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Extractive-dividing-wall column and multi-objective optimizations of green entrainer-based ultra-high-purity recovery of methyl di glycol and N-Methyl-2-Pyrrolidone
No full textThe waste solvent is frequently generated from the processes that highly rely on solvents. Diethylene glycol monomethyl ether or methyl di glycols (MDG) and N-methyl-2-pyrrolidone (NMP) are representative valuable solvents used broadly and removed as waste solvents during the semiconductor material manufacturing processes. Although waste solvent can be practically retrieved by distillation, azeotropic waste solvent mixture only can be recovered by advanced distillation process. In this study, optimal extractive distillation and extractivedividing wall column are used to recover waste solvent. The process is optimized by multi-objective optimization using genetic algorithm by linking Aspen Plus & REG; and MATLAB. All optimal cases are compared in terms of energy, exergy, economic and environmental parameter. As a result, the potential energy, total annual cost saving and exergy efficiency for extractive dividing wall column are 26.29%, 24.15% and 21.02%, respectively. Exergy loss that is associated with the number of trays can be significantly reduced by optimization while exergy loss that is associated with remixing only can be significantly reduced by dividing-wall column. Further, multiobjective optimization using a genetic algorithm and a range of population provides various results that determine process selection
Semi-analytic solutions and sensitivity analysis for an unsteady squeezing MHD Casson nanoliquid flow between two parallel disks
No full textThe transport phenomena of Casson nanofluid flow between two parallel disks subject to convective boundary conditions are analyzed in this paper. The mathematical model incorporates the impact of thermophoresis and Brownian motion since the Buongiorno's nanoliquid model is adopted to characterize the nanoliquid's transport features. The appropriate similarity transformations are applied to obtain the resulting nondimensional ordinary differential equations from the basic governing equations. The resulting ordinary differential equations and the associated boundary conditions are solved analytically by adopting the homotopy perturbation technique. Further, a statistical experiment is conducted to identify notable flow parameters which cause significant impact on the heat transfer rate. The characteristics of critical pertinent parameters on the flow field are graphically manifested. It is worth noting that the Casson nanofluid velocity escalates by augmenting the magnetic field parameter in the case of injection near the disks. Nanoparticle concentration is considerably diminished with an increment in thermophoresis parameter. In the cases of equal and unequal Biot numbers, the heat transfer rate is promoted with higher values of the Brownian motion parameter. Among the Casson fluid parameter, squeezing parameter and magnetic field parameter, the heat transfer rate discloses the highest positive sensitivity with the lowest value of the Casson fluid parameter
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No full textInfluence of organic matter on seawater battery desalination performance
No full textA rechargeable seawater battery desalination (SWB-D) system stores energy in a battery cell while removing salts from saline water via a sodium superionic conductor membrane and an anion exchange membrane. However, the electrochemical performance often degrades owing to the organic fouling generated on the ion exchange membranes. In this study, we investigated the fouling behavior of the SWB-D system by individually dissolving three different types of organic matter-humic acid, sodium alginate, and bovine-serum-albumin. In terms of the salt-removal performance of the SWB-D system, gradual degradation was observed over three charging cycles using hydrophobic humic acid (-13 %) and bovine-serum-albumin (-18 %), whereas no degradation was caused by hydrophilic sodium alginate. Continuous water flow mitigated the fouling behavior, and a large volume of saline water enabled longer charging. The increase in the electrical resistance of the SWB-D system was measured in the presence of organic matter using electrochemical impedance spectroscopy and the four-electrode method. Additionally, the presence of fouling layer was identified using field-emission scanningelectron microscopy, energy-dispersive X-ray spectroscopy, and Fourier-transform infrared spectrometry. In conclusion, the results demonstrated that the hydrophobic organic matter in the feed water could be unfavorable when operating the SWB-D system
Two distinct modes of dopaminergic modulation on striatopallidal synaptic transmission in health and diseases
No full textDopamine (DA) and its G-protein-coupled receptors (GPCRs) control willed movement through the D1-direct
