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Membrane separation has enjoyed tremendous advances in relevant material and engineering sciences, making it the fastest growing technology in water treatment. Although membranes as a broad-spectrum physical barrier have great advantages over conventional treatment processes in a myriad of applications, the need for higher selectivity and specificity in membrane separation is rising as we move to target contaminants at trace concentrations and to recover valuable chemicals from wastewater with low energy consumption. In this review, we discuss the drivers, fundamental science, and potential enabling materials for high selectivity membranes, as well as their applications in different water treatment processes. Membrane materials and processes that show promise to achieve high selectivity for water, ions, and small molecules—as well as the mechanisms involved—are highlighted. We further identify practical needs, knowledge gaps, and technological barriers in both material development and process design for high selectivity membrane processes. Finally, we discuss research priorities in the context of existing and future water supply paradigms.

Water matrix composition impacts water treatment performance. However, matrix composition impacts have rarely been studied for electrochemical water treatment processes, and the correlation between the composition and the treatment efficiency is lacking. This work evaluated the electrochemical reduction of nitrate (ERN) using different complex water matrices: groundwater, brackish water, and reverse osmosis (RO) concentrate/brine. The ERN was conducted using a tin (Sn) cathode because of the high selectivity towards nitrogen evolution reported for Sn electrocatalysts. The co-existence of calcium (Ca

Post-treatment of brine produced by reverse osmosis (RO) is a great challenge as it often requires high energy input and works under extreme operating conditions. In this study, brine from a RO plant in El Paso, TX USA was successfully treated using a pilot-scale nanophotonics enhanced solar membrane distillation (NESMD) system. The novel NESMD reactor has a nanophotonic membrane surface area of 0.2 m2 and an internal heat recovery system to recover the latent heat released during vapor condensation. By utilizing a sweeping gas operational mode under real solar irradiation (585–827 W m−2), the NESMD realized successful desalination of RO brine with the membrane flux reaching 0.45–0.65 kg m−2 h−1 and total dissolved solids (TDS) removal greater than 99.5% without an external heat condenser. The decrease in the feed flow rate to the evaporation channel of the NESMD system led to an increase in the gained output ratio (GOR) from 0.35 to 0.62. To the best of our knowledge, this is the largest photothermal reactor utilized for the desalination of real RO brine under practical solar irradiation. Compared with conventional brine treatment processes that require high temperature or pressure, the NESMD desalinates RO brine at near-ambient temperature and pressure with free solar energy, providing a promising approach for water desalination, and RO brine post treatment.

Per- and polyfluoroalkyl substances (PFAS), which are present in many waters, have detrimental impacts on human health and the environment. Reverse osmosis (RO) and nanofiltration (NF) have shown excellent PFAS separation performance in water treatment; however, these membrane systems do not destroy PFAS but produce concentrated residual streams that need to be managed. Complete destruction of PFAS in RO and NF concentrate streams is ideal, but long-term sequestration strategies are also employed. Because no single technology is adequate for all situations, a range of processes are reviewed here that hold promise as components of treatment schemes for PFAS-laden membrane system concentrates. Attention is also given to relevant concentration processes because it is beneficial to reduce concentrate volume prior to PFAS destruction or sequestration. Given the costs and challenges of managing PFAS in membrane concentrates, it is critical to evaluate both established and emerging technologies in selecting processes for immediate use and continued research.

Electro-driven technologies are viewed as a potential alternative to the current state-of-the-art technology, reverse osmosis, for the desalination of brackish waters. Capacitive deionization (CDI), based on the principle of electrosorption, has been intensively researched under the premise of being energy efficient. However, electrodialysis (ED), despite being a more mature electro-driven technology, has yet to be extensively compared to CDI in terms of energetic performance. In this study, we utilize Nernst-Planck based models for continuous flow ED and constant-current membrane capacitive deionization (MCDI) to systematically evaluate the energy consumption of the two processes. By ensuring equivalently sized ED and MCDI systems-in addition to using the same feed salinity, salt removal, water recovery, and productivity across the two technologies-energy consumption is appropriately compared. We find that ED consumes less energy (has higher energy efficiency) than MCDI for all investigated conditions. Notably, our results indicate that the performance gap between ED and MCDI is substantial for typical brackish water desalination conditions (e.g., 3 g L-1 feed salinity, 0.5 g L-1 product water, 80% water recovery, and 15 L m-2 h-1 productivity), with the energy efficiency of ED often exceeding 30% and being nearly an order of magnitude greater than MCDI. We provide further insights into the inherent limitations of each technology by comparing their respective components of energy consumption, and explain why MCDI is unable to attain the performance of ED, even with ideal and optimized operation.

Based upon an international workshop, this perspective evaluates how nano-scale pore structures and unique properties that emerge at nano- and sub-nano-size domains could improve the energy efficiency and selectivity of electroseparation or electrocatalytic processes for treating potable or waste waters. An Eisenhower matrix prioritizes the urgency or impact of addressing potential barriers or opportunities. There has been little optimization of electrochemical reactors to increase mass transport rates of pollutants to, from, and within electrode surfaces, which become important as nano-porous structures are engineered into electrodes. A “trap-and-zap” strategy is discussed wherein nanostructures (pores, sieves, and crystal facets) are employed to allow localized concentration of target pollutants relative to background solutes (i.e., localized pollutant trapping). The trapping is followed by localized production of tailored reactive oxygen species to selectively degrade the target pollutant (i.e., localized zapping). Frequently overlooked in much of the electrode-material development literature, nano-scale structures touted to be highly “reactive” towards target pollutants may also be the most susceptible to material degradation (i.e., aging) or fouling by mineral scales that form due to localized pH changes. A need exists to study localized pH and electric-field related aging or fouling mechanisms and strategies to limit or reverse adverse outcomes from aging or fouling. This perspective provides examples of the trends and identifies promising directions to advance nano-materials and engineering principles to exploit the growing need for near chemical-free, advanced oxidation/reduction or separation processes enabled through electrochemistry.

