4,717 research outputs found

    Heterocyclic terpenes: linear furano- and pyrroloterpenoids

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    The emphasis of this review is on linear furano- and pyrroloterpenoids, together with their relevant biological activities, source organisms and country of origin. First total syntheses that lead to the revision of structures or stereochemistries have been included, and 206 references are cited

    El golpe de ariete en tuberías de impulsión. Comentarios a las expresiones de Mendiluce

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    [ES] El dimensionado de las tuberías de impulsión es un problema clásico dentro del campo de la Ingeniería del Agua. Debido a la complejidad de las ecuaciones que gobiernan la transmisión de las perturbaciones que se generan como consecuencia de la parada del grupo impulsor motor-bomba en el contexto del modelo elástico, conocido coloquialmente como golpe de ariete, el uso de expresiones y fórmulas simplificadas de cálculo han gozado de gran predicamento. En la Península Ibérica han destacado, de entre todas ellas, las debidas a Mendiluce. El presente artículo revisa el problema del cálculo de las sobrepresiones por parada del grupo motor-bomba en tuberías de impulsión, establece las diferencias entre los modelos de análisis de los transitorios rápidos (modelo rígido u oscilación en masa y modelo elástico o golpe de ariete), delimita los campos de validez de cada uno de ellos para esta aplicación concreta, sitúa las fórmulas de Mendiluce en su contexto real y presenta unas gráficas para un primer cálculo de impulsiones que pueden ser de gran utilidad en un buen número de aplicaciones. Finalmente se presentan una serie de ejemplos que permiten reforzar las conclusiones establecidas.Abreu, JM.; Cabrera, E.; Iglesias, PL.; Izquierdo, J. (1995). El golpe de ariete en tuberías de impulsión. Comentarios a las expresiones de Mendiluce. Ingeniería del Agua. 2(2):37-52. https://doi.org/10.4995/ia.1995.2676SWORD375222Abreu, J.M.; Cabrera, E.; Izquierdo, J.; García-Serra, J., (1995a), "Flow Modelling in pressurized systems. From water hammer to steady state. I: Fundamentals", Remitido al Journal of Hydraulics Engineering, ASCE.Abreu, J.M.; Cabrera, E.; Izquierdo, J.; García-Serra, J., (1995b), "Flow Modelling in pressurized systems. From water hammer to steady state. II: Examples", Remitido al Journal of Hydraulics Engineering, ASCE.Abreu, J.M.; Guarga, R.; Izquierdo, J. Editores, (1995c), Transitorios y oscilaciones en sistemas hidráulicos a presión. Ed. U.D. Mecánica de Fluidos. Universidad Politécnica de Valencia.Allievi, L., (1903), "Teoría genérale del moto pertúrbalo dell'aqua nei tubi in pressione". Ann. Soc. Ing. Arch. Italiana.Bergeron. L., (1950), Du coup de belier en hydraulique an coup du foudre en electricite. Ed. Dunod, Paris.Betamio de Almeida, A., (1981), O golpe de ariete en condutas elevatorias. Sintese dos conhocimentos actuáis. Memorias do L.N.E.C. n° 550, Lisboa.Betamio de Almeida, A., (1989), Transientes