Amount Of Dilution Research Articles

Physicochemical and Electrochemical Compatibility of High-Concentrated Solvate Ionic Liquids and Low-Viscosity Dilute Solvent

Lithium-sulfur battery has been attracted attention as a next-generation battery of large capacity. Lithium-sulfur battery has reversible theoretical capacity of 1,672mA h g-1. This is 10 times the theoretical capacity compared with conventional positive electrode materials such as LiCoO2 using Li-ion battery. One serious problem of lithium sulfur battery is dissolution of lithium polysulfide (Li2S x ) as reaction intermediate into the electrolyte solution during charge/discharge reaction. This causes degradation of the charge/discharge cycle characteristics and coulombic efficiency of the battery. In order to solve this problem, “solvate ionic liquid (SIL)” is proposed as new electrolyte, because dissolution of Li2S x can be suppressed owing to weak Lewis acidity/basicity. For example, significant improvement for stability of electrolyte solution has been reported by high-salt concentration (ether series[1]/acetonitrile[2]) owing to strong interaction between Li salt and solvent molecule. However, high-concentration electrolyte exhibits large viscosity. And the electrolyte systems has risks of rate performance for high rate charge/discharge operations. Therefore, in order to obtain low viscosity electrolyte, we proposed to add low viscosity dilute solvent into electrolyte[3]. Most important demands for dilute solvent are, Improvement of rate performances for batteries by low viscosity of electrolyte solutionStabilization of solvated structure between Li salt and solvent molecule with/without dilute solvent. In this study, we investigated physicochemical effects for understanding compatibility of two effective approaches of super-concentrated Li salt electrolyte and non-interactive dilute solvent. In this study SIL sample, [Li(G4)0.8]TFSA (G4: CH3-O-(C2H4O)4-CH3, TFSA:N(SO2CF3)2) was prepared in Ar-filled glovebox. Molar ratio of [Li(G4)0.8]TFSA was G4:LiTFSA=0.8:1. In addition We added given amount of 1,1,2,2, - tetrafluoroethyl-2,2,3,3-tetrafluoropropylether (HFE) dilute solvent into SIL, and measured temperature dependences of viscosity and density of prepared sample. Fig.1(a) showed the composition dependences of the viscosity from 10 to 80℃ (h) for SIL/HFE mixtures. We confirmed that diluting HFE decreased viscosity [Li(G4)0.8]TFSA. Fig.1(b) showed the temperature dependences of the density from 10 to 80℃ (ρ) for SIL/HFE mixtures. ρ values of HFE were larger than that of SIL ones owing to the difference of fluorine density between SIL and HFE. At this time, we assumed SIL as one molecule, excess densities (E ρ) were expressed as following, E ρ=ρ-(xρSIL+(1-x)ρHFE) Where x, ρSIL and ρHFE are mole fraction of SIL, ρ of neat SIL and HFE, respectively. Fig.1(c) shows mole fraction dependences of E r for SIL-HFE mixtures. E r always shows a negative value in the temperature range below 30℃. Therefore, by mixing SIL and HFE, and suggested that the density decreasing. This result correlated with spectroscopic method that coordination structure of SIL and G4 doesn’t change significant in dilute HFE[4]. In this presentation, relationships between lithium-sulfur battery performance (rate properties) and composition of [Li(G4)0.8]TFSA/HFE will be reported, and also will be discussed optimum dilution amount of HFE. Reference s : [1]K. Yoshida et al, J. Am, Chem. Soc. 2011, 133, 13121. [2]Y. Yamada et al, J. Am. Chem. Soc. 2014, 136, 5039. [3]K. Dokko et al, J. Electrochem. Soc. 2013, 160, A1304. [4]S. Saito et al, J. Phys. Chem. B 2016, 120, 3378. Figure 1

Effect of stoichiometric mixture fraction on soot fraction and emission spectra with application to oxy-combustion

