Influence of support properties on the sound radiated from the vibrations of rectangular plates

The control of the forced vibration response of structures through the optimal tuning of its supports is desirable in many applications. Tuning may enhance the dissipation of vibration energy within the supports, thereby reducing fatigue and structure-borne noise. Two different models were developed to calculate the optimal support stiffness that minimizes the velocity response of homogeneous plates. The first model, based on the wave propagation at the edge, yields a good first cut approximation of the optimal properties. The optimal viscous and viscoelastic support stiffness for minimal reflection at the edge was calculated. Maximum absorption of the incident waves occurs when the viscous support stiffness matches the characteristic mechanical impedances of the plate. The second model, based on the Rayleigh-Ritz method, yields more accurate estimates of the optimal support stiffness required to minimize the forced velocity response of the finite rectangular plate. The optimal support properties calculated from the two different methods were in good agreement. This suggested that the modal response of the plate is strongly influenced by the wave reflections at the edges. Finally, the effects of support properties on the sound radiated from the plate were investigated. The optimal support stiffness that minimizes the radiated sound power was found to be smaller than the value that minimizes the velocity response. The results show that both the velocity response and sound radiation are strongly influenced by dissipation of vibration energy at the edges, and demonstrate that support tuning can yield significant noise and vibration reduction.     

ChipCheck--a program predicting total hybridization equilibria for DNA binding to small oligonucleotide microarrays

Presented here is the program ChipCheck that allows the computation of total hybridization equilibria for hybridization experiments involving small oligonucleotide arrays. The calculation requires the free energies of binding for all pairs of probes and targets as well as total strand concentrations and probe molecule numbers. ChipCheck has been tested computationally on microarrays with up to 100 spots and 42 target strands (4200 binding equilibria). It arrives at solutions through iterations employing the multidimensional Newton method. While currently running in simulation mode only, an extension of the approach to the exhaustive analysis of chip results is being outlined and may be implemented in the future. The output displays the extent of correct and cross hybridization both graphically and numerically. In principle, calculating total hybridization equilibria allows for eliminating noise from DNA chip results and thus an improvement in sensitivity and accuracy.     

Über die katalytische Spaltung von Azetalen an Aluminiumoxyd II

Ohne Zusammenfassung     

Studien über Chinhydrone

Ohne ZusammenfassungZum Schlüsse erlaube ich mir, meinem hochverehrten Lehrer Herrn Prof. Dr. W. Suida für seine Anregungen, sowie mir gütigst gewährte Unterstützungen bestens zu danken.     

Über Methylaminoterephtalsäuren und andere Terephtalsäureabkömmlinge

Ohne ZusammenfassungFür die Ausführung der im vorstehenden mitgeteilten Krystallmessungen gestatten wir uns, Herrn Hofrat v. Lang unseren besten Dank zu sagen.     

L2Roe: a low dissipation version of Roe's approximate Riemann solver for low Mach numbers

A modification of the Roe scheme called L²Roe for low dissipation low Mach Roe is presented. It reduces the dissipation of kinetic energy at the highest resolved wave numbers in a low Mach number test case of decaying isotropic turbulence. This is achieved by scaling the jumps in all discrete velocity components within the numerical flux function. An asymptotic analysis is used to show the correct pressure scaling at low Mach numbers and to identify the reduced numerical dissipation in that regime. Furthermore, the analysis allows a comparison with two other schemes that employ different scaling of discrete velocity jumps, namely, LMRoe and a method of Thornber et al. To this end, we present for the first time an asymptotic analysis of the last method. Numerical tests on cases ranging from low Mach number (M_∞=0.001) to hypersonic (M_∞=5) viscous flows are used to illustrate the differences between the methods and to show the correct behavior of L²Roe. No conflict is observed between the reduced numerical dissipation and the accuracy or stability of the scheme in any of the investigated test cases. Copyright © 2015 John Wiley & Sons, Ltd.