pathway and D2-indirect pathway within the basal ganglia. In a classical model, excessive activity in the indirect
pathway is one of the circuit mechanisms underlying parkinsonism. Although striatopallidal synapses serve as a
critical gateway of the indirect pathway, the physiological functions of dopamine on striatopallidal transmission
remain poorly understood. Here, we sought to understand how DA through the nigropallidal pathway modulates
striatopallidal transmission. We found that striatopallidal synapses region-specifically modulate indirect pathway via
directly released dopamine on the GPe. Notably, 6-OHDA-induced DA depletion particularly promotes D2R-mediated
presynaptic inhibition in ventrolateral and dorsomedial subregions of the GPe. To sum up, these results demonstrate
that synaptic information conveyed by the indirect pathway can be differentially regulated by DA via distinct modes of
action in the GPe subregions, which can be determined by anatomical locations of striatopallidal synapses
Chiral emission from perovskite metasurfaces via chiral quasi-bound states in the continuum
No full textChiral nanophotonic structures can significantly enhance the chiral optical responses and provide unprecedented design flexibility. However, achieving extreme chirality that approaches the ultimate theoretical limit remains challenging. Here, chiral quasi-bound states in the continuum are realized in the visible range by controlling the etching depths in the substrate and inducing out-of-plane symmetry breaking. A perovskite film is spin-coated on a patterned glass substrate. Grayscale lithography is employed to control the etching depths in the substrate and induce out-of-plane symmetry breaking. An extremely high level of chiral emission from the perovskite metasurface is experimentally achieved in the normal direction at room temperature. Chiral emission is maximally enhanced for one helicity via critical coupling while strongly suppressed for the other helicity. Approaching the ultimate limit of chiral interactions may lead to far-reaching consequences in a variety of important applications
Paper-Based Inkjet-Printed Carbon Nanotube Colorimetric Chemiresistors for Detection of Chemical Warfare Agents
No full textColorimetric papers have been widely used for the convenient and inexpensive detection of toxic chemicals including chemical warfare agents (CWAs). The majority of colorimetric papers, however, only detect liquid-phase analytes, exhibiting a limited gas-sensing performance. In this study, we report a colorimetric paper capable of detecting and identifying CWAs in both liquid and gas phases, achieved by inkjet-printing carbon nanotube (CNT)-based chemiresistors on the paper. The inkjet-printed CNTs generate electrical signals unique to liquid-phase CWAs (GB, VX) and their simulants without affecting the colorimetric responses, thereby enabling more accurate analyte identification. Inkjet printing can also be employed to noncovalently functionalize CNTs with various receptors. We fabricated a gas sensor array on the colorimetric paper by inkjet-printing three different receptors on the CNT chemiresistors and demonstrated the identification of four CWA simulants based on the response patterns of the array. This hybrid sensing platform, exhibiting both colorimetric and electrical signals, potentially serves as an inexpensive alternative to existing analytical tools for the analysis of CWAs and other toxic chemical compounds
Vision-Based Approximate Estimation of Muscle Activation Patterns for Tele-Impedance
No full textIt lies in human nature to properly adjust the muscle force to perform a given task successfully. While transferring this control ability to robots has been a big concern among researchers, there is no attempt to make a robot learn how to control the impedance solely based on visual observations. Rather, the research on tele-impedance usually relies on special devices such as EMG sensors, which have less accessibility as well as less generalization ability compared to simple RGB webcams. In this letter, we propose a system for a vision-based tele-impedance control of robots, based on the approximately estimated muscle activation patterns. These patterns are obtained from the proposed deep learning-based model, which uses RGB images from an affordable commercial webcam as inputs. It is remarkable that our model does not require humans to apply any visible markers to their muscles. Experimental results show that our model enables a robot to mimic how humans adjust their muscle force to perform a given task successfully. Although our experiments are focused on tele-impedance control, our system can also provide a baseline for improvement of vision-based learning from demonstration, which would also incorporate the information of variable stiffness control for successful task execution