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This work investigates the electrochemical dynamics and performance of additively manufactured composite electrolytes for resistive switching. Devices are comprised of a Ag/AgI–Al2O3/Pt stack, where the solid state electrolyte is additively manufactured using extrusion techniques. AgI–Al2O3 composite electrolytes are characterized by x-ray diffraction and electrochemical impedance spectroscopy. The ionic conductivities of the electrolytes were measured for different concentrations of Al2O3, observing a maximum conductivity of 4.5 times the conductivity of pure AgI for composites with 20 mol. % Al2O3. There was little change in activation energy with the addition of Al2O3. Setting the Ag layer as the positive electrode and the Pt layer as the negative electrode, a high conductivity state was achieved by applying a voltage to electrochemically establish an electrically conducting Ag filament within the solid state AgI–Al2O3 electrolyte. The low conductivity state was restored by reversing this applied voltage to electrochemically etch the newly grown Ag filament. Pure AgI devices switch between specific electrical resistivity states that are separated by five orders of magnitude in electrical conductivity. Endurance tests find that the AgI resistive switches can transition between a low and high electrical conductivity state over 8500 times. Composite AgI–Al2O3 resistive switches formed initial Ag filaments significantly faster and also demonstrated two orders of magnitude separation in resistivity when cycling for 1600 cycles. [ABSTRACT FROM AUTHOR]

Different machine learning (ML) methods were explored for the prediction of self-diffusion in Lennard-Jones (LJ) fluids. Using a database of diffusion constants obtained from the molecular dynamics simulation literature, multiple Random Forest (RF) and Artificial Neural Net (ANN) regression models were developed and characterized. The role and improved performance of feature engineering coupled to the RF model development was also addressed. The performance of these different ML models was evaluated by comparing the prediction error to an existing empirical relationship used to describe LJ fluid diffusion. It was found that the ANN regression models provided superior prediction of diffusion in comparison to the existing empirical relationships. [ABSTRACT FROM AUTHOR]

Excessive exposure to sunlight's ultraviolet (UV) radiation causes adverse effects such as premature aging, sunburn, and skin cancers. Monitoring daily exposure to sunlight is essential to avoid developing health risks. Colorimetric UV sensors change color as a function of UV exposure, provide onsite information about the level of exposure, and can act as a personal wearable device to assist in making informed decisions on sunlight exposure. These sensors utilize radiation-induced reactions on a dye to produce a color change. Here, BiOCl based UV sensor is reported for monitoring UV exposure where a white-to-black color transformation is induced due to the creation of oxygen vacancies in BiOCl. This color transformation is not quantifiable in bulk BiOCl; hence BiOCl was purposely dispersed on filter paper to form petal-like nanostructures that help quantify the color change. Four different dye molecules, 6-carboxyfluorescein, 5-carboxyfluorescein, rhodamine-B, and Prussian blue were evaluated, where 6-carboxyfluorescein gave the best color contrast. The sensor responds to UVA, UVB, and UVC and with proper UV filters can be made selective for specific UV radiations. This unique colorimetric UV sensor can help manage personal UV exposure and reduce the risk of sun exposure ailments. [ABSTRACT FROM AUTHOR]

Methane conversion into value‐added products such as olefins and aromatics is gaining increased attention in the wake of new natural gas reserve discoveries. Electrochemical oxidative coupling of methane (E‐OCM) provides better product selectivity as the product distribution can be controlled by applied potential as well as the oxide ion flux. Here a new catalyst based on Mg and Fe codoped barium niobate perovskites is reported. The prepared perovskites show excellent chemical stability in CH4‐rich environments up to 925 °C while showing methane activation properties from 600 °C. E‐OCM measurements indicate an ethylene production rate of 277 µmol cm−2 h−1 with a faradaic efficiency of 20% at 1 V and durable operation for six continuous days. X‐ray photoelectron spectroscopic measurements indicate significant Nb valency reorganization that can be the reason for its chemical stability. Nevertheless, the surface area of the catalyst is significantly lower and requires improvements in synthesis methodologies to improve catalytic activity further. The exceptional chemical stability of this perovskite material under methane exposure at high temperatures has significant importance as this material can be used as a catalyst and/or support in a wide variety of applications relevant for efficient energy conversion and storage. [ABSTRACT FROM AUTHOR]

