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In previous work, we have shown that a dilute suspension of colloidal particles will spontaneously flow when placed in a container. The flow is caused by interfacial tension gradients created by aggregates of the colloidal particles on the interface. In this paper, we present some results that show the interfacial tension of charged stabilized titania suspensions significantly decreases within certain volume fractions. The data show that the interfacial tension is indeed a strong function of the particle concentration and help explain the unusual results seen in the flow experiments. [Copyright &y& Elsevier]

In this study, a mathematical framework was developed for the sustainability prioritization of alternative low-carbon ammonia production routes. In the framework, a four-dimensional assessment system that can incorporate both quantitative and qualitative criteria from the environmental, economic, social-political, and technical concerns was firstly established. Subsequently, a hybrid Entropy-FANP method was employed to determine the criteria's weight by combining the objective data and subjective opinions; a novel PRSRV approach was developed to rigorously rank the alternative routes by aggregating the absolute sustainability performance and relative sustainability balance of each alternative. The proposed framework was applied to prioritize five promising low-carbon routes for ammonia production, i.e. wind turbine electrolysis (WGEA), solar photovoltaic electrolysis (PVEA), hydropower electrolysis (HPEA), biomass gasification electrolysis (BGEA), and nuclear high temperature electrolysis (NTEA), yielding the sustainability ranking of HPEA > BGEA > WGEA > PVEA > NTEA. The robustness and effectiveness of the proposed framework were verified by conducting the sensitivity analysis and comparing the results determined by the proposed framework with those determined using the previous approaches. [ABSTRACT FROM AUTHOR]

Abstract: Isobaric vapor–liquid equilibrium (VLE) data for water+n-propanol+n-butanol ternary system have been extensively measured at 99.2kPa using a recirculating still. The experimental data were then correlated using the extended UNIQUAC model, in which the binary interaction energy parameters between the three components were obtained through a simplex fitting method. The results showed that the calculated data by the extended UNIQUAC model using the same interaction energy parameters agree well with both the experimental data and the literature data. It demonstrated that the experimental data are very consistent with the literature data; and the extended UNIQUAC model is reliable to predict the VLE of the ternary system using the obtained interaction energy parameters. [ABSTRACT FROM AUTHOR]

Harnessing renewable energy (RE) sources to power desalination systems can migrate the pressures of freshwater scarcity and fossil fuel depletion. In this paper, a novel mathematical framework was developed to assess the sustainability of different RE-powered desalination systems, which is very essential for their portfolio selection, by resorting to the fuzzy multi-attribute decision making (MAMD) methods. In the framework, an evaluation system including ten attributes from four dimensions is introduced, while fuzzy triangular numbers and interval values are employed to capture the epistemic and aleatory uncertainties of decision information, respectively. More importantly, three fuzzy MADM methods were proposed in the framework to make the following methodological contributions: (1) fuzzy decision-making trial and evaluation laboratory-based analytic network process (DANP) offers a reliable weighting result by addressing the interrelationships among the attributes; (2) fuzzy full consistency method (FUCOM) can easily but rigorously quantify the qualitative attributes by using the simplified pair-wise comparisons; (3) interval vector-aided technique for order of preference by similarity to ideal solution (VATOPSIS) generates a rational ranking sequence by incorporating the balance among multi-attributes. To illustrate the proposed framework, six RE-powered desalination systems were studied, showing that the solar thermal-powered multi-effect distillation would be the best option under current conditions. Finally, the effectiveness and advantages of the proposed framework were verified by results comparison and discussion. Image 1 • A framework was proposed to assess the sustainability of RE-powered desalination. • The mathematical framework can address both the epistemic and aleatory uncertainties. • A fuzzy DANP approach was used to assign the weights to the interrelated attributes. • A fuzzy FUCOM method was developed to easily quantify the qualitative attributes. • An interval VATOPSIS method was introduced to rationally rank the alternatives. [ABSTRACT FROM AUTHOR]

