948 research outputs found
Spectroscopic temperature measurement in a applied field MPD
No full textIn this paper the temperature of the plasma inside an MPD thruster has been measured with and without applied magnetic field using spectroscopic measurement. The obtained spectra show the presence of C++, C+ and F atoms while the lines relative to C, F+ and F++ are out of scope. Using the measured line intensities, formulating three different sets of hypotheses and assuming that the corona equilibrium is valid for this plasma the temperature values have been calculated. The temperatures found are around 3 eV and show small variations with the application of magnetic field confirming
Dentin treatment effects on the bonding performance of self-adhesive resin cements
No full textThe effects of dentin surface treatments on the microtensile bond strengths and on the interfacial characteristics of self-adhesive resin cements were investigated. Flat dentin surfaces were obtained from human molars and were treated as follows: (i) no treatment of dentin; (ii) 0.1 M EDTA scrubbed for 60 s; or (iii) 10% polyacrylic acid applied for 30 s. Three self-adhesive cements were used to lute composite overlays on deep-coronal dentin surfaces in the presence of simulated pulpal pressure (15 cm of H(2)O). Bonded specimens were cut into beams 1 mm thick and stressed in tension until failure. Fractured sticks were examined under a scanning electron microscope. Additional specimens were stained with Masson's trichrome and observed under light microscopy for interfacial evaluations. The bond strength to dentin of the hydrophobic and solvent-free cement (RelyX Unicem) was unaffected by the tested dentin treatments. The bond strength of the 2-hydroxyethyl methacrylate (HEMA)-based cement (Bis-Cem) decreased after treatment of dentin with EDTA and/or polyacrylic acid. The hydrophilic and water-containing cement (G-Cem) attained a higher bond strength when luted on polyacrylic acid-conditioned dentin. In conclusion, smear layer removal, opening of dentinal tubules, and the water content of dentin differently influence the bond strengths and the interfacial characteristics of self-adhesive cement-dentin interface
Wall conditioning and density control in the reversed field pinch RFX-mod
No full textIn the reversed field pinch RFX-mod at the highest plasma current of 2 MA, when error fields are not effectively feedback controlled, localized thermal loads up to tens of MW m-2 can be produced. The graphite tiles withstand such high power loads, but the high hydrogen retention makes density control extremely difficult. Several wall conditioning techniques have been optimized in the last campaigns, including helium glow discharge cleaning and wall boronization by diborane glow discharges. More recently, lithium conditioning has been applied for the first time in a reversed field pinch by the evaporation technique. The main results are discussed in this paper. Lithization leads to important operational advantages: a significant improvement of the density control is obtained. Densities up to n/nG ≈ 0.5 can be produced in a controlled way. At the same value of input power, plasmas at higher densities can be sustained. However, due to the short particle confinement time, such densities are reached with high rates of gas puffing and the resulting profiles at high density are edge peaked. A lithium multipellet injector, to be applied in order to obtain a more uniform deposition, has been tested. © 2013 IAEA, Vienna
Ketones and pain: unexplored role of hydroxyl carboxylic acid receptor type 2 in the pathophysiology of neuropathic pain.
No full textThe mechanisms underlying neuropathic pain are poorly understood. Here we show the unexplored role of the hydroxyl carboxylic acid receptor type 2 (HCAR2) in 2 models of neuropathic pain. We used an oral treatment with dimethyl fumarate and the HCAR2 endogenous ligand -hydroxybutyrate (BHB) in wild-type (WT) and HCAR2-null mice. We found an up-regulation of the HCAR2 in the sciatic nerve and the dorsal root ganglia in neuropathic mice. Accordingly, acute and chronic treatment with dimethylfumarate (DMF) and BHB reduced the tactile allodynia. This effect was completely lost in the HCAR2-null mice after a 2-d starvation protocol, in which the BHB reached the concentration able to activate the HCAR2-reduced tactile allodynia in female WT mice, but not in the HCAR2-null mice. Finally, we showed that chronic treatment with DMF reduced the firing of the ON cells (cells responding with an excitation after noxious stimulation) of the rostral ventromedial medulla. Our results pave the way for investigating the mechanisms by which HCAR2 regulates neuropathic pain plasticity.Boccella, S., Guida, F., De Logu, F., De Gregorio, D., Mazzitelli, M., Belardo, C., Iannotta, M., Serra, N., Nassini, R., de Novellis, V., Geppetti, P., Maione, S., Luongo, L. Ketones and pain: unexplored role of hydroxyl carboxylic acid receptor type 2 in the pathophysiology of neuropathic pain
L'eterogeneità spaziale nello sviluppo locale in Italia: un'analisi basata sulla costruzione di un indicatore sintetico
No full textPioneras en geografía : mujeres en la docencia e investigación en las carreras de Geografía de Universidades Argentinas
