Mobile-robot pose estimation and environment mapping using an extended Kalman filter

In this paper an extended Kalman filter (EKF) is used in the simultaneous localisation and mapping (SLAM) of a four-wheeled mobile robot in an indoor environment. The robot’s pose and environment map are estimated from incremental encoders and from laser-range-finder (LRF) sensor readings. The map of the environment consists of line segments, which are estimated from the LRF’s scans. A good state convergence of the EKF is obtained using the proposed methods for the input- and output-noise covariance matrices’ estimation. The output-noise covariance matrix, consisting of the observed-line-features’ covariances, is estimated from the LRF’s measurements using the least-squares method. The experimental results from the localisation and SLAM experiments in the indoor environment show the applicability of the proposed approach. The main paper contribution is the improvement of the SLAM algorithm convergence due to the noise covariance matrices’ estimation.     

Unexpected Quasi-Axial Conformer in Thermally Activated Delayed Fluorescence DMAC-TRZ,Pushing Green OLEDs to Blue

Hidden photophysics is elucidated in the very well-known thermally activated delayed fluorescence (TADF) emitter, DMAC-TRZ. A molecule that, based on its structure, is considered not to have more than one structural conformation. However, based on experimental and computational studies, two conformers, a quasi-axial (QA) and a quasi-equatorial (QE) are found, and the effect of their co-existence on both optical and electrical excitation isexplored. The relative small population of the QA conformer has a disproportionate effect because of its strong local excited state character. The energy transfer efficiency from the QA to the QE conformer is high, even at low concentrations, dependent on the host environment. The current accepted triplet energy of DMAC-TRZ is shown to originate from the QA conformer, completely changing the understanding of DMAC-TRZ. The contribution of the QA conformer in devices helps to explain the good performance of the material in non-doped organic light-emitting diodes (OLEDs). Moreover, hyperfluorescence (HF) devices, using v-DABNA emitter show direct energy transfer from the QA conformer to v-DABNA, explaining the relatively improved Förster resonance energy transfer efficiency compared to similar HF systems. Highly efficient OLEDs where green light (TADF-only devices) is converted to blue light (HF devices) with the maximum external quantum efficiency remaining close to 30% are demonstrated.     

Continuous Photo-Electro-Catalytic Synthesis of Bio-Based Adipic Acid with Reaction Kinetics Modeling

Photo-electro-catalytic oxidation reactions of 1,6-hexanediol were carried out in a coil-type continuous-flow microreactor with an immobilized TiO₂ catalyst material. Bio-based adipic acid was formed as the only intermediate product before the total mineralization process. The production was stable, enabling green, selective and continuous resource conversion, but with low, non-optimized yields. In addition, the catalyzed chemical kinetics was modeled, based on mechanisms as well as approximated rate-determining steps. The Butler-Volmer relation was used for activation. The electro-catalytic oxidative pathway was demonstrated to dominate over photo-catalysis, also on account of the band gap characteristics of the titania nanotube electrode.     

Energy efficiency measurement of Chinese Yangtze River Delta’s cities transportation: a DEA window analysis approach

In this paper, the transportation energy efficiency of Yangtze River Delta’s 15 cities is studied in the period from 2009 to 2013. To measure transportation’s dynamic performance, the window analysis of data envelopment analysis (DEA) is used to estimate the efficiency in cross-sectional and time-varying data. Capital inputs and labor inputs are selected as the two non-energy inputs, energy consumption as the energy input, passenger volume and freight volume are selected as the two desirable outputs, and carbon dioxide is chosen as the undesirable output. The empirical study shows that Shanghai had the highest transportation energy efficiency, followed by Zhejiang province, and the average efficiency of Jiangsu province was the worst. A regression analysis on the efficiency values and their three influencing factors was carried out. The results show that per capita gross domestic product and the per capita area of paved roads in a city negatively influenced the efficiency values, while the number of public transportation vehicles per 10,000 persons positively influenced the transportation efficiency values. Lastly, some policy recommendations, conclusions, and suggestions for further research are given.     

Optodynamic Phenomena During Laser-Activated Irrigation Within Root Canals

Laser-activated irrigation is a powerful endodontic treatment for smear layer, bacteria, and debris removal from the root canal. In this study, we use shadow photography and the laser-beam-transmission probe to examine the dynamics of laser-induced vapor bubbles inside a root canal model and compare ultrasonic needle irrigation to the laser method. Results confirm important phenomenological differences in the two endodontic methods with the laser method resulting in much deeper irrigation. Observations of simulated debris particles show liquid vorticity effects which in our opinion represents the major cleaning mechanism.