Apparent Boundary Research Articles

Estimation of the excavation damage zone in TBM tunnel using large deformation FE analysis

This paper aims to estimate the range of the excavation damaged zone (EDZ) formation caused by the tunnel boring machine (TBM) advancement through dynamic three-dimensional large deformation finite element analysis. Large deformation analysis based on Coupled Eulerian-Lagrangian (CEL) analysis is used to accurately simulate the behavior during TBM excavation. The analysis model is verified based on numerous test results reported in the literature. The range of the formed EDZ will be suggested as a boundary under various conditions – different tunnel diameter, tunnel depth, and rock type. Moreover, evaluation of the integrity of the tunnel structure during excavation has been carried out. Based on the numerical results, the apparent boundary of the EDZ is shown to within the range of 0.7D (D: tunnel diameter) around the excavation surface. Through series of numerical computation, it is clear that for the rock of with higher rock mass rating (RMR) grade (close to 1st grade), the EDZ around the tunnel tends to increase. The size of the EDZ is found to be direct proportional to the tunnel diameter, whereas the depth of the tunnel is inversely proportional to the magnitude of the EDZ. However, the relationship between the formation of the EDZ and the stability of the tunnel was not found to be consistent. In case where the TBM excavation is carried out in hard rock or rock under high confinement (excavation under greater depth), large range of the EDZ may be formed, but less strain occurs along the excavation surface during excavation and is found to be more stable.

Contact Line and Adhesion Force of Droplets on Concentric Ring-Textured Hydrophobic Surfaces.

Advances made in fabrication of patterned surfaces with well-defined dimensions of topographic features and their lateral dissemination drive the progress in interpretation of liquid spreading, adhesion, and retreat on engineered solid surfaces. Despite extensive studies on liquid droplet spreading and adhesion on textured surfaces in recent years, conformation of the three-phase contact line and its effect on macroscopic contact angle and droplet adhesion remain the focus of intensive debate. Here, we investigate the effect of surface topography on the adhesion force of Cassie-Baxter-state droplets on concentric ring-textured hydrophobic surfaces having rings with lateral dimensions of 5, 10, and 45 μm and separated by 5, 6, and 7 μm trenches, respectively, with fixed depth of 15 μm. Unlike mostly tested surfaces textured with straight ridges, pores, and pillars, where the droplet base contact line is anisotropic and its conformation varies along the apparent boundary, concentric rings are symmetrical and reinforce the microscopic contact line to align to a circular one that reflects the shape of the pattern. In this study, adhesion forces were calculated based on surface tension and Laplace pressure forces and were compared with the experimental forces for both water and ethylene glycol droplets having a varying contact diameter on the concentric ring-pattern at the point of maximum adhesion force. Results show that the microscopic contact line of the liquid retains its circular shape controlled by circular rings of the pattern, irrespectively of the droplet base diameter larger than 0.8 mm, and there is a good agreement between the experimental and calculated adhesion forces.

Training and testing for a transformation of fear and avoidance functions via combinatorial entailment using the Implicit Relational Assessment Procedure (IRAP): Further exploratory analyses

Experiment 1 of the current research attempted to establish fear and avoidance functions for arbitrary stimuli via combinatorial entailment using training and testing versions of the Implicit Relational Assessment Procedure (IRAP). The critical tests for the transformation of functions involved exposure to two separate Test-IRAPs (one for fear and one for avoidance), but both failed to yield any evidence for the transformation of functions. The findings of Experiment 1 contrast with the clear evidence of a transformation of functions via mutually entailed relations that was reported by Leech et al. (2018), thus suggesting a potential boundary condition for the IRAP as a training and testing context (i.e., derived transformation occurs for mutual but not combinatorial entailing). In Experiment 2, we sought to manipulate two of the dimensions of the multi-dimensional multi-level (MDML) framework to determine if they would alter the apparent boundary condition suggested by the results of Experiment 1. Results indicate that levels of derivation and an opportunity to respond to the derived relations play an important role in the transformation of fear and avoidance functions via combinatorial entailment within the IRAP context.