hidráulicos en condutos forzados. Congreso Internacional sobre casos e accidentes em sistemas fluidos, Sao Paulo.Betamio de Almeida, A., (1990), Protecçao contra o golpe de ariete. Publicación interna del Instituto Superior Técnico, Lisboa.Betamio de Almeida, A.; Koelle, E., (1992), Fluid transients in pipe networks. Ed Computational Mechanics Publications, Southampton.Cabrera, E.; Martínez, F., (1978), Cálculo del diámetro más económico en tuberías de presión. Ingeniería Química. Marzo. 1978, pp. 71-78.Cabrera, E.; García-Serra, J.; Iglesias, P.L., (1995), Flow Modelling in water distribution networks. From water hammer to steady-state. Primera lección del Curso Internacional "Improving efficiency and reliability in water distribution systems". Kluwer Academic Publishers, Dordretch.Chaudhry, H., (1987), Applied hydraulic transients. Van Nostrand Reinhold Company Inc, New York.De Martino, G., (1973), Sul calcolo del GD2 negli impianti di sollevamento. L'Energia Elettrica, n° 8, pp. 487-500.Donsky, B., (1961), Complete pump characteristics and the effect of specific speeds in hydraulic transients. Journal Basic Engineering. ASME. Diciembre, pp. 685-699.Donsky, B.; Byrne, R.; Barlett, P., (1979), Upsurge and speed-rise charts due to pump shut-down. journal of the Hydraulics Division. ASCE. Junio, pp. 661-674.Joukowsky. N.E., (1898), Mem. Imperial Academy Soc. of St. Petersburg. Vol 9, n°5.Kinno, H.; Kennedy, J.F., (1965), Water-hammer charts for centrifugal pump systems. Journal of the Hydraulic Division. ASCE. Mayo, pp. 247-270.Knapp, R.T., (1937), Complete characteristics of centrifugal pumps and their use in the prediction of transient behaviour. Transactions ASME, vol 59, Noviembre.Marchal, M.; Flesh, G.; Suter, P., (1965), The calculation of waterhammer problems by means of digital computer. Proc. International Symposium on Waterhammer in pumped storage projects. ASME, pp. 168-188.Mendiluce, E. a), (1965), Investigación teórico-práctica de los valores reales del golpe de ariete por parada brusca del grupo motor bomba en impulsiones. Dyna, 1965, n° 3, pp. 155-170 y n° 4, pp. 205-215.Mendiluce, E., (1987), El golpe de ariete en impulsiones. Librería Editorial Bellisco. Madrid.Michaud, J., (1878), Coups de bélier dans les conduites. Etude des moyens employes pour en attenuer les effects. Bulletin de la Societé Vandoise des Inginers et des Architectes. Laussane, 4c anné. nos 3 y 4, septiembre y octubre, pp. 56-64 y 65-77.Parmakian, J., (1955), Waterhammer analysis. Prentice Hall Inc. New York.Streeter, V.L.; Wylie, E.B., (1967), Hydraulic Transients. Mc Graw Hill Book Co. Inc. New York.Symposium on Waterhammer, (1933), ASME y ASCE. New York.Thorley, A.R.D., (1991), Fluid Transients in pipeline systems. D&L George LTD. Herts. England.U.D. Mecánica de Fluidos, (1993), DYAGATS. Diseño y análisis de golpe de ariete en tuberías simples. Manual del usuario. Universidad Politécnica de Valencia.Wylie, E.B.; Streeter, V.L., (1993), Fluid transients in systems. Prentice Hall. Englewood Cliffs. New Yor

