65 research outputs found
Soil ecosystem services of the under different uses in the Colombian Amazonia
Agroforestry systems (AFs), where agricultural and livestock crops are associated with woody plants, are known as sustainable systems, that conserve biodiversity and improve the provision of ecosystem services without compromising productivity. This work focuses mainly on cacao AFs, which have been related to different ecosystem services in tropical regions. Especially, our study focuses on the ability of the cacao AFs to improve soil ecosystem services in the Colombian Amazon region. We focused on soil ecosystems ecosystem services in the Colombian Amazonia because: of the social importance of cacao production system in the study region, specifically within the post conflict context; the lack of knowledge on the capacity of cacao AFs to offer soil ecosystem services in the study zone and its capacity in restoring ecosystem services in degraded soils. Aim The objective of our work was to evaluate the soil quality in different cacao agroforestry systems in the Colombian Amazonia, and to compare these evaluated soil quality of soil quality in Forest and Pasture. Material and methods The study was conducted at the Macagual Amazon Research Center, located west of the Colombian Amazon. We evaluated soil quality in four types of AFs Cacao, presenting different establishment, composition and structural characteristics; but also in a plot of native forest composed of characteristic species of the area, and in a plot of pasture composed of grasses. In the different plot of each land use, we evaluated the diversity of macrofauna, the morphology of aggregate, the physical properties and the soil chemistry. We summarized these variables in a General Indicator of Soil Quality GISQ, characterizing soil quality in the different land uses. Major results and Conclusion It was found that the level of intensification among land uses (Bosque>AFs>Pasture) affects the decrease of the macrofauna populations, which was related to soil compaction (physical properties). Chemical fertility improved with the establishment of AFs influenced by the application of amendments and organic fertilizers. When establishing agroforestry systems from pasture areas at a certain level of degradation, the GISQ scale was found to increase by 42%. Our results indicate that AFs practices can definitely be used as a restoration strategy, for the recovery of degraded areas
Методическая работа в дошкольной образовательной организации как условие развития профессионально-педагогической культуры педагогов
Тема работы актуальна. В ВКР представлена методическая работа с педагогами ДОУ, по формирования профессионально-педагогической культуры. Работа имеет практическую значимост
Multi-level microfabrication method used for the 3D AC electroosmotic micropump optimization
Long-term ageing of PEDOT:PSS: wettability Study
© 2018 Elsevier B.V. Known for its electric properties, poly (3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) has emerged as a good candidate for organic electronics and more recently for bio-applications. Despite its growing use in engineering applications, little is known about the stability in time of its interface properties. Here, we consider the surface ageing of PEDOT:PSS when it is stored in environments with various relative humidity and tem perature conditions and as a function of the cross-linking agent's (3-glycidoxypropyltrimethoxysilane) concentration. Our systematic wettability study over 6 months reveals that the PEDOT:PSS interface undergoes significant reorganization and some irreversible changes on these timescales regardless of the concentration of cross-linker added
Electrowetting on Immersed Conducting Hydrogel.
Conducting polymers demonstrate an interesting ability to change their wettability at ultralow voltage (<1 V). While the conducting hydrogel poly(3,4-ethylenedioxythiophene) polystyrenesulfonate (PEDOT:PSS) is increasingly used as an interface with biology partly thanks to its mechanical properties, little is known about the electrical control of its wettability. We rely on the captive bubble technique to study this hydrogel property under relevant conditions (fully immerged). We here report that the wettability variations of PEDOT:PSS are driven by an electrowetting phenomenon in contrast to other conducting polymers which are thought to undergo wettability changes due to oxido-reduction reactions. In addition, we propose a modified electrowetting model to describe the wettability variations of PEDOT:PSS in aqueous solution under ultralow voltage and we show how these variations can be tuned in different ranges of contact angles (above or under 90°) by coating the PEDOT:PSS surface
Study of the electro-responsiveness and surface texturing of PEDOT:PSS for smart MEMS interface applications
In this study, we characterize the impact of electrical stimuli on the wettability and volume of thin films of poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) in aqueous solution. At low voltage (<1V), we demonstrate a 20° to 30° modulation of the contact angle controlled by an electrowetting phenomenon and not by electrochemical reactions like usually seen for other common conducting polymers. Consequently, the contact angle range can be tuned by chemical functionalization of its interface. Besides, we show that the polymer presents a small swelling (<4%) when the potential is turned from 0.2V to -0.8V. Finally, we develop fabrication processes to texture the PEDOT:PSS surface at microscale and nanoscale
Wettability of PEDOT:PSS films
Conducting polymers such as poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) are increasingly used to interface electronics with biology. Their wettability, however, remains poorly understood. We show that the frequently-used sessile drop technique yields results that are strongly dependent on the experimental conditions (measurement duration and relative humidity), due to the hydrogel-like behavior of PEDOT:PSS. In contrast, the captive bubble technique on a fully wet film overcomes these limitations. Dynamic wettability measurements provide hysteresis values for this polymer and clarify the physical meaning of the static contact angles measured by sessile drop and captive bubble. Finally we show that aging the films in water leads to loss of PSS chains which makes the films more hydrophobic. The addition of a crosslinker reduces and slows down these effects
Intégration silicium à l'IEMN : de l'architecture de composants aux circuits radiofréquences
Concentration/separation of cryptosporidium oocysts by on-chip hybrid AC-electrokinetics for digital microfluidics
Dynamic sensing of magnetic nanoparticles in microchannel using GMI technology
International audienceThis paper presents the detection of magnetic nanoparticles flowing into a microchannel using giant magnetic impedance (GMI) microwire sensor made up of CoFeSiBNb alloy (40 diameter and 1 cm long wire). Detection tests were performed using UltraSmall Particles of Iron Oxyde (USPIO) with diameter of 20 nm. Detection of volume of 180 nl with a concentration of 18 mmol (Fe)/l and flow rate of 260 nl/s was performed. Such type of measurement can find application in biomedical and clinical diagnosis for in vivo noninvasive detection
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