Optimal Design for the Passive Control of Vibration Based on Limit Cycles

The optimal design of damping parameters for passive vibration control remains a challenge for both research and industrial applications. Here, we introduce a design methodology based on limit cycle analysis in concert with design optimization. A state-space representation is used to model the vibrational behavior converged to its limit cycle. The design approach is outlined and applied to mechanical systems undergoing periodic forces. This method is applicable to both vibration mitigation and energy harvesting, and examples of both are shown. We conclude with a summary of the results and an outlook for future developments and applications

Evaluation of a Bayesian Algorithm to Detect Burned Areas in the Canary Islands’ Dry Woodlands and Forests Ecoregion Using MODIS Data

Burned Area (BA) is deemed as a primary variable to understand the Earth’s climate system. Satellite remote sensing data have allowed for the development of various burned area detection algorithms that have been globally applied to and assessed in diverse ecosystems, ranging from tropical to boreal. In this paper, we present a Bayesian algorithm (BY-MODIS) that detects burned areas in a time series of Moderate Resolution Imaging Spectroradiometer (MODIS) images from 2002 to 2012 of the Canary Islands’ dry woodlands and forests ecoregion (Spain). Based on daily image products MODIS, MOD09GQ (250 m), and MOD11A1 (1 km), the surface spectral reflectance and the land surface temperature, respectively, 10 day composites were built using the maximum temperature criterion. Variables used in BY-MODIS were the Global Environment Monitoring Index (GEMI) and Burn Boreal Forest Index (BBFI), alongside the NIR spectral band, all of which refer to the previous year and the year the fire took place in. Reference polygons for the 14 fires exceeding 100 hectares and identified within the period under analysis were developed using both post-fire LANDSAT images and official information from the forest fires national database by the Ministry of Agriculture and Fisheries, Food and Environment of Spain (MAPAMA). The results obtained by BY-MODIS can be compared to those by official burned area products, MCD45A1 and MCD64A1. Despite that the best overall results correspond to MCD64A1, BY-MODIS proved to be an alternative for burned area mapping in the Canary Islands, a region with a great topographic complexity and diverse types of ecosystems. The total burned area detected by the BY-MODIS classifier was 64.9% of the MAPAMA reference data, and 78.6% according to data obtained from the LANDSAT images, with the lowest average commission error (11%) out of the three products and a correlation (R2) of 0.82. The Bayesian algorithm—originally developed to detect burned areas in North American boreal forests using AVHRR archival data Long-Term Data Record—can be successfully applied to a lower latitude forest ecosystem totally different from the boreal ecosystem and using daily time series of satellite images from MODIS with a 250 m spatial resolution, as long as a set of training areas adequately characterising the dynamics of the forest canopy affected by the fire is defined

Combining safety and speed in collaborative assembly systems – An approach to time optimal trajectories for collaborative robots

Abstract Human-robot interaction is a key enabling technology of Industry 4.0 and the prospected pervasiveness of robotics in industrial environments will be not possible without enabling them to safety interact with humans. Such a fact imposes a relevant constraints because the limits imposed by the actual technical deliverables entail strong requirements in the operational velocity of robots when sharing their workspace with humans. In this paper, we address the theoretical limits of velocity under the light of current state-of-the-art trajectory planning and normative requirements. The main goal is to find a methodology to plan safe trajectories without neglecting cognitive ergonomics and production efficiency aspects. We start by considering the set of trajectories which are optimal with respect to a cognitive criteria and give a suitable parametrization to it. Then we are able to formulate the safety requirements in terms of constraints in an optimization problem. Finally, experimental results are provided. This allow the identification of the preferable sets of possible motions which satisfy the operator psychological wellbeing and the assembly process performance by complying the safety requirements in terms of mechanical risk prevention

Simulation Based Validation of Supply Chain Effects through ICT enabled Real-time-capability in ETO Production Planning

Abstract According to Industry 4.0, real-time information in production planning and control, shows a high potential for optimizing the whole supply chain. The paper considers the plant building industry, especially the off-site fabrication and on-site installation. Traditionally, production planning is centralized following a Master Schedule that rarely is up to date, ignoring deviations on-site. As a result, components are delivered in advance or too late, which create non-value adding activities and high inventory levels. The paper proposes an ICT-supported nearly real-time capable production planning approach, which by means of a simulation, shows a drastically reduction of the inventory level on-site

Macro- and Microscopic Characterization of Components of Resistance against Puccinia striiformis f. sp. tritici in a Collection of Spanish Bread Wheat Cultivars

