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Advanced zero-gap alkaline electrolyzers can be operated at a significantly higher current density than traditional alkaline electrolyzers. We have investigated how their performance is influenced by diaphragm thickness, temperature and pressure. For this a semi-empirical current-voltage model has been developed based on experimental data of a 20 Nm3/h electrolyzer. The model was extrapolated to thinner diaphragm thicknesses and higher temperatures showing that a nominal current density of 1.8 A cm−2 is possible with a 0.1 mm diaphragm at 100 °C. However, these operating parameters also lead to increased gas crossover, which limits the ability to operate at low loads. A gas crossover model has been developed, which shows that crossover is mainly driven by diffusive transport of hydrogen, caused by a high local supersaturation at the diaphragm surface. To enable a low minimum load of 10% the operating pressure should be kept below 8 bara.

The present study reports a simple, inexpensive, and direct method for the preparation of nanocomposite (NC) material (Ni/Co-NC) as advanced catalysts for hydrogen production (HP). The Ni/Co-NC was prepared using solvothermal method (STM) followed by thermal annealing, characterized and tested for HP in 0.6 M H2SO4. The as-synthesized Ni/Co-NC contains a high density of active edge sites, exhibits high electro-catalytic HP activity under small cathodic onset potential (VON-P) of −0.03 V, and a small Tafel slope of approximately 29 mV/decade, which exceeds the activity of previously studied Pt-free catalysis. Annealing temperature significantly affects the Ni/Co-NC activity toward HP by forming active nanoparticles with an optimum identified at 250 °C. The HP process is controlled via Volmer-Tafel charge-transfer mechanism over the electrode interface. The presented method can be used as a new strategy for manufacturing advanced electro-catalysts for the production of hydrogen from different resources.

Oxidizing an organic solute at the anode of an electrolysis cell can enhance the overall cell current, I, by supplementing the applied cell potential by an amount, Eboost, the difference in potenti...

Potentiometry is one of method on measuring metals based on cell potential. Measurements using potentiometry are divided into comparative cells and concentration cells. Concentration cells are measurements of a cell's potential by using two solutions with different concentrations. The aim of this study was to develop a concentration cell potentiometric method equipped with applications so measurements are easier and faster. The added application able to calculate the results of experiments so that the calculation process becomes faster and easier. Validation results give the results of the R the value of 0.9990; LoD 7.6484x10-7, LoQ 6.2103x10-7, RSD 0.64%, and recovery 98.05%. This optimum measurement was carried out at 30 oC and pH 5. The results of Cu measurements in well water obtained the result of 0.9633 ppm. Measurements using the development of this method, get good validation results and can be used on measurements similar to those in the aquatic environment. Keywords: Potentiometry, cell concentration, Copper (Cu), validation, aquatic environment

Potentiometric probes used in direct potentiometry are attractive sensing tools. They give information on ion activities, which is often uniquely useful. If, instead, concentrations are desired as sensor output, the ionic strength of the sample must be precisely known, which is often not possible. Here, for the first time, direct potentiometry can be made to report concentrations, rather than activities. It is demonstrated for the detection of monovalent anionic species by using a self-referencing Ag/AgI pulstrode as the reference element instead of a traditional reference electrode. This reference pulstrode releases a discrete quantity of iodide ions from the electrode and the resulting reference potential varies with the activity coefficient of iodide. The effects of activity coefficient on the indicator and reference electrode are therefore compensated and the observed cell potential may now be described in a Nernstian manner against anion concentration, rather than activity. Theoretical simulations and experimental results support the validity of this approach. For most monovalent anions of practical relevance, the potential difference between this approach and from a traditional activity coefficient calculation is less than 0.5 mV. The concept is validated with an all-solid-state nitrate sensor as well as a commercial fluoride-selective electrode, giving Nernstian responses in different ionic strength backgrounds against concentration without the need for correcting activity coefficients or liquid junction potentials.