Many proposed oxy-combustion concepts for carbon capture incorporate the recycling of flue gas which is used as a dilution gas to aid in the control of temperature and heat flux. Improvements in efficiency may be realized by significantly reducing the recycle flue gas (RFG), however, in application, care must be taken to avoid excessive radiant heat flux and gas temperature. One of the features oxy-combustion, unlike air-fired combustion, is that the oxygen and dilution gases are initially separated. RFG can, for example, be strategically blended with either the fuel stream, or oxidizer stream, or both, which affects the stoichiometric mixture fraction, Zst. In this work, the effects of the amount of dilution, or RFG, and Zst on soot fraction are experimentally investigated in a laminar coflow flame. Carbon dioxide is employed as the dilution gas to simulate the recycling of dry flue gas. Soot fraction and temperature are quantitatively determined by a flame image processing technique. In addition, the visible and near-IR emission spectra are given. When dilution, or RFG, is reduced, while holding Zst constant, soot formation and thermal radiation increase due to higher temperature. However, high temperature flames with reduced or zero soot are achieved by increasing Zst via the combination of fuel dilution and oxygen enrichment. This study highlights the inherent flexibility of oxy-fuel combustion, which offers the opportunity to control flame temperature and gas volume while independently controlling soot formation and radiant heat transfer.

Microphysical and kinematic processes associated with anomalous charge structures in isolated convection.

Microphysical and kinematic characteristics of two storm populations, based on their macroscale charge structures, are investigated in an effort to increase our understanding of the processes that lead to anomalous (or inverted charge) structures. Nine normal polarity cases (mid-level negative charge) with dual-Doppler and polarimetric coverage that occurred in northern Alabama, and six anomalous polarity cases (mid-level positive charge) that occurred in northeastern Colorado are included in this study. The results show that even though anomalous polarity storms formed in environments with similar instability, they had significantly larger and stronger updrafts. Moreover, the anomalous polarity storms evidently have more robust mixed-phase microphysics, based on a variety of metrics. Anomalous polarity storms in Colorado have much higher cloud base heights and shallower warm cloud depths in this study, leading us to hypothesize that anomalous polarity storms have lower amounts of dilution and entrainment. We infer positively charged graupel, and therefore high supercooled water contents, in the mid-levels of the anomalous storms based on the relationship between colocations of graupel and inferred positive charge from Lightning Mapping Array data. Using representative updraft speeds and warm cloud depths, the time required for a parcel to traverse from cloud base to the freezing level was estimated for each storm observation. We suggest this metric is the key discriminator between the two storm populations and leads us to hypothesize that it strongly influences the amount of supercooled water and the probability of positive charge in the midlevels, leading to an anomalous charge structure.

Examination of Yang’s marine water filter phenomenon

This paper examined Yang’s Marine Water Filter Phenomenon based a case study on plumbum (Pb) contents in Jiaozhou Bay 1988. Results showed that the horizontal absolute loss amounts of Pb in surface and bottom waters in Jiaozhou Bay in 1988 were 10.03-23.53 μg L-1, and the horizontal relative loss amounts of Pb in surface and bottom waters were 39.36-89.08%. The vertical absolute dilution amount and the vertical relative dilution amount were 0.96-23.12 μg L-1 and 6.37-93.94%, respectively. The vertical absolute accumulation amount and the vertical relative accumulation amount were 1.67 μg L-1 and 9.96 μg L-1, respectively. Once substances are transporting through a certain waters, the contents would be losing greatly, no matter from any direction, no matter in surface layer or bottom layer. This phenomenon was named as Yang’s Marine Water Filter Phenomenon. Finally, this phenomenon was examined and confirmed.

Graphene as a Mechanically Active, Deformable Two-Dimensional Surfactant.

In crystal growth, surfactants are additive molecules used in dilute amount or as dense, permeable layers to control surface morphologies. We investigate the properties of a strikingly different surfactant: a 2D and covalent layer with close atomic packing, graphene. Using in situ, real-time electron microscopy, scanning tunneling microscopy, kinetic Monte Carlo simulations, and continuum mechanics calculations, we reveal why metallic atomic layers can grow in a 2D manner below an impermeable graphene membrane. Upon metal growth, graphene dynamically opens nanochannels called wrinkles, facilitating mass transport while at the same time storing and releasing elastic energy via lattice distortions. Graphene thus behaves as a mechanically active, deformable surfactant. The wrinkle-driven mass transport of the metallic layer intercalated between graphene and the substrate is observed for two graphene-based systems, characterized by different physicochemical interactions, between graphene and the substrate and between the intercalated material and graphene. The deformable surfactant character of graphene that we unveil should then apply to a broad variety of species, opening new avenues for using graphene as a 2D surfactant forcing the growth of flat films, nanostructures, and unconventional crystalline phases.