Efficient conversion of methane to value-added products such as olefins and aromatics has been in pursuit for the past few decades. The demand has increased further due to the recent discoveries of shale gas reserves. Oxidative and non-oxidative coupling of methane (OCM and NOCM) have been actively researched, although catalysts with commercially viable conversion rates are not yet available. Recently, Sr 2 F e 1.5 + 0.075 M o 0.5 O 6 − δ (SFMO-075Fe) has been reported to activate methane in an electrochemical OCM (EC-OCM) set up with a C2 selectivity of 82.2%1. However, alkaline earth metal-based materials are known to suffer chemical instability in carbon-rich environments. Hence, here we evaluated the chemical stability of SFMO in carbon-rich conditions with varying oxygen concentrations at temperatures relevant for EC-OCM. SFMO-075Fe showed good methane activation properties especially at low overpotentials but suffered poor chemical stability as observed via thermogravimetric, powder XRD, and XPS measurements where SrCO3 was observed to be a major decomposition product along with SrMoO3 and MoC. Nevertheless, our study demonstrates that electrochemical methods could be used to selectively activate methane towards partial oxidation products such as ethylene at low overpotentials while higher applied biases result in the complete oxidation of methane to carbon dioxide and water. Catalytic conversion of methane to ethene is limited by poor conversion, selectivity, and catalyst stability. Here a solid oxide electrolysis process is reported as a promising method for selective, partial oxidation of methane with low overpotentials. [ABSTRACT FROM AUTHOR]

Summary: High energy density liquid fuel, ammonia, faces increasing interest globally as a carbon‐free energy carrier that can be transported over long distances for decentralized and remote distribution. The dominant ammonia production method, Haber‐Bosch, is both energy and carbon intensive to overcome the slow kinetics of the ammonia synthesis reaction from nitrogen and hydrogen. An early techno‐economic model for lithium mediated electrochemical ammonia synthesis at mild process conditions using feed rates of 27 metric ton/day for lithium hydroxide, 127 metric ton/day for cryogenic nitrogen and 264 metric ton/day electrolysis grade water is presented. Further analysis was carried out to analyze the energy consumption and reduction per metric ton of ammonia in comparison to electrochemical ammonia using H+ conductive membrane and small‐scale Haber‐Bosch technology. Electrochemical ammonia synthesis using lithium‐ion conductive membrane coupled with nitrogen generation by cryogenic distillation was found to be a sustainable pathway. The ammonia production cost via lithium mediated pathway was estimated to be less than $700 per metric ton and was found to be comparable with costs using traditional Haber Bosch. The environmental impact of electrochemical ammonia using the alkali group 1 metal, lithium, was also assessed from cradle to product. [ABSTRACT FROM AUTHOR]

Artificial neural networks (ANNs) were developed to accurately predict the self-diffusion constants for pure components in liquid, gas and super critical phases. The ANNs were tested on an experimental database of 6625 self-diffusion constants for 118 different chemical compounds. The presence of multiple phases results in a heavy skew in the distribution of diffusion constants and multiple approaches were used to address this challenge. First, an ANN was developed with the raw diffusion values to assess what the main drawbacks of this direct method were. The first approach for improving the predictions involved taking the log 10 of diffusion to provide a more uniform distribution and reduce the range of target output values used to develop the ANN. The second approach involved developing individual ANNs for each phase using the raw diffusion values. Results show that the log transformation leads to a model with the best self-diffusion constant predictions and an overall average absolute deviation (AAD) of 6.56%. The resultant ANN is a generalized model that can be used to predict diffusion across all three phases and over a diverse group of compounds. The importance of each input feature was ranked using a feature addition method revealing that the density of the compound has the largest impact on the ANN prediction of self-diffusion constants in pure compounds. [ABSTRACT FROM AUTHOR]

Molybdenum carbide has immense potential as an active catalyst for reaction systems such as synthesis of important chemicals like ammonia. However, the carbide is not used as a commercial catalyst or support as the current synthesis processes produce low surface area material or have contaminants such as excess carbon and surface and chemisorbed oxygen. Moreover, attempts to refine the synthesis pathways are usually not supported by any thermochemical modeling. In this study, a facile and reproducible method to synthesize high surface area molybdenum carbide was developed with the help of thermochemical modeling to better understand molybdenum‐carbon phase behavior. We have synthesized 2‐5 nm particles of MoxC with surface areas of up to 360 m2/g as characterized using a variety of techniques including X‐ray diffraction and electron microscopy. Refining synthesis pathways using thermochemical modeling. [ABSTRACT FROM AUTHOR]