Since the 1970s, The University of Texas at El Paso and El Paso Water have had a synergistic university-utility partnership, and in 2002, we began a sequence of investigations of enhanced recovery of water from silica-saturated reverse osmosis concentrate: (a) two-pass nanofiltration (NF) and reverse osmosis (RO) treatment, (b) lime softening for silica removal, (c) vibratory shear enhanced processing (VSEP), (d) continuous-flow seawater RO treatment of brackish RO concentrate, and finally (e) high-recovery concentrate enhanced-recovery reverse osmosis (CERRO) process. Studies funded by El Paso Water, Texas Water Development Board, U.S. Bureau of Reclamation, and WateReuse Research Foundation were conducted at the Kay Bailey Hutchison (KBH) Plant in El Paso and the Brackish Groundwater National Desalination Research Facility in Alamogordo, NM, and showed that as much as 88% of the water could be recovered from silica-saturated KBH concentrate using the CERRO process. Full-scale implementation of the CERRO process at well sites in El Paso has resulted in 70%-75% recovery of RO concentrate with a specific energy consumption of 1.23 kWh/m3 (4.6 kWh/kgal) and total estimated cost of approximately $0.59/m3 ($2.25/kgal). Cost-effective high-recovery desalination technologies such as CERRO are essential for drought-proof water supply in arid cities such as El Paso. PRACTITIONER POINTS: This two-decade UTEP-EPW research partnership was sustained by a long-term commitment to research and consistent financial support from EPW. Universities can collaborate to leverage utility funding toward larger external grant funding to advance research and development in a win-win partnership. The high-recovery CERRO process was developed through multiple phases of concentrate management research, which would not have been possible without long-term research commitment and risk tolerance from EPW. CERRO systems are being implemented at full scale in El Paso to recover water from silica-saturated RO concentrate at an estimated specific energy consumption of 1.23 kWh/m3 (4.6 kWh/kgal) and total amortized cost of $0.59/m3 ($2.25/kgal).

Poly(ether sulfone) (PES) is commonly used polymer in ultrafiltration (UF) membranes which, due to its hydrophobic nature, frequently incorporates the copolymer, polyvinylpyrrolidone (PVP), to impr...

Capacitive deionization (CDI), which is based on the electrosorption of ions by porous electrodes, is an emerging technology for brackish water desalination. Understanding the key drivers of energy consumption in CDI and benchmarking CDI with reverse osmosis (RO), the current state-of-the-art for brackish and seawater desalination, is crucial to guide the future development of desalination technologies. In this study, we develop system-scale models to analyze the energy consumption and energy efficiency of CDI and RO over a wide range of material properties and operating conditions. Using our models, we explore how the energetic performance of CDI and RO compare as a function of feed salinity, water recovery, salt rejection, and average water flux, which is normalized by electrode and membrane area in CDI and RO, respectively. Our analysis shows that RO is significantly more energy efficient than CDI, particularly when targeting higher salinity feed streams and higher salt rejection values. For brackish water with a salt concentration of 2000 mg L−1, achieving 50% water recovery and 75% salt rejection, with an average water flux of 10 L m−2 h−1 using CDI requires a specific energy consumption of 0.85 kWh m−3, more than eight times that of RO (0.09 kWh m−3). Importantly, our results also indicate that current efforts to improve electrode materials can only marginally reduce the energy consumption of CDI. We conclude with a discussion highlighting other important factors, such as capital cost, electrode stability, and membrane fouling, which affect the efficacy of CDI and RO for low-salinity desalination.

Electrodialysis (ED) desalination performance of different conventional and laboratory-scale ion exchange membranes (IEMs) has been evaluated by many researchers, but most of these studies used their own sets of experimental parameters such as feed solution compositions and concentrations, superficial velocities of the process streams (diluate, concentrate, and electrode rinse), applied electrical voltages, and types of IEMs. Thus, direct comparison of ED desalination performance of different IEMs is virtually impossible. While the use of different conventional IEMs in ED has been reported, the use of bioinspired ion exchange membrane has not been reported yet. The goal of this study was to evaluate the ED desalination performance differences between novel laboratory‑scale bioinspired IEM and conventional IEMs by determining (i) limiting current density, (ii) current density, (iii) current efficiency, (iv) salinity reduction in diluate stream, (v) normalized specific energy consumption, and (vi) water flux by osmosis as a function of (a) initial concentration of NaCl feed solution (diluate and concentrate streams), (b) superficial velocity of feed solution, and (c) applied stack voltage per cell-pair of membranes. A laboratory‑scale single stage batch-recycle electrodialysis experimental apparatus was assembled with five cell‑pairs of IEMs with an active cross-sectional area of 7.84 cm2. In this study, seven combinations of IEMs (commercial and laboratory-made) were compared: (i) Neosepta AMX/CMX, (ii) PCA PCSA/PCSK, (iii) Fujifilm Type 1 AEM/CEM, (iv) SUEZ AR204SZRA/CR67HMR, (v) Ralex AMH-PES/CMH-PES, (vi) Neosepta AMX/Bare Polycarbonate membrane (Polycarb), and (vii) Neosepta AMX/Sandia novel bioinspired cation exchange membrane (SandiaCEM). ED desalination performance with the Sandia novel bioinspired cation exchange membrane (SandiaCEM) was found to be competitive with commercial Neosepta CMX cation exchange membrane.