Quantification of vertical and horizontal loss of Hg in Jiaozhou Bay 1988

This paper quantified the horizontal and vertical loss of Hg in Jiaozhou Bay based on investigation data on surface and bottom waters in six sampling sites in April and July 1988. Results showed that the horizontal absolute loss amounts of Hg contents in surface and bottom waters were 0.004-0.048 μg L-1, and the horizontal relative loss amounts of Pb contents were 8.16-64.00%, respectively. The vertical absolute dilution amounts of Pb contents were 0.000-0.008 μg L-1, and the vertical relative dilution amounts were 0.00-16.32%. The vertical absolute accumulation amounts of Pb contents were 0.003-0.042 μg L-1, and the vertical relative accumulation amounts were 6.25-56.00%. During the transporting process through the bay mouth, no matter from the internal waters to the open water, or from the open waters to the internal waters, the loss of Hg at horizontal direction could be 8.16-64.00%. In case of the horizontal loss of Hg in surface waters was relative high/low, the horizontal loss of Hg in bottom waters would be also relative high/low. The changes of Hg contents in surface and bottom waters were determined by the migration distance of Hg in surface waters.

Porous metallosilicates for heterogeneous, liquid-phase catalysis: perspectives and pertaining challenges.

Porous silicates containing dilute amounts of tri-, tetra- and penta-valent metal sites, such as TS-1, Sn-β and Fe-ZSM-5, have recently emerged as state of the art catalysts for a variety of sustainable chemical transformations. In contrast with their aluminosilicate cousins, which are widely employed throughout the refinery industry for gas-phase catalytic transformations, such metallosilicates have exhibited unprecedented levels of performance for a variety of liquid-phase catalytic processes, including the conversion of biomass to chemicals, and sustainable oxidation technologies with H2O2. However, despite their unique levels of performance for these new types of chemical transformations, increased utilization of these promising materials is complicated by several factors. For example, their utilization in a liquid, and often polar, medium hinders process intensification (scale-up, catalyst deactivation). Moreover, such materials do not generally exhibit the active-site homogeneity of conventional aluminosilicates, and they typically possess a wide variety of active-site ensembles, only some of which may be directly involved in the catalytic chemistry of interest. Consequently, mechanistic understanding of these catalysts remains relatively low, and competitive reactions are commonly observed. Accordingly, unified approaches towards developing more active, selective and stable porous metallosilicates have not yet been achieved. Drawing on some of the most recent literature in the field, the purpose of this mini review is both to highlight the breakthroughs made with regard to the use of porous metallosilicates as heterogeneous catalysts for liquid-phase processing, and to highlight the pertaining challenges that we, and others, aim to overcome during the forthcoming years.

A framework for more ductile magnesium

Light Metals Development of ductile magnesium alloys is key to their use in reducing the weight of vehicles and other applications. Wu et al. tackle this issue by determining the underlying mechanisms in unprocessed magnesium alloys. Dilute amounts of solutes enhanced certain ductility-improving mechanisms over ones that cause brittle fracture. From this, the authors developed a theory that may be helpful for screening the large number of potential magnesium alloy compositions. Science , this issue p. [447][1] [1]: /lookup/doi/10.1126/science.aap8716

Mechanistic origin and prediction of enhanced ductility in magnesium alloys.

Pure magnesium exhibits poor ductility owing to pyramidal [Formula: see text] dislocation transformations to immobile structures, making this lowest-density structural metal unusable for many applications where it could enhance energy efficiency. We show why magnesium can be made ductile by specific dilute solute additions, which increase the [Formula: see text] cross-slip and multiplication rates to levels much faster than the deleterious [Formula: see text] transformation, enabling both favorable texture during processing and continued plastic straining during deformation. A quantitative theory establishes the conditions for ductility as a function of alloy composition in very good agreement with experiments on many existing magnesium alloys, and the solute-enhanced cross-slip mechanism is confirmed by transmission electron microscopy observations in magnesium-yttrium. The mechanistic theory can quickly screen for alloy compositions favoring conditions for high ductility and may help in the development of high-formability magnesium alloys.