    Stigma and obesity: comparative study between candidates to obesity surgery and patients already submitted to this treatment

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    Baratte François. Un trésor d'argenterie découvert en Asie centrale. In: Bulletin de la Société Nationale des Antiquaires de France, 2001, 2006. pp. 176-177

    Influence of the microstructure on the creep behaviour of Tin-Silver-Copper solder

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    A common failure mode of electronic printed circuit boards (PCB’s) is the appearance of cold solder joints between the component and PCB, during product life. This phenomenon is related to solder joint fatigue and is attributed mainly to the mismatch of the coefficients of thermal expansion (CTE) of component-solder-PCB assembly. With today’s solder joint thickness decreasing and increasing working temperatures, among others, the stresses and strains due to temperature changes are growing, leading to limited fatigue life of the products. As fatigue life decreases with increasing plastic strain, creep occurrence should have significant impact, especially during thermal cycles and, thus, should be studied. Through the cooling phase, on the production of PCB assembly’s by the reflow technology, the hoven atmosphere temperature is adjusted in order to control the cooling rate. Narrow criteria is used so as to control the inter-metallic compounds (IMC) thickness, PCB assembly distortion and defects due to thermal shock. The cooling rate also affects solder microstructure, which has direct impact on creep behaviour and, thus, on the soldered joint reliability. In this paper, a dynamic mechanical analyser (DMA) is used to study the influence of the solder cooling rate on its creep behaviour. SAC405 samples with two distinct cooling rates were produced: inside a hoven cooling and by water quenching. Creep tests were made on three-point-bending clamp configuration, isothermally at 25 °C, 50 °C and 75 °C and under three separate levels of stress, 3, 5 and 9 MPa. The results show that creep behaviour has a noticeable cooling rate dependence. It was also noticed that creep propensity is exacerbated by the temperature at which stresses are applied, especially for the slower cooling rates. Creep mechanisms were related to the solder microstructural constituents, namely by the amount of phases ant their morphology.The authors would like to express his acknowledgments for the support given by the Portugal Incentive System for Research and Technological Development. Project in co-promotion This research is sponsored by the Portugal Incentive System for Research and Technological Development. This work is supported by: European Structural and Investment Funds in the FEDER component, through the Operational Competitiveness and Internationalization Programme (COMPETE 2020) [Project nº 002814; Funding Reference: POCI-01-0247-FEDER-002814]. This work was financed by FCT, under the Strategic Project UID/SEM/04077/2013; PEst2015-2020 with the reference UID/CEC/00319/2013 and UID/FIS/04650/2013

    Analysis of Long-Lived Slepton NLSP in GMSB model at Linear Collider

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    We performed an analysis on the detection of a long-lived slepton at a linear collider with s=500\sqrt{s}=500 GeV. In GMSB models a long-lived NLSP is predicted for large value of the supersymmetry breaking scale F\sqrt{F}. Furthermore in a large portion of the parameter space this particle is a stau. Such heavy charged particles will leave a track in the tracking volume and hit the muonic detector. In order to disentangle this signal from the muon background, we explore kinematics and particle identification tools: time of flight device, dE/dX and Cerenkov devices. We show that a linear collider will be able to detect long-lived staus with masses up to the kinematical limit of the machine. We also present our estimation of the sensitivity to the stau lifetime.Comment: Minor changes, Ref. 10 fixed. 12 pages, RevTex, 4 eps figure

    AlergiaPT: A Portuguese media campaign to inspire people with allergies to make a positive change in their life

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    Allergic diseases comprise a significant cause of morbidity worldwide and a substantial burden on the health and medical systems of both developed and emerging economies. Although highly prevalent, relatively severe, and largely impactful on the quality of life of patients, allergic diseases are commonly trivialized. Increasing awareness of the relevance of allergic diseases as a major public health problem might lead to an improved acknowledgment by governments and health authorities. Based on the positive impact that media campaigns might have on health-related behaviors, as well as the large use of social media by different types of users, social media might be used as a powerful tool for spreading awareness and education even more effective than traditional face-to-face communication. Therefore, we aimed to develop a social media-based communication program, the AlergiaPT, reaching all stakeholders, to increase the awareness of allergic diseases tackling the causes, prevention, control, and economic impact. The AlergiaPT will provide user-generated and interactive content toward engagement, include both long-form and short-form video productions toward education, as well as stories and time-sensitive content toward empowerment. It will be targeted to all populations, engaging different stakeholders. Contents will address the 5 campaign goals: i) allergy health is promoted; ii) tolerance is actively reinforced, and avoidance reduced; iii) treatment control and guided self-management of patients of asthma, rhinitis, food allergy, and atopic eczema are strengthened; iv) recognition and treatment of severe allergy and anaphylaxis are improved, and v) indoor air quality is promoted. Engagement on the campaign will be promoted through stepwise educational takeaways meetings using different social media, and targeting all audience groups, by promoting the organization of resources for common goals and the involvement of social media to improve public awareness. The impact of AlergiaPT will be assessed through google analytics

    ANDES, the high resolution spectrograph for the ELT: science case, baseline design and path to construction