Apparent thinning of human visual cortex during childhood is associated with myelination

Human cortex appears to thin during childhood development. However, the underlying microstructural mechanisms are unknown. Using functional magnetic resonance imaging (fMRI), quantitative MRI (qMRI), and diffusion MRI (dMRI) in children and adults, we tested what quantitative changes occur to gray and white matter in ventral temporal cortex (VTC) from childhood to adulthood, and how these changes relate to cortical thinning. T1 relaxation time from qMRI and mean diffusivity (MD) from dMRI provide independent and complementary measurements of microstructural properties of gray and white matter tissue. In face- and character-selective regions in lateral VTC, T1 and MD decreased from age 5 to adulthood in mid and deep cortex, as well as in their adjacent white matter. T1 reduction also occurred longitudinally in children's brain regions. T1 and MD decreases 1) were consistent with tissue growth related to myelination, which we verified with adult histological myelin stains, and 2) were correlated with apparent cortical thinning. In contrast, in place-selective cortex in medial VTC, we found no development of T1 or MD after age 5, and thickness was related to cortical morphology. These findings suggest that lateral VTC likely becomes more myelinated from childhood to adulthood, affecting the contrast of MR images and, in turn, the apparent gray-white boundary. These findings are important because they suggest that VTC does not thin during childhood but instead gets more myelinated. Our data have broad ramifications for understanding both typical and atypical brain development using advanced in vivo quantitative measurements and clinical conditions implicating myelin.

Lath martensite plasticity enabled by apparent sliding of substructure boundaries

Lath martensite is widely present in advanced high strength steels as the key strengthening phase. Unexpectedly high ductility of lath martensite has been reported in the literature in both single-phase and multi-phase steels, however, without systematic identification of the underlying plasticity mechanisms. In this study, first, well-defined micro-tensile tests are carried out on fully martensitic steel with a clean large substructure and a variety of substructure boundary orientations with respect to the loading direction. Two deformation mechanisms of lath martensite were identified, namely, intra-lath crystallographic slip and apparent substructure boundary sliding, that compete with each other to carry the overall plasticity. The condition under which these two mechanisms are active has been clarified. It is found that boundary sliding is more easily activated than intra-lath crystallographic slip. In addition, for dual phase steel, as an example of multi-phase steels, the probability for sliding of lath martensite boundaries was estimated by boundary orientation characterization and micro-tensile tests. The results suggest that the apparent boundary sliding is also important for lath-martensite-containing multi-phase steels, which would explain prior reports in the literature of unexpectedly high local strains in the martensite regions.

Effects of tectonic stress environment on tectonophysical features of deformed coal

ABSTRACTTo study the effects of the tectonic stress environment on the tectonophysical features of deformed coal, No.8 Mine in the Pingdingshan mine area is used as a study area and the relationship between the development of deformed coal, distribution of fractures, formation of deformed coal and tectonic stress environment are analyzed. The results indicate that the thickness of the bedrock layer should be included in the analysis of the tectonic stress environment for a region of intense tectonic activity. Although the reverse faulting stress regime can control the development of deformed coal, the C seam is extremely sensitive to the stress regime. The most advantageous direction of the deformed coal fractures is consistent with the regional maximum principal stress, and the development of fractures is closely related to the evolution of the tectonic stress environment. The fracture density of the E seam presents a uniform distribution, yet that of the C seam is completely heterogeneous. Superposition and compounding of the tectonic communities evidently increase the fracture density of the deformed coal. There is a relatively apparent boundary between the different types of deformation, which gradually transform from brittle to ductile with a decreasing lateral pressure coefficient. A generalized deformation pattern of the deformed coal is proposed and can be divided into frictional sliding and solid flow.

Field-induced phase coexistence in an artificial spin ice

Artificial spin-ice systems are magnetic metamaterials consisting of nanomagnet arrays that can be designed to study exotic magnetic states not found in natural materials. Typically, these arrays are modelled as interacting binary macrospins that can only be in an up or down state and are described by the Ising model. These materials have demonstrated ordering transitions, but only via a spontaneous symmetry-breaking mechanism. We have designed and studied a quadrupole artificial spin-ice system consisting of interacting plaquettes of coupled single-domain nanomagnets that can be interpreted as a composite, ternary variable. After annealing this system in an external magnetic field, we observe both a ferroquadrupolar and an antiferroquadrupolar phase, with an apparent first-order phase boundary and a coexistence regime. The phase diagram of this material is reminiscent of a model used to describe phase coexistence in the superfluid transition of 4He with 3He impurities. These results illustrate how composite magnetic objects realize exotic statistical physics models beyond the Ising model. Artificial spin-ice materials are usually described by spins that are either up or down. Here, a new type of spin ice is fabricated where the spins can be in one of three states with different coexisting phases separated by a first-order transition.

