scholarly journals Functionalization and Modification of Bitumen by Silica Nanoparticles

2020 ◽  
Vol 10 (17) ◽  
pp. 6065
Author(s):  
Ainur Zhambolova ◽  
Anna Lisa Vocaturo ◽  
Yerbol Tileuberdi ◽  
Yerdos Ongarbayev ◽  
Paolino Caputo ◽  
...  
Keyword(s):  
Silica Nanoparticles ◽  
Rheological Properties ◽  
Crucial Role ◽  
Slight Improvement ◽  
Experimental Conditions ◽  
Alkyl Chains ◽  
Free Amine ◽  
Amine Groups ◽  
Significant Change

A study on the effect of silica nanoparticles (SNPs) dispersion in bitumen is herein reported. First, the size of the nanoparticles was finely tuned by controlling the experimental conditions during their synthesis, obtaining spherical SNPs with diameter ranging from 95 up to 900 nm. Subsequently, SNPs were embedded with peripheral amine groups by using APTES (3-aminopropyltriethoxysilane) as functionalized agent (NH2@SNP), and ultimately long alkyl chains were grafted by reacting the free amine with an alkylated aldehyde (C14N@SNP). All SNPs (ca. 1 wt%.) were dispersed in bitumen to probe their effect on the rheological properties of bitumen. No significant change in the thermorheological properties of bitumen was observed upon varying the size of the SNPs. Slight improvement was observed when using NH2@SNPs, while the best results were obtained by using C14N@SNPs, showing the crucial role that hydrophobic substituents play in bitumen binders which leads to significant improvements.

Interlaboratory Comparison on the Quantification of Total and Accessible Amine Groups on Silica Nanoparticles with qNMR and Optical Assays

2021 ◽  
Author(s):  
Filip Kunc ◽  
Nithiya Nirmalananthan-Budau ◽  
Bastian Rühle ◽  
Ying Sun ◽  
Linda J. Johnston ◽  
...  
Keyword(s):  
Silica Nanoparticles ◽  
Interlaboratory Comparison ◽  
Amine Groups

Super-Resolution Fluorescence Imaging of Arabidopsis thaliana Transfer Cell Wall Ingrowths using Pseudo-Schiff Labelling Adapted for the Use of Different Dyes

2020 ◽  
Vol 61 (10) ◽  
pp. 1775-1787
Author(s):  
Angus E Rae ◽  
Xiaoyang Wei ◽  
Neftali Flores-Rodriguez ◽  
David W McCurdy ◽  
David A Collings
Keyword(s):  
Plant Cell ◽  
Propidium Iodide ◽  
Cell Walls ◽  
Super Resolution ◽  
Plant Cell Walls ◽  
Free Amine ◽  
Resolution Imaging ◽  
Amine Groups ◽  
Schiff Reaction ◽  
Cell Wall Ingrowths

Abstract To understand plant growth and development, it is often necessary to investigate the organization of plant cells and plant cell walls. Plant cell walls are often fluorescently labeled for confocal imaging with the dye propidium iodide using a pseudo-Schiff reaction. This reaction binds free amine groups on dye molecules to aldehyde groups on cellulose that result from oxidation with periodic acid. We tested a range of fluorescent dyes carrying free amine groups for their ability to act as pseudo-Schiff reagents. Using the low-pH solution historically used for the Schiff reaction, these alternative dyes failed to label cell walls of Arabidopsis cotyledon vascular tissue as strongly as propidium iodide but replacing the acidic solution with water greatly improved fluorescence labeling. Under these conditions, rhodamine-123 provided improved staining of plant cell walls compared to propidium iodide. We also developed protocols for pseudo-Schiff labeling with ATTO 647N-amine, a dye compatible for super-resolution Stimulated Emission Depletion (STED) imaging. ATTO 647N-amine was used for super-resolution imaging of cell wall ingrowths that occur in phloem parenchyma transfer cells of Arabidopsis, structures whose small size is only slightly larger than the resolution limit of conventional confocal microscopy. Application of surface-rendering software demonstrated the increase in plasma membrane surface area as a consequence of wall ingrowth deposition and suggests that STED-based approaches will be useful for more detailed morphological analysis of wall ingrowth formation. These improvements in pseudo-Schiff labeling for conventional confocal microscopy and STED imaging will be broadly applicable for high-resolution imaging of plant cell walls.

