Application of the asymptotic solution to EM field scattering problem for creation of media with prescribed permeability

Scattering of electromagnetic (EM) waves by many small impedance particles (bodies), embedded in a homogeneous medium, is studied. Physical properties of the particles are described by their boundary impedances. The limiting equation is obtained for the effective EM field in the limiting medium, in the limit a→0, where a is the characteristic size of a particle and the number M(a) of the particles tends to infinity at a suitable rate. The proposed theory allows one to create a medium with a desirable spatially inhomogeneous permeability. The main new physical result is the explicit analytical formula for the permeability μ(x) of the limiting medium. The computational results confirm a possibility to create the media with various distributions of μ(x)

3D System Integration for high density Interconnects

3D-Integration is a promising technology towards higher interconnect densities and shorter wiring lengths between multiple chip stacks, thus achieving a very high performance level combined with low power consumption. This technology also offers the possibility to build up systems with high complexity by combining devices of different technologies. The fundamental processing steps will be described, as well as appropriate handling concepts and first electrical results of realized 3D-integrated stacks

Chemoconvection patterns in the methylene-blue–glucose system: weakly nonlinear analysis

The oxidation of solutions of glucose with methylene-blue as a catalyst in basic media can induce hydrodynamic overturning instabilities, termed chemoconvection in recognition of their similarity to convective instabilities. The phenomenon is due to gluconic acid, the marginally dense product of the reaction, which gradually builds an unstable density profile. Experiments indicate that dominant pattern wavenumbers initially increase before gradually decreasing or can even oscillate for long times. Here, we perform a weakly nonlinear analysis for an established model of the system with simple kinetics, and show that the resulting amplitude equation is analogous to that obtained in convection with insulating walls. We show that the amplitude description predicts that dominant pattern wavenumbers should decrease in the long term, but does not reproduce the aforementioned increasing wavenumber behavior in the initial stages of pattern development. We hypothesize that this is due to horizontally homogeneous steady states not being attained before pattern onset. We show that the behavior can be explained using a combination of pseudo-steady-state linear and steady-state weakly nonlinear theories. The results obtained are in qualitative agreement with the analysis of experiments

A Comparison of Sound Levels in Open Plan Versus Pods in a Neonatal Intensive Care Unit

Author version made available in accordance with publisher copyright policy.OBJECTIVE: The objective of this study was to compare the noise levels recorded in two different neonatal intensive care unit (NICU) settings: a pod and an open plan NICU located in the same hospital. BACKGROUND: The NICU is a busy environment with ambient noise levels that often exceed established recommendations. This noise deleteriously affects the physiological stability and developmental outcomes of sick and preterm infants. Pods have reduced numbers of cots (in this case, 6) compared to open plan NICUs (in this case, 11), yet the noise levels in pods have not been reported. METHOD: This study compared real-time decibel (dB) levels in an A-weighted scale, captured continuously by sound dosimeters mounted in both NICU settings for a period of 4 weeks: a pod setting and an open plan NICU. Researchers also collected observational data. RESULTS: The average noise level recorded in the pod was 3 dBs less than in the open plan NICU. This result was statistically significant. However, dB recordings in both areas were over the recommended limits by 4-6 dBs, with isolated peaks between 74.5 dBs (NICU) and 75.9 dBs (pod). Observational data confirmed this correlation. CONCLUSIONS: Further research to evaluate interventions to decrease the noise levels in both settings are needed, especially during times of peak activity. Staff working in these settings need to be more aware that control of acoustic levels is important in the neuroprotection of neonates. Coupling this with careful consideration to structural components and evidence-based design planning may contribute to lowering dB levels in the NICU environment