Membrane synthesis via in-situ pore formation in silica gels through dynamic miscibility with soybean oil

2021 ◽  
pp. 128183
Author(s):  
Karthikeyan Baskaran ◽  
Muhammad Ali ◽  
Brian J. Riley ◽  
Jeffrey S. Bates ◽  
Ilya Zharov ◽  
...  
Keyword(s):  
Soybean Oil ◽  
Pore Formation ◽  
Silica Gels ◽  
Membrane Synthesis

scholarly journals The Effect of Hydrogen on Pore Formation in Aluminum Alloy Castings: Myth Versus Reality

Metals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 368 ◽  
Author(s):  
Murat Tiryakioğlu
Keyword(s):  
Pore Formation ◽  
Liquid Aluminum ◽  
Nucleation Theory ◽  
Classical Nucleation Theory ◽  
Fundamental Change ◽  
Aluminum Casting ◽  
Solid Aluminum ◽  
Alloy Castings ◽  
Casting Industry

The solubility of hydrogen in liquid and solid aluminum is reviewed. Based on classical nucleation theory, it is shown that pores cannot nucleate either homogeneously or heterogeneously in liquid aluminum. Results of in situ studies on pore formation show that pores appear at low hydrogen supersaturation levels, bypassing nucleation completely. The results are explained based on the bifilm theory introduced by Prof. John Campbell, as this theory is currently the most appropriate, and most likely, the only mechanism for pores to form. Examples for the effect of hydrogen on pore formation are given by using extreme data from the literature. It is concluded that a fundamental change in how hydrogen is viewed is needed in aluminum casting industry.

Injectable poly(lactic-co-glycolic) acid scaffolds with in situ pore formation for tissue engineering

2009 ◽  
Vol 5 (8) ◽  
pp. 2847-2859 ◽  
Author(s):  
Melissa D. Krebs ◽  
Kathleen A. Sutter ◽  
Angela S.P. Lin ◽  
Robert E. Guldberg ◽  
Eben Alsberg
Keyword(s):  
Tissue Engineering ◽  
Pore Formation ◽  
Glycolic Acid

On-line in situ monitoring of the soybean oil and ethanol transesterification reaction by fluorescence spectroscopy

Fuel ◽  
2015 ◽  
Vol 145 ◽  
pp. 109-115 ◽  
Author(s):  
T. Izida ◽  
L. Bussler ◽  
J.R. Silva ◽  
L.H.C. Andrade ◽  
E. Simionatto ◽  
...  
Keyword(s):  
Fluorescence Spectroscopy ◽  
Soybean Oil ◽  
Transesterification Reaction ◽  
In Situ Monitoring ◽  
On Line

In Situ Studies of the Processing of Sol-Gel Produced Amorphous Materials Using Xanes, Saxs and Curved Image Plate XRD

1999 ◽  
Vol 590 ◽  
Author(s):  
DM Pickup ◽  
G Mountjoy ◽  
RJ Newport ◽  
ME Smith ◽  
GW Wallidge ◽  
...  
Keyword(s):  
Amorphous Materials ◽  
Sol Gel ◽  
Heat Treatments ◽  
Silica Gels ◽  
Ex Situ ◽  
High Count ◽  
X Ray ◽  
Image Plate ◽  
Wide Range

ABSTRACTSol-gel produced mixed oxide materials have been extensively studied using conventional, ex situ structural techniques. Because the structure of these materials is complex and dependent on preparation conditions, there is much to be gained from in situ techniques: the high brightness of synchrotron x-ray sources makes it possible to probe atomic structure on a short timescale, and hence in situ. Here we report recent results for mixed titania- (and some zirconia-) silica gels and xerogels. Titania contents were in the range 8–18 mol%, and heat treatments up to 500°C were applied. The results have been obtained from intrinsically rapid synchrotron x-ray experiments: i) time-resolved small angle scattering, using a quadrant detector, to follow the initial stages of aggregation between the sol and the gel; ii) the use of a curved image plate detector in diffraction, which allowed the simultaneous collection of data across a wide range of scattering at high count rate, to study heat treatments; and iii) x-ray absorption spectroscopy to explore the effects of ambient moisture on transition metal sites.