Despite many studies and several extensive reviews of redox flow batteries (RFBs) over the last three decades, information on engineering aspects is scarce, which hinders progress with scale-up and implementation of this energy storage technology. This review summarises cell design requirements then critically considers design, construction and cell features together with their benefits and problems, leading to good practice through improved cell performance, knowledge and experience. Techniques for the characterisation of the reaction environment are illustrated by measurements of mass transport to (and from) electrode surfaces as a function of flow conditions, as well as pressure drop and electrolyte flow dispersion. The influence of design features on performance is illustrated by the effect of process conditions on the components of cell potential. Adequate attention to engineering aspects is seen to be critical to the effective performance of RFBs, particularly during scale-up and long-term operation. Techniques for the characterisation of reaction environment are summarised and a list of essential design and construction factors is provided. Finally, critical areas needing research and development are highlighted.

The cell potential of magnesium metal anode batteries is currently limited by the lack of stable and non-corrosive electrolytes. In a recent issue of Nature Chemistry, Son et al. demonstrated an artificial interphase on Mg anode that extends the electrolyte stability range while enabling magnesium transport. This approach paves the way for practical assessment of high-voltage cathodes and the assembly of high-energy-density Mg cells. Extension of the concept to other multivalent systems is also exciting.

In this communication, effective cage radii of dodecahedral (D) cages in semiclathrate hydrates are investigated based on van der Waals and Platteeuw model. According to recent findings in semiclathrate hydrate structures, D cages in semiclathrate hydrates have anisotropic shapes which provide unique gas capacity and selectivity under mild temperature and pressure conditions. Since applications of these materials for cool energy storage and gas capture and storage technologies are expected, thermodynamic modeling of the semiclathrate hydrates is an emerging issue. So far, the van der Waals and Platteeuw model which is based on Langmuir adsorption theory has been used for modeling of canonical gas hydrates and semiclathrate hydrates. The model applies spherical cell potential to predict guest gas inclusion in the cages, and each cage is characterized by its radius with sphere approximation. While sizes of D cages in semiclathrate hydrates are quite similar to those in gas hydrates, their shapes are found to be irregularly anisotropic dodecahedra that can provide unique gas capture and storage properties. Therefore, when the van der Waals and Platteeuw model is applied to semiclathrate hydrates, it is necessary to discriminate the D cages in the model from those in canonical gas hydrates. Adjusting D cage radius in spherical cell potential model is a simple and convenient way to describe differences in cage shape between semiclathrate hydrates and canonical gas hydrates. Here, we investigated effective cage radii of D cages in the semiclathrate hydrates based on the conventional cell potential model with sphere approximation. Effective radii of D cages in the semiclathrate hydrates were found to be different from those in canonical gas hydrates. With the presently suggested radii, the conventional cell potential model can predict experimental data for cage occupancy in the semiclathrate hydrates more precisely.

During human development, pluripotency is present only in early stages of development. This ephemeral cell potential can be captured in vitro by obtaining pluripotent stem cells (PSC) with self-renewal properties, the human embryonic stem cells (hESC). However, diverse studies suggest the existence of a plethora of human PSC (hPSC) that can be derived from both embryonic and somatic sources, depending on defined culture conditions, their spatial origin, and the genetic engineering used for reprogramming. This review will focus on hPSC, covering the conventional primed hESC, naive-like hPSC that resemble the ground-state of development, region-selective PSC, and human induced PSC (hiPSC). We will analyze differences and similarities in their differentiation potential as well as in the molecular circuitry of pluripotency. Finally, we describe the need for human feeder cells to derive and maintain hPSC, because they could emulate the interaction of in vivo pluripotent cells with extraembryonic structures that support development. Developmental Dynamics 245:762-773, 2016. © 2016 Wiley Periodicals, Inc.