Grain size effect on the electrical conductivity of submicron Sm-heavily-doped ceria

In order to investigate the grain size effect on the electrical conductivity of the submicron samarium-heavily-doped ceria, the Ce0.8Sm0.2O1.9 (SDC20) ceramics with grain sizes from 128 nm to 533 nm were prepared by sintering at 1000–1300 °C in the air atmosphere. The crystalline structure, micro-morphology, density and electrical conductivity of the SDC20 ceramics were measured and characterized by XRD, SEM, TEM, Archimedes method and electrochemical impedance spectrum, respectively. All the sintered samples show the single SDC phase, low porosity and clean grain boundary without any impurities. The grain sizes of SDC ceramics grow continuously with the rising sintering temperature, and the relative densities increase as the sintering temperature rises from 1000 °C to 1200 °C and then decrease with the temperature from 1200 °C to 1300 °C. The specific grain boundary conductivity of SDC keeps decreasing while the grain and apparent grain boundary conductivities increase during the whole grain size range of 128–533 nm.

Microstructure and Ionic Conductivity of Tysonite-Type (La,Ba)F3

Recently, fluoride ion batteries have been attracting attentions because of their potential for large capacity far beyond that of conventional lithium ion batteries. However, fluoride ion batteries are still not into practical use. One of the problems with fluoride ion batteries is low ionic conductivity in the electrolyte. At this moment, no solid-state fluoride ion conductors, showing high ionic conductivity at room temperature together with a wide electrochemical window, have been developed. Among fluoride ion conductors, Tysonite-type (La,Ba)F3 (LBF) is known to have a wide electrochemical window and exhibit relatively high conductivity near room temperature. However, its conductivity is still needed to be improved. It was reported that the conductivity of a single crystalline LBF was approximately ten times higher than that of the polycrystalline ones. This indicated that microstructural factors in the polycrystalline LBF, such as the density and/or the grain boundary, deteriorate the ionic conduction. Thus, it is important to understand influences of the microstructures on the ionic conductivity for improving the ionic conductivity of LBF. From the above backgrounds, in this study, dense LBF samples with different grain sizes were prepared by using the spark plasma sintering (SPS) method, and their bulk and grain boundary conductivities were evaluated in order to clarify influences of the microstructures on the ionic conductivity. We first evaluated the relation between the microstructures and the ionic conductivity in Tysonite-type La0.93Ba0.07F2.93 by using the samples sintered at 700 to 1000 ºC. The dense samples, having the relative density higher than 95%, could be obtained by the SPS method when the sintering temperature was 800 ºC or higher. The average grain size was about 0.4, 0.5, and 1 μm in the samples sintered at 800, 900, and 1000 ºC, respectively. The conductivity increased with increasing the sintering temperature. From the AC impedance spectroscopy measurements, it was found that the bulk conductivity was almost independent of the sintering temperature, whereas the apparent grain boundary conductivity increased with increasing the sintering temperature. This indicated that the grain growth due to the high sintering temperature decreased the number of grain boundary, thus the apparent grain boundary resistance. Based on above results, we sintered the samples at 1100 and 1200 ºC, aiming further grain growth. The average grain size of the sintered samples became larger, about 20 and 60 μm by sintering at 1100 and 1200 ºC, respectively. However, the conductivity unexpectedly decreased with increasing the sintering temperature. From AC impedance spectroscopy measurements, a significant decrease in the grain boundary conductivity was observed with increasing the sintering temperature, while the bulk conductivity was almost the same regardless of the sintering temperature. In SEM observation, many pores were observed at the grain boundaries. These pores were considered as a main cause for the deterioration of the grain boundary conductivity. In order to suppress the pore formation at the grain boundaries, the sintering condition was re-examined. By decreasing the rate of rising temperature during the sintering process, the pore formation could be suppressed even for the sintering at 1200 ºC. The conductivity of the sample sintered at 1200 ºC was improved by decreasing the rate of raising temperature. For instance, the conductivity of the sample sintered at 1200 ºC with the slow rate, 2 ºC·min-1, was almost comparable with that sintered at 1000 ºC with the fast rate, 50 ºC·min-1. Throughout this work, it was concluded that the densification and the grain growth would be effective for the enhancement of ionic conductivity in Tysonite-type La0.93Ba0.07F2.93. Acknowledgement: This work was partly supported by JST. K.M appreciate Hatano Foundation for the support to his travel.