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    Ground-based and airborne instrumentation for astronomy IX (2022), Montreal, JUL 17-22, 2022.--Proceedings of SPIE - The International Society for Optical Engineering vol. 12184 Article number 1218424.-- Complete list of authors: Marconi, A.; Abreu, M.; Adibekyan, V.; Alberti, V.; Albrecht, S.; Alcaniz, J.; Aliverti, M.; Allende Prieto, C.; Gomez, J. D. Alvarado; Amado, P. J.; Amate, M.; Andersen, M. I.; Artigau, E.; Baker, C.; Baldini, V.; Balestra, A.; Barnes, S. A.; Baron, F.; Barros, S. C. C.; Bauer, S. M.; Beaulieu, M.; Bellido-Tirado, O.; Benneke, B.; Bensby, T.; Bergin, E. A.; Biazzo, K.; Bik, A.; Birkby, J. L.; Blind, N.; Boisse, I.; Bolmont, E.; Bonaglia, M.; Bonfils, X.; Borsa, F.; Brandeker, A.; Brandner, W.; Broeg, C. H.; Brogi, M.; Brousseau, D.; Brucalassi, A.; Brynnel, J.; Buchhave, L. A.; Buscher, D. F.; Cabral, A.; Calderone, G.; Calvo-Ortega, R.; Cantalloube, F.; Canto Martins, B. L.; Carbonaro, L.; Chauvin, G.; Chazelas, B.; Cheffot, A. -L.; Cheng, Y. S.; Chiavassa, A.; Christensen, L.; Cirami, R.; Cook, N. J.; Cooke, R. J.; Coretti, I.; Covino, S.; Cowan, N.; Cresci, G.; Cristiani, S.; Cunha Parro, V.; Cupani, G.; D'Odorico, V.; de Castro Leao, I.; De Cia, A.; De Medeiros, J. R.; Debras, F.; Debus, M.; Demangeon, O.; Dessauges-Zavadsky, M.; Di Marcantonio, P.; Dionies, F.; Doyon, R.; Dunn, J.; Ehrenreich, D.; Faria, J. P.; Feruglio, C.; Fisher, M.; Fontana, A.; Fumagalli, M.; Fusco, T.; Fynbo, J.; Gabella, O.; Gaessler, W.; Gallo, E.; Gao, X.; Genolet, L.; Genoni, M.; Giacobbe, P.; Giro, E.; Goncalves, R. S.; Gonzalez, O. A.; Gonzalez Hernandez, J. I.; Gracia Temich, F.; Haehnelt, M. G.; Haniff, C.; Hatzes, A.; Helled, R.; Hoeijmakers, H. J.; Huke, P.; Jaervinen, A. S.; Jaervinen, S. P.; Kaminski, A.; Korn, A. J.; Kouach, D.; Kowzan, G.; Kreidberg, L.; Landoni, M.; Lanotte, A.; Lavail, A.; Li, J.; Liske, J.; Lovis, C.; Lucatello, S.; Lunney, D.; MacIntosh, M. J.; Madhusudhan, N.; Magrini, L.; Maiolino, R.; Malo, L.; Man, A. W. S.; Marquart, T.; Marques, E. L.; Martins, C. J. A. P.; Martins, A. M.; Maslowski, P.; Mason, E.; Mason, C. A.; McCracken, R. A.; Mergo, P.; Micela, G.; Mitchell, T.; Molliere, P.; Monteiro, M. A.; Montgomery, D.; Mordasini, C.; Morin, J.; Mucciarelli, A.; Murphy, M. T.; N'Diaye, M.; Neichel, B.; Niedzielski, A. T.; Niemczura, E.; Nortmann, L.; Noterdaeme, P.; Nunes, N. J.; Oggioni, L.; Oliva, E.; Onel, H.; Origlia, L.; Ostlin, G.; Palle, E.; Papaderos, P.; Pariani, G.; Penate Castro, J.; Pepe, F.; Levasseur, L. Perreault; Petit, P.; Pino, L.; Piqueras, J.; Pollo, A.; Poppenhaeger, K.; Quirrenbach, A.; Rauscher, E.; Rebolo, R.; Redaelli, E. M. A.; Reffert, S.; Reid, D. T.; Reiners, A.; Richter, P.; Riva, M.; Rivoire, S.; Rodriguez-Lopez, C.; Roederer, I. U.; Romano, D.; Rousseau, S.; Rowe, J.; Salvadori, S.; Sanna, N.; Santos, N. C.; Diaz, P. Santos; Sanz-Forcada, J.; Sarajlic, M.; Sauvage, J. -F.; Schaefer, S.; Schiavon, R. P.; Schmidt, T. M.; Selmi, C.; Sivanandam, S.; Sordet, M.; Sordo, R.; Sortino, F.; Sosnowska, D.; Sousa, S. G.; Stempels, E.; Strassmeier, K. G.; Suarez