Electrocatalytic oxygen evolution reaction (OER) based on geometric structure and interfacial-site engineering of catalysts is an excellent strategy for the hydrogen production by water electrolysis. Herein, a novel class of three-dimensional (3D) CoMoOx/CoMoSx/CoSx (CoMoOS) nanoboxes (NBs) electrocatalysts with abundant interfaces is designed through a facile dissolution-regrowth and ion-exchange process employing ZIF-67 as the sacrificial template. Remarkably, the rich interfaces not only endow the CoMoOS with a high surface active area but also provide a “highway” for charge transport, thereby optimizing the binding strength of reaction intermediates on CoMoOS and drastically boosting the oxygen production. More interestingly, the unique nanobox structure also endows the catalyst with a 3D accessibility for reactants. As a result, the 3D CoMoOS NBs achieve not only an ultralow overpotential of 281 mV at 10 mA cm−2, but also high-performance overall water electrolysis at alkaline media, with a cell potential of 1.58 V at 10 mA cm−2.

Taguchi experimental design with the alternating and direct current (AC and DC) electrocoagulation (EC) using initial fluoride concentration of contaminant, retention time, pH, electrode type, and voltage was used on fluoride removal. DC current is significantly more efficient than AC, and Al has a higher performance than Fe electrode (p

The heart generates the strongest and most extensive rhythmic electromagnetic field in the body As all cells throughout the body are oriented according to the magnetic vector of the heart the heart has a powerful influence on everybody process The activity of immune cells is closely connected to their polarity when immune cells become depolarized they are deactivated as a result nbsp We hypothesize that the heart rsquo s electromagnetic signals are distributed throughout the body via the network of acupuncture meridians similar to the manner in which the heart propels blood throughout the body via blood vessels The heart rsquo s electromagnetic system governs the structure and organization of tissues as well as the potential ndash and thus the activity ndash of all the body rsquo s cells including immune cells This method of communication is implied in the control of cell proliferation and its failure in a bodily organ contributes to the cancer process nbsp Our aim was to determine whether we could monitor the electromagnetic activity in acupuncture points back SHU points and record this activity with electrocardiogram or electroencephalogram In our preliminary trial we succeeded in recording this electromagnetic activity using electrogram to record activity in back SHU acupuncture points also known as Associated Points or Paravertebral Reflex points but not in an inactive neighboring area control or ldquo sham rdquo points We found that the wave shape of electromagnetic activity recorded at SHU points was different in the presence of pathological conditions in a given internal organ while it remained constant in SHU points representing healthy organs In conclusion our preliminary research offers additional proof for the existence of a sovereign system of biological control over the organization and activity of all bodily tissues governed by the electromagnetic field generated by the heart and distributed through the network of acupuncture meridians Our research leads us to believe that the immunomodulating effect of acupuncture results from the restoration of tissue cell structure and cell potential The stimulation of acupuncture points restores the receptivity of target tissues and immune cells to the heart rsquo s electromagnetic signals thereby restoring the cells rsquo polarity and functional activity nbsp

The purpose of this work is to develop a one-dimensional mathematical model for predicting the cell performance of a direct formic acid fuel cell and compare this with experimental results. The predicted model can be applied to direct formic acid fuel cells operated with different formic acid concentrations, temperatures, and with various electrolytes. Tafel kinetics at the electrodes, thermodynamic equations for formic acid solutions, and the mass-transport parameters of the reactants are used to predict the effective diffusion coefficients of the reactants (oxygen and formic acid) in the porous gas diffusion layers and the associated limiting current densities to ensure the accuracy of the model. This model allows us to estimate fuel cell polarization curves for a wide range of operating conditions. Furthermore, the model is validated with experimental results from operating at 1–5 M of formic acid feed at 30–80 °C, and with Nafion-117 and silane-crosslinked sulfonated poly(styrene-ethylene/butylene-styrene) (sSEBS) membrane electrolytes reinforced in porous polytetrafluoroethylene (PTFE). The cell potential and power densities of experimental outcomes in direct formic acid fuel cells can be adequately predicted using the developed model.

