Preferential Solution Research Articles

Effect of ethanol on the density and viscosity of choline chloride/urea eutectic system

The densities and viscosities of choline chloride/urea deep eutectic solvents (DESs) at molar ratios of 1:1.5, 1:2, and 1:2.5 (abbreviated as [ChCl][Urea]1.5, [ChCl][Urea]2 and [ChCl][Urea]2.5) were measured in this work. In addition, the effects of ethanol on the density and viscosity of choline choloride/urea DESs were also investigated. The experimental density and viscosity data were obtained from 303.15 K to 323.15 K at atmospheric pressure. The measurements were carried out using digital vibrating U-tube densimeter and Ubbelohde capillary viscometer. The Jouyban-Acree model was used to correlate the experimental density and viscosity data. In addition, for comparison purpose, the viscosity model based on the preferential solution theory was also used for the viscosity correlation. The excess molar volumes and viscosity deviations of the studied mixtures were calculated from the experimental data, and the results were analyzed. The Redlich–Kister equation was used to correlate the excess molar volumes and viscosity deviations of the ethanol/[ChCl][Urea]x mixtures.

Exploration of Phase Dissolution during Solution Treatment for a New Al-3.86Cu-0.89Li-0.38Mg-0.28Ag Alloy

The dissolution of the second phase during solution treatment was of great importance for achieving preferential properties via aging treatment for Aluminum-Lithium (Al-Li) alloys. The microstructure characteristics of an extruded Al-Li alloy and its second phase dissolution during solution treatment were studied, while related electrical conductivity and tensile properties after ageing were tested for verification. The results indicated that as the alloy solution was treated from 500°C to 520°C with a soaking time of 1.5h, the Cu-rich phase dissolved into the matrix continuously. The statistics of remained phase area fraction ascertained no obvious decrement from 510°C to 520°C and only Fe-containing phase with large size was detected. Meanwhile, tensile properties under the same aging regime declared a higher strength was obtained at 510°C. As the solution time varied from 0.5h to 5h at 510°C, the Cu-rich phase was detected in a soaking time of 0.5h while disappeared after 1.5h and only the Fe-containing phase was observed. Correspondingly, electrical conductivity exhibited a moderate growth while tensile strength obviously increased from 0.5h to 1.5h and then maintained a platform, which revealed a preferential solution regime of 510°C/1.5h. This gives a reference for the second phase dissolution during solution treatments and furtherly obtaining preferential solution regimes.

Examining sediment infill dynamics at Naracoorte cave megafauna sites using multiple luminescence dating signals

Relatively little is known about the long-term sediment accumulation dynamics of Naracoorte Cave Complex (NCC) solution pipe cavities, and many of the megafauna-bearing infill deposits at this globally significant Australian Pleistocene fossil locality remain partially dated or lack any numerical age control. In this study, we assess the suitability of three different luminescence dating signals for improving existing chronologies at six Late and Middle Pleistocene NCC sites (n = 22 samples), and we undertake multi-site examinations of NCC sediment infill dynamics spanning the last 550 thousand years (ka). Modern analogue samples collected from above and beneath two active cave entrances confirm that single-grain OSL, single-grain TT-OSL and multi-grain pIR-IRSL signals can be reset down to insignificant residual levels (<10−1–100 Gy) when compared with the natural dose ranges of interest for most NCC palaeontological applications. Replicate luminescence dating comparisons performed at six NCC fossil sites (n = 15 samples) reveal consistent ages for twenty-eight out of thirty-one paired OSL–TT-OSL, OSL–pIR-IRSL and TT-OSL–pIR-IRSL datasets. Nineteen of the twenty Middle to Late Pleistocene samples analysed from the NCC sites produce homogeneous OSL, TT-OSL and pIR-IRSL De datasets suggesting that the NCC solution pipe deposits considered here are generally not affected by syn-depositional mixing complications that can take place within closed karst cavities (i.e., the remobilisation of unbleached grains from pre-existing cave floor sediments, and their subsequent translocation and incorporation into deposits within deeper parts of the cavity along with externally bleached, allochthonous grain populations). Detailed examination of solution pipe dynamics at Smoke Tortoise Cave (SMT) reveals a complex accumulation history focused on the marine isotope stage (MIS) 9 and MIS 7 interglacial complexes, as well as the MIS 8e interstadial. The SMT case study highlights that NCC solution pipes are not simply associated with short-lived opening and sediment accumulation events, but may involve multiple, discontinuous deposition episodes and reactivation events. An initial multi-site examination of all published NCC infill chronologies (n = 70) appears to suggest statistically significant, preferential solution pipe development during the relatively wet parts of interglacial or interstadial cycles. The non-uniform infill age distribution implies that NCC solution pipe dynamics may have exerted taphonomic biases on fossil accumulation, which should be taken into consideration when reconstructing long-term palaeoecological histories from NCC solution pipe cavities.