Quantitative analyzing for As’s transferring process in coastal waters in Jiaozhou Bay

This paper quantified the horizontal and vertical transferring processes of As in coastal waters in the southwest and the bay mouth of Jiaozhou Bay using investigation data in July and October 1982. Results showed that the horizontal absolute loss amounts of As contents in surface waters were 0.20-2.44 μg L-1, and the horizontal relative loss amounts in surface waters were 19.23%-87.14%, respectively. The horizontal absolute loss amounts of As contents in bottom waters were 0.27-2.44 μg L-1, and the horizontal relative loss amounts in bottom waters were 25.00%-54.46%, respectively. The vertical absolute dilution amounts of As contents were 0.02-0.28 μg L-1, and the vertical relative dilution amounts were 1.78-16.66%. The vertical absolute accumulation amounts of Pb contents were 0.10-0.86 μg L-1, and the vertical relative accumulation amounts were 7.35%-35.83%. The vertical absolute dilution amount and vertical relative dilution amount of As’s contents were 0.20-0.76 μg L-1 and 19.23%-27.14%, respectively. The vertical absolute accumulation amount and vertical relative accumulation amount of As’s contents were 0.28-4.12 μg L-1 and 25.00%-91.96%, respectively. The changes of As contents in surface and bottom waters were determined by the source inputs of As and the transferring distance of As from the terrisgenous sources.

Modelling for Arsenic’s transferring process in Jiaozhou Bay

This paper quantified the horizontal and vertical transferring processes of As in Jiaozhou Bay using investigation data in April and August 1988. Results showed that the horizontal absolute loss amounts of As contents in surface waters were 0.10-1.42 μg L-1, and the horizontal relative loss amounts in surface waters were 7.04%-25.00%, respectively. The horizontal absolute loss amounts of As contents in bottom waters were 0.04-1.00 μg L-1, and the horizontal relative loss amounts in bottom waters were 2.85%-41.66%, respectively. The vertical absolute dilution amounts of As contents were 0.02-0.28 μg L-1, and the vertical relative dilution amounts were 1.78%-16.66%. The vertical absolute accumulation amounts of Pb contents were 0.10-0.86 μg L-1, and the vertical relative accumulation amounts were 7.35%-35.83%. During the transferring processes through the bay mouth, no matter from the internal waters to the open water, or from the open waters to the internal waters, As contents in both surface and bottom layers were decreasing in a certain degree. The changes of As contents in surface and bottom waters were determined by the transferring distance of As in surface waters.

Yang’s marine bay filtration phenomenon on substance’s content

This paper established definition and formula for horizontal and vertical changes of substance’s contents were established, and provided a case study on plumbum (Pb) contents in Jiaozhou Bay 1987. Results showed that the horizontal absolute loss amounts of Pb contents in surface and bottom waters were 0.06 to 20.66 μg L-1, and the horizontal relative loss amounts of Pb contents were 2.30 to 83.84%, respectively. The vertical accumulation amounts of Pb contents were 0.00 to 8.61 μg L-1, and the vertical accumulation amounts were 0.00 to 68.38%. The vertical dilution amounts of Pb contents were 0.00 to 13.56 μg L-1, and the vertical dilution amounts were 0.00 to 55.03%. The bay mouth was playing a role of a filter. Pb contents were difficult to be transported from the open waters to the bay, and were difficult to be transported from the bay to the open waters. This phenomenon determined by the special geographic and geomorphic conditions of the bay, was named as Yang’s marine bay filtration phenomenon.