Spectral Analysis of the Slip-Length Model for Turbulence over Textured Superhydrophobic Surfaces

We assess the applicability of slip-length models to represent textured superhydrophobic surfaces. From the results of direct numerical simulations, and by considering the slip length from a spectral perspective, we discriminate between the apparent boundary conditions experienced by different lengthscales in the overlying turbulent flow. In particular, we focus on the slip lengths experienced by lengthscales relevant to the near wall turbulent dynamics. Our results indicate that the apparent failure of homogeneous slip-length models is not the direct effect of the texture size becoming comparable to the size of eddies in the flow. The texture-induced signal scatters to the entire wavenumber space, affecting the perceived slip length across all lengthscales, even those much larger than the texture. We propose that the failure is caused by the intensity of the texture-induced flow, rather than its wavelength, becoming comparable to the background turbulence.

Characterization of enterotoxin A-producing Staphylococcus aureus.

PurposeThis study aims to characterize the wild-type staphylococcal enterotoxin A (SEA)-producing Staphylococcus aureus.Materials and methodsWe identified 29 wild-type sea-positive S. aureus isolates from dairy and meat samples, as well as from patients, measured the amount of SEA produced under favorable cultivation conditions using enzyme-linked immunosorbent assay and sea mRNA transcriptional level and investigated the phage type as well as genetic diversity by means of pulsed-field gel electrophoresis and multilocus sequence typing.ResultsAmong 29 sea-positive isolates, 22 were from food sources (including one outbreak case) and seven from clinical patients. Five enterotoxin gene profiles, namely, sea (14 isolates), sea+sec (9 isolates), sea+seb (4 isolates), sea+seb+sec (1 isolate) and sea+seb+sed (1 isolate), were identified. Multilocus sequence typing generated sequence type (ST)1 (13 isolates), ST6 (5 isolates), ST59 (3 isolates), ST239 (3 isolates), ST5 (2 isolates), ST188 (2 isolate) and ST15 (1 isolate). The amount of SEA per 108 colony-forming unit (CFU) after 24 h of incubation was 1.1–33.5 (mean, 8.74; SD, 7.7) ng/108 CFU. The amount of SEA per hour incubation in the log growth phase was 0.1–12.0 (mean, 2.37; SD, 3.06) ng/108 CFU. Overall, 54.2% of SEA was produced in the log growth phase. Both the transcriptional level of sea mRNA and the amount of SEA in the log growth phase correlated well with the amount of SEA after 24 h of cultivation. Four isolates, namely, SA-212, SA-217, SA-340 and SA-341, were categorized to be of high SEA production (877–1,109 ng/mL, 24 h). The total amount of SEA was mainly based on the amount of SEA in 108 CFU, not the relatively fixed bacterial cell counts (21.1–43×108 CFU/mL). Seven isolates from patients all carried the ФMu3A phage, whereas 21 of the 22 isolates from the environmental sources all carried the ФSa3ms phage.ConclusionThe present study exhibits varied SEA production capacity of the wild sea-positive S. aureus strains. An apparent boundary in phage types between strains from the clinical samples and strains from the environment was also identified.

Enhanced ionic conductivity in LAGP/LATP composite electrolyte**Project supported by the National Key Research and Development Program of China (Grant No. 2016YFB0100100), the National Natural Science Foundation of China (Grant Nos. 52315206 and 51502334), Fund from Beijing Municipal Science & Technology Commission, China (Grant No. D171100005517001).

Nasicon materials (sodium superionic conductors) such as Li1.5Al0.5Ge1.5(PO4)3 (LAGP) and Li1.4Al0.4Ti1.6(PO4)3 (LATP) have been considered as important solid electrolytes due to their high ionic conductivity and chemical stability. Compared to LAGP, LATP has higher bulk conductivity around 10−3 S/cm at room temperature; however, the apparent grain boundary conductivity is almost two orders of magnitude lower than the bulk, while LAGP has similar bulk and grain boundary conductivity around the order of 10−4 S/cm. To make full use of the advantages of the two electrolytes, pure phase Li1.5Al0.5Ge1.5(PO4)3 and Li1.4Al0.4Ti1.6(PO4)3 were synthesized through solid state reaction, a series of composite electrolytes consisting of LAGP and LATP with different weight ratios were designed. XRD and variable temperature AC impedance spectra were carried out to clarify the crystal structure and the ion transport properties of the composite electrolytes. The results indicate that the composite electrolyte with the LATP/LAGP weight ratio of 80:20 achieved the highest bulk conductivity which shall be due to the formation of solid solution phase Li1.42Al0.42Ge0.3Ti1.28(PO4)3, while the highest grain boundary conductivity appeared at the LATP/LAGP weight ratio of 20:80 which may be due to the excellent interfacial phase between Li1+xAlxGeyTi2−x−y(PO4)3/LATP. All the composite electrolytes demonstrated higher total conductivity than the pure LAGP and LATP, which highlights the importance of heterogeneous interface on regulating the ion transport properties.

