Three-dimensional numerical modeling of an induction heated injection molding tool with flow visualization

Using elevated mold temperature is known to have a positive influence of final injection molded parts. Induction heating is a method that allow obtaining a rapid thermal cycle, so the overall molding cycle time is not increased. In the present research work, an integrated multi-turn induction heating coil has been developed and assembled into an injection molding tool provided with a glass window, so the effect of induction heating can directly be captured by a high speed camera. In addition, thermocouples and pressure sensors are also installed, and together with the high speed videos, comparison of the induction heating and filling of the cavity is compared and validated with simulations. Two polymer materials ABS and HVPC were utilized during the injection molding experiments carried out in this work. A nonlinear electromagnetic model was employed to establish an effective linear magnetic permeability. The three-dimensional transient thermal field of the mold cavity was then calculated and compared with the experiments. This thermal field was transferred to an injection molding flow solver to compare simulations and experimental results from the high speed video, both with and without the effect of induction heating. A rapid thermal cycle was proved to be feasible in a mold with an integrated induction coil. Furthermore, it was shown that the process can be modeled with good accuracy, both in terms of the thermal field and of the flow pattern.     

Elastic constants of polycrystalline Ti3AlC2 and Ti3SiC2 measured using coherent inelastic neutron scattering

The magnitude of the single‐crystal elastic constant c₄₄ in the MAX phase Ti₃SiC₂ is under debate. In this paper, estimates for the magnitude of c₄₄ for MAX phases Ti₃AlC₂ and Ti₃SiC₂ are determined from a partially oriented polycrystalline sample via coherent inelastic neutron scattering. The largely quasi‐isotropic nature of these M_n+1AX_n phase elastic constants as previously predicted by density functional theory calculations is confirmed experimentally for Ti₃AlC₂ to be c₄₄=115.3 ± 30.7 GPa. In contrast, Ti₃SiC₂ is confirmed to be shear stiff with c₄₄=402.7 ± 78.3 GPa supporting results obtained by earlier elastic neutron diffraction experiments.     

Diffusional and orientational dynamics of various single terylene diimide conjugates in mesoporous materials

Mesoporous silica materials are ideally suited as host–guest systems in nanoscience with applications ranging from molecular sieves, catalysts, nanosensors to drug-delivery-systems. For all these applications a thorough understanding of the interactions between the mesoporous host system and the guest molecules is vital. Here, we investigate these interactions using single molecule spectroscopy (SMS) to study the dynamics of three different terylene diimide (TDI) dyes acting as molecular probes in hexagonal and lamellar mesoporous silica films. The diffusion behaviour in the hexagonal phase is represented by the trajectories of the single molecules. These trajectories are highly structured and thus provide information about the underlying host structure, such as domain size or the presence of defects inside the host structure. The three structurally different TDI derivatives allowed studying the influence of the molecular structure of the guest on the translational diffusion behaviour in the hexagonal phase and the lamellar phase. In the lamellar phase, the differences between the three guests are quite dramatic. First, two populations of diffusing molecules – one with parallel orientation of the molecules to the lamellae and the other with perpendicular orientation – could be observed for two of the TDI derivatives. These populations differ drastically in their translational diffusion behaviour. Depending on the TDI derivative, the ratio between the two populations is different. Additionally, switching between the two populations was observed. These data provide new insights into host–guest interactions like the influence of the molecular structure of the guest molecules on their diffusional as well as on their orientational behaviour in structurally confined guest systems.     

CMOS monolithic mechatronic microsystem for surface imaging and force response studies

We report on a standalone single-chip (7 mm /spl times/10mm) atomic force microscopy (AFM) unit including a fully integrated array of cantilevers, each of which has individual actuation, detection, and control units so that standard AFM operations can be performed only by means of the chip without any external controller. The system offers drastically reduced overall size and costs and can be fabricated in standard CMOS technology with some post-CMOS micromachining steps to form the cantilevers. Full integration of microelectronic and micromechanical components on the same chip allows for controlling and monitoring all system functions. The on-chip circuitry notably improves the overall system performance. Circuitry includes analog signal amplification and filtering stages with offset compensation, analog-to-digital converters, digital proportional-integral-derivative (PID) deflection controllers, sensor-actuator compensation (SAC) filters, and an on-chip digital interface for data transmission. The microsystem characterization evidenced a vertical resolution of better than 1 nm and a force resolution of better than 1 nN as shown in the measurement results. This CMOS monolithic AFM microsystem allows for precise and fully controlled mechanical manipulation in the nanoworld.     

CSF amine metabolites, clinical symptoms, and body movement in psychiatric patients

The relationships between CSF monoamine metabolites (HVA and 5HIAA), nurses' ratings of clinical symptoms, and telemetered measures of motor movement of ten schizophrenic and ten depressed patients were investigated. There was a significant negative correlation between CSF 5HIAA and both agitation ratings and motor movement in the schizophrenics. CSF HVA correlated positively to anxiety and anger in the depressives. The schizophrenics had a significantly higher CSF HVA than the depressives which appeared unrelated to motor movement. The effects of serotonin turnover and arousal in schizophrenia and the association between CSF metabolite gradients, stress, motor movement, and biogenic amine levels in depression are discussed.