Reliable forecasts of water demand that account for factors that drive demand are imperative to understanding future urban water needs. The effects of meteorological dynamics and sociocultu...

International audience; Electrochemical advanced oxidation processes (EAOPs) have shown excellent capabilities to the abatement of recalcitrant organic pollutants. The Fenton-based electrochemical systems have shown great performance for in-situ generation of H2O2, allowing an efficient • OH production for the mineralization of organic pollutants. These systems have been widely applied at bench scale; however, studies to scale-up to a higher technology readiness level (TRL) are lacking. One of the main scale-up challenges of the Fenton-based systems is the implementation of air diffusion electrodes (ADE) in flow-by electrochemical cells. The ADE adds additional complexity with respect to mass transfer effects due to hydraulic reactor design and ADE gas pressure control. Therefore, this work experimentally investigated residence time distribution and platinum-sheet electrode mass transfer effects due to (a) the liquid cross-flow velocity through the electrochemical cell, (b) the gas pressure of the air-diffusion electrode (ADE), and (c) the presence of mesh sheet mass transfer promoters between the electrodes. Analysis of experimental results revealed a synergistic improvement of mass transfer with the ADE gas flow and the presence of mesh promoters. Engineers could exploit this synergistic effect to design electrochemical cells with significantly lower capital cost.

The resistivity of aggregates used as fill within mechanically stabilized earth (MSE) walls has been found to be a good indicator of its potential to corrode metal reinforcements. As such it is important to accurately measure the fill resistivity. Previous studies have found that resistivity is affected by the gradation of the material, as finer particles normally have much lower resistivity than coarse particles. The resistivity is also greatly dependent on moisture content. To estimate how the variation in moisture content can affect the resistivity, and the in-service performance of MSE walls, laboratory resistivity measurements were performed on 23 materials at varying moisture contents. The results were used to develop a model to estimate the resistivity of a given material knowing its minimum resistivity, porosity, and degree of saturation greater than 50%. Model predictions can potentially be used to estimate the resistivity of in-service wall fill and to harmonize field and laboratory resistivity measurements. The model could be used in future corrosion modeling that considers the seasonal or long-term moisture contents of the fill, similar to the recently developed Mechanistic Empirical Pavement Design (MEPDG) procedure.

Membrane capacitive deionization (MCDI) is a simple and low-cost method for brackish water desalination involving reversible electrosorption using high surface area, porous electrodes paired with ion-exchange membranes. Ion-exchange membranes improve charge efficiency and salt adsorption capacity by limiting the transport of co-ions and inhibiting faradaic reactions at the electrode surface. Effective ion-exchange membranes for MCDI should have high permselectivity and low ionic resistance, but there is typically a trade-off between these two properties. In this work, we studied partially sulfonated pentablock copolymer (sPBC) as a cation-exchange coating for MCDI electrodes. sPBC ion exchange coatings of varying ion exchange capacity (IEC, 1.0, 1.5, 2.0 meq g−1) and a range of casting solvent compositions (10–60 wt% n-propanol in toluene) were prepared. Transmission electron microscopy analysis of the membranes showed a morphological change from a micellar to lamellar and then to an inverse micellar structure with increasing polarity of the casting solvent. Water uptake and salt permeability increased with increasing IEC and casting solvent polarity over the entire range of conditions tested. MCDI device studies indicated that charge efficiency and salt adsorption capacity both increased with water uptake over a range of casting solvent compositions due to morphological changes in the sPBC film. This work demonstrates an effective solution-processible ion-exchange layer for MCDI using a self-assembling block copolymer and suggests that ideal ion-exchange coatings for MCDI should have high water uptake to minimize ionic resistance while at the same time maintaining a high charge density of fixed charged groups to achieve high permselectivity.

The service life of mechanically stabilized earth walls depends on the corrosion rate of the metallic reinforcement used in their construction. The resistivity of the backfill aggregates needs to be measured accurately to estimate realistically the corrosion rate of the reinforcement. Resistivity testing is usually performed using the traditional soil box on the portion of the aggregates that passes a No. 10 or No. 8 sieve to either select or reject the backfill. For a more reasonable characterization of the corrosivity of coarse backfills, it is desirable to use their actual gradations. To that end, several resistivity boxes that were double and quadruple the dimensions of the original box were constructed. In addition to the three standard gradations specified by the Texas Department of Transportation, over 20 backfill materials sampled from sources throughout Texas were fractionated to fines, fine sand, coarse sand, and gravel. Resistivity tests were performed separately on each of these four constituents for each backfill. The results were used to evaluate a relationship that would allow the estimation of the resistivity of any desired backfill gradations from the resistivity values of these four constituents. The proposed model looks promising since the resistivity of the backfill composed of the actual gradation can be estimated with reasonable certainty. The results of this study can potentially help highway agencies and contractors use a number of local quarries that are currently disqualified based on the resistivity values obtained from only testing materials that pass a No. 8 or No. 10 sieve.

Summary Consumers are welcoming the use of locally sourced ingredients in their beer, and hops are now beginning to be grown in new regions. One new region is the province of Nova Scotia, Canada. Four different hop varieties (Cascade, Mt. Hood, Golding and Nugget) were sourced from Nova Scotia, and matching varieties (Cascade, Mt. Hood and Nugget) were sourced from Oregon, USA, and England, UK. The main objective of this study was to identify whether differences in the hop aroma exist based on their geographic origin. Projective mapping trials (n = 2) were conducted for the aroma of all eight hops varieties. The first trial utilised crushed whole-leaf hops, while the second consisted of a dry-hopped conventional Canadian lager. Results indicated that there are differences in the hop aromas of both whole-leaf hops and dry-hopped lager.

