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The capillary force drives the edges of solid thin films to retract. The distance a film edge has retracted over time is usually fitted to a power law. However, experiments and numerical simulations suggest that edge retraction does not follow a power-law. In this work, a simple geometric model for edge retraction is presented that reproduces the retraction distance versus time scalings of simulations for both isotropic and highly-anisotropic films, and is consistent with experiments. The earliest time at which a power-law fit becomes a reasonable approximation is calculated as a function of substrate–film contact angle. [ABSTRACT FROM AUTHOR]

Highlights: [•] Our study tests affect control theory predictions about a specific deviant identity (stripper). [•] Our findings indicate that strippers do not act as predicted by affect control theory. [•] We suggest that strippers (and possibly other deviants) will tend to perceive their own identities generally more positively than will others. [•] We argue that the veracity of affect control theory predictions about deviance is contingent on the perspective of the individual(s) imputing meaning about the behavior. [Copyright &y& Elsevier]

A diffuse-interface model for microstructure with an arbitrary number of components and phases was developed from basic thermodynamic and kinetic principles and formalized within a variational framework. The model includes a composition gradient energy to capture solute trapping and is therefore suited for studying phenomena where the width of the interface plays an important role. Derivation of the inhomogeneous free energy functional from a Taylor expansion of homogeneous free energy reveals how the interfacial properties of each component and phase may be specified under a mass constraint. A diffusion potential for components was defined away from the dilute solution limit, and a multi-obstacle barrier function was used to constrain phase fractions. The model was used to simulate solidification via nucleation, premelting at phase boundaries and triple junctions, the intrinsic instability of small particles, and solutal melting resulting from differing diffusivities in solid and liquid. The shape of metastable free energy surfaces is found to play an important role in microstructure evolution and may explain why some systems premelt at phase boundaries and phase triple junctions, whereas others do not. [ABSTRACT FROM AUTHOR]

Juvenile drug courts have been developed with the explicit mission of reducing juvenile substance use and related delinquency, and adult crime. Research has shown that juvenile drug courts continue to be popular and effective alternatives to other juvenile court initiatives in terms of decreasing juvenile recidivism. This study is the first to focus on the link between juvenile drug court participation and conviction for adult crime. The juvenile records of 79 former juvenile drug court participants in Tennessee were compared with their adult criminal convictions. Our findings indicate that graduating from juvenile drug court reduced adult felonies, but not misdemeanors, Racial differences between Whites and non-Whites were noted. [ABSTRACT FROM AUTHOR]

Abstract: Recent experimental developments reveal that nanoscale lithium iron phosphate (LiFePO4) olivine particles exhibit very different phase transition behavior from the bulk olivine phase. A crystalline-to-amorphous phase transition has been observed in nanosized particles in competition with the equilibrium phase transition between the lithium-rich and lithium-poor olivine phases. Here we apply a diffuse-interface (phase-field) model to study the kinetics of the different phase transition pathways in nanosized LiFePO4 particles upon delithiation. We find that the nucleation and growth kinetics of the crystalline-to-crystalline and crystalline-to-amorphous phase transformations are sensitive to the applied electrical overpotential and particle size, which collectively determine the preferred phase transition pathway. While the crystalline-to-crystalline phase transition is favored by either faster nucleation or growth kinetics at low or high overpotentials, particle amorphization dominates at intermediate overpotentials. Decreasing particle size expands the overpotential region in which amorphization is preferred. The asymmetry in the nucleation energy barriers for amorphization and recrystallization results in a phase transition hysteresis that should promote the accumulation of the amorphous phase in electrodes after repeated electrochemical cycling. The predicted overpotential- and size-dependent phase transition behavior of nanoscale LiFePO4 particles is consistent with experimental observations. [ABSTRACT FROM AUTHOR]

The thermodynamics and kinetics of phase transformations in electrochemical systems are reviewed. Phase transitions in Li MPO4 ( M = Fe, Mn, Ni, Co) olivines are highlighted. The phase transformation phenomena in Li MPO4 are diverse and include thermodynamic effects of particle size and applied overpotential, the appearance of metastable phases, and the effects of defects from atomic disorder and aliovalent doping. Such phenomena also include kinetic effects such as interface motion and diffusion of Li-electron complexes. The nature of phase transitions directly influences electrode performance in battery applications. Reduced particle size and doping can reduce or eliminate room-temperature Li miscibility gaps, which in turn affect characteristics of state of charge versus voltage and the elastic energy due to volume mismatches between phases. Near the conditions for a phase transition, Li diffusion coefficients are reduced. Nucleation and growth kinetics produce a series of phase transition sequences, which can result in the accumulation of noncrystalline phases during electrochemical cycling. [ABSTRACT FROM AUTHOR]

