Triacetic acid lactone (TAL), an emerging bioprivileged molecule, can be produced microbially and further chemically upgraded to several high-value chemicals. In this work, several acidic and basic ion-exchange resins and activated charcoal were evaluated for their ability to adsorb microbially produced TAL. Activated charcoal and a weak base resin, Dowex 66, showed similar TAL adsorption capacity of 0.18 ± 0.002 g/g. At 15% w/v activated charcoal, about 98% of TAL present in fermentation broth could be adsorbed. Further, ethanol washing allowed recovery of 72% of adsorbed TAL. A biorefinery producing TAL from sucrose was designed, simulated, and evaluated (through technoeconomic analysis) under uncertainty, for an estimated TAL minimum product selling price (MPSP) of $4.27/kg ($3.71-4.94/ kg; 5th-95th percentiles) given the current state of technology and $2.83/kg ($2.46-3.29/kg) following potential near-term improvements to fermentation. This work provides an adsorptive process for the recovery of microbially produced TAL that can be upgraded chemically to a range of industrial products.
Modern fuel injection systems operate at high pressures and flow velocities. Injectors can be pressurized in excess of 10 MPa, resulting in fuel velocities on the order of hundreds of meters/second in the mm and sub-mm internal confines of a fuel injector. Subsequent ejection velocities at the nozzle yield characteristic atomization droplet size distributions and spread angles. Studies have shown or inferred the presence of cavitation in such fuel injectors, typically beneficially decreasing ejection droplet sizes while increasing the spray spreading angle. While beneficial for fuel atomization, it is known that bubble collapse near a solid surface produces a strong jet which impinges on the surface and causes erosion. In this study, Fourier based image reconstruction is used to perform Passive Cavitation Imaging (PCI) in laboratory nozzles to detect, characterize, and most importantly localize inertial cavitation. [Work funded by DOE.]
Cavitation erosion is a common cause of damage of fuel injectors, pumps, and other hydrodynamic equipment. For fuel injectors, cavitation can also have a beneficial effect on the resultant spray angle and aerosol size distribution. Because collapsing cavitation bubbles emit pressure waves, the occurrence and extent of cavitation can be characterized using an ultrasonic transducer in the spirit of passive cavitation detection, commonly employed in biomedical acoustics. Experiments use a two-part acrylic nozzle: a contraction portion of length 1 in. (contracting from the feed tube diameter of 1.14 in. to the diameter of the cylindrical portion) and a cylindrical outlet of length 1 in. Two different outlet diameters have been considered. Water is caused to flow at increasing rates which span the inception and development of hydrodynamic cavitation. Acoustic and optical results will be presented and compared. The results indicate that introducing a tapered change in the nozzle diameter delays the onset of cavitation with respect to the mean flow rate, as does decreasing the taper angle with respect to the flow axis. [Work supported by DOE DE-EE0007332.]
Over the past few decades, microscale duct flow has been the key element for many applications, such as drug delivery and microelectronics cooling. To enhance the performance of such systems and to save more energy, looking for new ways to control the hydrodynamic and thermal characteristics of the microchannel flow has been of great interest lately. The aim of this research is to gain a better understanding of the flow physics within microchannels with microtextured walls. Therefore, a set of numerical study has been conducted on the combined effect of flow and heat transfer for spanwise rectangular trenches. The surface microstructures increase the wetting surface area, which is supposed to increase friction (skin drag). Recirculation produced inside the grooves, on the other hand, aids in increasing main flow slippage and lowering pressure drop along the microchannel. It is also worth noting that recirculation creates a negative pressure difference in the opposite direction of the flow (pressure drag). The geometrical parameters of the trenches have a significant impact on the trade-off between the drag reducing and drag increasing factors in textured microchannel flow, which is addressed in this research. Furthermore, the textures disrupt the thermal boundary layer, which can boost thermal transport through recirculation mixing. However, the stagnant fluid trapped within the grooves has weak convective heat transfer. So far, the results have been promising and a drag reduction of about 25% has been reported for wide trenches at low Reynolds numbers. Thermal transport enhancement is also possible for some tested geometries when the flow has not achieved the thermally fully development.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.