Zero Discharge Desalination (ZDD) is a very-high-recovery hybrid desalination system, typically comprised of a primary desalter (such as reverse osmosis (RO) or nanofiltration (NF)) and electrodialysis metathesis (EDM). The EDM acts as a “kidney” by removing troublesome salts from the concentrate of the primary desalter, which allows for additional recovery of potable water. A mathematical model was developed to simulate ZDD system performance using mass balance, desalination design equations, and experimental data. Model results confirm that ZDD can achieve >97% system recovery for brackish water with (a) a feed total dissolved solids (TDS) concentration of 60% of the TDS); and (c) a silica content of

This study compares the scaling behavior of membrane distillation (MD) with that of nanophotonics-enabled solar membrane distillation (NESMD). Previous research has shown that NESMD, due to its localized surface heating driven by photothermal membrane coatings, is an energy-efficient system for off-grid desalination; however, concerns remained regarding the scaling behavior of self-heating surfaces. In this work, bench-scale experiments were performed, using model brackish water, to compare the scaling propensity of NESMD with MD. The results showed NESMD to be highly resistant to scaling; a three times higher salt concentration factor (c/c0) was achieved in NESMD compared to MD without any decline in flux. Analyses of the scaling layer on NESMD membranes revealed that salt deposition was 1/4 of that observed for MD. Scaling resistance in NESMD is attributed to its lower operating temperature, which increases the solubility of common scalants and decreases salt precipitation rates. Precipitation kinetics measurements revealed an order of magnitude faster precipitation under heated conditions (62 °C, k = 8.7 × 10-2 s-1) compared to ambient temperature (22 °C, k = 7.1 × 10-3 s-1). These results demonstrate a distinct advantage of NESMD over MD for the treatment of high scaling potential water, where scaling is a barrier to high water recovery.

Pervaporation desalination has several advantages over competing desalination technologies, most notably an ability to select for or against volatile organic compounds and the ability to process high salinity feeds at a low transmembrane pressure. Pervaporation has not been commercialized for desalination applications because of its energy intensity. However, emerging processes such as hydraulic fracturing produce high total dissolved solids (>30–45 g L−1) byproduct streams that exceed the operational limits of traditional reverse osmosis and could be treated by pervaporation. Here, we demonstrate free-standing pervaporation membranes with excellent permeance and high salt removal based on a partially sulfonated pentablock terpolymer with the tradename Nexar™. Pervaporation membranes were easily cast from this material with desalination performances comparable or superior to commercially available membranes. We found that the polymer degree of sulfonation and casting solvent polarity had a significant impact on the membranes’ water uptake but only a modest impact on the pervaporation desalination performance. Membranes with a degree of sulfonation of 52% (2.0 meq g−1 IEC) and a casting solution composed of 50 wt% n-propanol and 50 wt% toluene achieved a water flux of 3.32 kg m−2 h−1 (permeance 135 kg m−2 h−1 bar−1) with 99.5% salt removal in pervaporation from a 32 g L−1 sodium chloride feed solution at room temperature. We demonstrated that dense, non-porous Nexar™ pervaporation membrane permeance and salt separation performance were superior to commercial pervaporation membranes and equivalent to commercial membrane distillation membranes, which have much larger pores. This study demonstrates that commercially available sulfonated pentablock terpolymers are excellent membranes for pervaporation desalination because of their ease of casting and excellent performance.

Technologies capable of selective removal of target contaminants from water are highly desirable to achieve “fit-for-purpose” treatment. In this study, we developed a simple yet highly effective method to achieve calcium-selective removal in an electrosorption process by coating the cathode with a calcium-selective nanocomposite (CSN) layer using an aqueous phase process. The CSN coating consisted of nano-sized calcium chelating resins with aminophosphonic groups in a sulfonated polyvinyl alcohol hydrogel matrix, which accomplished a Ca2+-over-Na+ selectivity of 3.5–5.4 at Na+:Ca2+ equivalent concentration ratio from 10:1 to 1:1, 94 – 184% greater than the uncoated electrode. The CSN coated electrode exhibited complete reversibility in repeated operation. Mechanistic studies suggested that the CSN coating did not contribute to the adsorption capacity, but rather allowed preferential permeation of Ca2+ and hence increased Ca2+ adsorption on the carbon cathode. The CSN-coated electrode was very stable, showing reproducible performance in 60 repeated cycles.

Electrocatalytic-driven processes show promise for water purification, including abating persistent organic pollutants via advanced oxidation processes. Since the early 90s, thousands of research articles have systematically explored degradation of organic pollutants in batch systems and synthetic waters. Despite these research efforts, commercial treatment units for water treatment in the field are barely reported. Translation of scientific and technological advances into the market place requires identification of niche applications. Here we consider point-of-use devices. Techno-economic analysis (TEA) of electrochemical oxidation was benchmarked against commercially-available competition in the water purification sector, specifically carbon block adsorption devices. Results identified electrode material as one of the driving capital costs. Decreasing boron-doped diamond cost by ten-fold or exploring alternative emergent materials such as Ti4O7 can enhance competitiveness of electrochemical devices in the market. Meanwhile, the first-order rate constant was identified as one of the most relevant parameters because it affects operational expenses. Strategies to enhance target pollutant selectivity in real water matrices is a research need to ensure efficient water purification with minimum electrical energy requirements. TEA showed a promising scenario for electrocatalytic devices to overcome commercially-available technologies. This initial TEA identified key challenges and research needs to overcome cost limitations and to beat traditional systems in reliability in the road map towards market implementation.