The conditions for grain boundary (GB) structural transitions are determined from a diffuse interface model that incorporates structural disorder and crystallographic orientation. A graphical construction and numerical calculations illustrate the existence of a first-order GB order–disorder transition below the bulk melting point. When thermodynamic conditions permit their existence, disordered GB structures tend to be stable at higher temperatures and are perfectly wet by liquid at the melting point, while ordered grain boundaries are meta-stable against preferential melting. We calculate GB phase diagrams which are analogous to those for liquid–vapor phase transitions. [ABSTRACT FROM AUTHOR]

A statistical approach for modeling fracture in brittle materials is presented. In particular, a microstructural-based finite element code called OOF is used in conjunction with a stochastic representation of failure that relies on the Weibull law. The OOF code, which maps materials microstructures onto finite element meshes, enables to calculate the local stress states; these stresses are used along with the statistical criterion for brittle fracture in order to determine microcrack formation and propagation. Computer simulations are performed on several microstructures of different materials types, e.g., laminates, particulate composites and polycrystals. The damage accumulation due to microcracking is characterized by the stereological measure of failed material and is investigated in order to assess the effect of microstructural features on the failure mechanism. Moreover, the approach allows to analyze the influence of the characteristic parameters for brittle materials on damage evolution. [ABSTRACT FROM AUTHOR]

Previous numerical methods that calculate equilibrium particle shape to study thermodynamic and kinetic processes depend on interfacial (surface) free energy functions γ( $$\skew7\hat{n}$$) that have cubic symmetry and thus produce Wulff shapes W of cubic symmetry. This work introduces a construction yielding the minimal surface energy density γconvex( W) that can be determined for any W. Each γ( $$\skew7\hat{n}$$) that belongs to the equivalence class γ( W) bounded by γconvex( W) can be used in an energy-minimizing calculation that depends only on W. For practical numerical calculations, this work gives two methods taking directional distance from specified orientation minima as a parameter to produce analytic forms of γ( $$\skew7\hat{n}$$) giving W as the equilibrium shape for (an otherwise unconstrained) fixed volume. Included are several two- and three-dimensional examples that demonstrate the application and utility of the model γ( $$\skew7\hat{n}$$) functions. [ABSTRACT FROM AUTHOR]

The effects of crystallographic texture and microstructure are analyzed for polycrystalline tetragonal BaTiO3, pseudotetragonal PZN-PT, and cubic BaTiO3. For tetragonal BaTiO3 and pseudotetragonal PZN-PT, we demonstrate that a high anisotropy of the single-crystal properties induces an apparent enhancement in the macroscopic piezoelectric response. For tetragonal BaTiO3, the predicted macroscopic piezoelectric constants d31 and d33 are enhanced with respect to its single-crystal value at the expense of the spatial contributions from d15. For samples possessing fiber texture, an optimal response is predicted for samples that arc not perfectly textured. Similarly, an apparent enhancement of the macroscopic value of d,5 is predicted for PZN-PT. For cubic BaTiO3, the low anisotropy of the underlying crystal properties induces a uniform decrease of the macroscopic electrostrictive constant, Q11, with decreasing texture. A completely random polycrystal provides 0.85±0.05 times its single-crystal response. [ABSTRACT FROM AUTHOR]

The Wulff construction yields the equilibrium shape of a particle of fixed volume embedded in a single phase at constant temperature. When the particle attaches to an interface (boundary) between two distinct phases or grains of the same phase, the Wulff construction must be modified to account for the abutment of Wulff shapes at the boundary as well as the boundary energy that is replaced by the particle. If the boundary is non-deformable, a portion of the particle interface is constrained to replace the image (i.e. the exact position) of the boundary that is removed, and the Winterbottom construction yields the equilibrium particle shape. If the boundary can deform, the particle is not constrained to replace the image of removed boundary, and the particle shape is determined by a more general modification of the Wulff construction. In two dimensions, the particle attaches to an initially flat boundary and creates two disjoint segments that remain flat at equilibrium. In three dimensions, the boundary surrounding the particle is contiguous, and numerical calculations show that such a boundary is not necessarily flat but maintains a constant mean curvature of zero at equilibrium. [ABSTRACT FROM AUTHOR]

The article comments on a study by Alvin Chua, Nicole Benedek and coauthors on the computational technique for predicting grain boundaries interface structures which was published in the earlier issue of the journal. As stated the technique merges ab initio calculations with genetic algorithm and thereby simplifies the process of predicting grain boundaries interface structures. It also provides suitable solutions of the atomic structures that were difficult to imagine earlier.