Growth of defect-free GaAsSbN axial nanowires via self-catalyzed molecular beam epitaxy

Bandgap reduction of 10% by incorporation of a dilute amount of N is reported for the first time, in axial GaAsSb nanowires (NWs) grown on Si (111) via Ga-assisted molecular beam epitaxy. Impact of N incorporation on the surface morphology, NW growth kinetics, and their structural and optical properties were examined. Dilute nitride NWs with Sb composition of 7 at% did not exhibit any noticeable planar defects, as revealed by the absence of satellite twin peaks in the selected-area diffraction pattern and high-resolution transmission electron microscopy imaging. Point defects were also minimal in as-grown dilute nitride NWs, as ascertained from the comparison of low-temperature photoluminescence spectra as well as the shape and shift of Raman modes, with in situ annealed NWs in different ambients. Evidence of enhanced incorporation of N was found in the NWs in situ annealed in N ambient, but with deteriorated optical quality due to simultaneous creation of N-induced defects. The lack of any noticeable defects in the as-grown GaAsSbN NWs demonstrates the advantage of the vapor–liquid–solid mechanism responsible for growth of axial configuration over the vapor–solid growth mechanism for core–shell NWs as well as their thin film counterpart, which commonly exhibit N-induced point defects.

Single Pt atoms deposition on g-C3N4 nanosheets for photocatalytic H2 evolution or NO oxidation under visible light

Generally, the outstanding photoactivity of the semiconductor photocatalyst often attributes to the loaded Pt or H2PtCl6 solution. However, the utilization efficiency of Pt is relatively low due to the agglomeration during the loading or photocatalytic reaction process. Here, we have successfully synthesized the single Pt atoms supported on g-C3N4 nanosheets (Pt-SA-CN) with dilute amounts of Pt (<0.3 wt% Pt) by a facile incipient wetness impregnation. The single Pt atoms are uniformly embedded into the g-C3N4 nanosheets via PtN coordination bonds. Surprisingly, with the introduction of single Pt atoms, the Pt-SA-CN photocatalysts exhibit both higher photocatalytic H2 evolution and photo-oxidation of NO to NO3−. Especially, the Pt0.2-SA-CN photocatalyst displays the most excellent photocatalytic performance in the series of Pt-SA-CN samples, and even higher than that of the g-C3N4 nanosheets in H2PtCl6 (1 wt% Pt) solution and the Pt loaded on g-C3N4 surface by photodeposition method. The utilization efficiency of Pt has a considerable enhancement and the photoactivity is also improved. The reasons for the enhanced photocatalytic performance of Pt-SA-CN samples are also further discussed.

Flame fluctuations in Oxy-CO2-methane mixtures in swirl assisted distributed combustion

Swirl assisted oxy-methane combustion investigated here has focused on the impact of carbon dioxide dilution. Carbon dioxide dilution is essential as it lowers the flame adiabatic temperature and flame speed of oxy-fuel combustion leading to a more stable operation. However, carbon dioxide dilution may result in flame fluctuations, under fuel lean conditions. Experiments using a swirl burner examined the flame fluctuations with different amounts of CO2 dilution, with the goal to achieve stable oxy-CO2-methane combustion via colorless distributed combustion (CDC). This novel CDC technique has shown significant performance gains in gaseous fuel-air flames on emission reduction, enhanced thermal field uniformity, noise reduction, and improved flame stability. Results have shown that for oxy-CO2-fuel combustion, most of the heat release fluctuations had frequencies below 60Hz. The results obtained revealed that increase in CO2 dilution increased the magnitude of flame fluctuation till a maximum of 28% O2 concentration in the oxidizer. Further increase in dilution gases and reduction in O2 concentration led to a more stable flame, along with more favorable conditions for colorless distributed combustion. Data analysis of flame images revealed the source of oscillations under different conditions. At maximum fluctuations with 28% O2, the flame oscillated between two modes leading to unstable operation and large fluctuation in the heat release signal. Decrease in oxygen concentration to below 27%, promoted a more stable flame behavior, occupying a larger flame volume, which is characteristic of distributed combustion. Further reduction in O2 led to flame blow off at around 21% O2. This work outlines the importance CO2 dilution in oxy-fuel flames for achieving stable distributed combustion and mitigate the increased oscillations normally encountered in higher oxygen concentration flames.