Mascareno, A.; Sulich, A.; Sun, X.; Tanvir, N. R.; Tenegi-Sangines, F.; Thibault, S.; Thompson, S. J.; Tozzi, A.; Turbet, M.; Vallee, P.; Varas, R.; Venn, K. A.; Veran, J. -P.; Verma, A.; Viel, M.; Wade, G.; Waring, C.; Weber, M.; Weder, J.; Wehbe, B.; Weingrill, J.; Woche, M.; Xompero, M.; Zackrisson, E.; Zanutta, A.; Zapatero Osorio, M. R.; Zechmeister, M.; Zimara, J.The first generation of ELT instruments includes an optical-infrared high resolution spectrograph, indicated as ELT-HIRES and recently christened ANDES (ArmazoNes high Dispersion Echelle Spectrograph). ANDES consists of three fibre-fed spectrographs (UBV, RIZ, YJH) providing a spectral resolution of similar to 100,000 with a minimum simultaneous wavelength coverage of 0.4-1.8 mu m with the goal of extending it to 0.35-2.4 mu m with the addition of a K band spectrograph. It operates both in seeing- and diffraction-limited conditions and the fibre-feeding allows several, interchangeable observing modes including a single conjugated adaptive optics module and a small diffraction-limited integral field unit in the NIR. Its modularity will ensure that ANDES can be placed entirely on the ELT Nasmyth platform, if enough mass and volume is available, or partly in the Coude room. ANDES has a wide range of groundbreaking science cases spanning nearly all areas of research in astrophysics and even fundamental physics. Among the top science cases there are the detection of biosignatures from exoplanet atmospheres, finding the fingerprints of the first generation of stars, tests on the stability of Nature's fundamental couplings, and the direct detection of the cosmic acceleration. The ANDES project is carried forward by a large international consortium, composed of 35 Institutes from 13 countries, forming a team of more than 200 scientists and engineers which represent the majority of the scientific and technical expertise in the field among ESO member states.The Italian effort for ANDES is supported by the Italian National Institute for Astrophysics (INAF). The Portuguese participation is supported by FCT -Fundacao para a Ciencia e a Tecnologia through national funds and by FEDER through COMPETE2020 -Programa Operacional Competitividade e Internacionalizacao by these grants: UID/FIS/04434/2019, UIDB/04434/2020 & UIDP/04434/2020; POCI-01-0145-FEDER-032113 & PTDC/FIS-AST/32113/2017. Swedish participation in the ANDES project is made possible through the national Swedish ELT Instrumentation Consortium (SELTIC), suppored by the Swedish Research Council (VR). CJM acknowledges FCT and POCH/FSE (EC) support through Investigador FCT Contract 2021.01214.CEECIND/CP1658/CT0001. JLB acknowledges funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation program under grant agreement No 805445. MTM acknowledges the support of the Australian Research Council through Future Fellowship grant FT180100194 SS acknowledges funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation program under grant agreement No 804240. TMS acknowledgment the support from the SNF synergia grant CRSII5-193689 (BLUVES)With funding from the Spanish government through the Severo Ochoa Centre of Excellence accreditation SEV-2017-0709Peer reviewe
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