Yellow (stripe) rust, caused by the biotrophic fungus Puccinia striiformis f. sp. tritici (Pst), stands as the most serious wheat disease worldwide, affecting approximately 88% of world wheat production. Even though yellow rust generally develops in cool humid weather conditions, the expansion of new races adapted to warmer climates threatens zones where severe P. striiformis epidemics were infrequent, such as Andalusian wheat cropping areas. In order to characterize yellow rust resistance mechanisms in Spanish germplasm, our study evaluated 19 Spanish bread wheat cultivars against P. striiformis under controlled conditions for percentage of disease severity (DS) and infection type (IT). From this visual evaluation, 74% of evaluated cultivars showed resistant responses against P. striiformis infection with only five cultivars considered susceptible. Subsequently, macroscopic and microscopic components of resistance were identified through image analysis and histological studies, respectively, in six selected cultivars. Macroscopic parameters such as total pustule area and total affected area (%), together with microscopic parameters such as early-aborted and established microcolonies regarding plant cell death responses (%), and microcolony length (µm), were identified as capable of differentiating cultivars quantitatively. Thus, these parameters could be used as a basis for screening resistant responses in future breeding programs, complementary to physiology, genetic and biochemical studies of plant-Pst interaction. Finally, our study seems to be the first macroscopic and microscopic characterization of P. striiformis infection in a collection of Spanish bread wheat cultivars in controlled conditions

a human in the loop cyber physical system for collaborative assembly in smart manufacturing

Abstract Industry 4.0 rose with the introduction of cyber-physical systems (CPS) and Internet of things (IoT) inside manufacturing systems. CPS represent self-controlled physical processes, having tight networking capabilities and efficient interfaces for human interaction. The interactive dimension of CPS reaches its maximum when defined in terms of natural human-machine interfaces (NHMI), i.e., those reducing the technological barriers required for the interaction. This paper presents a NHMI bringing the human decision-making capabilities inside the cybernetic control loop of a smart manufacturing assembly system. The interface allows to control, coordinate and cooperate with an industrial cobot during the task execution

Photosynthetic responses of trees in high-elevation forests: comparing evergreen species along an elevation gradient in the Central Andes

Plant growth at extremely high elevations is constrained by high daily thermal amplitude, strong solar radiation and water scarcity. These conditions are particularly harsh in the tropics, where the highest elevation treelines occur. In this environment, the maintenance of a positive carbon balance involves protecting the photosynthetic apparatus and taking advantage of any climatically favourable periods. To characterize photoprotective mechanisms at such high elevations, and particularly to address the question of whether these mechanisms are the same as those previously described in woody plants along extratropical treelines, we have studied photosynthetic responses in Polylepis tarapacana Philippi in the central Andes (18 degrees S) along an elevational gradient from 4300 to 4900 m. For comparative purposes, this gradient has been complemented with a lower elevation site (3700 m) where another Polylepis species (P. rugulosa Bitter) occurs. During the daily cycle, two periods of photosynthetic activity were observed: one during the morning when, despite low temperatures, assimilation was high; and the second starting at noon when the stomata closed because of a rise in the vapour pressure deficit and thermal dissipation is prevalent over photosynthesis. From dawn to noon there was a decrease in the content of antenna pigments (chlorophyll b and neoxanthin), together with an increase in the content of xanthophyll cycle carotenoids. These results could be caused by a reduction in the antenna size along with an increase in photoprotection. Additionally, photoprotection was enhanced by a partial overnight retention of de-epoxized xanthophylls. The unique combination of all of these mechanisms made possible the efficient use of the favourable conditions during the morning while still providing enough protection for the rest of the day. This strategy differs completely from that of extratropical mountain trees, which uncouple light-harvesting and energy-use during long periods of unfavourable, winter conditions.This research was carried out with the aid of grants from the Chilean Research Council (FONDECYT 1120965 and FONDAP 15110009) awarded to D.A.C., and BFU 2010-15021 from the Spanish Ministry of Economy and Competitiveness (MINECO) and the European Regional Development Fund ERDF(FEDER) and the Basque Government (UPV/EHU-GV IT-299-07) awarded to J.I.G.-P

Implementation of Industrial Internet of Things and Cyber-Physical Systems in SMEs for Distributed and Service-Oriented Control

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Sustancias tóxicas y antinutricionales de Amaranthus dubius Mart. ex Thell. Efecto de la parte de la planta y la época de recolecta