Acoustic and heat release signatures for swirl assisted distributed combustion

The acoustic signal and heat release fluctuations are examined from a swirl combustor using methane as the fuel. The focus was on flame stability and noise emission that have direct relevance in further developing distributed combustion for gas turbine applications and oxy-fuel combustion. Three regimes are examined in this paper, the first being a swirl mode at equivalence ratios between 0.9 and 0.55. The second one being distributed combustion, achieved through N2/CO2 dilution to reach oxygen concentration below 15%, fostering distributed reaction. The third was oxy-fuel flame using increased amounts of CO2 dilution to reach distributed reaction. For the first case, lowering the equivalence ratio led to a reduction in the peak sound pressure level around 500Hz and a decrease in heat release fluctuations. For all the equivalence ratios, close coupling between acoustic signature and heat release fluctuations existed around 200Hz. Distributed combustion, achieved at oxygen concentration below 15%, showed a much lower peak sound pressure levels at the 500Hz range with no coupling between heat release fluctuations and acoustic signal, outlining the flame stability at this regime. Also, the noise emission levels were significantly reduced under this mode. For the third regime, increase in CO2 dilution resulted in high heat release fluctuations and an unstable flame which oscillated between two different flame modes, a feature that did not exist in the first two regimes. Further increase in CO2 led to achieving distributed reaction and a much more stable flame as compared to its oscillatory behavior at lower CO2 amounts, along with reduced noise emission levels. This outlines the possibility of achieving distributed combustion in a stable manner via CO2 dilution in oxy-fuel flames.

The Use of Activated Partial Thromboplastin Time As a Surrogate to Predict Residual FVIII Activity in the Bethesda Assay

Introduction: Bethesda assays, used in the quantification of factor VIII inhibitors, are time and labor intensive. They are performed by mixing one part of normal pooled plasma (NPP) with an equal amount of serial dilutions of patient plasma in imadizole buffered saline (IBS), and incubating at 37°C for 2 hours. After the incubation time, most laboratories perform factor VIII (FVIII) activities on each tube. These results are divided by the activity resulted on the control (NPP+IBS) to obtain the percent residual activity. The dilution with a percent residual FVIII activity between 25-75% is then converted to a Bethesda Unit using the Bethesda graph. This value is multiplied by the dilution to calculate final Bethesda units/mL.We propose an alternative method, involving performing partial thromboplastin times (PTTs) on all dilution tubes and only performing FVIII activity testing on a limited number of tubes e.g. 2 tubes rather than all 10 tubes. The study below describes the methodology and provides data to show how the PTT can be used as a surrogate. Using PTTs may reduce cost per test by reducing the amount of FVIII deficient plasma used for FVIII activity testing, especially in the case of very high titer inhibitors.Methods: Serial dilutions of patient plasma with IBS are prepared to the 512 dilution (10 tubes) and incubated with an equal amount of NPP along with a control consisting of IBS and NPP. PTTs are run using Siemens Actin FSL reagent on the BCS coagulometer (Siemens) on all 10 tubes and the control. The tube with a resultant PTT within 5 seconds above the control is identified and then that tube, along with the next higher dilution, are tested for residual factor VIII activity (ACL TOP, Instrumentation Laboratory). These results are used to calculate the percent residual FVIII activity and Bethesda units/mL as described above. To support our hypothesis, we performed PTT and FVIII activities on all dilution tubes.Results: We performed 14 inhibitor assays on 9 patients. 44% (4/9) had congenital hemophilia A with an inhibitor and 56% had acquired hemophilia A. Table 1 shows results from dilution tubes that resulted in residual FVIII activities between 25-75%. The dilutions with residual activity closest to 50% were used in the final interpretation and are bolded. Using the 5 seconds above control PTT to identify dilutions to limit FVIII assays correlated with residual FVIII activities in 12 of the 14 samples tested (86%). Furthermore, this method identified the dilution with the residual FVIII activities closest to 50% in 10 of the 12 samples.Two samples demonstrated no correlation between PTT and FVIII activities. These samples had low titer inhibitors (<5 BU), which could have been predicted by the low PTTs in the first two dilutions. In these cases, serial FVIII activities were used in calculations. More data is needed to definitively say whether this methodology could not be used for low titer inhibitors.Conclusion: An alternative method, using PTT testing to perform targeted FVIII activity testing, may be used in the Bethesda Assay. [Display omitted] DisclosuresSarode:CSL Behring: Consultancy, Honoraria.