In Situ Observation of an Electrochemical Etching Reaction in Silicon

1995 ◽  
Vol 404 ◽  
Author(s):  
Frances M. Ross ◽  
Peter C. Searson
Keyword(s):  
Pore Formation ◽  
Electrochemical Etching ◽  
Ex Situ ◽  
In Situ Observation ◽  
Specimen Holder

AbstractWe describe a TEM specimen holder which has been designed and constructed in order to observe the process of electrochemical pore formation in silicon. The holder incorporates electrical feedthroughs and a sealed reservoir for the electrolyte and it accepts lithographically patterned silicon specimens. We present ex situ observations of progressive pore propagation and show dynamic, in situ observations of electrolyte movement within the pores.

Hydrothermal Transformation of Inorganic and Biogenic Silica as Studied Using in Situ Hydrothermal Infrared Microspectroscopy

2018 ◽  
Vol 72 (10) ◽  
pp. 1487-1497
Author(s):  
Naoto Morifuji ◽  
Satoru Nakashima
Keyword(s):  
Activation Energy ◽  
Rate Constants ◽  
Biogenic Silica ◽  
Zero Order ◽  
Silica Gels ◽  
Dissolution Rates ◽  
First Order ◽  
Order Rate ◽  
Hydrothermal Transformation

Infrared (IR) spectral changes with time of biogenic and inorganic silica have been examined using in situ IR micro-spectroscopy by using an original hydrothermal diamond cell. Centric diatoms (diameters = 100–350 µm) and silica gels (C-300, Wako Chemicals) were heated at 125–185 ℃ range with a pressure of 3 MPa. Decreases of 950 cm−1 (Si–OH) peak heights could be fitted by a combination of exponential and linear decreases (y = A1 exp (−k1t) − k0 t + A0). The first-order rate constants k1 [s−1] for Si–OH decreases of diatoms and silica gels are similar but the activation energy was lower for diatoms (61 kJċmol−1 < 106 kJċmol−1). The first-order rate constants k1 [s−1] for Si–OH decreases of diatoms and silica gels are much faster than reported hydrothermal transformation rates of silica (Opal A to Opal CT and Opal CT to quartz). These results indicate that the exponential Si–OH decreases observed in biogenic and inorganic silica during hydrothermal reactions are considered to correspond to dehydration–condensation reactions in the amorphous states (Si–OH + HO–Si → Si–O–Si). In fact, band area ratios 1220 cm−1/1120 cm−1 increased exponentially indicating more bridging of Si–O–Si. On the other hand, the linear decreases of Si–OH of silica gels (k0 [s−1]) were considered to be due to dissolution of silica. By using the grain size and density of silica gels, the zero-order dissolution rate constants k0* [molċm−2ċs−1] were calculated from k0 [s−1]. The obtained dissolution rates k0* are larger than reported values for silica glass and quartz. The zero-order dissolution rates k0 [s−1] for diatoms are similar to those for silica gels but with a lower activation energy (32 kJċmol−1 < 60 kJċmol−1). The smaller activation energy values for diatoms than silica gels both for the first and zero-order decrease rates of Si–OH might indicate catalytic effects of organic components bound to biogenic silica for the dehydration–condensation reaction and dissolution. The present in situ hydrothermal IR micro-spectroscopy is useful for characterizing transformation of amorphous materials including inorganic–organic composites.

A Model to Predict Pore Shape in Solid During Solidification

2009 ◽  
Author(s):  
S. Y. Hsiao ◽  
P. S. Wei
Keyword(s):  
Solidification Front ◽  
Pore Formation ◽  
Mass Conservation ◽  
Bubble Surface ◽  
Time Dependent ◽  
Dissolved Gas ◽  
Chemical Equilibria ◽  
Physico Chemical ◽  
Perturbation Solutions

The shapes of a growing or decaying bubble entrapped by a solidification front are predicted in this work. The bubble results from supersaturation of a dissolved gas in the liquid ahead of the solidification front. Pore formation is one of the most serious issues affecting properties, microstructure, and strength in materials. In this study, the bubble entrapped as a pore in solid are realistically predicted by utilizing perturbation solutions of Young-Laplace equation governing the tiny bubble shape in the literature. The analytical solutions can account for necking of a bubble beyond the solidification front. Satisfying energy, momentum, mass conservation and physico-chemical equilibria on the bubble surface, the predicted time-dependent pore shapes are found to agree with in-situ measurements.

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