The influence of grain boundaries and grain orientations on the stochastic responses to low load nanoindentation in Cu

Mechanical properties that are considered to be deterministic in the macro-scale have been shown to be stochastic in the sub-micron length scale. The origin of such stochastic responses is not well understood. This work examines the potential influence of grain boundaries and grain orientations on the stochastic nature of pop-in and hardness measurement in annealed high purity polycrystalline Cu samples during low load nanoindentation. Statistical analysis on pop-in load and hardness showed that variations of these measurements depend on crystal orientations and is influenced by the indenter probe size. Analysis on the pop-in load statistics showed that pop-ins are likely initiate from an atomic sized precursor that leads to dislocation generation or expansion. Variation in hardness measurements near an arbitrary chosen grain boundary and the apparent grain boundary hardening effect observed may be related to the higher density of dislocations at and near the grain boundary.

Non-CMC Solutions of the Einstein Constraint Equations on Compact Manifolds with Apparent Horizon Boundaries

In this article we continue our effort to do a systematic development of the solution theory for conformal formulations of the Einstein constraint equations on compact manifolds with boundary. By building in a natural way on our recent work in Holst and Tsogtgerel (2013), and Holst, Nagy, and Tsogtgerel (2008, 2009), and also on the work of Maxwell (2004, 2005, 2009) and Dain (2004), under reasonable assumptions on the data we prove existence of both near- and far-from-constant mean curvature solutions for a class of Robin boundary conditions commonly used in the literature for modeling black holes, with a third existence result for constant mean curvature (CMC) appearing as a special case. Dain and Maxwell addressed initial data engineering for space-times that evolve to contain black holes, determining solutions to the conformal formulation on an asymptotically Euclidean manifold in the CMC setting, with interior boundary conditions representing excised interior black hole regions. Holst and Tsogtgerel compiled the interior boundary results covered by Dain and Maxwell, and then developed general interior conditions to model the apparent horizon boundary conditions of Dain and Maxwell for compact manifolds with boundary, and subsequently proved existence of solutions to the Lichnerowicz equation on compact manifolds with such boundary conditions. This paper picks up where Holst and Tsogtgerel left off, addressing the general non-CMC case for compact manifolds with boundary. As in our previous articles, our focus here is again on low regularity data and on the interaction between different types of boundary conditions. While our work here serves primarily to extend the solution theory for the compact with boundary case, we also develop several technical tools that have potential for use with the asymptotically Euclidean case.

Numerical study of three-dimensional natural convection in a cubical cavity at high Rayleigh numbers

A systematic numerical study of three-dimensional natural convection of air in a differentially heated cubical cavity with Rayleigh number (Ra) up to 1010 is performed by using the recently developed coupled discrete unified gas-kinetic scheme. It is found that temperature and velocity boundary layers are developed adjacent to the isothermal walls, and become thinner as Ra increases, while no apparent boundary layer appears near adiabatic walls. Also, the lateral adiabatic walls apparently suppress the convection in the cavity, however, the effect on overall heat transfer decreases with increasing Ra. Moreover, the detailed data of some specific important characteristic quantities is first presented for the cases of high Ra (up to 1010). An exponential scaling law between the Nusselt number and Ra is also found for Ra from 103 to 1010 for the first time, which is also consistent with the available numerical and experimental data at several specific values of Ra.

What should be recycled: An integrated model for product recycling desirability

This research was focused on developing a new scientific approach for prioritising recycling of end-of-life products in a circular economy. To date, product complexity based on the mixture of materials has been used as a predictor of what gets recycled. While the separation of materials that make up a product has been modelled as a measure of product complexity, this does not taken into account the benefits and considerations in recycling products. In this paper, a new agenda and approach to prioritise the recycling of products was developed based on a recycling desirability index. The material mixing complexity measure was inverted into a simplicity index and then extended by modelling the security index for the mix of materials and the technological readiness level of recycling technologies. The extended model is proposed as an integrated measure of the desirability of recycling end-of-life products. From this analysis, an apparent recycling desirability boundary, enabling products to be prioritised for recycling, was developed. This model and analysis can be used as an information source in developing policies and product recycling priorities.

