Separation of fuel additives based on mechanism analysis and thermodynamic phase behavior

tert-butanol and ethyl acetate,as fuel additives and oxygenated fuels,can improve fuels quality and reduce exhaust emissions.Therefore,the recovery of these compounds from azeotropic systems is of great significance.Ionic liquids(ILs)are promising green solvents for separating azeotropic systems.In this study,an efficient extraction strategy based on 1-butyl-3-methylimidazolium acetate([Bmim][AC])is proposed.The mechanism by which ILs enable the separation of binary alcohol-ester azeotropes was revealed by evaluating the lowest conformational energy through combining an independent gradient model based on the Hirshfeld partition(IGMH)and frontier molecular orbitals,to preliminarily screen the extractants.The range of extractants was further reduced by a vapor–liquid phase equilibrium(VLE)experiment,and a modeling method for separating the alcohol–ester system and recovering the solvent using[Bmim][AC]and 1-ethyl-3-methyl-3-imidazolium acetate([Emim][AC])is established.Under the optimal operating conditions,the use of[Bmim][AC]can reduce the total annual cost(TAC)per year by 17.78%,and the emissions of CO_(2),SO_(2),and NO can be reduced by 10.86%.In this study,a comprehensive method for screening extractants is proposed,and the simulation process is optimized in combination with the economic and environmental impact.The results have important guiding significance for realizing efficient,energy-saving,and green azeotropic separation systems in industry.

Dynamic control analysis of interconnected pressure-swing distillation process with and without heat integration for separating azeotrope

Dynamic controls of pressure-swing distillation with an intermediate connection(PSDIC) process of ethyl acetate and ethanol separation were investigated.The double temperature/composition cascade control structure can perfectly implement effective control when ±20% feed disturbances were introduced.This control structure did not require the control of the flowrate of the side stream.The dynamic controllability of PSDIC with partial heat integration(PHIPSDIC) was also explored.The improved control structure can effectively control ±20% feed disturbances.However,in industrial production,simple controller,sensitive and easy to operate,is the optimal target.To avoid the use of component controllers or complex control structure,the original product purities could be maintained using the basic control structure for the PSDIC process if the product purities in steady state were properly increased,albeit by incurring a slight rise in the total annual cost(TAC).This alternative method without a composition controller combined with the energy-saving PSDIC process provides a simple and effective control scheme in industrial production.

Mechanism analysis of solvent selectivity and energy-saving optimization in vapor recompression-assisted extractive distillation for separation of binary azeotrope

Octane and p-xylene are common components in crude gasoline,so their separation process is very important in petroleum industry.The azeotrope and near azeotrope are often separated by extractive distillation in industry,which can realize the recovery and utilization of resources.In this work,the vapor–liquid equilibrium experiment was used to obtain the vapor–liquid equilibrium properties of the difficult separation system,and on this basis,the solvent extraction mechanism was studied.The mechanism of solvent separation plays a guiding role in selecting suitable solvents for industrial separation.The interaction energy,bond length and charge density distribution of p-xylene with solvent are calculated by quantum chemistry method.The quantum chemistry calculation results and experiment results showed that N-formylmorpholine is the best solvent among the alternative solvents in the work.This work provides an effective and complete solvent screening process from phase equilibrium experiments to quantum chemical calculation.An extractive distillation simulation process with N-formylmorpholine as solvent is designed to separate octane and p-xylene.In addition,the feasibility and effectiveness of the intensified vapor recompression assisted extraction distillation are also discussed.In the extractive distillation process,the vapor recompression-assisted extraction distillation process is globally optimal.Compared with basic process,the total annual cost can be reduced by 43.2%.This study provides theoretical guidance for extractive distillation separation technology and solvent selection.

Drug repurposing screening and mechanism analysis based on human colorectal cancer organoids

Colorectal cancer(CRC)is a highly heterogeneous cancer and exploring novel therapeutic options is a pressing issue that needs to be addressed.Here,we established human CRC tumor-derived organoids that well represent both morphological and molecular heterogeneities of original tumors.To efficiently identify repurposed drugs for CRC,we developed a robust organoid-based drug screening system.By combining the repurposed drug library and computation-based drug prediction,335 drugs were tested and 34 drugs with anti-CRC effects were identified.More importantly,we conducted a detailed transcriptome analysis of drug responses and divided the drug response signatures into five representative patterns:differentiation induction,growth inhibition,metabolism inhibition,immune response promotion,and cell cycle inhibition.The anticancer activities of drug candidates were further validated in the established patient-derived organoids-based xenograft(PDOX)system in vivo.We found that fedratinib,trametinib,and bortezomib exhibited effective anticancer effects.Furthermore,the concordance and discordance of drug response signatures between organoids in vitro and pairwise PDOX in vivo were evaluated.Our study offers an innovative approach for drug discovery,and the representative transcriptome features of drug responses provide valuable resources for developing novel clinical treatments for CRC.