Crystalline disorder in complex oxides can have a pronounced effect on mass transport, but the role of disorder within the complex landscape of material and microstructural defects is not uniquely understood. In this work, we use radiation damage, not to study the fundamental damage response, but rather as a tool to induce and control the extent of disorder of a single oxide composition in order to explore the relationship between intrinsic disorder and transport. Thin films of the ordered pyrochlore Gd2Ti2O7 (GTO) were irradiated with light ions and transitioned from ordered pyrochlore to disordered crystalline defect fluorite to an amorphous structure, disordering monotonically with increasing fluence, but nonhomogeneously throughout the film. Conductivity increased substantially with increasing disorder, where only slight disordering results in the majority of the change in conductivity. Additionally, while the pristine GTO films exhibited mixed ionic and p-type electronic conductivity, the total conductivity of the material that exhibited maximum disorder prior to the onset of amorphization was ionic in nature. [ABSTRACT FROM AUTHOR]

Abstract: A hydrothermal approach to generate a platinum‐group‐metal‐free (PGM‐free) Fe−N−C catalyst for the oxygen reduction reaction (ORR) is introduced. The process involves partial carbonization by hydrothermal means followed by thermal treatment to obtain the final catalysts. Detailed X‐ray scattering analysis of the glucose−imidazole catalysts (termed as GLU‐IMID‐C catalysts), obtained for the first time with the use of CarbonXS GUI program, reveals the presence of face‐centered cubic (FCC) iron nanoparticles embedded in partially graphitic carbon in all catalyst variations. We also report the physical characterization of these catalysts by using X‐ray photoelectron spectroscopy, Brunauer−Emmett−Teller surface area analysis, and transmission electron microscopy. The electrocatalytic behavior of the catalysts towards oxygen reduction is studied separately in acidic and alkaline electrolytes by rotating ring disk electrode measurements. The catalysts exhibit high ORR activity in acidic (0.5 M H2SO4) and alkaline (0.1 M KOH) electrolytes. A precursor structure−performance relationship of these catalysts and their performance trends in both electrolytes has been discussed in this work. [ABSTRACT FROM AUTHOR]

We report herein a density functional theory study of the nitrogen electroreduction and hydrogen evolution reactions on cubic molybdenum carbide (MoC) in order to investigate the viability of using this material as an electro-catalyst for ammonia synthesis. Free energy diagrams for associative and dissociative Heyrovsky mechanisms showed that nitrogen reduction on cubic MoC(111) can proceed via an associative mechanism and that small negative potentials of −0.3 V vs. standard hydrogen electrode can onset the reduction of nitrogen to ammonia. Kinetic volcano plots for hydrogen evolution showed that the MoC[110] surface is expected to have a high rate for the hydrogen evolution reaction, which could compete with the reduction of nitrogen on cubic MoC. The comparison between the adsorption energies of H-adatoms and N-adatoms also shows that at low potentials adsorption of hydrogen atoms competes with nitrogen adsorption on all the MoC surfaces except the MoC(111) surface. The hydrogen evolution and accumulation of H-adatoms can be mitigated by introducing carbon vacancies i.e. increasing the ratio of metal to carbon atoms, which will significantly increase the affinity of the catalytic surface for both nitrogen molecules and N-adatoms. [ABSTRACT FROM AUTHOR]

The crystallographic structure of disordered carbons impacts their performance in components for fuel cells, batteries and catalyst supports. Obtaining parameters such as lattice constants and crystal domain size requires an appropriate model for these carbons, a task accomplished with the Fortran program CarbonXS published in 1993. CarbonXS GUI contains an updated version of CarbonXS and a graphical user interface wrapper. This new version provides a graphical method of configuring and operating CarbonXS, a calculation mode to simulate diffraction patterns, and immediate feedback in the form of fit-source and difference plots. CarbonXS GUI is available for free on Windows, Linux and Mac OSX at . [ABSTRACT FROM AUTHOR]

