Properties of B-site substituted {\mathbf{La}}_{{0.5}} {\mathbf{Sr}}_{{0.5}} {\mathbf{FeO}}_{{3 - {\mathbf{\delta }}}} perovskites for application in oxygen separation membranes

Mixed ionic–electronic conducting $La_{0.5} Sr_{0.5} Fe_{1 - x} B_x O_{3 - \delta } $ (B: Al, Cr, Zr, Ga, Ti, Sn, Ta, V, Mg, and In with x?=?0, 0.1, 0.2) perovskite materials were produced via solid-state synthesis. In order to study the effect of B-site substitution on the expansion behavior of these materials, their thermal expansion in air up to 900°C and isothermal expansion at the same temperature from air to Ar were measured by dilatometry. Ti and Ta were found to be the most effective substitutions in suppressing the isothermal expansion. The isothermal expansion at 900°C from air to Ar was reduced by 50% by substitution of 20% Ti or 10% Ta. Therefore, these compositions were further characterized by 4-probe total DC conductivity and permeation measurements under air/Ar gradient. The total conductivity of $La_{0.5} Sr_{0.5} FeO_{3 - \delta } $ was decreased by more than one order of magnitude at low temperatures and from 430 S/cm, which is the maximum, to around 100 S/cm at 500°C with the addition of Ti and Ta. The normalized oxygen permeation of LSF at 900°C decreased from 0.18 to 0.05 μmol/cm²s and 0.07 μmol/cm²s with the substitution of 20% Ti and 10% Ta, respectively.     

Kinetic and kinematic responses of post mortem human surrogates and the Hybrid III ATD in high-speed frontal sled tests

Despite improvements in vehicle design and safety technologies, frontal automotive collisions continue to result in a substantial number of injuries and fatalities each year. Although a considerable amount of research has been performed on PMHSs and ATDs, matched dynamic whole-body frontal testing with PMHSs and the current ATD aimed at quantifying both kinetic and kinematic data in a single controlled study is lacking in the literature. Therefore, a total of 4 dynamic matched frontal sled tests were performed with three male PMHSs and a Hybrid III 50th percentile male ATD (28.6 g, Δv = 40 kph). Each subject was restrained using a 4 kN load limiting, driver-side, 3-point seatbelt. Belt force was measured for the lap belt and shoulder belt. Reaction forces were measured at the seat pan, seat back, independent foot plates, and steering column. Linear head acceleration, angular head acceleration, and pelvic acceleration were measured for all subjects. Acceleration of C7, T7, T12, both femurs, and both tibias were also measured for the PMHSs. A Vicon motion analysis system, consisting of 12 MX-T20 2 megapixel cameras, was used to quantify subject 3D motion (±1 mm) at a rate of 1 kHz. Excursions of select anatomical regions were normalized to their respective initial positions and compared by test condition and between subject types. Notable discrepancies were observed in the responses of the PMHSs and the ATD. The reaction forces and belt loading for the ATD, particularly foot plate, seat back, steering column, and lap belt forces, were not in agreement with those of the PMHSs. The forward excursions of the ATD were consistently within those of the PMHSs with the exception of the left upper extremity. This could potentially be due to the known limitations of the Hybrid III ATD shoulder and chest. The results presented herein demonstrate that there are some limitations to the current Hybrid III ATD under the loading conditions evaluated in the current study. Overall, this study presents a comprehensive data set of belt forces, reaction forces, accelerations, and bilateral displacement data that can be used to evaluate the performance of ATDs and validate computational models.     

Intermetallic compounds dynamic formation during annealing of stacked elemental layers and its influences on the crystallization of Cu2ZnSnSe4 films

A combined in-situ investigation using X-ray diffraction and differential scanning calorimetry during annealing was carried out to investigate the formation of intermetallic compounds in the stacked elemental layers and to reveal its influences on the crystallization of kesterite Cu₂ZnSnSe₄. The Mo/Cu/Zn, Mo/Cu/Sn/Zn, Mo/Cu/Zn/Se and Mo/Cu/Sn/Zn/Se stacked films were prepared with a composition resembling a typical kesterite Cu-poor and Zn-rich metallic composition. In-situ experiments during annealing of pure metallic stacked films reveal a dynamic intermetallic compounds formation of Cu₅Zn₈ → CuZn → Cu₂Zn → Cu₃Zn and Cu₆Sn₅ → Cu₄₁Sn₁₁. The CuZn and Cu₅Zn₈ layer formed at the interface of metals/Se may prevent the stacked metallic layers from selenization below 320 °C. On the other side, the dynamic formation of Cu–Zn phases in the stacked films is found to be an origin of a ZnSe gradual formation starting from 320 °C. Phase analysis suggests that the ternary Cu₂SnSe₃ phase forms almost immediately after the formation of Cu₂Se and SnSe. The formation of Cu₂SnSe₃ is indicated by the consumption of SnSe by the Cu₂Se which occurs at 530–540 °C. Crystallization of kesterite takes place above 540 °C. On a phenomenological basis of present results, consequences for the thin film kesterite fabrication for solar cell application are discussed.     

Particle In-Flight and Coating Properties of Fe-Based Feedstock Materials Sprayed with Modern Thermal Spray Systems

New developments in the field of thermal spraying systems (increased particle velocities, enhanced process stability) are leading to improved coatings. Innovations in the field of feedstock materials are supporting this trend. The combination of both has led to a renaissance of Fe-based feedstocks. Using modern APS or HVOF systems, it is now possible to compete with classical materials for wear and corrosion applications like Ni-basis or metal-matrix composites. This study intends to give an analysis of the in-flight particle and spray jet properties achievable with two different modern thermal spraying systems using Fe-based powders. The velocity fields are measured with the Laser Doppler Anemometry. Resulting coatings are analyzed and a correlation with the particle in-flight properties is given. The experiments are accompanied by computational fluid dynamics simulations of spray jet and particle velocities, leading to a comprehensive analysis of the achievable particle properties with state-of-the-art HVOF and APS systems.     

Parallel Open Source CFD-DEM for Resolved Particle-Fluid Interaction

A parallelized resolved method for the simulation of the dynamics of immersed bodies within fluids is presented. The algorithm uses a FDM （fictitious domain method） and combines the Lagrangian DEM （discrete element method） for tracking the bodies with a CFD （computational fluid dynamics） method for calculating the dynamics of the fluid phase. First the CFD-calculation is carried out, disregarding the solid bodies. Afterwards, the velocity information from the bodies is included and the force, the fluid imposes onto the bodies, is computed. The last step consists of a correction-operation which ensures the fulfillment of the conservation equation. Dynamic local mesh refinement is used for minimizing the number of fluid cells. The CFD-DEM coupling is realized within the Open Source framework CFDEMcoupling （www.cfdem.com）, where the DEM software LIGGGHTS （www.liggghts.com） is linked against an OpenFOAM~-based CFD solver. While both LIGGGHTS and the CFD solver were already parallelized, only a recent improvement of the algorithm permits the fully parallel computation of resolved problems. This parallelization permits the treatment of large-scale problems. The enclosed validation and application examples show the dynamics of the flow around settling and rotating spheres as well as an investigation of the settling of spheres regarding the Boycott effect.