Effect of blood pH and ischemia on kinetic constants for cerebral glucose transport

1983 ◽  
Vol 245 (4) ◽  
pp. E384-E390
Author(s):  
J. M. Yanushka ◽  
D. J. Costello ◽  
D. D. Gilboe
Keyword(s):  
Glucose Transport ◽  
Recovery Period ◽  
Kinetic Constants ◽  
Experimental Conditions ◽  
Control Value ◽  
Unidirectional Flux ◽  
Blood Ph ◽  
Glucose Flux ◽  
Net Flux ◽  
Significant Change

In 117 experiments, the isolated canine brain was subjected either to 4-min pulses with blood ranging from pH 6.8 to 7.8, 30 min of hypoxia (PaO2 30 mmHg or 40 mmHg), or 30 min of complete ischemia followed by 60 min of perfusion with normal oxygenated blood. Unidirectional and net glucose fluxes were measured under all experimental conditions, and kinetic constants were calculated for unidirectional transport at each pH and after ischemia. In brains perfused with blood having a PaO2 of 30 or 40 mmHg, we observed a 58 and a 55% increase, respectively, in the net flux; however, there was no significant change in the unidirectional flux either during hypoxia or during the recovery period. Exposure of the brains to blood with a pH of 6.8, 7.0, and 7.2 had no effect on the unidirectional flux; however, as pH was raised above 7.4 both the Km and Vmax increased, reaching a maximum of 12.06 +/- 2.34 mM and 2.38 +/- 0.28 mumol X g-1 X min-1, respectively, at pH 7.8. The V/K ratio was unchanged. After 30 min of ischemia, there was a significant change (P less than 0.05) in the Km of the unidirectional glucose transport process from a control value of 5.84 +/- 1.75 mM to 17.40 +/- 5.50. These studies suggest that unidirectional flux is impaired after ischemia due to a decrease in the carrier's affinity for glucose; however, the observed changes are apparently unrelated to a fall in tissue pH. A similar mechanism is believed to be responsible for the decrease in unidirectional glucose flux after hypoxia.

scholarly journals Evaluating the potential of surface-modified silica nanoparticles using internal olefin sulfonate for enhanced oil recovery

2019 ◽  
Vol 17 (3) ◽  
pp. 722-733 ◽  
Author(s):  
Afaque Ahmed ◽  
Ismail Mohd Saaid ◽  
Abdelazim Abbas Ahmed ◽  
Rashidah M. Pilus ◽  
Mirza Khurram Baig
Keyword(s):  
Silica Nanoparticles ◽  
Rheological Properties ◽  
Oil Recovery ◽  
Displacement Efficiency ◽  
Shear Rates ◽  
Oil Water ◽  
Core Flood ◽  
The Stability ◽  
Modified Silica Nanoparticles ◽  
Surface Modified

