerships and primary care groups. Health Libr Rev 1999; 16:157-65. [PMID: 10620850 DOI: 10.1046/j.1365-2532.1999.00223.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In a primary-care led National Health Service it is imperative for librarians not only to develop user-centred services for health professionals based in the community but also to facilitate information management within Primary Care Groups. In this article recent research in the field is discussed, and challenges intrinsic to delivering information services to primary care are identified. Drawing on the experience of one Practice Librarian in the Aylesbury area, the importance of organizational culture is considered, along with its implications for making successful approaches to partnerships. Five factors that motivated these practices to contract the services of an independent librarian are identified. The information needs of Primary Care Groups are discussed and the essential characteristics of future service provision are noted.
Collapse
|
49
|
Abstract
OBJECTIVE The present study compared reported histories and severity of child sexual abuse, child physical abuse, and both, in college men and women. METHOD Four hundred and eighty-six consenting undergraduates completed measures of suicidality, sexual abuse (SA), and physical abuse (PA). Based on their responses, they were categorized into 12 mutually exclusive groups: no PA/no SA (n = 234), moderate PA/no SA (n = 78), severe PA/no SA (n = 34), no PA/mild SA (n = 21), moderate PA/mild SA (n = 12), severe PA/mild SA (n = 5), no PA/moderate SA (n = 20), moderate PA/moderate SA (n = 15), and severe PA/moderate SA (n = 10). RESULTS Participants who reported both severe sexual and severe physical abuse reported more lifetime suicidality than participants who reported either mild sexual and/or physical abuse. Those who reported sexual abuse involving invasive sexual acts such as rape, and physical abuse involving behaviors that resulted in physical injury to the child, were more suicidal than those who reported less severe abuse. In addition, although combined sexual and physical abuse correlated with increased suicidality, unexpectedly, there was no interaction. Finally, women students endorsed more reasons for living than men and about the same level of suicidal ideas and global suicidality, despite a greater likelihood of having been abused. CONCLUSIONS The absence of an interaction between sexual and physical abuse suggests that this increased suicidality is additive rather than multiplicative. An implication is that college counseling personnel need to be aware of the suicidal risk of women and men students reporting either sexual or physical abuse.
Collapse
Affiliation(s)
- S L Bryant
- Department of Psychology, University of Southern Mississippi, Hattiesburg 39406-5025, USA
| | | |
Collapse
|
50
|
Abstract
Librarians and GPs share an interest in exploring different approaches to providing information to general practice and improving information management within it. Describing the aims, policy, collections, enquiries and services of three Practice Libraries in the Aylesbury area, this paper demonstrates that an information professional can make a significant impact on the management of printed information whilst facilitating access to external sources. A wealth of opportunities lie ahead for those willing to apply information handling skills to general practice. Medical librarians will need to strike a careful balance between providing direct access to sources and the development of information services tailored to meet the needs of primary health care workers.
Collapse
|