Taking the pulse of Earth's tropical forests using networks of highly distributed plots

Tropical forests are the most diverse and productive ecosystems on Earth. While better understanding of these forests is critical for our collective future, until quite recently efforts to measure and monitor them have been largely disconnected. Networking is essential to discover the answers to questions that transcend borders and the horizons of funding agencies. Here we show how a global community is responding to the challenges of tropical ecosystem research with diverse teams measuring forests tree-by-tree in thousands of long-term plots. We review the major scientific discoveries of this work and show how this process is changing tropical forest science. Our core approach involves linking long-term grassroots initiatives with standardized protocols and data management to generate robust scaled-up results. By connecting tropical researchers and elevating their status, our Social Research Network model recognises the key role of the data originator in scientific discovery. Conceived in 1999 with RAINFOR (South America), our permanent plot networks have been adapted to Africa (AfriTRON) and Southeast Asia (T-FORCES) and widely emulated worldwide. Now these multiple initiatives are integrated via ForestPlots.net cyber-infrastructure, linking colleagues from 54 countries across 24 plot networks. Collectively these are transforming understanding of tropical forests and their biospheric role. Together we have discovered how, where and why forest carbon and biodiversity are responding to climate change, and how they feedback on it. This long-term pan-tropical collaboration has revealed a large long-term carbon sink and its trends, as well as making clear which drivers are most important, which forest processes are affected, where they are changing, what the lags are, and the likely future responses of tropical forests as the climate continues to change. By leveraging a remarkably old technology, plot networks are sparking a very modern revolution in tropical forest science. In the future, humanity can benefit greatly by nurturing the grassroots communities now collectively capable of generating unique, long-term understanding of Earth's most precious forests. Resumen Los bosques tropicales son los ecosistemas más diversos y productivos del mundo y entender su funcionamiento es crítico para nuestro futuro colectivo. Sin embargo, hasta hace muy poco, los esfuerzos para medirlos y monitorearlos han estado muy desconectados. El trabajo en redes es esencial para descubrir las respuestas a preguntas que trascienden las fronteras y los plazos de las agencias de financiamiento. Aquí mostramos cómo una comunidad global está respondiendo a los desafíos de la investigación en ecosistemas tropicales a través de diversos equipos realizando mediciones árbol por árbol en miles de parcelas permanentes de largo plazo. Revisamos los descubrimientos más importantes de este trabajo y discutimos cómo este proceso está cambiando la ciencia relacionada a los bosques tropicales. El enfoque central de nuestro esfuerzo implica la conexión de iniciativas locales de largo plazo con protocolos estandarizados y manejo de datos para producir resultados que se puedan trasladar a múltiples escalas. Conectando investigadores tropicales, elevando su posición y estatus, nuestro modelo de Red Social de Investigación reconoce el rol fundamental que tienen, para el descubrimiento científico, quienes generan o producen los datos. Concebida en 1999 con RAINFOR (Suramérica), nuestras redes de parcelas permanentes han sido adaptadas en África (AfriTRON) y el sureste asiático (T-FORCES) y ampliamente replicadas en el mundo. Actualmente todas estas iniciativas están integradas a través de la ciber-infraestructura de ForestPlots.net, conectando colegas de 54 países en 24 redes diferentes de parcelas. Colectivamente, estas redes están transformando nuestro conocimiento sobre los bosques tropicales y el rol de éstos en la biósfera. Juntos hemos descubierto cómo, dónde y porqué el carbono y la biodiversidad de los bosques tropicales está respondiendo al cambio climático y cómo se retroalimentan. Esta colaboración