AbstractRecently, nanoparticles have proven to enhance oil recovery on the core-flood scale in challenging high-pressure high-temperature reservoirs. Nanomaterials generally appear to improve oil production through wettability alteration and reduction in interfacial tension between oil and water phases. Besides, they are environmentally friendly and cost-effective enhanced oil recovery techniques. Studying the rheological properties of nanoparticles is critical for field applications. The instability of nanoparticle dispersion due to aggregation is considered as an unfavorable phenomenon in nanofluid flooding while conducting an EOR process. In this study, wettability behavior and rheological properties of surface-treated silica nanoparticles using internal olefins sulfonates (IOS20–24 and IOS19–23), anionic surfactants were investigated. Surface modification effect on the stability of the colloidal solution in porous media and oil recovery was inspected. The rheology of pure and surface-treated silica nanoparticles was investigated using a HPHT rheometer. Morphology and particle size distributions of pure and coated silica nanoparticles were studied using a field emission scanning electron microscope. A series of core-flood runs was conducted to evaluate the oil recovery factor. The coated silica nanoparticles were found to alter rheological properties and exhibited a shear-thinning behavior as the stability of the coated silica nanoparticles could be improved considerably. At low shear rates, the viscosity slightly increases, and the opposite happens at higher shear rates. Furthermore, the surface-modified silica nanoparticles were found to alter the wettability of the aqueous phase into strongly water-wet by changing the contact angle from 80° to 3° measured against glass slides representing sandstone rocks. Oil–water IFT results showed that the surface treatment by surfactant lowered the oil–water IFT by 30%. Also, the viscosity of brine increased from 0.001 to 0.008 Pa s by introducing SiO2 nanoparticles to the aqueous phase for better displacement efficiency during chemical-assisted EOR. The core-flood experiments revealed that the ultimate oil recovery is increased by approximately 13% with a surfactant-coated silica nanofluid flood after the conventional waterflooding that proves the potential of smart nanofluids for enhancing oil recovery. The experimental results imply that the use of surfactant-coated nanoparticles in tertiary oil recovery could facilitate the displacement efficiency, alter the wettability toward more water-wet and avoid viscous fingering for stable flood front and additional oil recovery.

scholarly journals Synthesis of diamine functionalised graphene oxide and its application in the fabrication of electrically conducting reduced graphene oxide/polymer nanocomposite films

2020 ◽  
Vol 2 (10) ◽  
pp. 4702-4712
Author(s):  
Namrata Maslekar ◽  
Rabiatul A. Mat Noor ◽  
Rhiannon P. Kuchel ◽  
Yin Yao ◽  
Per B. Zetterlund ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Electrical Properties ◽  
Reduced Graphene Oxide ◽  
Polymer Nanocomposite ◽  
Nanocomposite Films ◽  
Electrically Conducting ◽  
Free Amine ◽  
Reduced Graphene ◽  
Amine Groups

The study focussed on synthesis of colloidally stable diamine functionalised graphene oxide (GO) with dangling free amine groups, and exhibited physicochemical and electrical properties of these functionalised sheets in a polymer-based nanocomposite.

Friction and Wear of Epoxy Composites Containing Silica Nanoparticles Grafted by Hyperbranched Aromatic Polyamide

2012 ◽  
Vol 20 (8) ◽  
pp. 673-682
Author(s):  
Ying Yu ◽  
Min Zhi Rong ◽  
Ming Qiu Zhang
Keyword(s):  
Silica Nanoparticles ◽  
Sliding Wear ◽  
Friction And Wear ◽  
Frictional Coefficient ◽  
Aromatic Polyamide ◽  
Epoxy Composites ◽  
Linear Polymers ◽  
Curing Mechanism ◽  
The Matrix ◽  
Amine Groups

Nano-sized SiO2 particles grafted with hyperbranched aromatic polyamide were employed as fillers for fabricating epoxy based composites. The hyperbranched aromatic polyamide was selected because its terminal amine groups could take part in the curing reaction of epoxy resin and covalently connect silica nanoparticles with the matrix. The experimental results proved the occurrence of this reaction, and indicated that the presence of the grafted SiO2 in epoxy does not change the overall curing mechanism of epoxy. In comparison to the composites filled with untreated nano-SiO2 particles, the composites with the grafted nano-SiO2 exhibited significantly improved sliding wear resistance and reduced frictional coefficient owing to the strong filler/matrix interfacial bonding. Moreover, hyperbranched aromatic polyamide grafted nano-SiO2 was more effective to enhance tribological properties of epoxy than linear polymers grafted versions.

Tuning the structure, thermal stability and rheological properties of liquid crystal phases via the addition of silica nanoparticles

2019 ◽  
Vol 21 (46) ◽  
pp. 25649-25657 ◽  
Author(s):  
Joshua B. Marlow ◽  
Thomas M. McCoy ◽  
Cat Q. Ho ◽  
Liliana de Campo ◽  
Robert Knott ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Liquid Crystal ◽  
Light Microscopy ◽  
Surface Chemistry ◽  
Silica Nanoparticles ◽  
Rheological Properties ◽  
Small Angle ◽  
Angle Scattering ◽  
Liquid Crystal System ◽  
Crystal Phases

The effects of adding silica nanoparticles of varying size and surface chemistry to a liquid crystal system were analysed using small-angle scattering and polarising light microscopy, with varying temperature and applied shear.