Improving the bonding capacity of recycled concrete aggregate by creating a reactive shell with aqueous carbonation

Recycling end-of-life concrete back to construction industry in the form of aggregate has been a preferential solution to deal with the huge quantities of waste concrete. However, the recycled concrete aggregate (RCA) contains residual cement paste which adversely affects its properties and the resulting new concrete. Based on previous literature, enhancing the ITZ is one of the significant principles to improve the performance of the new concrete. Therefore, in this study, an innovative aqueous carbonation (AC) method was employed to treat modelled RCA, aiming at modifying the surface of the RCA to improve its bonding ability with new mortar and revealing the mechanism. Subsequently, AC was also applied to real RCA to validate its structural changes were compatible with the modelled RCA. Multi-scale investigations including thermogravimetric analysis, scanning electron microscopy, energy-dispersive X-ray spectroscopy line scanning, nanoindentation, solution chemistry analysis, etc. were conducted to characterize the structural changes and the reaction kinetics. The experimental results showed that the surface layers of RCA were significantly modified after AC. A shell-core structure was formed, which included, starting from the outermost region of the RCA, a calcite coating, a silica-rich layer, a partially decalcified layer, and an uncarbonated matrix. The surface modification significantly improved the frictional and tensile bonding strength of RCA with the new mortar by triggering physicochemical changes to the interface. Generally, AC can be considered as an efficient approach for improving the bonding capacity of RCA and therefore promoting the recycling of waste concrete.

Short-term forecasting for supercharged boiler safety performance based on advanced data-driven modelling framework

The safety of boilers is directly related to the operation of steam power plants. Consequently, accurate short-term forecasting model is needed for the robust control of important safety performance parameters. In this study, an advanced data-driven modelling framework based on neural networks is proposed to establish short-term forecasting (STF) models for three safety indicators of a supercharged boiler: main steam temperature (MST), drum pressure (DP) and drum level (DL). To overcome the challenges of external noise and non-stationarity, locally weighted regression (LWR) and differencing method are introduced to improve the model performance. Convolutional neural network (CNN) and long short-term memory network (LSTM) are proved as practical options for STF modelling, while CNN has a lower computational cost. The models show excellent performance on a real dataset containing multiple dynamic processes: the mean absolute percentage errors of the three targets are 0.0041%, 0.0355% and 0.0221% respectively and the forecasting horizon is future 60 timesteps. The sensitivity of STF models to outliers is analyzed. The results show that the models are not sensitive to eroded input. The proposed framework and methods can be a preferential solution to the forecasting modelling of power systems.

First Detection of the Adventive Egg Parasitoid of Halyomorpha halys (Stål) (Hemiptera: Pentatomidae) Trissolcus mitsukurii (Ashmead) (Hymenoptera: Scelionidae) in France.