TiO2 nanotube (TiO2NT) surfaces can achieve a high area surface and enhanced electrocatalytic properties. One of the key challenges is the insertion of nanostructured titanates deeply into the pores of TiO2NT. We describe the electrophoretic deposition (EPD) of two different titanates - nanosheets (TiNSs) and nanotubes (TiNTs) into the pores of TiO2NT to produce controlled hierarchical surfaces. A sufficiently high applied cell potential and mechanical stimulation of the surface are important to incorporate TiNSs and TiNTs inside the pores of TiO2NTs. The electrodes show improved hydrophobicity after deposition of titanates. The beneficial effect of a counter electrode equipped with a brush to avoid the accumulation of a thick outer layer on TiO2NTs is highlighted.

In the March issue of Chem, Andrews, Banerjee, and colleagues devise a clever strategy to synthesize a metastable one-dimensional polymorph of V2O5 and demonstrate reversible chemical and electrochemical Mg intercalation, with 90 mAh/g capacity retained after 50 cycles at an average cell potential of 1.65 V versus Mg metal. Their approach proves fruitful not only in identifying a new functional multivalent cathode material, but also in validating a general concept that metastable compounds can offer sufficiently low migration energies to support reversible cycling with multivalent ions.

In this study, the effects of hydrogen flow rate, oxygen flow rate, cell and humidification temperature on power density were examined experimentally. The experiments have been carried out on a single proton exchange membrane (PEM) fuel cell with the active area of 25 cm(2). Response surface methodology (RSM) was used to determine the optimum conditions of PEM fuel cell by Design-Expert 8.0 (trial version). It was found that temperature had an important effect on the performance of PEM fuel cell by the results of experiments. Increasing both cell and humidification temperature increased the performance of the fuel cell system. Even cell performance decreases after exceeding a definite temperature. An increase occurred in performance at low cell potential with increasing the hydrogen flow rates. And, maximum power density, whose value was 0.5495 mW/m(2), was reached at these conditions of 0.4 V, 5 L/min hydrogen flow rate, 70 degrees C humidification temperatures and 40 degrees C cell temperatures.

Pitting corrosion of stainless steel has been investigated with high-resolution in situ X-ray microtomography. The growth of pits at the tip of stainless steel pins has been observed with 3D microtomography under different conditions of applied current and cell potential. The results demonstrate how pits evolve in stainless steel, forming a characteristic “lacy” cover of perforated metal. In addition, it is shown how the shape of pits becomes modified by MnS inclusions.

Bipolar membrane electrodialysis for the production of organic bases, in contrast to organic acids, has received little attention in the scientific literature. In the present work we have investigated and compared different membrane configurations for the alkalinization of monoethanolamine salts into the organic base monoethanolamine. A current utilization of only 36% has been obtained for a two compartment configuration with bipolar and anion-exchange membranes. Proton tunneling through the anion-exchange membrane has been identified as the main reason for this relatively low current utilization. Minimizing proton tunneling by employing proton blocking anion-exchange membranes and using a three compartment configuration, the current utilization could be increased to 80%. This bipolar membrane configuration acts as a concentration step as well. A MEA concentration of 32 wt% in the base compartment could be achieved. A disadvantage of the three compartment configuration is the relatively high unit cell potential drop of 3.1 V at a current density of 1000 A m−2 using a compartment thickness of 0.75 mm.

In our previous paper, a new experimental technique based on the potentiometric method was developed to obtain thermodynamic activity data (in form of activity ratio) particularly for ternary electrolyte+nonelectrolyte+H 2 O solutions supersaturated with the nonelectrolyte. In this paper, a rigorous thermodynamic approach is proposed to derive activity data for binary nonelectrolyte+H 2 O solutions in the supersaturated region, via cell potentials of an electrolyte tracer and solubility data of the nonelectrolyte. An analysis of thermodynamic consistency is presented to evaluate the reliability and accuracy of the measured data. A systematic experimental investigation of three ternary electrolyte+nonelectrolyte+H 2 O and two binary nonelectrolyte+H 2 O systems is reported in both under-saturated and supersaturated regions (up to a supersaturation level of approximately 27%). Interesting thermodynamic behaviors are observed and their significance is discussed, with the role of thermodynamics in exploration of crystallization phenomena highlighted.