The separation of a ternary mixture of methyl acetate (MeAc), tetrahydrofuran (THF), and methanol (MeOH) produced from chemical or pharmaceutical plants can not only recover the valuable chemicals but also reduce the environmental pollution caused by the emission of waste organics. In this study, a two-step extractive distillation process with four columns (FCED) with dimethyl sulfoxide and p -xylene serving as the entrainers was firstly proposed to separate the ternary mixture by using Aspen Plus simulation. The vapor recompression heat pump (VRHP) technology was introduced to improve the thermodynamic efficiency of the proposed FCED process. Subsequently, a multi-objective optimization using the non-dominated sorting genetic algorithm-II was employed to optimize the designed processes to accomplish a Pareto front trade-off in three crucial indicators, i.e., total annual cost (TAC), CO 2 emission, and exergy efficiency. A Pareto ranking method, i.e., the technique for order of preference by similarity to ideal solutions combined with entropy weighting approach, was used to choose the best solution from the Pareto front. The results indicate that, compared to the FCED process, TAC (8-year payback period) and CO 2 emissions of the VRHP-assisted FCED are reduced by 8.75% and 33.26%, respectively, while the exergy efficiency is increased by 8.06% from 3.67% to 3.96%, demonstrating that the introduction of VRHP can significantly improve the performance of the FCED process. [Display omitted] • THF/isopentyl acetate and THF/ p -xylene vapor-liquid equilibrium data are measured. • Dimethyl sulfoxide and p -xylene are chosen as the entrainers. • The novel processes for separating methyl acetate/THF/methanol are proposed. • Multi-objective optimization framework is applied to optimize the processes. • Heat pump can increase economic, environment, and exergy efficiency performance. [ABSTRACT FROM AUTHOR]

The location of coke deposited on HZSM-5 zeolite catalyst during the supercritical catalytic cracking (400 °C, 4.0 MPa) of n -dodecane was systematically characterized by special temperature-programmed oxidation (TPO) and isothermal oxidation methods, and a steric hindrance model describing the interactions of the coke deposited on different locations was proposed to support the methods theoretically. Accord to the results, the sharp shoulder peak that appears on the TPO profile at high temperature range (> 700 °C) with low concentration of oxygen in the oxygen/nitrogen mixed carrier gas (≤ 2.0 Vol.%) can be ascribed to the characteristic peak representing the oxidation of the coke blocked in micropores, while the appearance of the CO peak during the isothermal oxidation at high temperature (≥ 550 °C) using air as carrier gas provides another method to detect the coke blocked in micropores. Through checking whether the characteristic sharp shoulder peak of the TPO profile appears or not as expected according to the steric hindrance model during the re-oxidation of several samples with different coke content and spatial distribution, which were prepared by partial oxidation of the spent catalyst using TPO and isothermal oxidation methods, the special TPO and isothermal oxidation methods combined with their theoretical support of the steric hindrance model were proved to be self-consistent in the characterization of the location of coke. The location information of coke was further verified by the typical method of nitrogen adsorption-desorption analyses of a series of partially oxidized samples prepared by TPO method. [ABSTRACT FROM AUTHOR]

The combination with carbon capture and storage (CCS) can significantly reduce CO 2 emission in power generation systems, however, it remains to be clarified whether the CCS combination can make the power generation systems more sustainable by comprehensively taking account of economic, social and environmental effects. In this study, a novel multi-criteria decision-making (MCDM) mathematical framework was developed to evaluate the sustainability of power generation systems using either fossil energy (with or without CCS) or renewable energy sources. In the mathematical framework, interval numbers are used to retain the objective uncertainties, and an improved Grey-Decision Making Trial and Evaluation Laboratory (G-DEMATEL) method is employed to determine the weights of the evaluation criteria, which can avoid subjective uncertainties while considering the interactions between evaluation criteria. According to the affecting factors calculated by G-DEMATEL, the interaction between criteria can be visualized and key criteria can be identified more intuitively. Finally, the interval Vlsekriterijumska Optimizacijia I Kompromisno Resenje (VIKOR) method is employed to rank the sustainability of alternative power generation systems. In order to verify the developed framework, the sustainability of 6 power generation systems was assessed and compared by considering 10 criteria from dimensions of technology, environment, economy and society. The results show that "Wind power" is assessed as the most sustainable technology and the criterion of "Global warming" has the greatest impact on the sustainability of power generation systems, while the sustainability of power generation systems using fossil energy can be significantly improved by combining with CCS. • A framework for assessing the sustainability of power generation systems is proposed. • The effect of combining with carbon capture and storage is investigated. • An objective weighting method that consider the interaction of criteria is developed. • An approach is developed for visualizing the interaction between the criteria. [ABSTRACT FROM AUTHOR]