The structural equilibrium parameters, the adsorption energies, and the vibrational frequencies of the nitrogen molecule and the hydrogen atom adsorbed on the (111) surface of rhodium have been investigated using different generalized-gradient approximation (GGA), nonlocal correlation, meta-GGA, and hybrid functionals, namely, Perdew, Burke, and Ernzerhof (PBE), Revised-RPBE, vdW-DF, Tao, Perdew, Staroverov, and Scuseria functional (TPSS), and Heyd, Scuseria, and Ernzerhof (HSE06) functional in the plane wave formalism. Among the five tested functionals, nonlocal vdW-DF and meta-GGA TPSS functionals are most successful in describing energetics of dinitrogen physisorption to the Rh(111) surface, while the PBE functional provides the correct chemisorption energy for the hydrogen atom. It was also found that TPSS functional produces the best vibrational spectra of the nitrogen molecule and the hydrogen atom on rhodium within the harmonic formalism with the error of −2.62 and −1.1% for the NN stretching and RhH stretching frequency. Thus, TPSS functional was proposed as a method of choice for obtaining vibrational spectra of low weight adsorbates on metallic surfaces within the harmonic approximation. At the anharmonic level, by decoupling the RhH and NN stretching modes from the bulk phonons and by solving one- and two-dimensional Schrödinger equation associated with the RhH, RhN, and NN potential energy we calculated the anharmonic correction for NN and RhH stretching modes as −31 cm−1 and −77 cm−1 at PBE level. Anharmonic vibrational frequencies calculated with the use of the hybrid HSE06 function are in best agreement with available experiments. © 2014 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

We used density functional theory to study the electrochemical conversion of nitrogen to ammonia on the (001), (100/010), (101), and (111) surfaces of γ-Mo2N. Based on the calculated free energy profiles for the reduction of nitrogen by the associative and dissociative mechanisms, reactivity was found to decrease in the order (111) ＞ (101) ＞ (100/010) ≈ (001). Namely, the cell potentials needed to drive the reduction to ammonia increase in the following order: −0.7 V on (111), −1.2 V on (101), and −1.4 V on (100/010) and (001) surfaces. The (111) surface was found to be the most reactive for nitrogen due to (i) its ability to adsorb the N2 in the side-on position which activates N–N bonding and (ii) its high affinity for N-adatoms which also prevents accumulation of H-adatoms on the catalytic surface at low cell potentials. We have also calculated vibrational frequencies of different NxHy species adsorbed on various γ-Mo2N surfaces. The frequencies are found to depend strongly on the type of the binding sites available on the crystal facets. A comparison of the calculated frequencies with the frequencies of the corresponding species in transition metal complexes and other metal surfaces shows that the frequencies of several signature modes fall in a similar region and might be used to assign the spectra of hydrogen and nitrogen containing surface species on different metal surfaces. [ABSTRACT FROM AUTHOR]

More clinicians are using mindfulness-based therapeutic strategies; however, Evangelical Christian clients sometimes worry about the Buddhist origins of these treatments. Christian accommodative mindfulness (CAM) attempts to address these concerns with culturally sensitive adaptations to mindfulness methods. We present a definition of CAM and propose some worldview adjustments to typical mindfulness constructs when working with these clients. The empirical research on Christian-derived meditation strategies and Christian-adapted mindfulness strategies will then be reviewed. We introduce a four-session group CAM protocol currently being researched that focuses on scripture meditation, breath meditation, body awareness, and loving-kindness meditation. Sample scripts are included. [ABSTRACT FROM AUTHOR]

Recent neuroscientific discoveries are refining our understanding of what makes therapy work and how God image difficulties can be addressed effectively in counseling. This article discusses neural networks, implicit and explicit memory systems, hemispheric specialization and neurological aspects of trauma in regards to how these impact our assumptions about traditional psychotherapy and God image transformation. Given the varying levels of neuroscientific training in the pastoral and mental health professions, this discussion is written in an introductory fashion. Implications are highlighted through a case study demonstrating spiritually-based intervention strategies. [ABSTRACT FROM AUTHOR]

This exploratory survey investigated Theophostic Ministry, a recently developed inner healing prayer technique that has simultaneously garnered much anecdotal support and criticism. Specifically, the survey sought to assess who is using Theophostic Ministry, what disorders are being treated, and regular practitioners’ perceptions of this technique’s efficacy. The survey was administered during an advanced training seminar given by Ed Smith, the technique’s developer. Of the 148 participants 74% completed the survey (Respondent N = 111). Survey results suggested a wide variety of people are using Theophostic Ministry - from pastors to lay counselors to psychologists. Overall, the respondents believe this technique is very effective and have used the prayer ministry in treating a wide variety of disorders including some quite complex. Training level issues therefore emerged from this survey’s findings. These issues are explored and recommendations made. The limitations of the survey are discussed. [ABSTRACT FROM AUTHOR]

Recently, research has begun to explore the clinical utility of forgiveness in the psychotherapeutic context. This article will clarify a variety of issues seen in the psychotherapeutic community in regards to forgiveness. Myths will be addressed, models explored, and research on one process model of forgiveness will be examined. Ethical considerations also will be discussed. [ABSTRACT FROM PUBLISHER]