Simple SummaryThe invasive brown marmorated stink bug (BMSB), Halyomorpha halys, is a polyphagous species and a serious pest worldwide. Classical biological control (CBC), i.e., the introduction of a natural enemy from the native area of the pest, is considered as the preferential solution for BMSB regulation. Adventive populations of exotic egg parasitoids of BSMB, Trissolcus japonicus and T. mitsukurii, have been reported worldwide. With the aim to characterize the French diversity of egg parasitoids associated to various stink bugs including BMSB, field surveys were conducted between 2018 and 2020. Surprisingly, morphological and molecular analyses unambiguously revealed 12 specimens of T. mitsukurii, an Asian egg parasitoid of BSMB. Although its permanent establishment has to be confirmed, this first record in France could actually facilitate CBC initiatives, T. mitsukurii being considered with T. japonicus as the two most promising biological control agents against BMSB.We report the first detection of Trissolcus mitsukurii in France. More than 1860 sentinel egg masses of Halyomorpha halys (BMSB) were exposed in the field during the 2018–2020 period, and 12 specimens of T. mitsukurii emerged from one egg mass. Their taxonomic identification was confirmed both by morphological and molecular analysis. Trissolcus mitsukurii, similar to T. japonicus, is an egg parasitoid of BMSB in its area of origin in Asia, and both species are considered to be candidates for a classical biological control strategy against BMSB. Trissolcus mitsukurii was previously recorded in Italy where it is well established and widespread, and this may be the source of the French population. Possible permanent establishment and dispersion of T. mitsukurii in France should be monitored with emphasis on its potential effect on BMSB populations.

Theoretical Insight into Preferential Interaction Issues and Solution Structure, and Contentious Apparent Hydrated Molar Volume of Cosolute

Background: There seems to be a mathematical or a conceptual error in an equation whose substitution into other equations for the determination of an apparent hydrated molar volume (V1) of a cosolute leads to an incorrect answer.&#x0D; Objectives: The objectives are 1) To show theoretically that the preferential interaction parameter (PIP) is an extensive thermodynamic quantity, 2) rederive new equations and reexamine various equations related to solution structure, 3) apply derived equation for the determination of V1, and 4) determine m-values and cognate preferential interaction parameter (PIP).&#x0D; Methods: The research is mainly theoretical and partly experimental. Bernfeld method of enzyme assay was adopted for the generation of data.&#x0D; Results and Discussion: The investigation showed that equation linking chemical potential of osmolyte to solution structure is dimensionally invalid; PIP was seen as a thermodynamically extensive quantity. Equations for the graphical determination of V1 of the osmolyte were derived. With ethanol alone, there were - m-value and + PIP; with aspirin alone, there were + m-value and - PIP. There was a change in sign in m-value with sucrose and ethanol/aspirin mixture, and a change in sign in PIP when the latter is taken as function of [ethanol]/[aspirin] and [sucrose](c3).&#x0D; Conclusion: A solution structure is as usual determined by either a relative excess or a deficit of the solution component either in the bulk or around the macromolecular surface domain; the PIP remains thermodynamically an extensive quantity. To be valid there is a need to introduce a reference standard molar concentration or activity to some equations in literature. The slope from one of the equations seems to give a valid value for V1 (V1 is «1; is activity coefficient). A known destabiliser may behave as a stabiliser being excluded. Like ethanol, aspirin as cosolute is destabilising and opposed by sucrose.

Surfactant modulated interaction of hydrophobically modified ethoxylated urethane (HEUR) polymers with impenetrable surfaces

HypothesisThe presence of surfactant modulates the surface-chemistry-specific interaction of hard colloidal particles (latex) with HEUR polymers, principally through introducing a preferential solution interaction rather than a competitive surface interaction; addition of surfactant leads to a preponderance of polymer/surfactant solution complexes rather than surface-bound complexes. ExperimentsA range of model formulations comprising a hexyl end-capped urethane polymer (C6-L-(EO100-L)9-C6), sodium dodecylsulfate (SDS) and a series of polystyrene-butylacrylate latices (PS-BA-L) have been characterised in terms of rheology, particle surface area (solvent relaxation NMR), polymer conformation (small-angle neutron scattering) and solution composition to build up a detailed picture of the distribution of the HEUR in the presence of both surfactant and latex. FindingsThere is very weak adsorption of C6-L-(EO100-L)9-C6 to only the most hydrophobic latex surface studied, an adsorption that is further weakened by the addition of low levels of surfactant. Macroscopic changes in the hydrophobic latex system may be interpreted in terms of bridging flocculation at low polymer concentrations. No adsorption of C6-L-(EO100-L)9-C6 is observed in the case of hydrophilic surfaces. In most cases, the observed behaviour of the ternary system (polymer/surfactant/particle) is highly reminiscent of the binary (polymer/surfactant) system at the appropriate composition, suggesting that the polymer/surfactant solution interaction is the dominant one.