Amaranth species are gaining increasing interest for human and animal nutrition, although its use is limited due to their toxic and antinutritional substances contents. The contents of toxic and antinutritionals substances (oxalates, phytates, total phenols, condensate tannins, hydrolysable tannins and cyanide) in the leaves, stems, and panicles of Amaranthus dubius Mart. ex Thell., not yet investigated, were evaluated in both rainy and dry seasons. The plants were cultivated in El Néctar Hacienda, located in Merecure, in the municipality of Acevedo, Miranda State, Venezuela (10º31’38" N, 66º33’16" W). The concentration of oxalates, phytates, total phenols, condensate and hydrolysable tannins were determined by classic colorimetric techniques, the cyanide being determined by silver nitrate titration. The content of toxic and antinutrients in A. dubius ranged from 169.6 to 368.5 mg of oxalates.kg-1 DM, 0.771 to 7.482 mg of phytates.g-1 DM, 0.47 to 1.77 mg of total phenols.g-1 DM, and 0.22 to 1.20 mg of condensate tannins.g-1 DM. Cyanide and hydrolysable tannins were not detected. The values of most of these substances presented differences according to harvesting seasons and plant part (P<0.001), as well as an interaction between both factors. The content of toxic and antinutrients was generally higher in the dry than in the rainy season for all parts of the plant. The harvesting season and the plant part affect the content of toxic and antinutritional substances in A.dubius, whose values were, however, below the maximum levels allowed by regulators for human consumption. Therefore, as raw material it does not need to be processed in order to guarantee its harmlessnessLas especies de amaranto están generando creciente interés para la nutrición humana y animal, aunque su uso es limitado debido al contenido de sustancias tóxicas y antinutricionales. El contenido de sustancias tóxicas y antinutrientes (oxalatos, fitatos, fenoles totales, taninos condensados, taninos hidrolizables y cianuro) en las hojas, tallos y panículas de Amaranthus dubius Mart. ex Thell., no ha sido investigado, por ello se evaluaron en época lluviosa y seca. Las plantas fueron cultivadas en la hacienda El Néctar, localizada en Merecure, municipio Acevedo, estado Miranda, Venezuela (10º31’38'’ N, 66º33’16'’ O). La concentración de oxalatos, fitatos, fenoles totales, taninos condensados y taninos hidrolizables se determinaron mediante técnicas colorimétricas clásicas y el cianuro se determinó por titulación con nitrato de plata. El contenido de tóxicos y antinutrientes en A. dubius osciló entre 169,6-368,5 mg de oxalatos.kg-1 en biomasa seca (BS); 0,771-7,482 mg de fitatos.g-1 BS; 0,47-1,77 mg de fenoles totales.g-1 BS y 0,22-1,20 mg de taninos condensados.g-1 BS. No se detectó cianuro ni taninos hidrolizables. Los valores de la mayoría de estas sustancias presentaron diferencias de acuerdo a la época de recolecta y partes de la planta (P<0,001), así como interacción entre ambos factores. El contenido de tóxicos y antinutrientes fue generalmente mayor en la época seca que en la época lluviosa para todas las partes de la planta. La época de recolecta y la parte de la planta afectaron el contenido de sustancias tóxicas y antinutricionales de A. dubius; sin embargo, los valores estuvieron por debajo de los niveles máximos permitidos regulados para el consumo humano. Por lo tanto, la materia prima no necesita ser procesada para garantizar su inocuida

Acetylated nanocellulose for single-component bioinks and cell proliferation on 3D-printed scaffolds

Nanocellulose has been demonstrated as a suitable material for cell culturing, given its similarity to extracellular matrices. Taking advantage of the shear thinning behavior, nanocellulose suits three-dimensional (3D) printing into scaffolds that support cell attachment and proliferation. Here, we propose aqueous suspensions of acetylated nanocellulose of a low degree of substitution for direct ink writing (DM). This benefits from the heterogeneous acetylation of precursor cellulosic fibers, which eases their deconstruction and confers the characteristics required for extrusion in DIW. Accordingly, the morphology of related 3D printed architectures and their performance during drying and rewetting as well as interactions with living cells are compared with those produced from typical unmodified and TEMPO-oxidized nanocelluloses. We find that a significantly lower concentration of acetylated nanofibrils is needed to obtain bioinks of similar performance, affording more porous structures. Together with their high surface charge and axial aspect, acetylated nanocellulose produces dimensionally stable monolithic scaffolds that support drying and rewetting, required for packaging and sterilization. Considering their potential uses in cardiac devices, we discuss the interactions of the scaffolds with cardiac myoblast cells. Attachment, proliferation, and viability for 21 days are demonstrated. Overall, the performance of acetylated nanocellulose bioinks opens the possibility for reliable and scaleup fabrication of scaffolds appropriate for studies on cellular processes and for tissue engineering.Peer reviewe