No full textTabla de contenidos: Introducción / Malena Mazzitelli Mastricchio, Perla Zusman, Cristina Hevilla. Alicia Andrada. La importancia del trabajo de campo en la formación en geografía (1948-2019) / Cristina Hevilla. Elena Chiozza. Enseñanza, investigación-acción y edición (1919-2011) / Guillermo Gustavo Cicalese. María Luisa D'Angelo. Una vida dedicada el campo de la didáctica de la geografía / María Florencia Panigo. Nidia Ester Formiga. profesora destacada en el campo de la geografía y los estudios de población / Graciela Benedetti. María estela Furnari de Civit. Ciencia, decencia y pasión por la geografía (1935-2020) / Diego Bombal. María Celia García. Una referente de la geografía física en las Sierras Septentrionales Bonaerenses, con contribuciones en materia de calidad de vida ambiental / Jorge Lapena. Ana María Goicochea. Una lectura crítica de la ciudad y de la región en la Patagónia Norte / María Laura Silveira. Myriam Susana González. El estudio de las migraciones desde la perspectiva de género en Patagónia / Cristina Massera. Marta Isabel Kollmann. La promoción de la geografía analítica en la Universidad de Buenos Aires / Jorge Blanco. Alejandra Marek.Crear otras didácticas para la geografía / María Laura Visintini. María Margarita Papalardo. Una militante por los derechos de los y las trabajadores y trabajadoras en general y de la geografía en particular en la Universidad de La Plata / Daniela Patricia Nieto. Sela Elvira Santillán de Andrés. Los inicios de los estudios de los paisajes de Tucumán desde la geografía humana (1919-1999) / Jaqueline Salim Grau. Anexo. Algunos textos publicados por las pioneras..Fil: Mazzitelli Mastricchio, Malena. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación; Argentina.Fil: Nieto, Daniela Patricia. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación. Instituto de Investigaciones en Humanidades y Ciencias Sociales (UNLP-CONICET); Argentina
Thermal load analysis and real time hot spots recognition in TOKAMAK using cellular nonlinear networks
No full textA recent innovative technology in the field of plasma-wall interaction in nuclear fusion experiments is represented by the Liquid Lithium Limiter (LLL), a Limiter with a cooling system based on Liquid Lithium. Since its performance depends on the spatial temperature distribution, a thermal load analysis is important for long term developments. Furthermore, temperature is often not uniformly distributed leading to hot spots formation, that should be detected in real time to avoid any plasma disruptions. In this paper, an approach based on the definition of a suitable Cellular Nonlinear Network algorithm for the real-time image processing of thermal images taken during a plasma experiment is introduced. It allows both to map the LLL temperature and to detect hot spots over the limiter surface. Offline testing of the proposed procedure reveals the effectiveness of the approach paving the way to the modeling of the limiter surface temperature providing reliable information. © 2015 IEEE
A software tool for the correction of infrared images for fusion applications
No full textInfrared (IR) thermal cameras are often used to measure surfaces temperature and heat loads in environments with extreme operating conditions. IR devices had always revealed to be useful in nuclear fusion experiments, especially to monitor the thermal behavior of plasma-facing components (PFCs). The main drawback in using IR thermography relies on the fact that measurements are always affected by an error due to the different emissivity of the materials pointed by the IR camera with respect to the ideal black body. As a consequence, an image processing stage is required in order to correct raw data. Furthermore, in the specific conditions at which PFCs operate, unwanted phenomena, such as oxidation, deviates the actual emissivity values from the tabulated ones. Therefore, specific strategies to cope with these issues must be developed. In Frascati Tokamak Upgrade (FTU), two cooled liquid metal limiter devices have been investigated: a cooled liquid lithium limiter (CLL) and a liquid tin limiter (TLL). In this paper, we introduce a software tool for the automatic correction of the emissivity error exploiting a-priori knowledge on the specific metal. The output of the procedure is the definition of suitable correction maps based on the detection of the metal melting point. © 2017 IOP Publishing Ltd
Temperature model identification on FTU liquid lithium limiter
No full textIn this paper, the model identification of the temperature over the surface of the limiter adopted in the Frascati Tokamak Upgrade (FTU) is presented. Tokamaks are considered as the most interesting facilities to study self-sustained nuclear fusion reactions. Recently, a Liquid Lithium Limiter (LLL) has been introduced in the FTU with the aim of reducing impurities in the plasma. However, the performance of the LLL are maximized when temperature over its surface is uniformly distributed. In this paper, we face the problem of modeling the thermal behavior of the limiter surface following two different data-driven approaches: a linear autoregressive model, and a nonlinear autoregressive model. A comparison among the two models will be given, showing also which physical quantities are relevant to the specific modeling problem. © 2016 IEEE
Limited decalcification/diffusion of self-adhesive cements into dentin
No full textResin cement diffusion into dentin may differ as a function of the pre-treatment regimen. Since self-adhesive cements do not require substrate pre-treatment for luting, penetration of and interaction with the underlying dentin are questioned. We hypothesized that differences in the resin cement diffusion into dentin may exist among current commercial adhesive cements. Composite cylinders were luted on mid-coronal dentinal surfaces by an etch-and-rinse cement (Calibra), a self-etching system (Panavia F 2.0), and 4 self-adhesive cements (Multilink Sprint, Rely X Unicem, G-Cem, Bis-Cem). Dentin/ cement interfacial characteristics were analyzed by a staining technique (Masson's trichrome) and by scanning electron microscopy. Conventional acid etching resulted in partially infiltrated adhesive interfaces differing from those achieved with the application of self-etching primer. No hybrid layer and/or resin tag formation was detectable at the interfaces bonded with self-adhesive cements. Limited decalcification/infiltration was observed for self-adhesive cements into the underlying dentin. Self-adhesive cements were not able to demincralize/dissolve the smear layer completely
- …