An energy model of nanoclusters-chain self-organized on the functional vicinal surfaces is established to investigate the self-ordering processes, which provides a promising and challenging nanomaterial-design method by means of the energy minimum principle and entropy change principle. The cluster-chain structure can be predicted through controlling the linear coverage of nanoclusters (PM) and the step width (L). The different interactions including the steps and terraces will perform a positive influence on the self-ordering due to their long-range forces. [ABSTRACT FROM AUTHOR]

Several three-dimensional dielectric network structures possessing large photonic band gaps are presented. Two of these photonic crystals show gaps as large as 26% of the midgap frequency for a refractive index contrast 3.6:1. Four of the proposed structures consist of three-connected networks and a fifth structure has a mixture of three- and four-connected nodes. The realization of these structures using block polymer self-assembly, interference lithography and layer-by-layer lithography is briefly discussed. © 2003 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Diffusion-induced phase transitions typically change the lattice symmetry of the host material. In battery electrodes, for example, Li ions (diffusing species) are inserted between layers in a crystalline electrode material (host). This diffusion induces lattice distortions and defect formations in the electrode. The structural changes to the lattice symmetry affect the host material's properties. Here, we propose a 2D theoretical framework that couples a Cahn-Hilliard (CH) model, which describes the composition field of a diffusing species, with a phase-field crystal (PFC) model, which describes the host-material lattice symmetry. We couple the two continuum models via coordinate transformation coefficients. We introduce the transformation coefficients in the PFC method to describe affine lattice deformations. These transformation coefficients are modeled as functions of the composition field. Using this coupled approach, we explore the effects of coarse-grained lattice symmetry and distortions on a diffusion-induced phase transition process. In this paper, we demonstrate the working of the CH-PFC model through three representative examples: First, we describe base cases with hexagonal and square symmetries for two composition fields. Next, we illustrate how the CH-PFC method interpolates lattice symmetry across a diffuse phase boundary. Finally, we compute a Cahn-Hilliard type of diffusion and model the accompanying changes to lattice symmetry during a phase transition process. [ABSTRACT FROM AUTHOR]

Provides information on the applications of a digital image model for the interplay of capillary and elastic driving forces during microstructural evolution. Information on curvature and elastic energy density; Detailed information on randomly packed particles; Discussion on the application.

A framework is presented that treats the combined effects of nonlinear elastic deformation, lattice constraints, and electrochemical potentials. The electro-chemo-mechanical diffusion potential is derived, and the particular case where ionic species are subject to a crystal lattice constraint is also derived. By combining energy balance and local entropy production, the framework provides a consistent method to treat the evolution of charged species which also carry anelastic deformations in a crystal lattice. The framework is used to derive a finite element formulation that applies to general cases of interest for diffusion of active species in battery electrodes and in fuel cells. We demonstrate the application of the finite element formulation with two cases: ambipolar diffusion and kinetic demixing. The predicted system response demonstrates how mechanical effects cannot be disregarded, even in the presence of dominant electrostatic forces acting on ion transport. A cation rich surface layer is predicted when elastic forces, due to Vegard's stress, participate in the migration of defects in a multicomponent oxides. Simulations show how stress plays a central role in the cation segregation to interfaces, a phenomenon regarded as critical to power and durability of solid oxide fuel cells. [ABSTRACT FROM AUTHOR]

Abstract: A mathematical model of flow cell operation incorporating hydrodynamic and electrochemical effects in three dimensions is developed. The model and resulting simulations apply to recently demonstrated high energy-density semi-solid flow cells. In particular, state of charge gradients that develop during low flow rate operation and their effects on the spatial non-uniformity of current density within flow cells are quantified. A one-dimensional scaling model is also developed and compared to the full three-dimensional simulation. The models are used to demonstrate the impact of the choice of electrochemical couple on flow cell performance. For semi-solid flow electrodes, which can use solid active materials with a wide variety of voltage–capacity responses, we find that cell efficiency is maximized for electrochemical couples that have a relatively flat voltage vs. capacity curve, operated under slow flow conditions. For example, in flow electrodes limited by macroscopic charge transport, an LiFePO4-based system requires one-third the polarization to reach the same cycling rate as an LiCoO2-based system, all else being equal. Our conclusions are generally applicable to high energy density flow battery systems, in which flow rates can be comparatively low for a given required power. [Copyright &y& Elsevier]

