Weibull Analysis of Electrical Breakdown Strength as an Effective Means of Evaluating Elastomer Thin Film Quality

To realize the commercial potential of dielectric elastomers, reliable, large‐scale film production is required. Ensuring proper mixing and subsequently avoiding demixing after, for example, pumping and coating of elastomer premix in an online process is not facile. Weibull analysis of the electrical breakdown strength of dielectric elastomer films is shown to be an effective means of evaluating the film quality. The analysis is shown to be capable of distinguishing between proper and improper mixing schemes where similar analysis of ultimate mechanical properties fails to distinguish.

     

Variability of operator performance in remote-sensing image interpretation: the importance of human and external factors

This study tackles a common, yet underrated problem in remote-sensing image analysis: the fact that human interpretation is highly variable among different operators. Despite current technological advancements, human perception and interpretation are still vital components of the map-making process. Consequently, human errors can considerably bias both mapping and modelling results. In our study, we present a web-based tool to quantify operator variability and to identify the human and external factors affecting this variability. Human operators were given a series of images and were asked to hand-digitize different point, line, and polygon objects. The quantification of performance variability was achieved using both thematic and positional accuracy measures. Subsequently, a series of questions related to demographics, experience, and personality were asked, and the answers were also quantified. Correlation and regression analysis was then used to explain the variability in operator performance. From our study, we conclude that: (1) humans were seldom perfect in visual interpretation; (2) some geographic objects were more complex to accurately digitize than others; (3) there was a high degree of variability among image interpreters when hand-digitizing the same objects; and (4) operator performance was mainly determined by demographic, non-cognitive, and cognitive personality factors, whereas external and technical factors influenced operator performance to a lesser extent. Finally, the results also indicated a gradual decline in performance over time, mimicking classical mental fatigue effects.     

A systematic review on the use of quantitative imaging to detect cancer therapy adverse effects in normal-appearing brain tissue

Cancer therapy for both central nervous system (CNS) and non-CNS tumors has been previously associated with transient and long-term cognitive deterioration, commonly referred to as ‘chemo fog’. This therapy-related damage to otherwise normal-appearing brain tissue is reported using post-mortem neuropathological analysis. Although the literature on monitoring therapy effects on structural magnetic resonance imaging (MRI) is well established, such macroscopic structural changes appear relatively late and irreversible. Early quantitative MRI biomarkers of therapy-induced damage would potentially permit taking these treatment side effects into account, paving the way towards a more personalized treatment planning.

This systematic review (PROSPERO number 224196) provides an overview of quantitative tomographic imaging methods, potentially identifying the adverse side effects of cancer therapy in normal-appearing brain tissue. Seventy studies were obtained from the MEDLINE and Web of Science databases. Studies reporting changes in normal-appearing brain tissue using MRI, PET, or SPECT quantitative biomarkers, related to radio-, chemo-, immuno-, or hormone therapy for any kind of solid, cystic, or liquid tumor were included. The main findings of the reviewed studies were summarized, providing also the risk of bias of each study assessed using a modified QUADAS-2 tool. For each imaging method, this review provides the methodological background, and the benefits and shortcomings of each method from the imaging perspective. Finally, a set of recommendations is proposed to support future research.

     

A minimal solution for relative pose with unknown focal length

Assume that we have two perspective images with known intrinsic parameters except for an unknown common focal length. It is a minimally constrained problem to find the relative orientation between the two images given six corresponding points. To this problem which to the best of our knowledge was unsolved we present an efficient solver. Through numerical experiments we demonstrate that the algorithm is correct, numerically stable and useful. The solutions are found through eigen-decomposition of a 15×15 matrix. The matrix itself is generated in closed form.     

Erzeugung synthetischer Daten zum Test IT-forensischer Werkzeuge

Eine M?glichkeit zur Erkennung gesch?ftssch?digender Handlungen unter Zuhilfenahme von IT-Systemen besteht in der IT-forensischen Analyse von Datenbest?nden. Bevor ITforensische Werkzeuge zum Einsatz kommen, sollten diese jedoch getestet werden — h?ufig stehen dafür allerdings keine Echtdaten zur Verfügung. In diesem Beitrag wird 3LSPG vorgestellt, ein von Fraunhofer SIT entwickeltes Verfahren, mit dem geeignete Testdaten synthetisch erzeugt werden k?nnen.     