Effect of Nb content on corrosion behavior of Ti-based bulk metallic glass composites in different solutions

The effect of Nb content on the corrosion behavior of in-situ (Ti0.45Zr0.31Be0.17Cu0.07)100−xNbx (x = 4, 6, 8, 10, and 12) was evaluated in 0.5 mol/L H2SO4, 0.6 mol/L NaCl, and 1 mol/L NaOH solutions. A dual-phase microstructure which composed of an amorphous matrix and dendrites was observed. Electrochemical measurements in each corrosion medium showed the same trend. The corrosion resistance first increased and then decreased with the addition of Nb content from 4 to 12 at.%. The results show the best corrosion resistance in terms of × = 8 for the alloys. Notably, Nb addition improved the pitting-corrosion resistance of samples in a chloride-containing solution, whereas spontaneous passivation occurred in chloride-free solutions. A preferential solution was observed in the amorphous matrix region in NaCl solution, but a part of dark spots and dents appeared on the surface after the polarization in chloride-free solutions. X-ray photoelectron spectroscopic measurements showed that Nb addition promoted the formation of metal oxide on the surface film, thus inducing a superior corrosion resistance for the bulk metallic glass matrix composites.

Preferential flow behaviour in unsaturated packed beds and heaps: Incorporating into a CFD model

Heap leach stockpiles inevitably contain local voidage heterogeneities due to non-uniform particle size distributions of the ore and other factors that lead to preferential flow paths and solution channelling. The stockpile can also encounter diverse flow conditions due to a number of factors, including storm events, infiltration into dry ore material, cyclic drain down, compaction, migration of fines, all contributing to large variations in local ore permeability and the creation of preferential flow pathways. Non-uniform and adverse flow behaviour within the heap reduces the leaching efficiency which can lead to lower metal recoveries. Therefore, capturing the local flow variations that affect the transport of leach solution within the heap is critical to accurately predicting the leaching kinetics. Experimental data shows how channelling develops due to local heterogeneities that cannot be eliminated by packing alone. Thus, effective modelling of heap leach stockpiles should account for these channelling affects. This paper utilises a robust computational fluid dynamics (CFD) framework that incorporates techniques to account for local preferential flow paths in the heap leach system. The results are compared against liquid flow behaviour in a pseudo two-dimensional column of narrowly sized particles and a more realistic particle size distribution. The methods are then applied to a hypothetical leach to assess the impact of accounting for the flow variability in the heap.

Anisotropic modelling of Opalinus Clay behaviour: From triaxial tests to gallery excavation application

Deep repository in geological formations is the preferential solution considered in many countries to manage high-level nuclear wastes. In Switzerland, the Opalinus Clay is a candidate host rock. In this context, in situ and laboratory tests are conducted on Opalinus Clay to demonstrate the feasibility of deep disposal in this argillaceous formation. This paper presents a constitutive model able to fit the experimental data obtained from some triaxial tests conducted by Jahns (2013) on cores from borehole Schlattingen SLA-1. The elasto-plastic behaviour of Opalinus Clay is reproduced thanks to a Drucker-Prager model, taking into account the anisotropy behaviour of this sedimentary rock. The objective is to employ a single set of parameters representative of the material. In a second version of the model, the stress-dependence of the elastic properties and damage are taken into account. Finally, the parameters calibrated with experimental tests are used to simulate the excavation of a gallery with a second gradient approach.

An Empirical Study of Aggregation Operators with Pareto Dominance in Multiobjective Genetic Algorithm

ABSTRACT Genetic algorithms (GAs) have been widely used in solving multiobjective optimization problems (MOP). The foremost hindrance limiting strength of GA is the large number of nondominated solutions and the computational complexity involved in selecting a preferential candidate among the set of nondominated solutions. In this paper, we analyze the approach of applying aggregation operator in place of density-based indicator mechanism in cases where Pareto dominance method fails to decide the preferential solution. We also propose a new aggregation function () and compare the results obtained with prevailing aggregation functions suggested in the literature. We demonstrate that the proposed method is computationally less expensive with overall complexity of . To show the efficacy and consistency of the proposed method, we applied it on different, two- and three-objective benchmark functions. Results indicate a good convergence rate along with a near-perfect diverse approximation set.

