133 research outputs found

    Conducting polymer microactuators operating in air

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    We report for the first time on microsized conducting polymer actuators, which operate in air and in liquids. These actuators are potentially useful for a wide range of applications from biotechnology to microrobots. Furthermore, the actuators are fabricated using an excimer laser ablation technique, which does not require clean-room facilities and can provide high throughput production. Preliminary characterization results presented show that the tip displacement of the microactuators is linearly proportional to the magnitude of the input voltage

    Hydrovoltaic cells. Part II: Thermogalvanic cells and numerical simulations of thermal diffusion potentials

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    When two electrolyte solutions of different temperature are placed in contact, a thermal diffusion potential (TDP) is established. The phenomenon is studied numerically using finite element simulations of the temperature distribution within a hydrodynamic cell. Experimentally, the hydrovoltaic flow cell is used to demonstrate how a temperature difference can induce redox reactions at electrodes placed in the two liquids in order to extract a current continuously in an external circuit resulting in a power-generating unit. When the concentration of the redox couple introduced in the solution is moderated, it is shown that the TDP is not negligible, even if the main driving force is due to the temperature effect on the standard potential of the couple present. The numerical model may also be applied in more general situations involving thermal effects in microsystems

    Mechanical characterization of porous Ti base alloys produced by sintering space-holder method

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    [ES] La búsqueda de materiales adecuados para su uso como implante implica una mayor investigación sobre los biomateriales, como lo son el titanio y sus aleaciones. Respecto a sus propiedades mecánicas, se debe garantizar una resistencia mecánica suficiente como para soportar cargas en uso, al igual que su rigidez ha de ser parecida a la del hueso humano. En el presente trabajo se miden diferentes propiedades mecánicas de materiales porosos de titanio y de la aleación Ti6Al4V, producidos por vía pulvimetalúrgica mediante sinterización con espaciador. Los resultados muestran la relación entre la porosidad y las propiedades mecánicas, indicando los casos en los que se presenta un compromiso entre la rigidez y la resistencia mecánica.[EN] The search of suitable materials for use as an implant involves more research of biomaterials, like titanium and its alloys. Regarding their mechanical properties, it must be guaranteed mechanical strength to support loads in use, as well as its stiffness must be similar to the bone. In this paper it have been measured several mechanical properties of porous titanium and Ti6Al4V alloy, produced by sintering powder metallurgy with space-holder method. The results show the relationship between porosity and mechanical properties and it is indicated in which cases it is presented a compromise between the stiffness and mechanical strength.Los autores agradecen al área de Ciencia de Materiales e Ingeniería Metalúrgica de la Universidad de Sevilla la ayuda prestada en el cálculo de la rigidez por ultrasonidos. Igualmente, los autores desean agradecer la financiación obtenida por el Ministerio de Ciencia e Innovación (proyecto PET2008_0158_02) y a la beca Grisolia /2009/040.Tojal Domenech, C.; Devaud, J.; Amigó, V.; Calero, JA. (2010). Caracterización mecánica de aleaciones porosas, base Ti, producidas mediante la técnica de sinterización con espaciador. Revista de Metalurgia. 46:27-32. https://doi.org/10.3989/revmetalmadrid.02.2XIIPMSS27324

    TiO2 Printed Aluminum Foil: Single-Use Film for a Laser Desorption/Ionization Target Plate

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    Single-use aluminum foil-based laser desorption/ionization (LDI) target plates have been developed for mass spectrometry (MS) analysis and provide detection results comparable to those of commercial stainless steel plates while offering a convenient way to avoid the time-consuming surface cleaning process. Additionally, arrays of TiO2 nanoparticle spots are coated on the foil either by screen-printing or rotogravure-printing followed by sintering to form a mesoporous layer spot to act as an anchor for sample deposition. These TiO2 spots offer further functions to the Al foil, such as matrix-free laser desorption/ionization or specific affinity for in situ enrichment of phosphopeptides. The single-use TiO2-Al foils are cheap to produce, easy to use, and well suited for high-throughput proteomics research. They can also be of interest for protein post-translational modifications study

    Elemental and configural olfactory coding by antennal lobe neurons of the honeybee (Apis mellifera)

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    When smelling an odorant mixture, olfactory systems can be analytical (i.e. extract information about the mixture elements) or synthetic (i.e. creating a configural percept of the mixture). Here, we studied elemental and configural mixture coding in olfactory neurons of the honeybee antennal lobe, local neurons in particular. We conducted intracellular recordings and stimulated with monomolecular odorants and their coherent or incoherent binary mixtures to reproduce a temporally dynamic environment. We found that about half of the neurons responded as ‘elemental neurons’, i.e. responses evoked by mixtures reflected the underlying feature information from one of the components. The other half responded as ‘configural neurons’, i.e. responses to mixtures were clearly different from responses to their single components. Elemental neurons divided in late responders (above 60 ms) and early responder neurons (below 60 ms), whereas responses of configural coding neurons concentrated in-between these divisions. Latencies of neurons with configural responses express a tendency to be faster for coherent stimuli which implies employment in different processing circuits

    Simple Ways to Measure Behavioral Responses of Drosophila to Stimuli and Use of These Methods to Characterize a Novel Mutant

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    The behavioral responses of adult Drosophila fruit flies to a variety of sensory stimuli – light, volatile and non-volatile chemicals, temperature, humidity, gravity, and sound - have been measured by others previously. Some of those assays are rather complex; a review of them is presented in the Discussion. Our objective here has been to find out how to measure the behavior of adult Drosophila fruit flies by methods that are inexpensive and easy to carry out. These new assays have now been used here to characterize a novel mutant that fails to be attracted or repelled by a variety of sensory stimuli even though it is motile

    A collaborative VR Murder Mystery using Photorealistic User Representations

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    The VRTogether project has developed a Social VR platform for remote communication and collaboration. The hyper-realistic representation of users, as volumetric video, allows for natural interaction in a virtual environment with others. This video shows one of the use cases, an escape room style, where remote users need to collaboratively resolve a murder mystery. The experience takes place in the victim’s apartment where the police team (avatars) together with up to four real-time captured users (point clouds), work as a team to find clues and come up with a conclusion about what happened to the victim and who was the criminal. This experience includes a layer of interaction, enabling the users to interact with the environment, by touching objects, and to talk to the characters. It also allows for navigating between the rooms of the apartment. The experience provides immersion and social connectedness, where users are protagonists of the story, sharing the virtual environment and following the narrative. The combination of virtual reality environments (space and characters) with novel technologies for real-time volumetric video conferencing enables unique new experiences in a number of areas such as healthcare, broadcasting, and gaming. The video can be watched here: https://youtu.be/Hsj1YWo55k
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