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.     

Inhibition of HIV-1 by a peptide ligand of the genomic RNA packaging signal Psi

The interaction of the nucleocapsid NCp7 of the human immunodeficiency virus type 1 (HIV-1) Gag polyprotein with the RNA packaging signal Psi ensures specific encapsidation of the dimeric full length viral genome into nascent virus particles. Being an essential step in the HIV-1 replication cycle, specific genome encapsidation represents a promising target for therapeutic intervention. We previously selected peptides binding to HIV-1 Psi-RNA or stem loops (SL) thereof by phage display. Herein, we describe synthesis of peptide variants of the consensus HWWPWW motif on membrane supports to optimize Psi-RNA binding. The optimized peptide, psi-pepB, was characterized in detail with respect to its conformation and binding properties for the SL3 of the Psi packaging signal by NMR and tryptophan fluorescence quenching. Functional analysis revealed that psi-pepB caused a strong reduction of virus release by infected cells as monitored by reduced transduction efficiencies, capsid p24 antigen levels, and electron microscopy. Thus, this peptide shows antiviral activity and could serve as a lead compound to develop new drugs targeting HIV-1.     

Wireless sensor marking and temperature measurement with SAW-identification tags

A wireless sensor marking system based on surface acoustic wave (SAW) identification tags is presented. The proposed solution is compatible with existing measurement systems and can be applied directly in the sensor or by means of a unique sensor identification cable (SIC). The SAW tag operates completely passive, and withstands temperatures up to 400 °C as well as shocks up to 35 000 m/s². It contains a unique serial identification number, which is encoded on the high-temperature stable SAW device by means of metallic reflector gratings. The interrogation unit uses the sensor cable for transmission but is not directly connected to it, thus the identification system can be even used with high impedance measurement equipment, e.g. charge amplifiers. Interrogation is done in frequency-domain based on well-known radar principles and is realized in a low-cost add-on circuit to the existing sensor evaluation circuitry. Furthermore, by simply enhancing the evaluation software, a temperature measurement of the SAW tag itself, and thus often of the sensor or the sensor environment can be done without additional hardware requirements.     

An efficient numerical technique for solving population balance equation involving aggregation, breakage, growth and nucleation

A new discretization for simultaneous aggregation, breakage, growth and nucleation is presented. The new discretization is an extension of the cell average technique developed by the authors [J. Kumar, M. Peglow, G. Warnecke, S. Heinrich, and L. Mörl. Improved accuracy and convergence of discretized population balance for aggregation: The cell average technique. Chemical Engineering Science 61 (2006) 3327-3342.]. It is shown that the cell average scheme enjoys the major advantage of simplicity for solving combined problems over other existing schemes. This is done by a special coupling of the different processes that treats all processes in a similar fashion as it handles the individual process. It is demonstrated that the new coupling makes the technique more useful by being not only more accurate but also computationally less expensive. At first, the coupling is performed for combined aggregation and breakage problems. Furthermore, a new idea that considers the growth process as aggregation of existing particle with new small nuclei is presented. In that way the resulting discretization of the growth process becomes very simple and consistent with first two moments. Additionally, it becomes easy to combine the growth discretization with other processes. The new discretization of pure growth is a little diffusive but it predicts the first two moments exactly without any computational difficulties like appearance of negative values or instability etc. The numerical scheme proposed in this work is consistent only with the first two moments but it can easily be extended to the consistency with any two or more than two moments. Finally, the discretization of pure and coupled problems is tasted on several analytically solvable problems.     

Three-dimensional numerical study of heat and mass transfer in fluidized beds with spray nozzle

The numerical computations of temperature and concentration distributions inside a fluidized bed with spray injection in three-dimensions are presented. A continuum model, based on rigorous mass and energy balance equations developed from Nagaiah et al., is used for the three-dimensional simulations. The three-dimensional model equation for nozzle spray is reformulated in comparison to Heinrich. For solving the non-linear partial differential equations with boundary conditions a finite element method is used for space discretization and an implicit Euler method is used for time discretization.The time-dependent behavior of the air humidity, air temperature, degree of wetting, liquid film temperature and particle temperature is presented using two different sets of experimental data. The presented numerical results are validated with the experimental results. Finally, the parallel numerical results are presented using the domain decomposition methods.