Effect of charcoal addition on the properties of a coke subjected to simulated blast furnace conditions

A pilot oven produced coke with the addition of 7.5wt% charcoal (bio-coke) and the similarly produced base blend coke were subjected to gasification and annealing under the simulated blast furnace conditions. The effect of charcoal addition on the coke properties after gasification and annealing was characterised using Raman spectroscopy, ultra-micro indentation and tensile testing. The addition of charcoal significantly increased the coke reactivity with CO2 as a result of its increased surface area by charcoal. The addition of charcoal made no further contribution to the devolatilisation or mineral reactions of coke during annealing. The charcoal particles were well preserved after annealing at 2273K, but preferentially consumed in the gasification. Annealing temperature had less effect on the graphitisation of the charcoal component compared to the coexisting inert maceral derived component (IMDC) and reactive maceral derived component (RMDC). The charcoal addition had no effect on the microstructure and microstrength of coexisting microtextural types during annealing and gasification. The charcoal presented a higher resistance to fracture than IMDC and RMDC under annealing conditions. The addition of charcoal did not deteriorate the coke resistance to strength degradation under the thermal load of blast furnace. However, charcoal addition caused more severe degradation by gasification as demonstrated by more reduction in the tensile strength of the bio-coke. This was attributed to the preferential solution loss reaction of the charcoal particles leaving voids which coalesced the pores in coke, thereby increasing the defects that cause stress concentration under loading.

A novel interactive preferential evolutionary method for controller tuning in chemical processes

In response to many multi-attribute decision-making (MADM) problems involved in chemical processes such as controller tuning, which suffer human's subjective preferential nature in human–computer interactions, a novel affective computing and preferential evolutionary solution is proposed to adapt human–computer interaction mechanism. Based on the stimulating response mechanism, an improved affective computing model is introduced to quantify decision maker's preference in selections of interactive evolutionary computing. In addition, the mathematical relationship between affective space and decision maker's preferences is constructed. Subsequently, a human–computer interactive preferential evolutionary algorithm for MADM problems is proposed, which deals with attribute weights and optimal solutions based on preferential evolution metrics. To exemplify applications of the proposed methods, some test functions and, emphatically, controller tuning issues associated with a chemical process are investigated, giving satisfactory results.

Hydrogen solubility in zirconium intermetallic second phase particles

The enthalpies of solution of H in Zr binary intermetallic compounds formed with Cu, Cr, Fe, Mo, Ni, Nb, Sn and V were calculated by means of density functional theory simulations and compared to that of H in α-Zr. It is predicted that all Zr-rich phases (formed with Cu, Fe, Ni and Sn), and those phases formed with Nb and V, offer lower energy, more stable sites for H than α-Zr. Conversely, Mo and Cr containing phases do not provide preferential solution sites for H. In all cases the most stable site for H are those that offer the highest coordination fraction of Zr atoms. Often these are four Zr tetrahedra but not always. Implications with respect to H-trapping properties of commonly observed ternary phases such as Zr(Cr,Fe)2, Zr2(Fe,Ni) and Zr(Nb,Fe)2 are also discussed.