Membrane capacitive deionization (MCDI) is a low-cost technology for desalination. Typically, MCDI electrodes are fabricated using a slurry of nanoparticles in an organic solvent along with polyvinylidene fluoride (PVDF) polymeric binder. Recent studies of the environmental impact of CDI have pointed to the organic solvents used in the fabrication of CDI electrodes as key contributors to the overall environmental impact of the technology. Here, we report a scalable, aqueous processing approach to prepare MCDI electrodes using water-soluble polymer poly(vinyl alcohol) (PVA) as a binder and ion-exchange polymer. Electrodes are prepared by depositing aqueous slurry of activated carbon and PVA binder followed by coating with a thin layer of PVA-based cation- or anion-exchange polymer. When coated with ion-exchange layers, the PVA-bound electrodes exhibit salt adsorption capacities up to 14.4 mg/g and charge efficiencies up to 86.3%, higher than typically achieved for activated carbon electrodes with a hydrophobic polymer binder and ion-exchange membranes (5-13 mg/g). Furthermore, when paired with low-resistance commercial ion-exchange membranes, salt adsorption capacities exceed 18 mg/g. Our overall approach demonstrates a simple, environmentally friendly, cost-effective, and scalable method for the fabrication of high-capacity MCDI electrodes.

It has been recognized that numerous synthetic compounds like Bisphenol A (BPA) and nonylphenols (NP) are present in effluents from wastewater treatment plants (WWTP) at levels of parts per billion (μg L(-1)) or even parts per trillion (ng L(-1)) with a high potential to cause endocrine disruption in the aquatic environment. Constructed wetlands (CW) are a cost-effective wastewater treatment alternative with promising performance to treat these afore mentioned compounds. This research was aimed to evaluate the efficacy of CW treatment of WWTP effluent for mitigating the effects endocrine disrupting compounds (EDCs). This research goal was accomplished by (1) quantifying the removal of BPA and NP in CWs; (2) isolating CW fungal strains and testing for laccase production; and (3) performing endocrine disruption (reproduction) bioassays using the fruit fly Drosophila melanogaster. Three pilot scale horizontal subsurface flow constructed wetlands (HSSF-CW) were operated for eight weeks: one planted with Phragmites australis; one planted with Heliconia psitacorum; and one unplanted. The Heliconia CW showed a removal efficiency of 73.3(± 19%) and 62.8(± 20.1%) for BPA and NP, respectively; while the Phragmites CW demonstrated a similar removal for BPA (70.2 ± 27%) and lower removal efficiency for NP 52.1(± 37.1%).The unplanted CW achieved 62.2 (± 33%) removal for BPA and 25.3(± 37%) removal for NP. Four of the eleven fungal strains isolated from the Heliconia-CW showed the capacity to produce laccase. Even though complete removal of EDCs was not achieved by the CWs, the bioassay confirmed a significant improvement (p < 0.05) in fly viability for all CWs, with Heliconia sp. being the most effective at mitigating adverse effects on first and second generational reproduction. This study showed that a CW planted with a native Heliconia sp. CW demonstrated a higher removal of endocrine disrupting compounds and better mitigation of reproductive disruption in the bioassay.

Reverse electrodialysis (RED) can produce electric energy from waste heat using thermolytic solutions (e.g., NH4HCO3) where waste heat is used to regenerate the high concentration (HC) and low concentration (LC) solutions. The salinity difference between the two solutions in RED is converted into electric potential across an ion exchange membrane (IEM), exploiting the liquid junction potential. Theoretical calculation of the junction potential is cumbersome because the activity coefficients and equilibrium speciation of individual ions are complicated for highly concentrated NH4HCO3 solution. We used a simplification of the Planck–Henderson equation to approximate the junction potential in thermolytic RED systems based on conductivity measurements, and this approximation was consistent with experimentally measured junction potentials. The experimental results also found that NH4HCO3 created greater junction potentials across anion exchange membranes than (NH4)2CO3 solution for a given molar concentration ratio. The junction potential was hardly affected by the magnitude of HC as long as the concentration ratio between HC and LC was maintained. Based on the experimental findings, we recommend that thermolytic RED systems be operated under neutral pH and high concentration ratio conditions (above 1:100 ratio). These findings provide information essential for designing and operating thermolytic RED systems for future study and practical application.

Purpose:To investigate the influence of prior knowledge of exercise duration on the pacing strategies employed during gamebased activities.Methods:Twelve semiprofessional team-sport athletes (mean ± SD age 22.8 ± 2.1 y) participated in this study. Players performed 3 small-sided games in random order. In one condition (Control), players were informed that they would play the small-sided game for 12 min and then completed the 12-min game. In a 2nd condition (Deception), players were told that they would play the small-sided game for 6 minutes, but after completing the 6-min game, they were asked to complete another 6 min. In a 3rd condition (Unknown), players were not told how long they would be required to play the small-sided game, but the activity was terminated after 12 min. Movement was recorded using a GPS unit sampling at 10 Hz. Post hoc inspection of video footage was undertaken to count the number of possessions and the number and quality of disposals.Results:Higher initial intensities were observed in the Deception (130.6 ± 3.3 m/min) and Unknown (129.3 ± 2.4 m/min) conditions than the Control condition (123.3 ± 3.4 m/min). Greater amounts of high-speed running occurred during the initial phases of the Deception condition, and more low-speed activity occurred during the Unknown condition. A moderately greater number of total skill involvements occurred in the Unknown condition than the Control condition.Conclusions:These findings suggest that during game-based activities, players alter their pacing strategy based on the anticipated endpoint of the exercise bout.

