9,396 research outputs found
Delayed acquisition of non-adjacent vocalic dependencies
The ability to compute non-adjacent regularities is key in the acquisition of a new language. In the domain of phonology/phonotactics, sensitivity to non-adjacent regularities between consonants has been found to appear between 7 and 10 months. The present study focuses on the emergence of a posterior-anterior (PA) bias, a regularity involving two non-adjacent vowels. Experiments 1 and 2 show that a preference for PA over AP (anterior-posterior) words emerges between 10 and 13 months in French-learning infants. Control experiments show that this bias cannot be explained by adjacent or positional preferences. The present study demonstrates that infants become sensitive to non-adjacent vocalic distributional regularities between 10 and 13 months, showing the existence of a delay for the acquisition of non-adjacent vocalic regularities compared to equivalent non-adjacent consonantal regularities. These results are consistent with the CV hypothesis, according to which consonants and vowels play different roles at different linguistic levels
Constant probe orientation for fast contact-based inspection of 3D free-form surfaces using (3+2)-axis inspection machines
A new probe optimization method for contact based (3+2)-axis inspection machines is proposed. Given an inspection path of a stylus on a free-form surface, an optimal orientation of the stylus is computed such that (i) the inclination angle of the stylus is within a given angular range with respect to the surface normal, (ii) the motion of the stylus is globally collision free, and (iii) the stylus remains constant in the coordinate system of the measuring machine. The last condition guarantees that the inspection motion requires only the involvement of the three translational axes of the measuring machine. The numerical simulations were validated through physical experiments on a testcase of a tooth of a bevel gear due to the surface complexity and probe accessibility. This optimized method was compared to 3-axis and 5-axis inspection strategies, showing that the fixed (3+2)-axis stylus returns more accurate inspection results compared to the traditional 3-axis approach and similar to 5-axis approach.RYC-2017-2264
Boosting early years learning during COVID-19
High-quality, centre-based Early Childhood Education and Care (ECEC) benefits toddlers’ development. New research investigated the effects of the COVID-19 disruptions on attendance and learning. It showed that ECEC boosted language and thinking skills throughout the pandemic, particularly in children from less advantaged backgrounds. This shows the importance of fully-funded ECEC for developing key skills and for levelling inequalities
Definition of tailor made cutting tools for machining of complex surfaces based on final surface shape
In this work a design methodology to define the best geometry of cutting tool for complex surfaces is defined, being based on the final part surface geometry. The manufacture of components with tailor made shaped tools, based on algorithm calculation and adapted to the geometry of the final piece surface, reduces manufacturing time and maintains piece quality in comparison with traditional cutting tools. Cutting tools are usually cylindrical (end mills) or ball-end mills. With mathematical algorithms can be defined diamond & CBN electroplated form tools, multi-tooth endmills, abrasive grinding tools and so on. The approach here presented can enable the production of tools for manufacturing process such as Super Abrasive Machining (SAM) and Flank milling strategies. Comparison between standard tools and traditional machining processes versus custom-shaped tools was studied in terms of process time. Final applications are numerous, such as, integral blade rotors, spiral bevel gears, blisks and impellers, complex screws, and others
5-axis double-flank CNC machining of spiral bevel gears via custom-shaped tools – Part II: physical validations and experiments
Recently, a new methodology for 5-axis flank computer numerically controlled (CNC) machining, called double-flank machining,
has been introduced (see “5-axis double-flank CNC machining of spiral bevel gears via custom-shaped milling tools–Part I: Modeling and simulation”). Certain geometries, such as curved teeth of spiral bevel gear, admit this approach where the machining tool has tangential contact with the material block on two sides, yielding a more efficient variant of flank machining. To achieve high machining accuracy, the path-planning algorithm, however, does not look only for the path of the tool, but also for the shape of the tool itself. The proposed approach is validated by series of physical experiments using an abrasive custom-shaped tool specifically designed for a particular type of a spiral bevel gear. The potential of this new methodology is shown in the semifinishing stage of gear manufacturing, where it outperforms traditional ball end milling by an order of magnitude in terms of machining time, while keeping, or even improving, the machining error.RYC-2017-22649
KK-2020/0010
Blisk blades manufacturing technologies analysis
The paper presents blisk blades manufactured by different manufacturing processes. In this sense, different milling trajectories are presented, and, super abrasive machining strategies and EDM technologies are also tested. Machining times, costs and surface finish are analysed in order to determine optimal machining process for blisk manufactured in low machinability materials.RYC-2017-2264
Constant probe orientation for fast contact-based inspection of 3D free-form surfaces using (3+2)-axis inspection machines
A new probe optimization method for contact based (3+2)-axis inspection machines is proposed. Given an inspection path of a stylus on a free-form surface, an optimal orientation of the stylus is computed such that (i) the inclination angle of the stylus is within a given angular range with respect to the surface normal, (ii) the motion of the stylus is globally collision free, and (iii) the stylus remains constant in the coordinate system of the measuring machine. The last condition guarantees that the inspection motion requires only the involvement of the three translational axes of the measuring machine. The numerical simulations were validated through physical experiments on a testcase of a tooth of a bevel gear due to the surface complexity and probe accessibility. This optimized method was compared to 3-axis and 5-axis inspection strategies, showing that the fixed (3+2)-axis stylus returns more accurate inspection results compared to the traditional 3-axis approach and similar to 5-axis approach
Characterization of a Subsurface Biosphere in a Massive Sulfide Deposit At Rio Tinto, Spain: Implications For Extant Life On Mars
The recent discovery of abundant sulfate minerals, particularly Jarosite by the Opportunity Rover at Sinus Merdiani on Mars has been interpreted as evidence for an acidic lake or sea on ancient Mars [1,2], since the mineral Jarosite is soluble in liquid water at pH above 4. The most likely mechanism to produce sufficient protons to acidify a large body of liquid water is near surface oxidation of pyrite rich deposits [3]. The acidic waters of the Rio Tinto, and the associated deposits of Hematite, Goethite, and Jarosite have been recognized as an important chemical analog to the Sinus Merdiani site on Mars [4]. The Rio Tinto is a river in southern Spain that flows 100 km from its source in the Iberian pyrite belt, one of the Earth's largest Volcanically Hosted Massive Sulfide (VHMS) provinces, into the Atlantic ocean. The river originates in artesian springs emanating from ground water that is acidified by the interaction with subsurface pyrite ore deposits. The Mars Analog Rio Tinto Experiment (MARTE) has been investigating the hypothesis that a subsurface biosphere exists at Rio Tinto living within the VHMS deposit living on chemical energy derived from sulfur and iron minerals. Reduced iron and sulfur might provide electron donors for microbial metabolism while in situ oxidized iron or oxidants entrained in recharge water might provide electron acceptors
Analysis of the water-food nexus for food security in a high Andean Community
Water and food are facing increasing demand worldwide. This increase is significant in mountainous regions where glaciers are melting, and water availability is in danger. Food demand has also increased with the population growth. This study sought to evaluate relationships between water supply and food demand in a community located in the Peruvian Andes mountainous region. The developed methodology reveals a practical way to identify future problems with food availability. Water supply was evaluated using historical precipitation data. On the other hand, water demand was estimated using meteorological data. Irrigated areas were determined using 2019 agricultural data from the local government. Food consumption was evaluated using a 2019 per capita regional consumption. Results show a water deficit for the current agricultural demand for ten out of the twelve months. The potato was the main crop being produced in the community, among sixteen studied crops. A high percentage of the time, many products were found do not satisfy local demand. For example, the potato was found to secure only fifty-five percent of the total local-demand fifty percent of the time. Current results can help the management of food security
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