Percolation thresholds and critical exponents for universal scaling laws are computed for microstructures that derive from phase-transformation processes in two dimensions. The computed percolation threshold for nucleation and growth processes, Pc ≈ 0.66 12, is similar to those obtained by random placement of disks and greater than that of spinodal decomposition, Pc ≈ 0.4987. Three critical exponents for scaling behavior were computed and do not differ significantly from universal values. The time evolution of a characteristic microstructural length was also computed: For spinodal decomposition, this length grows according to a power law after a short incubation period; for nucleation and growth, there are several transitions in the nature of the growth law. We speculate that the transitions in nucleation and growth derive from competing effects of coalescence at short times and then subsequent coarsening. Short-range order is present, but different, for both classes of microstructural evolution. [ABSTRACT FROM AUTHOR]

Abstract: Interfaces and the movement of atoms within an interface play a crucial role in determining the processing and properties of virtually all materials. However, the nature of interfaces in solids is highly complex and it has been an ongoing challenge to link material performance with the internal interface structure and related atomic transport mechanisms. Interface complexions offer a missing link to help solve this universal problem. We have theoretically predicted the existence of multiple interface complexions by thermodynamics, but the present work represents the most comprehensive characterization and proof of their existence in a real material system. An interface complexion can be considered as a separate phase, which can be made to transform into different complexions (phases) with vastly different properties by chemistry and heat treatment, thereby enabling the engineering control of material properties on a level not previously realizable. As such, complexions offer a solution to outstanding fundamental scientific mysteries, such as the origin of abnormal grain growth in inorganic materials, a problem which leading researchers in the field have struggled to explain for the past 50 years. It is also described how interface complexions will likely have widespread impact across all branches of material science and related disciplines. [Copyright &y& Elsevier]

Abstract: A diffuse-interface model for interfaces in multi-component systems with energetic contributions from chemistry, defects, structure, orientation, electrostatics and gradients is proposed. The energy minimizing profiles of planar grain boundaries in the pseudo-binary SiO2–SiN4/3 system are calculated in the SiN4/3-rich single-phase field. Intergranular films are found to be stable below the eutectic temperature. Evidence of first-order grain boundary order–disorder transitions is found in misorientation and chemical potential space. Interface transitions predicted with the model can be plotted on equilibrium phase diagrams to produce “interfacial phase diagrams.” These could be a tool for designing processing routes to optimize bulk, polycrystalline material properties through control of grain boundary characteristics. [Copyright &y& Elsevier]

A model and numerical framework is developed for piezoelectric materials. The model treats the piezoelectric and electrostrictive effects by incorporating orientation-dependent single-crystal properties. The method is implemented in Object Oriented Finite Element program, a public domain finite element code, so it can be applied to arbitrary two-dimensional microstructures with crystallographic anisotropy. The model is validated against analytic solutions. Consistency of the method for known cases permits application of the technique to more complicated two-dimensional systems. The piezoelectric and electrostrictive response is determined for a few simple device geometries and provides insight for design and convergence criteria. [ABSTRACT FROM AUTHOR]

We propose a theoretical framework to derive thermodynamically consistent equilibrium equations and kinetic driving forces to describe the time evolution for electrically and magnetically active materials. This procedure starts from the combined statement of the first and second laws of thermodynamics, naturally incorporates Maxwell’s equations, and accommodates the description of continuous phase transformations for conserved and non-conserved order parameters. The kinetics of conserved and non-conserved ordered parameters are introduced, the adequate gradient flow is identified, thus the appropriate kinetics (e.g., Allen–Cahn, Cahn–Hilliard) are derived. Example applications of this theory include the electromechanical fields of piezoelectric materials and the wave equation in the limit of chemically homogeneous solids. Moreover, we derive a thermodynamically consistent set of partial differential equations which describe the transport of charged species in conductive, non-polarizable, magnetizable solids, and in polarizable, electrically insulating, non-magnetizable solids. [Copyright &y& Elsevier]

A stability analysis of phase separation of charged species by spinodal decomposition is presented. The charge effects introduce a short wave number cutoff for linear perturbations about the homogeneous, neutral solution. Phase field calculations using a semi-implicit spectral method support this conclusion. This suggests that coarsening is limited in ionic solid systems that are unstable with respect to charged-phase separation. [Copyright &y& Elsevier]

Examines the approaches to modeling surface-diffusion-controlled pore shape morphology evolution. Factors influencing rate of pore shape evolution; Effect of the equilibrium Wulff shape on the features of evolution; Importance of surface structure in pore evolution; Dominance of surface diffusion in the alumina diffusional process.