The effect of silica nanoparticles on polysulfone–polyethylene glycol (PSF/PEG) composite membrane on gas separation and rheological properties of nanocomposites

2020 ◽  
Author(s):  
Iman Salahshoori ◽  
Danial Nasirian ◽  
Niloufar Rashidi ◽  
Md Kamal Hossain ◽  
Ali Hatami ◽  
...  
Keyword(s):  
Polyethylene Glycol ◽  
Silica Nanoparticles ◽  
Rheological Properties ◽  
Gas Separation ◽  
Composite Membrane

Rheological Properties of Magnetorheological Fluid with Silica Nanoparticles Stabilizers—A Comparison with Ferrofluid

2013 ◽  
Vol 2 (2) ◽  
pp. 75-84 ◽  
Author(s):  
Leona J. Felicia ◽  
Reji John ◽  
John Philip
Keyword(s):  
Silica Nanoparticles ◽  
Rheological Properties ◽  
Magnetorheological Fluid

A biomechanical study of the instrumented and adjacent lumbar levels after In-Space interspinous spacer insertion

2010 ◽  
Vol 12 (5) ◽  
pp. 560-569 ◽  
Author(s):  
Seoung Woo Park ◽  
T. Jesse Lim ◽  
Jon Park
Keyword(s):  
Biomechanical Testing ◽  
Axial Rotation ◽  
Biomechanical Study ◽  
Lumbosacral Spine ◽  
Experimental Conditions ◽  
Interspinous Spacer ◽  
Spine Model ◽  
Cadaver Specimen ◽  
Significant Change ◽  
Group 2

ObjectInterspinous process implants are becoming more common for the treatment of lumber disc degeneration. The authors undertook this study to evaluate the effect of the In-Space interspinous spacer on the biomechanics of the lumbosacral spine.MethodsSeven L2–S1 cadaver spines were physiologically loaded in extension, flexion, lateral bending, and axial rotation modes. The range of motion (ROM) and intervertebral disc pressure (DP) at the level implanted with an In-Space device and at adjacent levels were measured under 4 experimental conditions. Biomechanical testing was carried out on 7 sequentially prepared specimens in the following states: 1) the intact L2–S1 cadaver spine and 2) the L2–S1 cadaver specimen implanted with an In-Space interspinous spacer at L3–4 (Group 1), 3) after an additional L3–4 discectomy (with the In-Space interspinous spacer still in place) (Group 2), and finally, 4) after removal of the In-Space interspinous spacer, leaving only the discectomized (that is, destabilized) spine model (Group 3).ResultsThe extension ROM at the implanted level after experimental conditions 2 and 3 above was statistically significantly reduced. An increase of ROM at the adjacent levels compensated for the reduction at the implanted level. However, there was no statistically significant change in ROM in any of the other modes of motion at any of the levels studied. Likewise, the DP reduction at L3–4 during extension was statistically significant, but in all other modes of motion, there was no statistically significant change in DP at any measured level. The In-Space interspinous spacer statistically significantly reduced the ROM of the L3–4 motion segment in Groups 1 and 2 (extension: 67%, p = 0.018 and 70%, p = 0.018; flexion: 72%, p = 0.028 and 80%, p = 0.027). After placement of the In-Space interspinous spacer, the DP was decreased at L3–4 in extension for Groups 1 and 2 in the posterior anular region (63%, p = 0.028; 59%, p = 0.043), Group 2 in the center region (73%, p = 0.028), and Groups 1 and 2 in the anterior anular region (57%, p = 0.018; 60%, p = 0.018).ConclusionsThe In-Space interspinous spacer both stabilizes the spine and reduces the intervertebral DP at the instrumented level during extension. The biomechanics for other modes of motion and at the adjacent levels are not affected statistically significantly, however. The device thus performed as intended. It significantly stabilized the motion segments at the instrumented level, but not at the segment adjacent to the instrumented level.

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