The objective of this research was to investigate the sensitivity of electrodialysis performance to variations in voltage application and membrane type when treating brackish water reverse osmosis (BWRO) concentrate waste, which typically exceeds multiple salt solubility limits. Synthetic BWRO concentrates from Arizona, Texas, and Florida of 7890–18,600 mg/L total dissolved solids were prepared with 6–10 mg/L of poly-phosphonate antiscalants. Experimentation was performed using a laboratory-scale electrodialyzer a nominal transfer area of 64 cm 2 per membrane. Flow, pressure, conductivity, temperature, and pH were measured continuously, and periodic process samples were analyzed for anion and cation concentrations. The three BWRO concentrates were successfully treated with stack voltage applications of 1.0–1.5 V/cell-pair with initial current densities of 200–600 A/m 2 and final salinity removal ratios up to 98%. This paper shows consistent specific energy consumption (approximately 0.03 kWh/m 3 per Volt/cell-pair applied per meq/L separated) for electrodialysis treatment for several concentrates across a range of salinity and composition. Successive electrodialysis treatment recovered more than 78% of BWRO concentrate without precipitation, corresponding to calcite and dolomite saturation ratios of 15. These results demonstrate that electrodialysis processes can effectively minimize concentrate waste from BWRO processes, with simulated system recoveries up to 95%.

The objective of this research was to investigate the sensitivity of electrodialysis performance to variations in voltage application and membranes when treating brackish water reverse osmosis concentrate waste. Synthetic BWRO concentrates from Arizona and Texas of 7890–14,800 mg/L total dissolved solids were prepared with poly-phosphonate antiscalants. Experimentation was performed using a laboratory-scale electrodialyzer with two sets of membranes (AMV-CMV and PCSA-PCSK) with a nominal transfer area of 64 cm 2 per membrane. Flow, pressure, conductivity, temperature, and pH were measured continuously, and periodic samples were analyzed for specific anion and cation concentrations. The BWRO concentrates were successfully treated with stack voltage applications of 0.5–1.5 V/cell-pair for salinity removal ratios up to 99% with current density less than 500 A/m 2 . This paper highlights that (1) the specific energy consumption was proportional to the applied voltage and equivalent concentration separated ( i.e. , approximately 0.03 kW h/m 3 per Volt/cell-pair applied per meq/L separated); (2) lower voltage applications decreased the relative separation rate of sulfate compared to chloride; and (3) water transport by electro-osmosis was independent of voltage application or resulting current densities, while it is affected by the ion exchange membranes.

The objective of this research was to investigate the sensitivity of electrodialysis performance to variations in hydraulic flow when treating brackish water reverse osmosis (BWRO) concentrate waste. A synthetic BWRO concentrate from Arizona of 7890 mg/L total dissolved solids was prepared with poly-phosphonate antiscalants, and desalinated with a laboratory-scale electrodialyzer with 10 cell-pairs and a transfer area of 64 cm 2 per membrane. Flow, pressure, conductivity, temperature, and pH were measured continuously, and periodic process samples were analyzed by ion chromatography and inductively coupled plasma-optical emission spectrometry for anion and cation concentrations, respectively. The BWRO concentrate was successfully treated with a stack voltage application of 1.0 V/cell-pair and current densities less than 280 A/m 2 for salinity removal ratios up to 99% (without precipitation). The superficial velocities were controlled in a range of 1.2 to 4.8 cm/s, which corresponded to Reynolds numbers of 10 to 40. This paper shows the polarization parameter (ranging from 2.0 to 3.6 A/m 2 per meq/L) as a function of Reynolds number and removal ratio, and, at maximum sensitivity, the polarization parameter was proportional to Reynolds number raised to the 0.132 power.

In Texas, Arizona, and New Mexico, colonias refer to unincorporated rural settlements along the U.S.–Mexico border. Colonias lack governance and public services normally provided by local government (Ward, 1999). Residents typically rely on well water or hauled water stored in above-ground containers. This study attempted to quantify and compare water-related perceptions and practices of colonia residents. No significant differences were observed between colonia residents using well water versus hauled-stored water for water quality perceptions and water use practices. Most, however, had negative perceptions of their water supply; a majority perceived daily water supplies as not potable. Significant paradoxical discrepancies between perceptions and practice were identified. This study adds to a small but growing literature on subjective dimensions of quality of life indicators for colonia residents. Additional studies are needed to quantify the type and level of health risks posed by compromised water supplies for this vulnerable population. Understanding differences in perceptions and practices associated with water sources could help to identify which subpopulations of colonia residents are in greatest need of water infrastructure or remediation.