Dewetting is a well-known degradation mechanism for thin films at elevated temperatures. It is driven by surface energy minimization and occurs while the film is solid. The dewetting process is characterized by the formation of holes, retracting edges, and the formation of thickened rims on retracting edges. In anisotropic single-crystal thin films, holes are initially faceted. It is often observed that the corners of the holes retract faster than the edges of the hole, leading to dendritic or star-shaped holes. This so-called "corner instability" is one of the defining morphological characteristics of the dewetting process, and an understanding of this instability may lead to new film patterning techniques. In this work, we present a study of the growth of natural and patterned initially square holes in single-crystal Ni thin films on MgO substrates. A characteristic structure near the corners of the holes was observed, and a model for the growth of faceted holes was developed based on these observations. Despite its simplicity, the model reproduces the observed phenomenology and is in quantitative agreement with experiments. The model reveals that the corner instability arises from a redistribution of mass to create a new hole perimeter, which can only be created at the corner. The consequence is that the corner reaches a steady-state constant retraction rate while mass accumulation at the rims causes their retraction rate to continuously decrease. [ABSTRACT FROM AUTHOR]

[Display omitted] The infiltration of a non-wetting liquid, such as molten metal, into a porous solid, such as a ceramic preform, is influenced by the wetting angle of the liquid on the solid. The link between local wetting and the minimum pressure required for initiation of infiltration or the pressure required for full preform infiltration can deviate strongly from what one would expect on the basis of elementary thermodynamic considerations or simple geometrical models. In this work, we explain the trends observed in experimental studies of pressure infiltration of molten metal into ceramic preforms by means of a percolation model, in which the pores themselves are given a simple geometric shape. This gives a simple yet rich and realistic treatment of the infiltration process. Specifically, the pop-through pressure necessary to traverse a throat between two neighboring circular (2D) or spherical (3D) pores can easily be calculated and incorporated in a 3D network model of many pores produced by generating a packing of slightly overlapping circles or spheres. The resulting pore structure defines a bond percolation network that agrees overall both with predictions of percolation theory and observations from experiment, and which can be extended to address a range of other aspects of multi-phase flow through porous media. [ABSTRACT FROM AUTHOR]

The theoretical reflectance spectrum of a one-dimensional photonic crystal with large amounts of interfacial roughness has been calculated using a previously proposed method, and compared to the actual experimental reflectivity of the structure. The photonic crystal was fabricated using a simple and fast method involving the holographic exposure of a liquid crystal/photosensitive prepolymer syrup via the self-interference patterns from two laser beams. The calculated reflectance spectrum for this structure matched the experimental one extremely well, giving very similar reflectivity peak positions and intensities. Slight discrepancies between the two reflectance spectra are attributed to either small variations in the microstructure of the reflection grating beyond that which is captured in the transmission electron micrograph, or the dispersion of the polymer which was not taken into account. These results serve as experimental verification of the theory for rough photonic crystals reported previously. [ABSTRACT FROM AUTHOR]

Li deposition is observed and measured on a solid electrolyte in the vicinity of a metallic current collector. Four types of ion-conducting, inorganic solid electrolytes are tested: Amorphous 70/30 mol% Li2S-P2S5, polycrystalline β-Li3PS4, and polycrystalline and single-crystalline Li6La3ZrTaO12 garnet. The nature of lithium plating depends on the proximity of the current collector to defects such as surface cracks and on the current density. Lithium plating penetrates/infiltrates at defects, but only above a critical current density. Eventually, infiltration results in a short circuit between the current collector and the Li-source (anode). These results do not depend on the electrolytes shear modulus and are thus not consistent with the Monroe-Newman model for 'dendrites.' The observations suggest that Li-plating in pre-existing flaws produces crack-tip stresses which drive crack propagation, and an electrochemomechanical model of plating-induced Li infiltration is proposed. Lithium short-circuits through solid electrolytes occurs through a fundamentally different process than through liquid electrolytes. The onset of Li infiltration depends on solid-state electrolyte surface morphology, in particular the defect size and density. [ABSTRACT FROM AUTHOR]