pan-tropical de largo plazo ha expuesto un gran sumidero de carbono y sus tendencias, mostrando claramente cuáles son los factores más importantes, qué procesos se ven afectados, dónde ocurren los cambios, los tiempos de reacción y las probables respuestas futuras mientras el clima continúa cambiando. Apalancando lo que realmente es una tecnología antigua, las redes de parcelas están generando una verdadera y moderna revolución en la ciencia tropical. En el futuro, la humanidad puede beneficiarse enormemente si se nutren y cultivan comunidades de investigadores de base, actualmente con la capacidad de generar información única y de largo plazo para entender los que probablemente son los bosques más preciados de la tierra. Resumo Florestas tropicais são os ecossistemas mais diversos e produtivos da Terra. Embora uma boa compreensão destas florestas seja crucial para o nosso futuro coletivo, até muito recentemente os esforços de medições e monitoramento foram amplamente desconexos. É essencial formarmos redes para obtermos respostas que transcendem fronteiras e horizontes de agências financiadoras. Neste estudo nós mostramos como uma comunidade global está respondendo aos desafios da pesquisa de ecossistemas tropicais, com equipes diversas medindo florestas, árvore por árvore, em milhares de parcelas monitoradas à longo prazo. Nós revisamos as maiores descobertas científicas deste trabalho, e mostramos também como este processo está mudando a ciência de florestas tropicais. Nossa abordagem principal envolve unir iniciativas de base a protocolos padronizados e gerenciamento de dados a fim de gerar resultados robustos em escalas ampliadas. Ao conectar pesquisadores tropicais e elevar seus status, nosso modelo de Rede de Pesquisa Social reconhece o papel-chave do produtor dos dados na descoberta científica. Concebida em 1999 com o RAINFOR (América do Sul), nossa rede de parcelas permanentes foi adaptada para África (AfriTRON) e Sudeste asiático (T-FORCES), e tem sido extensamente reproduzida em todo o mundo. Agora estas múltiplas iniciativas estão integradas através de uma infraestrutura cibernética do ForestPlots.net, conectando colegas de 54 países de 24 redes de parcelas. Estas iniciativas estão transformando coletivamente o entendimento das florestas tropicais e seus papéis na biosfera. Juntos nós descobrimos como, onde e por que o carbono e a biodiversidade da floresta estão respondendo às mudanças climáticas, e seus efeitos de retroalimentação. Esta duradoura colaboração pantropical revelou um grande sumidouro de carbono persistente e suas tendências, assim como tem evidenciado quais direcionadores são mais importantes, quais processos florestais são mais afetados, onde eles estão mudando, seus atrasos no tempo de resposta, e as prováveis respostas das florestas tropicais conforme o clima continua a mudar. Dessa forma, aproveitando uma notável tecnologia antiga, redes de parcelas acendem faíscas de uma moderna revolução na ciência das florestas tropicais. No futuro a humanidade pode se beneficiar incentivando estas comunidades basais que agora são coletivamente capazes de gerar conhecimentos únicos e duradouros sobre as florestas mais preciosas da Terra. Résume Les forêts tropicales sont les écosystèmes les plus diversifiés et les plus productifs de la planète. Si une meilleure compréhension de ces forêts est essentielle pour notre avenir collectif, jusqu'à tout récemment, les efforts déployés pour les mesurer et les surveiller ont été largement déconnectés. La mise en réseau est essentielle pour découvrir les réponses à des questions qui dépassent les frontières et les horizons des organismes de financement. Nous montrons ici comment une communauté mondiale relève les défis de la recherche sur les écosystèmes tropicaux avec diverses équipes qui mesurent les forêts arbre après arbre dans de milliers de parcelles permanentes. Nous passons en revue les principales découvertes scientifiques de ces travaux et montrons comment ce processus modifie la science des forêts tropicales. Notre approche principale consiste à relier les initiatives de base à long terme à des protocoles standardisés et une gestion de données afin de générer des résultats solides