Pingos are circular to elongate ice-cored mounds that form by injection and freezing of pressurized water in near-surface permafrost. Here we use a digital surface model (DSM) derived from an airborne Interferometric Synthetic Aperture Radar (IfSAR) system to assess the distribution and morphometry of pingos within a 40,000 km2 area on the western Arctic Coastal Plain of northern Alaska. We have identified 1247 pingo forms in the study region, ranging in height from 2 to 21 m, with a mean height of 4.6 m. Pingos in this region are of hydrostatic origin, with 98% located within 995 drained lake basins, most of which are underlain by thick eolian sand deposits. The highest pingo density (0.18 km− 2) occurs where streams have reworked these deposits. Morphometric analyses indicate that most pingos are small to medium in size (

The performance of electrodialysis is strongly dependent on the boundary layer thickness near an ion-exchange membrane. While a thinner boundary layer is known to enhance the ionic separation, the effects of statistical properties of the boundary layer thickness, such as the variation of the thickness and the correlation between the two boundary layers facing across the spacer, have not been elucidated. These effects were estimated by the Monte Carlo method incorporated into an analytical model. The analytical model simulates the binary ionic transport in four distinct regions of an electrodialysis cell pair: the bulk solution, boundary layer, ion-exchange membrane, and interface between the aqueous solution and ion-exchange membrane. The model current and potential relationships found that a greater variation or more positive correlation improves the ionic separation in the non-Ohmic regime. A bench-scale electrodialyzer was operated in a batch recycle system to develop steady-state current and potential relationships. Comparison between the model and experimental results found that the mean boundary layer thickness was tens of micrometers and the standard deviation of the thickness was similar to or greater than the mean thickness with the sheet-flow type mesh spacer.

In ion-exchange membrane systems such as electrodialysis, the overlimiting current phenomenon still remains a difficult topic to study due to the complicated solution method for the Nernst–Planck–Poisson model. In this study, the Nernst–Planck–Poisson equations were prepared to simulate the steady-state binary ionic transport in the diffusion boundary layer near an ion-exchange membrane. The system of differential equations was converted into the Painleve equation of the second kind in such a way that the converted model domain explicitly shows the transition point from the space-charge region to the electroneutral region in the diffusion boundary layer even before the differential equation is solved. Based on this property, mathematical expressions were proposed to estimate the limiting current density and the width of the space-charge region in the diffusion boundary layer near an ideally perm-selective ion-exchange membrane. The so-called Airy solution of the Painleve equation of the second kind was used to describe the ionic transport in the space-charge region. It was also found that the Airy function of the second kind with its derivative describes the behavior of the electric double layer developed from the ion-exchange membrane surface. In addition, a relatively simple numerical method, including a stability criterion, was used to solve the Painleve equation of the second kind to simulate the ionic transport in the diffusion boundary layer near an ion-exchange membrane.

This article focuses on the adoption and adaptation of methodologies drawn from research in psychology for the evaluation of user response as a manifestation of the mental processes of perception, cognition and emotion. The authors present robust alternative conceptualizations of evaluative methodologies which allow the surfacing of views, feelings and opinions of individual users producing a richer, more informative texture for user centered evaluation of software. This differs from more usual user questionnaire systems such as the Questionnaire of User Interface Satisfaction (QUIS). (Norman et al, 1989) The authors present two different example methodologies so that the reader can firstly, review the methods as a theoretical exercise and secondly, applying similar adaptation principles, derive methods appropriate to their own research or practical context. Copyright © 2010, IGI Global.

A number of commonly consumed fruits and vegetables (e.g., kiwifruit, pineapple and taro) cause oral irritation, and there is anecdotal evidence that this influences the acceptability of such products. In each of these foods, oral irritation is produced by free crystalline calcium oxalate (raphides). The psychophysics of the mechanical oral irritation caused by raphides was studied in two experiments using a model system based on kiwifruit. In the first experiment, the location of irritant sensations and perceived intensity of the irritation caused by suspensions of raphides were determined using a ten-member trained sensory panel. Stinging and numbing were found to increase significantly with increasing concentrations of raphides. Stinging occurred principally on the tongue as well as in the throat and numbing principally on the tongue. The number of oral areas irritated was shown to increase with raphide concentration and to decrease over a 60-min period. In the second experiment, sugars (fructose, sucrose, glucose and inositol), acids (citric, malic and quinic) and an enzyme (actinidin) were added to the model to examine interactions between these chemical stimuli and the mechanical action of the raphides. Addition of acids to the model was shown to enhance irritation in addition to increasing sourness and suppressing sweetness. The addition of actinidin had no significant effects on irritation or tastes. It is suggested that acidity may aggravate irritation at low raphide concentration, but beyond a critical level of mechanical irritation the presence of acids has little additional effect. These results provide the first detailed data of the psychophysics of mechanical oral irritation in food, and have important implications for producing foods with lower levels of irritation and increased acceptability.

Bisphenol A (BPA) and nonylphenols (NPs), with a high potential to cause endocrine disruption, have been identified at levels of nanograms per liter and even micrograms per liter in effluents from wastewater treatment plants. Constructed wetlands (CWs) are a cost-effective wastewater treatment alternative due to the low operational cost, reduced energy consumption, and lower sludge production, and have shown promising performance for treating these compounds. A CW pilot study was undertaken todetermine its potential to remove BPA and NP from municipal wastewater. Three CWs were used: the first CW was planted with Heliconia sp., a second CW was planted with Phragmites sp., and the third CW was an unplanted control. The removal efficiency of the Heliconia-CW was 73 ± 19% for BPA and 63 ± 20% for NP, which was more efficient than the Phragmites-CW (BPA 70 ± 28% and NP 52 ± 23%) and the unplanted-CW (BPA 62 ± 33% and NP 25 ± 37%). The higher capacity of the Heliconia-CW for BPA and NP removal suggests that a native plant from the tropics can contribute to a better performance of CW for removing these compounds.