Ga-catalyzed growth of GaAs nanowires on Si is a candidate process for achieving seamless III/V integration on IV. In this framework, the nature of silicon's surface oxide is known to have a strong influence on nanowire growth and orientation and therefore important for GaAs nanowire technologies. We show that the chemistry and morphology of the silicon oxide film controls liquid Ga nucleation position and shape; these determine GaAs nanowire growth morphology. We calculate the energies of formation of Ga droplets as a function of their volume and the oxide composition in several nucleation configurations. The lowest energy Ga droplet shapes are then correlated to the orientation of nanowires with respect to the substrate. This work provides the understanding and the tools to control nanowire morphology in self-assembly and pattern growth. [ABSTRACT FROM AUTHOR]

Electroanalytical, structural, and microanalytical techniques are combined to demonstrate the first clear and convincing case of electrochemical storage by Al‐ion intercalation in a Prussian blue analog host. In addition, a high power asymmetric capacitor using Al‐ion intercalation is demonstrated. Al, Fe, and Cu elemental maps of intercalated Al0.18 K0.02Cu[Fe(CN)6]0.7·3.7H2O obtained by transmission electron microscopy (TEM) energy‐dispersive X‐ray spectroscopy (EDX) area scan are shown. [ABSTRACT FROM AUTHOR]

Flowable suspensions that conduct both electrons and ions can enable the use of energy-dense electroactive species in flow batteries [M. Duduta et al., Adv. Energy Mater. , 1 , 511 (2011); Z. Li et al., Phys. Chem. Chem. Phys. , 15 , 15,833 (2013); F. Fan et al., Nano Lett. , 14 , 2210 (2014)]. In comparison with conventional flow batteries where electrochemical reactions are confined to a fixed current-collector region, electronically conductive flow electrodes permit electrochemical reactions to extend outside of the physical confines of the stack. We have measured and modeled how mixed-conduction enables an electroactive zone (EAZ, in which electrochemical reactions occur) that is of greater spatial extent than current collectors, the extension being termed side zone, SZ. Electrochemical reactions in SZs can reduce coulombic and energetic efficiency. Here we show that for realistic suspension properties and operating conditions, the added inefficiency is small in practice, and can be further mitigated by using appropriate operating conditions and/or materials choices. For the specific example of a non-aqueous Li 4 Ti 5 O 12 suspension, we show that EAZ extension contributes less than 1% additional efficiency loss at C/10 rates for current collectors greater than 20 mm long. [ABSTRACT FROM AUTHOR]

A new approach to flow battery designis demonstrated wherein diffusion-limitedaggregation of nanoscale conductor particles at ∼1 vol % concentrationis used to impart mixed electronic-ionic conductivity to redox solutions,forming flow electrodes with embedded current collector networks thatself-heal after shear. Lithium polysulfide flow cathodes of this architectureexhibit electrochemical activity that is distributed throughout thevolume of flow electrodes rather than being confined to surfaces ofstationary current collectors. The nanoscale network architectureenables cycling of polysulfide solutions deep into precipitation regimesthat historically have shown poor capacity utilization and reversibilityand may thereby enable new flow battery designs of higher energy densityand lower system cost. Lithium polysulfide half-flow cells operatingin both continuous and intermittent flow mode are demonstrated forthe first time. [ABSTRACT FROM AUTHOR]

Ultrafast rate capability (>100 C current rates) and superior high‐rate cycling stability (>1500 cycles) in aqueous NaTi2(PO4)3/Na0.44MnO2 cells are demonstrated. Aqueous NaTi2(PO4)3/Na0.44MnO2 cell may be a candidate for safe, low cost, high power storage systems. [ABSTRACT FROM AUTHOR]