Influence of the laser pre-quenched substrate on an electroplated chromium coating/steel substrate

The chromium coatings were electroplated onto a laser pre-quenched steel substrate to improve the interfacial adhesion properties of chromium coating/steel substrate system. The influence of laser pre-treatment on the substrate, coating as well as interface was investigated by using microstructure characterization, hardness testing, tensile testing and finite element analysis. An apparent boundary line instead of an interlayer was identified between chromium coating/pre-quenched steel substrate. The Vickers hardness and yield strength of steel substrate were significantly improved after laser pre-quenching. The fracture toughness of chromium coating was increased by about 28.6% compared to the un-treated counterpart. The energy release rate for an interfacial crack in the chromium coating/laser-quenched substrate was smaller than that in the untreated specimen. These results may help understand the life prolongation mechanism for the laser pre-quenched chromium/coated steel parts.

On the Fallacy of Quantitative Segmentation for T1-Weighted MRI.

T1-weighted magnetic resonance imaging (MRI) generates contrasts with primary sensitivity to local T1 properties (with lesser T2 and PD contributions). The observed signal intensity is determined by these local properties and the sequence parameters of the acquisition. In common practice, a range of acceptable parameters is used to ensure "similar" contrast across scanners used for any particular study (e.g., the ADNI standard MPRAGE). However, different studies may use different ranges of parameters and report the derived data as simply "T1-weighted". Physics and imaging authors pay strong heed to the specifics of the imaging sequences, but image processing authors have historically been more lax. Herein, we consider three T1-weighted sequences acquired the same underlying protocol (MPRAGE) and vendor (Philips), but "normal study-to-study variation" in parameters. We show that the gray matter/white matter/cerebrospinal fluid contrast is subtly but systemically different between these images and yields systemically different measurements of brain volume. The problem derives from the visually apparent boundary shifts, which would also be seen by a human rater. We present and evaluate two solutions to produce consistent segmentation results across imaging protocols. First, we propose to acquire multiple sequences on a subset of the data and use the multi-modal imaging as atlases to segment target images any of the available sequences. Second (if additional imaging is not available), we propose to synthesize atlases of the target imaging sequence and use the synthesized atlases in place of atlas imaging data. Both approaches significantly improve consistency of target labeling.

Tension determination of stay cable or external tendon with complicated constraints using multiple vibration measurements

A novel concept of combining the mode shape ratios with the modal frequencies was recently introduced to develop an accurate method for the determination of stay cable force. A crucial restriction of symmetric boundary constraints at both ends was imposed in this method for the optimization of effective vibration length. However, there certainly exist a number of cases with apparent unsymmetrical boundary constraints such as the case of stay cables with supplementary dampers and that of external tendons affected by intermediate diaphragms. To deal with such difficulties, this method is further generalized in the current study by introducing a shifting parameter in the shape function to effectively consider the unsymmetrical boundary constraints. The numerical difficulty of the more complicated nonlinear optimization process associated with this new formulation is first discussed, followed by extensive numerical investigations, practical verifications, and real applications.

A mechanistic model for electrochemical nutrient recovery systems

Electrochemical membrane technologies such as electrodialysis have been identified as key technologies to enable nutrient recovery from wastewater. However, current electrochemical models are focused on simpler solutions than wastewater and omit key outputs such as pH, or total cell potential. A combined physico-chemical and electrochemical model was developed which includes the mechanisms of competitive transport of ions, implicit inclusion of H+ and OH−, pH (including ionic activity and ion pairing), different factors contributing to total cell potential and a novel method for ion exchange membrane transport. The model outputs compare well with measurements from experiments and simulate secondary effects such as electrode reactions and current leakage. Results found that membrane, rather than boundary layer or bulk resistance was the major contributor to potential drop, and that apparent boundary layers were relatively thick (3 ± 1 mm). Non-ideal solution effects such as ion-pairing and ionic activity had a major impact, particularly on multi-valent Ca2+ ions, which enhances the capability of electrodialysis to recover monovalent nutrient ions such as K+ and NH4+. Decreased resistivity of ion exchange membranes to specific ions (for example, in this case nitrate) could also be detected. The methods here are validated using a comparatively simple synthetic solution of five ionic components, but are able to be easily scaled for a more complex solution, and are also compatible with additional mechanisms such as precipitation, fouling, and scaling.