Effect of broadband-noise masking on the behavioral response of a harbor porpoise (Phocoena phocoena) to 1-s duration 6-7 kHz sonar up-sweeps

Naval sonar systems produce signals which may affect the behavior of harbor porpoises, though their effect may be reduced by ambient noise. To show how natural ambient noise influences the effect of sonar sweeps on porpoises, a porpoise in a pool was exposed to 1-s duration up-sweeps, similar in frequency range (6-7 kHz) to those of existing naval sonar systems. The sweep signals had randomly generated sweep intervals of 3-7 s (duty cycle: 19%). Behavioral parameters during exposure to signals were compared to those during baseline periods. The sessions were conducted under five background noise conditions: the local normal ambient noise and four conditions mimicking the spectra for wind-generated noise at Sea States 2-8. In all conditions, the sweeps caused the porpoise to swim further away from the transducer, surface more often, swim faster, and breathe more forcefully than during the baseline periods. However, the higher the background noise level, the smaller the effects of the sweeps on the surfacing behavior of the porpoise. Therefore, the effects of naval sonar systems on harbor porpoises are determined not only by the received level of the signals and the hearing sensitivity of the animals but also by the background noise.     

Digitalizing line segments

We introduce a novel and general approach for digitalization of line segments in the plane that satisfies a set of axioms naturally arising from Euclidean axioms. In particular, we show how to derive such a system of digital segments from any total order on the integers. As a consequence, using a well-chosen total order, we manage to define a system of digital segments such that all digital segments are, in Hausdorff metric, optimally close to their corresponding Euclidean segments, thus giving an explicit construction that resolves the main question of [J. Chun, M. Korman, M. Nöllenburg, and T. Tokuyama. Consistent digital rays. Discrete Comput. Geom., 42(3):359–378, 2009].     

Simulation of short crack propagation under hydrogen influence using a hybrid boundary element technique for anisotropic elastic solids

A two-dimensional model for stage I short crack propagation on multiple slip planes under the influence of hydrogen is presented. It considers elastic-plastic material behaviour by allowing sliding on the active slip planes in the corresponding slip directions. A crack propagation law based on the crack tip sliding displacement is used to simulate crack growth. The activation of slip bands and the sliding on these active slip bands will be influenced by the local hydrogen concentration. The model is solved numerically using the boundary element method. (© 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Light emitting diodes based on a discotic main chain polymer

We prepared light emitting diodes with a discotic main chain polymer doped with a tristilbene amine derivative. X-ray investigations showed the formation of a hexagonal columnar structure in the annealed devices. This increased order leads to a significant reduction of the onset voltage for light emission down to 4 · 10⁵ V/cm.     

Lattice Parameter Study in the Bi1–xSbx Solid-solution System

The lattice parameters of Bi_1–xSb_x single crystals were measured for 0 ≦ x ≦ 1 by a special X-ray diffractometer technique using reflections chosen so that minimum errors were achieved. Corrections for thermal expansion and refraction were applied. The antimony concentration was determined by means of electron microprobe analysis. The dependences of the lattice parameters on x (in nm) can be described with good approximation by a = 0.45469 – 0.02398x and c = 1.186294 – 0.058632 [1 + 1.26 (x⁻¹ – 1)]⁻¹, resp. The behaviour of the parameter a is in agreement with the earlier study by CUCKA and BARRETT , whereas their linear expression for c(x) (0 ≦ x ≦ 0.3) was not confirmed.     

Implementation of Thermomechanical Coupling for Shape Memory Alloys into the Finite Element Method

NiTi alloys open up new fields of application on the basis of their distinctive thermomechanical properties. Many options of practical application of shape memory alloys are imaginable. For example catheters or stents made of NiTi play an important role in medical technology. Thus the further development and optimisation of simulation tools for shape memory alloys (SMA) structures will play an important role in the future. Based on the powerful material model of Helm [1] the present contribution focuses on the coupling between mechanical and thermal fields. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)     

High performance – low VOC-content: innovative and trend-setting coating systems for industrial applications

This paper describes low VOC coating systems successfully implemented and operating in two industrial branches. For Light Alloy Wheels, the innovative coating process comprises ecofriendly chromium-free surface pre-treatment, epoxy polyester powder primer, water-borne base coat and acrylate powder clear coat. The coating process as an example for agricultural machinery includes iron phosphatizing surface pre-treatment for steel substrates; the coating system itself consists of a water-borne stove-type dip priming operation (for all objects). Finish coat type (Plant I): 2-component water-borne PUR top coat; (Plant II): TGIC-free polyester powder top coat. These new coating systems have proved successful in existing series production. All technical requirements and the provisions of the VOC Regulations are fully complied with.