Abstract: A Li4Ti5O12–Li0.29La0.57TiO3–Ag electrode composite was fabricated via sintering the corresponding powder mixture. The process achieved a final relative density of 97% the theoretical. Relatively thick, ∼100μm, electrodes were fabricated to enhance the energy density relatively to the traditional solid-state thin film battery electrodes. The sintered electrode composite delivered full capacity in the first discharge at C/40 discharge rate. Full capacity utilization resulted from the 3D percolated network of both solid electrolyte and metal, which provide paths for ionic and electronic transport, respectively. The electrodes retained 85% of the theoretical capacity after 10 cycles at C/40 discharge rate. The tensile strength and the Young''s modulus of the sintered electrode composite are the highest reported values to date, and are at least an order of magnitude higher than the corresponding value of traditional tapecast “composite electrodes”. The results demonstrate the concept of utilizing thick all-solid electrodes for high-strength batteries, which might be used as multifunctional structural and energy storage materials. [Copyright &y& Elsevier]

An objective in battery development for higher storage energy density is the design of compounds that can accommodate maximum changes in ion concentration over useful electrochemical windows. Not surprisingly, many storage compounds undergo phase transitions in situ, including production of metastable phases. Unique to this environment is the frequent application of electrical over- and underpotentials, which are the electrical analogs to undercooling and superheating. Surprisingly, overpotential effects on phase stability and transformation mechanisms have not been studied in detail. Here we use synchrotron X-ray diffraction performed in situ during potentiostatic and galvanostatic cycling, combined with phase-field modeling, to reveal a remarkable dependence of phase transition pathway on overpotential in the model olivine Li1-xFePO4. For a sample of particle size ∼113 nm, at both low (e.g., 75 mV) overpotentials a crystal-to-crystal olivine transformation dominates, whereas at intermediate overpotentials a crystalline-to-amorphous phase transition is preferred. As particle sizes decrease to the nanoscale, amorphization is further emphasized. Implications for battery use and design are considered. [ABSTRACT FROM AUTHOR]

Abstract: Oppositely charged colloidal particles in suspension undergo rapid coagulation in the absence of any repulsive component in the interaction potential. With an added steric component serving as the repulsive force it is possible to order oppositely charged particles, which are also weakly charged, in solution. However given the novel features obtainable for an ordered structure from strong oppositely charged particles it becomes imperative to gain a full understanding of methods that can order these particles. Here we report a simple and rapid layer-by-layer method to order strongly and oppositely charged particles. Although this method is in principle scalable to order multiple layers of oppositely charged particles, herein we report ordering of one layer of positively charged particles onto a substrate made of negatively charged particles. This method utilizes a non-ionic surfactant to induce a steric repulsive force between particles and involves spin-coating to disperse and order particles on a very short time scale. The ordered structure obtained through this process is verified as the structure with one of the lowest interaction energies. [Copyright &y& Elsevier]

Abstract: Recent observations of nanoscale surficial amorphous films in Bi2O3-doped ZnO are briefly reviewed. The experimental results are modeled with two approaches. A pressure-balance model with the volumetric free energy being the dominant temperature-dependent interaction extended from Clarke''s intergranular films model is proposed and numerically evaluated. This quantitative model predicts thicknesses versus temperature behavior for subeutectic films consistent with experimental results. Alternatively, the sequence of adsorption and wetting events as a function of temperature and composition is interpreted as a case of combined surface prewetting and premelting in a two-component system with a bulk eutectic reaction as a generalization of Cahn''s critical point wetting model. In this second approach that better represents the through-thickness gradients, diffuse-interface formulation is proposed and analyzed for assessing surficial film stability as well as associated drying and complete wetting transitions. The observation made for Bi2O3 on ZnO can be represented by one of the possible surface prewetting/premelting phase diagrams. [Copyright &y& Elsevier]

Fragmentation of substance abuse treatment represents a major barrier to effective treatment for individuals with cooccurring substance abuse and mental and physical health disorders. Linkages of substance abuse treatment organizations with primary care and mental health agencies are widely considered to be a feasible way to integrate services. In this study, we analyzed information collected from a national sample of 62 outpatient substance abuse treatment units (OSATs) to understand the extent of services linkages in these organizations and to identify facilitators and barriers to service linkages. Results showed that OSATs had limited service linkages with primary care and mental health providers. The cited barriers to linkages included clients' financial problems, managed care restrictions, and limited organizational capacity. Onsite service provision was implemented in some OSATs. The pattern of service linkages in OSATs appeared to reflect the health needs of substance abuse clients. [ABSTRACT FROM AUTHOR]

Examines the magnitudes of residual stresses in polycrystalline alumina using experimentally-determined crystal orientation and finite element analysis. Stress distribution; Crack initiation and propagation; Ratio between grain boundary energy and surface energy.