Present and Future of SLAM in Extreme Underground Environments

This paper reports on the state of the art in underground SLAM by discussing different SLAM strategies and results across six teams that participated in the three-year-long SubT competition. In particular, the paper has four main goals. First, we review the algorithms, architectures, and systems adopted by the teams; particular emphasis is put on lidar-centric SLAM solutions (the go-to approach for virtually all teams in the competition), heterogeneous multi-robot operation (including both aerial and ground robots), and real-world underground operation (from the presence of obscurants to the need to handle tight computational constraints). We do not shy away from discussing the dirty details behind the different SubT SLAM systems, which are often omitted from technical papers. Second, we discuss the maturity of the field by highlighting what is possible with the current SLAM systems and what we believe is within reach with some good systems engineering. Third, we outline what we believe are fundamental open problems, that are likely to require further research to break through. Finally, we provide a list of open-source SLAM implementations and datasets that have been produced during the SubT challenge and related efforts, and constitute a useful resource for researchers and practitioners.Comment: 21 pages including references. This survey paper is submitted to IEEE Transactions on Robotics for pre-approva

Cross-cultural dataset for the evolution of religion and morality project

A considerable body of research cross-culturally examines the evolution of religious traditions, beliefs and behaviors. The bulk of this research, however, draws from coded qualitative ethnographies rather than from standardized methods specifically designed to measure religious beliefs and behaviors. Psychological data sets that examine religious thought and behavior in controlled conditions tend to be disproportionately sampled from student populations. Some cross-national databases employ standardized methods at the individual level, but are primarily focused on fully market integrated, state-level societies. The Evolution of Religion and Morality Project sought to generate a data set that systematically probed individual level measures sampling across a wider range of human populations. The set includes data from behavioral economic experiments and detailed surveys of demographics, religious beliefs and practices, material security, and intergroup perceptions. This paper describes the methods and variables, briefly introduces the sites and sampling techniques, notes inconsistencies across sites, and provides some basic reporting for the data set

Wpływ hydrolizy z rozszerzalnością cieplną odpadów lignocelulozowych na produkcję biogazu

The thermal-expansion hydrolysis is one of physical pre-treatments used as a preliminary step to improve biodegrability of lignocellulosic wastes. Its impact on wheat straw and effect of expansion on particle size were investigated. The results have shown a significant increase in biodegrability and reduction in size of raw material. The optimized conditions for treatment of substrate containing 5% of untreated wheat straw by weight were found to be at 200°C for 20 minutes at least.Hydroliza z rozszerzalnością cieplną należy do grupy fizycznych operacji obróbki wstępnej stosowanej w celu polepszenia biodegradowalności odpadów lignocelulozowych. Badano oddziaływanie tego procesu na słomę pszeniczną oraz wpływ rozszerzalności na rozmiar cząstek. Wyniki badań wykazały znaczący wzrost biodegradowalności oraz redukcję rozmiarów cząstek surowca. Optymalne warunki procesu dla substratu zawierającego 5% wag. nieprzerobionej słomy zbożowej określono jako 200°C w czasie nie krótszym niż 20 minut

Charakterystyka wstępnej obróbki słomy pszenicznej metodą termograwimetryczną

The sequential static thermogravimetry was used in the assessment of effect of hydrolysis temperature on wheat straw pre-treatment. It was found that temperature of 50% conversion T0.5 was lower for all studied solid residues after hydrolysis comparing with untreated straw, regardless of hydrolysis temperature. Lower value of T0.5 indicates that the straw structure was destructed by hydrolysis into more volatile products. The minimum temperature T0.5 and corresponding highest participation of light fraction was observed at hydrolysis temperature of 185°C.Statyczną termograwimetrię sekwencyjną wykorzystano do oceny wpływu temperatury hydrolizy we wstępnej obróbce słomy pszenicznej Stwierdzono, że temperatura T0.5 konwersji 50% jest niższa dla wszystkich przebadanych stałych pozostałości po hydrolizie w porównaniu ze słomą przed przeróbką, bez względu na temperaturę hydrolizy. Niższe wartości temperatury T0.5 wskazuję na to, że hydroliza zniszczyła strukturę słomy tworząc ardziej lotne frakcje. Minimalna temperatura T0.5 oraz odpowiadający jej wysoki udział lekkiej frakcji zaobserwowano dla temperatury hydrolizy wynoszącej 185 °C

Wpływ mechanicznej dezintegracji na biodegradowalność słomy pszennej

Present-day operating biogas plants are based on the treatment of lignocellulosic biomass presented in such materials as agriculture and forestry wastes, municipal solid waste, waste paper, wood and herbaceous energy crops. The biodegradability of untreated substrates is generally very low because of physical and chemical barriers caused by structure of lignocelulosic biomass. Therefore, pretreatment of biomass is an essential step in order to increase biomass digestibility. This paper is devoted to the mechanical disintegration of straw by the newly developed prototype of mill named MACERATOR. Its effectiveness is evaluated by the energy requirement for disintegration of wheat straw, by changes in particle sizes and also by biogj tests.Obecnie, czynne biogazownie opierają się na obróbce masy lignocelulozowej, która zawarta jest w takich materiałach jak: rolnicze i leśne odpady, stałe odpady komunalne, zużyty papier, drewno i rośliny energetyczne. Biodegradowalność nieprzerobionych substratów ogólnie jest bardzo niska ze względu na fizyczne i chemiczne bariery, spowodowane przez strukturę masy lignocelulozowej. Dlatego też obróbka biomasy jest istotnym etapem podniesienia jej fermentowalności. Artykuł ten poświęcony jest mechanicznej dezintegracji słomy pszennej za pomocą nowo utworzonego prototypu młyna o nazwie MACERATOR. Jego efektywność jest oceniana na podstawie zapotrzebowania energetycznego na dezintegrację słomy pszennej poprzez zmiany wymiaru cząstek i testów na wydajność biogazu

Mixing system for highly concentrated fine-grained suspensions

The mixing equipment for highly concentrated fine-grained suspensions must be designed differently from the equipment in which a suspension with a low concentration of the solid phase or bigger particles is mixed. It is due to the different rheological properties of the suspensions. In this work we are trying to find a suitable mixing system for a highly concentrated fine-grained suspension. The aim was to determine an effect of particular geometrical parameters of the tested mixing systems on a suspension process, especially from the energetic viewpoint. The energetic costs of all the used mixing systems were compared on the basis of the power consumption which was necessary for reaching the state of sufficient suspension movement in the whole mixed bulk. As a result, it was confirmed that multistage impellers can be used even in standard vessels (with a liquid level height equal to a vessel diameter) with a profit. During experiments, the state of sufficient movement was determined by a visual observation of the suspension at the vessel bottom, at the wall and also at the suspension level