More and more groundwater has been polluted recently, and technologies for groundwater contamination remediation are of vital importance; however, it is usually difficult for the users to select the most suitable technology among multiple alternatives. In order to address this, this study aims at developing a sustainability assessment framework for prioritizing the technologies for groundwater contamination remediation by combining the concept of sustainability and multi-criteria decision making (MCDM) method. A criterion system which consists of six criteria in three aspects has been proposed for sustainability assessment of technologies for groundwater contamination remediation, and a novel MCDM method by combining the logarithmic fuzzy preference programming based fuzzy analytic hierarchy process and the improved ELECTRE method has been developed for prioritizing the alternatives. In order to illustrate the developed methodology, four technologies including pump-treat (P&T), monitored natural attenuation (MNA), permeable reactive barriers (PRB), and air sparging (AS) have been studied, and the results show that the proposed methodology is feasible for prioritizing the technologies for groundwater contamination remediation for the stakeholders/decision-makers. [ABSTRACT FROM AUTHOR]

• Double liquid-only side-stream distillation (DLSD) for separating ethanol, n -propanol and n -butanol mixture. • Temperature control schemes without composition measurement for DLSD are proposed. • Single temperature control (STC) and temperature difference control (TDC) for DLSD are compared. • TDC with feedforward action has better performance by a factor of 5 or more in total integral absolute error. The investigation of dynamic controllability of double liquid-only side-stream distillation (DLSD) is necessary due to its good potential for separating multicomponent mixtures in industrial practice. However, control strategy for DLSD is unique and complex owing to the existence of liquid side transfer streams. This study proposed three temperature control schemes without composition measurement for DLSD, i.e., single temperature control without feedforward structure (CS1), single temperature control and temperature difference control with feedforward structure (CS2 and CS3). Results demonstrate that DLSD process can be operated smoothly under ±20% feed flow rate and composition disturbances. The use of feedforward structure in CS2 and CS3 eliminates the transient deviations in the responses of product purities in CS1. Overall, CS3 provides better control for DLSD than CS1 and CS2 in terms of lower total sum of integral absolute error (by a factor of nearly 50 and 10, respectively). [ABSTRACT FROM AUTHOR]

Abstract: An unsteady-state model is proposed to describe the complete dynamic process of a positively pulsed corona discharge nonthermal plasma reactor. Case studies of the NO removal in an atmosphere of nitrogen are conducted with different initial NO concentrations. The electron collision reaction kinetics can be treated with a conventional Arrhenius rate expression. The removal of NO proceeds mainly via destruction by the N and N2(A). Twenty reactions with eight species can describe the reaction mechanism for NO removal in nitrogen very well. Two different initial conditions were applied to study the two dependent concentration distributions. It is demonstrated that the steady state model is a special case of the unsteady state model. Simulation results show excellent agreement with experimental data. The approach presented in this work is universal and can be applied to other pulsed corona discharge systems. [Copyright &y& Elsevier]

[Display omitted] • Neutralization titration can reduce the acid density and strength of HZSM-5 zeolite. • The neutralization reaction just occurs in liquid phase rather than in solid phase. • Nature of neutralization titration is solid phase ion exchange between Na+ and H+. • Neutralization method facilitates the removal of extremely strong acid sites. • Both coke amount and harmfulness per unit mass of coke can be suppressed. Reducing the acid density and strength of HZSM-5 zeolite are typical strategies to inhibit coke deposition during catalytic cracking reactions. Herein, direct titration of HZSM-5/H 2 O suspension using dilute NaOH aqueous solution at room temperature was introduced to neutralize excessive Brønsted acid sites of HZSM-5 zeolite (Si/Al = 25). SEM, XRD, N 2 adsorption and n -propylamine temperature-programmed decomposition confirmed that simultaneous acid strength weakening and acid density reducing were achieved without obvious influence on crystalline or textural property. The evolution of the surface charge during the titration process tracked by Zeta-potential measurement reveals that the mechanism of such neutralization is: liquid phase neutralization between H+ and OH− & solid phase ion exchange between Na+ and H+. Supercritical catalytic cracking of n -dodecane over a series of partial neutralized HZSM-5 catalysts showed that moderate neutralization can enhance the conversion of n -dodecane by alleviating both the coke amount and harmfulness per unit mass of coke. [ABSTRACT FROM AUTHOR]