Johnston, RD, Gabbett, TJ, Walker, S, Walker, B, and Jenkins, DG. Are three contact efforts really reflective of a repeated high-intensity effort bout? J Strength Cond Res 29(3): 816–821, 2015—The use of 3 or more efforts (running and contact), separated by short recovery periods, is widely used to define a “repeated high-intensity effort” (RHIE) bout in rugby league. It has been suggested that due to fatigue, players become less effective after RHIE bouts; however, there is little evidence to support this. This study determined whether physical performance is reduced after performing 1, 2, or 3 efforts with minimal recovery. Twelve semiprofessional rugby league players (age: 24.5 ± 2.9 years) competed in 3 “off-side” small-sided games (2 × 10-minute halves) with a contact bout performed every 2 minutes. The rules of each game were identical except for the number of contact efforts performed in each bout. Players performed 1, 2, or 3 × 5-second wrestling bouts in the single-, double- and triple-contact game, respectively. Movement demands of each game were monitored using global positioning system units. From the first to the second half, there were trivial reductions in relative distance during the single-contact game (ES = −0.13 ± 0.12), small reductions during the double-contact game (ES = −0.47 ± 0.24), and moderate reductions during the triple-contact game (ES = −0.74 ± 0.27). These data show that running intensity is progressively reduced as the number of contact efforts per bout is increased. Targeting defensive players and forcing them to perform 2 or more consecutive contact efforts is likely to lead to greater reductions in running intensity. Conditioning performing multiple contact efforts while maintaining running intensity should therefore be incorporated into training for contact team sports.

Viscosifying agents are used in foods as thickeners to produce improved mouthfeel and as stabilizers to prevent settling out of particulate matter. While viscosifying agents are also known to influence the sensory profile of the products in which they are used, previous studies have examined the effects of viscosifying agents at levels that are not typical of those used in foods. The current study used a descriptive analysis panel to examine the effects of both viscosity and viscosifying agent on the sensory properties of apple juice using three viscosifying agents (carboxymethylcellulose, xanthan and pectin) at levels of usage similar to those recommended for drink products. Gas chromatographyflame ionization detection and gas chromatography-mass spectrometry were conducted on the samples to relate alteration in physico-chemical parameters to changes in sensory profile. Results from the descriptive panel showed that increasing viscosity tended to decrease some aspects offlavor intensity (sourness and cooked apple odor). Individual viscosifiing agents were shown to have specific effects on odor and flavor attributes, e.g. pectin enhanced cereal odor. Gas chromatography-flame ionization detection and mass spectrometry suggested that this effect was related to isopropyl alcohol contributed by the pectin in solution. Pectin also suppressed honey odor and flavor, lemon odor and cooked apple flavor.

A kiwifruit (Actinidia deliciosa (A Chev) Liang et Ferguson cv Hayward) pulp was made using fruit harvested immature to minimize the presence of aroma volatiles. This pulp was modified by incorporating sugars and acids to simulate kiwifruit with a range of Brix and acid levels. Using sensory evaluation, flavor acceptability was found to increase with increasing Brix. As expected, perceived “ sweetness intensity” increased with increasing Brix. Acidity did not influence flavor acceptability. At high Brix, sugars were able to suppress the effects of variations in acidity. Changes in Brix did not influence “ flavor intensity”, suggesting that aroma volatiles may be important contributors to kiwifruit flavor intensity.

Consumer ratings of overall liking and creaminess were compared using internal preference mapping for a range of liquid dairy products. Two dimensions were found to explain ratings of overall liking. The first dimension was related to dairy flavour notes and the texture attributes of mouthcoating, oily/greasy, slipperiness and viscosity and the second dimension was related to the sweet and sour taste of the products plus a number of off-flavours. The same two dimensions were found for creaminess ratings although dimension two had far less significance. A wide variation in consumer liking was found and four segments were identified through cluster analysis. In contrast, there was a consensus in consumer ratings of creaminess, which was related to the fat content of the products tested.

The Gemini Multi-conjugate adaptive optics System (GeMS) at the Gemini South telescope in Cerro Pach{\'o}n is the first sodium-based multi-Laser Guide Star (LGS) adaptive optics system. It uses five LGSs and two deformable mirrors to measure and compensate for atmospheric distortions. The GeMS project started in 1999, and saw first light in 2011. It is now in regular operation, producing images close to the diffraction limit in the near infrared, with uniform quality over a field of view of two square arcminutes. The present paper (I) is the first one in a two-paper review of GeMS. It describes the system, explains why and how it was built, discusses the design choices and trade-offs, and presents the main issues encountered during the course of the project. Finally, we briefly present the results of the system first light., Comment: 17 pages, 7 figures, Accepted for publication in MNRAS

The University of Texas at El Paso (UTEP) and the Franklin W. Olin College of Engineering (Olin) are establishing a student-centered hands-on interactive approach to engineering education (similar to Olin's) at UTEP, where it will reside in UTEP's innovative B.S. in Leadership Engineering (LE) program. The goal of the proposed collaboration is to catalyze UTEP's educational innovation through a cross-campus collaboration between the two institutions by incorporating the Olin educational process, both design and features, into the first offerings of the Bachelor of Science in Leadership Engineering (BSLE) program. Specifically, the collaboration includes faculty exchanges between the two institutions; a series of retreats for planning and assessment; curriculum development; and student recruitment practices. The 21st century workplace demands a new engineer - one who effectively contributes to solving problems using innovation, creativity, and strategic foresight. Graduates of the Olin-UTEP developed Bachelor of Science in Leadership Engineering (LE) program will possess these attributes through the program's rigorous yet flexible major in engineering, and in-depth study of leadership and its effect upon technology and society. In this panel we will share the context for our innovative approach, key features of the partnership to date, and acclaim the value of inter-institutional sharing.