Valence band edges and optical band gaps of alternating substituted poly(phenylenevinylenes)

Summary A collection of sixteen different PPVs with an alternating substituent pattern and three reference compounds MEH-PPV (poly(2-methoxy-5-ethylhexyloxy-1,4-phenylenevinylene)), CN-MEH-PPV (poly(2-methoxy-5-ethylhexyloxy-1,4-phenylenecyanovinylene)) and P3HT (poly(3-hexylthiophene)) were studied by ultraviolet photoelectron spectroscopy on gold substrates and by optical absorption spectroscopy in solution. Together these two techniques were combined to give a picture of the uppermost part of the electronic structure of these materials and allowed for a comparison based on the molecular substitution pattern under the same experimental conditions.     

Johnny: An Autonomous Service Robot for Domestic Environments

In this article we describe the architecture, algorithms and real-world benchmarks performed by Johnny Jackanapes, an autonomous service robot for domestic environments. Johnny serves as a research and development platform to explore, develop and integrate capabilities required for real-world domestic service applications. We present a control architecture which allows to cope with various and changing domestic service robot tasks. A software architecture supporting the rapid integration of functionality into a complete system is as well presented. Further, we describe novel and robust algorithms centered around multi-modal human robot interaction, semantic scene understanding and SLAM. Evaluation of the complete system has been performed during the last years in the RoboCup@Home competition where Johnnys outstanding performance led to successful participation. The results and lessons learned of these benchmarks are explained in more detail.     

Green synthesis and characterization of poly(glycerol-azelaic acid) and its nanocomposites for applications in regenerative medicine

A series of novel bio-polyester nanocomposites based on glycerin and azelaic acid as monomers incorporating hydroxyapatite (HA) nanoparticles were fabricated via in situ polymerization method. Chemical structure of the samples was investigated by ¹H-NMR, ¹³C-NMR, and Fourier-transform infrared spectroscopy (FTIR). Energy dispersive X-ray-mapping analysis illustrated that the nanoparticles were well dispersed in the poly (glycerol azelaic acid) (PGAZ) matrix. Viscoelastic properties of the samples under various frequencies were examined in which the PGAZ specimen containing 1.0 wt% of HA nanoparticles (PGAZH1.0) exhibited superlative properties. Furthermore, the alterations in the glass transition temperature of the samples were comprehensively discussed. Thermal gravimetric analysis displayed that nanocomposites generally have a difference in degradation patterns from that of the pristine sample. Dynamic contact angle demonstrated that the presence of HA nanoparticles imposed a significant influence on hydrophilicity. The hydrolytic degradation values at pH = 7 and pH = 11 were measured and determined that the degradation rate for the PGAZ sample containing 1.5 wt% HA (PGAZH1.5) was higher than those of the other samples. Moreover, in vitro studies elucidated that cell attachment on PGAZH1.0 and PAZH1.5 surfaces were acceptable.     

Compact Slanted Grating Couplers Between Optical Fiber and InP–InGaAsP Waveguides

We present theoretical and experimental results for compact slanted gratings for vertical coupling between single-mode fiber and InP-InGaAsP waveguides. The maximum calculated coupling efficiency is 59%. We have measured a coupling efficiency of 16% for a 10-mum-long slanted grating     

Stick‐slip with the slip phase as the starting point

In the literature, the stick‐slip phenomenon is always explained and modelled as starting from an initial stick phase. However, stick‐slip can also occur after a decrease in the imposed velocity, commencing above the critical (stick‐slip‐free) velocity. In this paper, it will be shown how stick‐slip can originate from a situation of pure sliding (without stick phases), if the slope of the friction force‐relative sliding velocity relation (F‐v_rel gradient) is negative. The F‐v_rel gradient used to study stick‐slip must, because of the interaction between the friction force and the dynamic behaviour of the mechanical system, be derived from velocity changes with the same time‐constant as the mechanical system of which the friction interface is part. It will also be shown that steady‐state friction data, and dynamic (non‐stationary) friction results obtained for relatively large (but fast) velocity variations, can lead to completely false conclusions related to stick‐slip.