M{sub 2}Mn{sub 3}O{sub 8} (M=Ca{sup 2+}, Cu{sup 2+}) compounds were synthesized and characterized in lithium cells. The M{sup 2+} cations, which reside in the van der Waal's gaps between adjacent sheets of Mn{sub 3}O{sub 8}{sup 4-}, may be replaced chemically (by ion-exchange) or electrochemically with Li. More than 7 Li{sup +}/Cu{sub 2}Mn{sub 3}O{sub 8} may be inserted electrochemically, with concomitant reduction of Cu{sup 2+} to Cu metal, but less Li can be inserted into Ca{sub 2}Mn{sub 3}O{sub 8}. In the case of Cu{sup 2+}, this process is partially reversible when the cell is charged above 3.5 V vs. Li, but intercalation of Cu{sup +} rather than Cu{sup 2+} and Li{sup +}/Cu{sup +} exchange occurs during the subsequent discharge. If the cell potential is kept below 3.4 V, the Li in excess of 4Li{sup +}/Cu{sub 2}Mn{sub 3}O{sub 8} can be cycled reversibly. The unusual mobility of +2 cations in a layered structure has important implications both for the design of cathodes for Li batteries and for new systems that could be based on M{sup 2+} intercalation compounds.

This paper presents a mathematical model based on a porous-electrode theory to describe the discharge of a lithium ion cell. The expression for the electrostatic cell potential has been obtained by subtracting the overpotential at the front of the anode from the overpotential at the back of the cathode plus the integral of the solution phase electrostatic potential in the cathode and the separator. The resulting expression is used to plot the cell potential against time and is compared with experimental results using parameter values from the literature.

Embryonic chimeras of the mouse are well-established tools for studying cell lineage and cell potential. They are also a key part of the analysis of complex phenotypes of mutant mice. By combining embryonic stem cell technology, molecularly tagged mutations and sensitive cell lineage markers,chimeras can provide invaluable insights into the tissue-specific requirement and the mode of action of many mouse genes.

A mathematical model for phosphoric acid fuel cell (PAFC) cathodes has been developed. The model, based on equations that take activation and diffusional problems into account, provides a description of the electrochemical behaviour of the electrode. These studies allow optimization of the morphological characteristics of this cell component and improvement in the performance of the whole fuel cell. In particular, the sensitivity analysis carried out on the model provides information on the influence of single parameters. Accordingly, the as optimized cathode allowed a performance of 700 mV at 200 mAcm−2 in air; the corresponding cell potential also increased from 500 mV at 150 mAcm−2 to 510mV at 200 mAcm−2.

World-wide a number of activities are concerned with the optimisation and development of cell materials and microstructures with the aim of reducing the solid oxide fuel cell (SOFC) operating temperature. Advantages for reduced operating temperatures are considered to be longer life time and reduced costs of the total system. Conventional zirconia based electrolyte cells with highly optimised electrodes have produced 500 mA/cm2 at 700 mV and 800°C. At a similar temperature and cell potential, small scale, co-fired, electrode supported thin-electrolyte cells have produced 700 mA/cm2. For SOFC operation at temperatures below 750°C the conventional 8 mol% Y2O3–ZrO2 electrolyte is replaced with either Ce0.9Gd0.1O1.95 (10GCO) or La0.9Sr0.1Ga0.8Mg0.2O3 (LSGM) electrolytes. Up-scaled 10×10 cm2 or 12 cm circular 10GCO and LSGM cells have been manufactured and the initial results of cell tests are very promising.