à grande échelle. En reliant les chercheurs tropicaux et en élevant leur statut, notre modèle de réseau de recherche sociale reconnaît le rôle clé de l'auteur des données dans la découverte scientifique. Conçus en 1999 avec RAINFOR (Amérique du Sud), nos réseaux de parcelles permanentes ont été adaptés à l'Afrique (AfriTRON) et à l'Asie du Sud-Est (T-FORCES) et largement imités dans le monde entier. Ces multiples initiatives sont désormais intégrées via l'infrastructure ForestPlots.net, qui relie des collègues de 54 pays à travers 24 réseaux de parcelles. Ensemble, elles transforment la compréhension des forêts tropicales et de leur rôle biosphérique. Ensemble, nous avons découvert comment, où et pourquoi le carbone forestier et la biodiversité réagissent au changement climatique, et comment ils y réagissent. Cette collaboration pan-tropicale à long terme a révélé un important puits de carbone à long terme et ses tendances, tout en mettant en évidence les facteurs les plus importants, les processus forestiers qui sont affectés, les endroits où ils changent, les décalages et les réactions futures probables des forêts tropicales à mesure que le climat continue de changer. En tirant parti d'une technologie remarquablement ancienne, les réseaux de parcelles déclenchent une révolution très moderne dans la science des forêts tropicales. À l'avenir, l'humanité pourra grandement bénéficier du soutien des communautés de base qui sont maintenant collectivement capables de générer une compréhension unique et à long terme des forêts les plus précieuses de la Terre. Abstrak Hutan tropika adalah di antara ekosistem yang paling produktif dan mempunyai kepelbagaian biodiversiti yang tinggi di seluruh dunia. Walaupun pemahaman mengenai hutan tropika amat penting untuk masa depan kita, usaha-usaha untuk mengkaji dan mengawas hutah-hutan tersebut baru sekarang menjadi lebih diperhubungkan. Perangkaian adalah sangat penting untuk mencari jawapan kepada soalan-soalan yang menjangkaui sempadan dan batasan agensi pendanaan. Di sini kami menunjukkan bagaimana sebuah komuniti global bertindak balas terhadap cabaran penyelidikan ekosistem tropika melalui penglibatan pelbagai kumpulan yang mengukur hutan secara pokok demi pokok dalam beribu-ribu plot jangka panjang. Kami meninjau semula penemuan saintifik utama daripada kerja ini dan menunjukkan bagaimana proses ini sedang mengubah bidang sains hutan tropika. Teras pendekatan kami memberi tumpuan terhadap penghubungan inisiatif akar umbi jangka panjang dengan protokol standar serta pengurusan data untuk mendapatkan hasil skala besar yang kukuh. Dengan menghubungkan penyelidik-penyelidik tropika dan meningkatkan status mereka, model Rangkaian Penyelidikan Sosial kami mengiktiraf kepentingan peranan pengasas data dalam penemuan saintifik. Bermula dengan pengasasan RAINFOR (Amerika Selatan) pada tahun 1999, rangkaian-rangkaian plot kekal kami kemudian disesuaikan untuk Afrika (AfriTRON) dan Asia Tenggara (T-FORCES) dan selanjutnya telah banyak dicontohi di seluruh dunia. Kini, inisiatif-inisiatif tersebut disepadukan melalui infrastruktur siber ForestPlots.net yang menghubungkan rakan sekerja dari 54 negara di 24 buah rangkaian plot. Secara kolektif, rangkaian ini sedang mengubah pemahaman tentang hutan tropika dan peranannya dalam biosfera. Kami telah bekerjasama untuk menemukan bagaimana, di mana dan mengapa karbon serta biodiversiti hutan bertindak balas terhadap perubahan iklim dan juga bagaimana mereka saling bermaklum balas. Kolaborasi pan-tropika jangka panjang ini telah mendedahkan sebuah sinki karbon jangka panjang serta arah alirannya dan juga menjelaskan pemandu-pemandu perubahan yang terpenting, di mana dan bagaimana proses hutan terjejas, masa susul yang ada dan kemungkinan tindakbalas hutan tropika pada perubahan iklim secara berterusan di masa depan. Dengan memanfaatkan pendekatan lama, rangkaian plot sedang menyalakan revolusi yang amat moden dalam sains hutan tropika. Pada masa akan datang, manusia sejagat akan banyak mendapat manfaat jika memupuk komuniti-komuniti akar umbi yang kini berkemampuan secara kolektif menghasilkan pemahaman unik dan jangka panjang mengenai hutan-hutan yang paling berharga di dunia