Experimental performance comparison of Duobinary and PSBT modulation formats for long-haul 40 Gb/s transmission on G 0652 fibre

Duobinary formats are today considered as being one of the most promising cost-effective solutions for the deployment of 40 Gb/s technology with direct detection on existing 10 Gb/s WDM long-haul (metropolitan and core) transmission infrastructures. Various methods for generating duobinary formats have been developed in the past few years but to our knowledge their respective performances for 40 Gb/s transmission have never been really compared experimentally. Here, we propose to evaluate at 40 Gb/s their respective robustness with respect to the most stringent transmission impairments, namely ASE noise, chromatic dispersion, polarization mode dispersion and nonlinear effects. We demonstrate that, owing to its enhanced resistance to intra-channel nonlinearities as compared to non-return-to-zero, duobinary can permit to reach transmission distances compliant with metropolitan and core applications on G.652 standard single mode fibre when quasi single-channel transmission conditions are met. We show furthermore that shifting optical duobinary filtering from the transmitter output to the receiver input can be of high interest to improve further the system maximum reach. We show also that phase-shaped binary transmission (PSBT) formats are fully compliant with 50-GHz channel spacing and that they are, in terms of transmission performance, as good as partial differential phase shift keying (Partial-DPSK), which is considered by equipment suppliers as the preferential transport solution for deployment of 40 Gb/s technology with direct detection on existing 10 Gb/s WDM metropolitan and core transmission infrastructures.

Recovery of rare earth and cobalt from Co-based magnetic scraps

The reuse of RE and cobalt in Co-based magnetic scraps was studied. The optimized feat lixiviated condition was: 200 mesh, sulfuric acid dosage was of 1.4 times theoretic dosage, temperature was 80 °C and leaching time 1 h. The optimum technology conditions was: Na 2S 2O 8 dosage was of 8 times theoretic dosage, oxidation temperature 80 °C, oxidation time 2 h and pH=4.5. Rare earth was precipitated by saturated (NH 4) 2C 2O 4 solution, after roasting of rare earth oxalate, rare earth oxide was received. Cobalt-iron residue was soaked by hydrochloric acid, the Fe(OH) 3 was preferential solution, pH was adjusted to 1.4 by hydrochloric acid, Co(OH) 3 did not dissolve, cobalt and iron were separated, after roasting of Co(OH) 3, cobalt oxide was received. The total recovery of cobalt was found to be 97% and rare earths was 96%.

Single particle detection: Phase control in submicron Hall sensors

We present a phase-sensitive ac-dc Hall magnetometry method which allows a clear and reliable separation of real and parasitic magnetic signals of a very small magnitude. High-sensitivity semiconductor-based Hall crosses are generally accepted as a preferential solution for non-invasive detection of superparamagnetic nanobeads used in molecular biology, nanomedicine, and nanochemistry. However, detection of such small beads is often hindered by inductive pick-up and other spurious signals. The present work demonstrates an unambiguous experimental route for detection of small magnetic moments and provides a simple theoretical background for it. The reliability of the method has been tested for a variety of InSb Hall sensors in the range 600 nm–5 μm. Complete characterization of empty devices, involving Hall coefficients and noise measurements, has been performed and detection of a single FePt bead with diameter of 140 nm and magnetic moment of μ≈108 μB has been achieved with a 600 nm-wide sensor.

Ordinal preference and inter-rater pattern recognition: Hopfield neural network vs. measures of association

In decision analysis, if the criterion is an ordinal rather than a cardinal one, a preferential solution depends on the inter-rater agreement. The Kendall coefficient of concordance W, the Friedman ranks statistic F r , and the Page L statistic are often used to determine the association among M sets of rankings. However, they may get some anomalies because they all use the cardinal variable "variance" to judge the association. In order to correct the anomalies, we use the modified Hopfield neural network instead to determine the association among M sets of rankings. The results are not only to reduce the unidentified cases but also to solve the anomalies.

Bioleaching of low-grade copper sulphides

The bioleaching behavior of low-grade copper sulphides under the condition of preferential solution flow was investigated through experiments. The experiment of bioleaching was conducted within the multifunction autocontrol bioleaching apparatus. The results show that the concentrations of Cu 2+ and total Fe increase slowly at the beginning. The recovery rate decreases with the increase of depth of dump. The preferential solution happens within the fine region when the application rate is low, and the recovery rate of the fine region is higher than that of the coarse region. The content of fine ore particles within both fine and coarse regions increases during the leaching period, and the preferential solution flow shifts from fine region to coarse region. The surface of the ores at the top of dump is attacked seriously, and the ores in the middle is attacked slightly. There are plenty of crackles on the surface of bottom ores because of the precipitation layer on the surface.