Linear Three-Phase Power Flow for Unbalanced Active Distribution Networks with PV Nodes

High penetration of distributed renewable energy promotes the development of an active distribution network(ADN).The power flow calculation is the basis of ADN analysis.This paper proposes an approximate linear three-phase power flow model for an ADN with the consideration of the ZIP model of the loads and PV nodes.The proposed method is not limited to radial topology and can handle high R/X ratio branches.Case studies on the IEEE 37-node distribution network show a high accuracy and the proposed method is applicable to practical uses such as linear or convex optimal power flow of the ADN.

Broadband adiabatic polarization rotator-splitter based on a lithium niobate on insulator platform

Polarization rotator-splitters(PRSs)are crucial components for controlling the polarization states of light in classical and quantum communication systems.We design and experimentally demonstrate a broadband PRS based on the lithium niobate on insulator(LNOI)platform.Both the rotator and splitter sections are based on adiabatically tapered waveguide structures,and the whole device only requires a single etching step.We show efficient PRS operation over an experimentally measured bandwidth of 130 nm at telecom wavelengths,potentially as wide as 500 nm according to simulation prediction,with relatively low polarization crosstalks of~-10 d B.Our PRS is highly compatible with the design constraints and fabrication processes of common LNOI photonic devices,and it could become an important element in future LNOI photonic integrated circuits.

Systematic investigation of millimeter-wave optic modulation performance in thin-film lithium niobate

Millimeter-wave(mmWave)band(30–300 GHz)is an emerging spectrum range for wireless communication,short-range radar,and sensor applications.mmWave-optic modulators that could efficiently convert mmWave signals into the optical domain are crucial components for long-haul transmission of mmWave signals through optical networks.At these ultrahigh frequencies,however,the modulation performances are highly sensitive to the transmission line loss as well as the velocity-and impedance-matching conditions,while precise measurements and modeling of these parameters are often non-trivial.Here we present a systematic investigation of the mmWave-optic modulation performances of thin-film lithium niobate modulators through theoretical modeling,electrical verifications,and electro-optic measurements at frequencies up to 325 GHz.Based on our experimentally verified model,we demonstrate thin-film lithium niobate mmWave-optic modulators with a measured 3-dB electro-optic bandwidth of 170 GHz and a 6-dB bandwidth of 295 GHz.The device also shows a low RF half-wave voltage of 7.3 V measured at an ultrahigh modulation frequency of 250 GHz.This work provides a comprehensive guideline for the design and characterization of mmWave-optic modulators and paves the way toward future integrated mmWave photonic systems for beyond-5G communication and radar applications.

Unveiling the Growth Mechanism of Faceted Primary Al_(2)Cu with Complex Morphologies During Solidification

The growth characteristic of primary faceted Al_(2)Cu intermetallic compounds(IMCs)during solidification was observed directly by synchrotron radiography.The formation and transition mechanisms of Al_(2)Cu IMCs with diverse morphologies were elucidated by first-principle calculations combined with electron backscatter diffraction analysis.The Al_(2)Cu crystals preferred to grow along the[001]direction and were bounded by{110}planes with the lowest surface energy.The faceted Al_(2)Cu rod-like clusters consisted of multiple crystals with complete rod,hollowness and partial sides,which was attributed to the increase in strain energy and solute redistribution during solidification.The faceted Al_(2)Cu with branches was characteristic with the perpendicular relationship between the main branches and side steps and partial coalescence at the junction,which was ascribed to the continuous propagation and growth of newly formed crystals along the diagonal direction.

Copolymer of lactide and ε-caprolactone catalyzed by bimetallic Schiff base aluminum complexes

A series of copolymers of lactide(LA) and e-caprolactone(ε-CL) with different monomer feed ratios were achieved using three kinds of bimetallic Schiff aluminum complexes as catalysts. The ratios of LA and ε-CL units in different copolymers and the average segments length were determined by NMR analysis. The comparative kinetic study of L-LA/ε-CL and rac-LA/ε-CL copolymerization systems showed that the polymerization rate of LA was faster than ε-CL, and L-LA showed polymerization rate slightly faster than rac-LA. It was inferred that the copolymers achieved by these complexes were gradient copolymers with gradual change in distribution of LA and e-CL units. The thermal properties of these copolymers were characterized by DSC analysis, which showed that the glass transition temperature(Tg) of these copolymers changed regularly according to the pro-portion change of two structural units.

Broadband adiabatic polarization rotator-splitter based on a lithium niobate on insulator platform: publisher's note

The second paragraph in Section 2 of this article was corrected as follows.In the polarization rotator (Step I), the LN rib waveguide adiabatically widens from a top width of 1.2 to 3.6μm via a linear taper, such that the effective index of the second-order TE (TE;) mode surpasses that of the fundamental TM (TM;)mode [Fig. 1(c)].