Vinylidene fluoride- and trifluoroethylene-containing fluorinated electroactive copolymers. How does chemistry impact properties?

International audienceFluoropolymers are attractive niche polymers used in high added value materials for high-tech appli-cations in aerospace, electronics, coatings, membranes, cables, and the automotive industries. Amongthem, VDF- and TrFE-based copolymers exhibit remarkable electroactive properties allowing their incor-poration into a wide range of devices such as printed memories, sensors, actuators, artificial muscles,and energy storage devices. In a first section, a detailed overview of semi-crystalline poly(VDF-co-TrFE)copolymers and of their ferroelectric (FE) properties from the point of view of polymer chemists is sup-plied. In addition to the polymer microstructure that may sometimes be controlled or influenced by thesynthesis strategies, physical properties such as the phase transitions, and electroactivity are also affectedby processing, such as annealing for example, and film thickness for example. Building on the conclusionsand understanding obtained from the first section, the effect of the introduction of a termonomer (leadingto poly(VDF-ter-TrFE-ter-M) terpolymers) is detailed in a second section of this review. Modifying theterpolymer chain microstructure has a major impact on the crystalline phase of the terpolymers that mayresult in a relaxor-ferroelectric behavior (RFE). The distribution of the termonomer along the polymerchain, the capacity of the termonomer units to enter the crystal lattice, as well as its dipole momentgovern in large part the terpolymer electroactive properties. Poly(VDF-ter-TrFE-ter-CFE) and poly(VDF-ter-TrFE-ter-CTFE) terpolymers appeared to be the best candidates for RFE properties and were thus themost studied. In two following sections, the block or graft architectures of VDF- and TrFE- based copoly-mers, and the various crosslinking strategies used so far for such copolymers are described. Chemicalmodification is indeed a very powerful tool to tune electroactive properties of copolymers or to impartadditional properties. Finally, in the last section, a few examples of emerging applications for these fluo-rinated electroactive polymers (EAPs) are briefly discussed. This review aims to provide a comprehensivereport on the use of polymer chemistry as a tool to produce better electroactive fluorinated polymers, andhighlights possible opportunities and perspectives for future progress in this field. Research in this inter-disciplinary field requires different kinds of expertise, ranging from organic and polymer chemistries,polymer films engineering, physics of semi-crystalline polymers and electroactivity, to the design andfabrication of electronic devices

From solvent-cast to annealed and poled poly(VDF-co-TrFE) films: New insights on the defective ferroelectric phase

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Phase diagram of poly(VDF-ter-TrFE-ter-CTFE) copolymers: Relationship between crystalline structure and material properties

Depending on their CTFE content (from 0 to 10 mol %), poly(VDF-ter-TrFE-ter-CTFE), poly(vinylidene fluoride-ter-trifluoroethylene-ter-chlorotrifluoroethylene) copolymers, exhibit ferroelectric (FE) or relaxor ferroelectric (RFE) properties at room temperature. Solvent cast films of these terpolymers can crystallize in three orthorhombic phases: FE, DFE (Defective Ferroelectric) or RFE according to their amount of CTFE. The relative amount of each crystalline phase depends on the amount of CTFE and evolves after annealing. We study the dependence of the electric displacement−electric field (D−E) loop with the amount of CTFE and with annealing step. We observed a closely link between the remnant polarization, PR, and the fraction of (FE + DFE) crystalline phase. Macroscopic properties, studied using thermo-mechanical experiments (DSC and DMA) and dielectric spectroscopy, evolve continuously with the CTFE amount and are well correlated with the structural properties. Finally, a temperature versus mol% CTFE phase diagram is established and discussed in relation-ship with material properties.“Plate-forme de l’Université de Bordeaux pour l’organique électronique imprimable : de la molécule aux dispositifs et systèmes intégrés - valorisation et commercialisation

Semicrystalline Organization of VDF- and TrFE-Based ElectroactiveTerpolymers: Impact of the trans-1,3,3,3-TetrafluoropropeneTermonomer