Effect of thermal annealing and nitrogen composition on quantum transport in GaInNAs alloy based modulation doped quantum well structures

Effect of thermal annealing on quantum transport properties have been investigated on as-grown and annealed n-type modulation doped GaInNAs/GaAs quantum well (QW) structures with various nitrogen concentration in low (B < 0.1 T) and high magnetic field (up to 18 T) regions between 75 mK and 1 K. We have observed pronounced plateaus in quantum Hall effect results. The shape of the plateaus do not have a temperature-dependent characteristic for both as-grown and annealed samples. On the other hand, because electron mobility decreases with increasing nitrogen concentration and enhances upon annealing process, the plateaus have more flattened characteristic. The temperature-dependent low field magnetoresistance measurements reveal that the samples exhibit weak antilocalization, which is affected from nitrogen concentration and thermal annealing. Electronic transport parameters such as spin coherence, phase coherence and elastic scattering times, Rashba parameter and spin-splitting energy are extracted from low field magnetoconductivity plots. It is shown that dilute amount of nitrogen composition is an important parameter, which affects the strength of the spin-orbit interaction due to the strongly localized electron states and disorder-induced electron momentum scattering. The longest spin relaxation time is observed for the sample with the highest nitrogen composition and the lowest electron mobility. The calculated Rashba parameter, spin-orbit splitting energy and spin relaxation time for as-grown and annealed samples reveal that thermal annealing causes a decrement in these parameters, but increasing nitrogen composition leads to an increase in spin relaxation time. Therefore both nitrogen composition and thermal annealing can be used to manipulate the spin-orbit coupling strength in GaInNAs-based modulation doped QW structures.

Precipitation behavior and its effects on tensile properties of FeCoNiCr high-entropy alloys

In this work, we present a systematic study on the precipitation behavior and mechanical properties of a FeCoNiCr-based high-entropy alloy alloyed with dilute amounts of Ti and Al, (FeCoNiCr)100-x-yTixAly (where x = 1–3, y = 4–9 at.%). It was found that, upon aging, nano-sized L12-Ni3(Ti, Al) particles are formed within grains, whilst L21-(Ni, Co)2TiAl Heusler particles are formed mainly along grain boundaries. The relative thermal stability of the two phases were studied at different aging temperatures (700–900 °C) with various durations of time (up to 48 h) and the results were directly compared with Thermo-calc calculations. Tensile tests were also conducted on alloys aged under different conditions. The measured properties, including strength and ductility, were correlated with the microstructure of aged (FeCoNiCr)100-x-yTixAly alloys, with particular attention on the distribution and morphology of the two kinds of precipitate. Whereas both phases could contribute to the strengthening of the alloys via either Orowan bowing or particle shearing mechanism, the brittle (Ni, Co)2TiAl Heusler phase was found to mainly affect the tensile plasticity. A simple composite model was proposed to describe the plastic strain of alloys. Based on observed microstructure and its corresponding mechanical performance, the alloy with the composition of (FeCoNiCr)94Ti2Al4, when aged between 700 and 800 °C, gives the best balanced strength/ductility properties.

Groundwater Infiltration Potential (GWIP) as an aid to determining the cause of dilution of waste water

Groundwater infiltration through leaking sewers represents a considerable fraction of the total amount of wastewater dilution. In search for an easy-to-determine yet acceptably accurate estimation of the likelihood of groundwater infiltration into leaking sewers, the parameter ‘groundwater infiltration potential’ or shortly GWIP was defined. GWIP expresses the extent to which groundwater infiltration could – in contrast to the inflow of surface water – be a cause of dilution of sewage. The GWIP is determined by a comparison between the elevation of the groundwater table with the position of the sewer conduits per geo-spatial aggregation level (GAL). This first order analysis compares sets of three representative figures of the groundwater table’s elevation, i.e. the minimum, the maximum and the average level with sets of two representative values of the pipes’ positions, i.e. average invert and soffit levels.A GWIP map can be set-up indicating per GAL a GWIP score that represents a generic evaluation of the common (i.e. most occurring or representative) situation regarding the presence of the groundwater table versus the elevations of the sewer system. In this way the GWIP map can assist in the determination of the overall most likely origin – either surface water or groundwater – of dilution per GAL. Eventually this facilitates strategic decisions regarding the search for particular locations of dilution, and subsequently for the selection of specific remediation measures. The methodology is developed on a local scale of Flanders, Belgium but is generic and therefore applicable to any other region provided that information on the elevation of the sewer system and groundwater table is available.