Millimeter-Wave Tomographic Imaging of Composite Materials Based on Phase Evaluation

A novel data processing algorithm for the generation of tomographic images of composite materials, based on measurements acquired via frequency-modulated continuous-wave (FMCW) radars operating in the millimeter wave regime, is presented. The presented algorithm, in tandem with the applied method and achieved results, provides valuable information for the optimization of the quality and efficiency of composite-based components. By utilizing the high sensitivity of the signals’ phase, the detection and classification of defect type, shape, and position are possible. Since the ambiguity of the phase generates radar images resembling optical fringe patterns, the data evaluation is inspired by the respective fringe pattern analysis, as often utilized in optics. The signal processing is adapted accordingly to match the radar-based data. To demonstrate the feasibility of the proposed algorithm, glass fiber reinforced plastic samples with deliberate and predefined defects, including resin wedges and dry fibers, are measured with a radar system operating in W-band (75–110 GHz), with the used bandwidth of 24 GHz and the signal focused to the sample under test

Large and deep perialpine lakes: a paleolimnological perspective for the advance of ecosystem science

Large perialpine lakes represent important components of the Alpine landscape. Due to their piedmont location in the most densely populated regions of the Alps, they play a crucial socio-economic role as resource for drinking water, irrigation, industry, tourism, hydroelectric production, and biodiversity conservation. These uses expose perialpine lakes to multiple human pressure, while the extension of their catchment to the glacial Alpine range make them particularly exposed to the consequences of global warming. Limnological surveys outlined coherent responses by perialpine lakes to the massive nutrient enrichment during the 1950s-1970s, while recent development is rather heterogeneous. Past and ongoing paleolimnological studies confirmed the coherence of the lakes’ evolution within a secular perspective, but outlined individual trends as resulting from local management policies, lake morphology, and superimposed effects of climate change. A review of the paleolimnological literature published from 1975 to April 2017on perialpine lakes of different lake districts north and south of the Alps, was performed aiming at reviewing current knowledge of large and deep perialpine lakes due to sediment studies, and at summarizing how paleolimnological studies can contribute in defining past ecological status and in outlining lake sensitivity to current and future human impacts. This is particularly important when defining reference conditions, as inappropriate restoration targets might prove to become unachievable within the present context of global change. The review outlined an heterogeneous distribution of amount and topics of sediment studies among perialpine lake districts as well as knowledge gaps on the long term evolution of perialpine lakes

Non-Standard Errors

In statistics, samples are drawn from a population in a data-generating process (DGP). Standard errors measure the uncertainty in estimates of population parameters. In science, evidence is generated to test hypotheses in an evidence-generating process (EGP). We claim that EGP variation across researchers adds uncertainty: Non-standard errors (NSEs). We study NSEs by letting 164 teams test the same hypotheses on the same data. NSEs turn out to be sizable, but smaller for better reproducible or higher rated research. Adding peer-review stages reduces NSEs. We further find that this type of uncertainty is underestimated by participants