International audienceIn the search for fluorinated polymers with newelectroactive properties, the radical polymerization of vinylidenefluoride (VDF), trifluoroethylene (TrFE), and trans-1,3,3,3-tetrafluoropropene (1234ze) was achieved. The crystallineorganization and the electroactive properties of semicrystallinepoly(VDF-ter-TrFE-ter-1234ze) terpolymer films with 1234zemolar contents ranging from 0 to 6%, obtained by solventcasting,were investigated using a combination of structural,dielectric, and electromechanical techniques. For 0 mol %1234ze, poly(VDF-co-TrFE) copolymers exhibited a Curietransition from the ferroelectric (FE) phase to the paraelectric (PE) phase at the Curie temperature (TC ∼ 95 °C). DSC,dielectric spectroscopy, and FTIR experiments revealed the preservation of this Curie transition (TC ∼ 75 °C) while increasingthe termonomer content. WAXS measurements confirmed the persistence of the FE phase as the main phase at roomtemperature but also showed the appearance of a secondary ZFE phase (expanded FE phase incorporating 1234ze units) in lowerproportion. The WAXS crystallinity was halved (42 to 23%) from 0 to 6 mol % 1234ze terpolymer annealed films. Furthermore,SAXS and WAXS experiments highlighted a decrease of the crystalline lamellae thickness and a significant modification of theelectronic density distribution upon increase of 1234ze units. A new model for this particular arrangement of crystalline lamellaewas thus proposed with the location of the ZFE phase at the interface between the FE crystalline lamellae and the amorphousphase. Finally, reduced remnant polarization (Pr ∼ 15 mC/m2) and transverse piezoelectric coefficient (d33 ∼ −5 pC/N),compared to those of the reference poly(VDF-co-TrFE) copolymer (Pr ∼ 50 mC/m2 and d33 ∼ −20 pC/N), were mainlyassigned to the decrease of the FE phase content in terpolymer poled films

Crystal-Crystal transitions in poly(VDF-ter-TrFE-ter-CTFE): Influence of CTFE termonomers

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Crystal-Crystal transitions in poly(VDF-ter-TrFE-ter-CTFE): Influence of CTFE termonomers

The increasing industrial interest for printed organic electronics these last years has led to the development of VDF-based electroactive polymers for numerous energy-related applications (sensors, actuators, capacitors) [1]. Depending on their CTFE content (from 0 to 10 mol %), poly (VDF-ter-TrFE-ter-CTFE), poly(vinylidene fluoride-ter-trifluoroethylene-ter-chlorotrifluoroethylene) copolymers exhibit ferroelectric (FE) or relaxor ferroelectric (RFE) properties at low temperature whereas they all present paraelectric (PE) behavior at high temperature. This thermal evolution of their electro-active properties is related to reversible crystal-crystal transitions. Using simultaneous SAXS-WAXS experiments along thermal cycles, we studied these structural transitions for three different copolymers with various amount of CTFE (0, 5 and 10 mol %). We identified two types of crystalline phase at low temperature with their proper crystal-crystal transition: the first one containing all-trans conformations (orthorhombic FE phase) presents a discontinuous transition towards the hexagonal PE phase, the second one which incorporates gauche disordered conformations (orthorhombic DFE (Defective Ferroelectric) or RFE) transits continuously towards the same hexagonal PE phase. The discontinuous FE to PE transition is the predominant transition observed in the copolymer without CTFE, it is the well-known Curie transition. The unique transition observed in the terpolymer with 10 mol % of CTFE is the continuous RFE to PE transition. For the intermediate composition, we observe the coexistence of these two simultaneous phase transitions, FE to PE and RFE to PE. These observations are well correlated with the ferroelectric and relaxor-ferroelectric behaviors of each terpolymer. All the conclusions and discussion of this study were recently published in Polymer [2]. At the epf2019 congress, we will focus on the SAXS-WAXS structural study

Static and Dynamic Studies of Electro-Active Polymer Actuators and Integration in a Demonstrator

Nowadays, the haptic effect is used and developed for many applications—particularly in the automotive industry, where the mechanical feedback induced by a haptic system enables the user to receive information while their attention is kept on the road and on driving. This article presents the development of a vibrotactile button based on printed piezoelectric polymer actuation. Firstly, the characterization of the electro-active polymer used as the actuator and the development of a model able to predict the electromechanical behavior of this device are summarized. Then, the design of circular membranes and their dynamic characterization are presented. Finally, this work is concluded with the construction of a fully functional demonstrator, integrating haptic buttons leading to a clear haptic sensation for the user