155 research outputs found
Research in the general area of non-linear dynamical systems Final report, 8 Jun. 1965 - 8 Jun. 1967
Nonlinear dynamical systems research on systems stability, invariance principles, Liapunov functions, and Volterra and functional integral equation
Theoretical and Experimental Studies of Schottky Diodes That Use Aligned Arrays of Single Walled Carbon Nanotubes
We present theoretical and experimental studies of Schottky diodes that use
aligned arrays of single walled carbon nanotubes. A simple physical model,
taking into account the basic physics of current rectification, can adequately
describe the single-tube and array devices. We show that for as grown array
diodes, the rectification ratio, defined by the
maximum-to-minimum-current-ratio, is low due to the presence of m-SWNT shunts.
These tubes can be eliminated in a single voltage sweep resulting in a high
rectification array device. Further analysis also shows that the channel
resistance, and not the intrinsic nanotube diode properties, limits the
rectification in devices with channel length up to ten micrometer.Comment: Nano Research, 2010, accepte
Ghrelin Indirectly Activates Hypophysiotropic CRF Neurons in Rodents
Ghrelin is a stomach-derived hormone that regulates food intake and neuroendocrine function by acting on its receptor, GHSR (Growth Hormone Secretagogue Receptor). Recent evidence indicates that a key function of ghrelin is to signal stress to the brain. It has been suggested that one of the potential stress-related ghrelin targets is the CRF (Corticotropin-Releasing Factor)-producing neurons of the hypothalamic paraventricular nucleus, which secrete the CRF neuropeptide into the median eminence and activate the hypothalamic-pituitary-adrenal axis. However, the neural circuits that mediate the ghrelin-induced activation of this neuroendocrine axis are mostly uncharacterized. In the current study, we characterized in vivo the mechanism by which ghrelin activates the hypophysiotropic CRF neurons in mice. We found that peripheral or intra-cerebro-ventricular administration of ghrelin strongly activates c-fos â a marker of cellular activation â in CRF-producing neurons. Also, ghrelin activates CRF gene expression in the paraventricular nucleus of the hypothalamus and the hypothalamic-pituitary-adrenal axis at peripheral level. Ghrelin administration directly into the paraventricular nucleus of the hypothalamus also induces c-fos within the CRF-producing neurons and the hypothalamic-pituitary-adrenal axis, without any significant effect on the food intake. Interestingly, dual-label immunohistochemical analysis and ghrelin binding studies failed to show GHSR expression in CRF neurons. Thus, we conclude that ghrelin activates hypophysiotropic CRF neurons, albeit indirectly
Hybrid method for selection of the optimal process of leachate treatment in waste treatment and valorization plants or landfills
âThe final publication is available at Springer via http://dx.doi.org/10.1007/s10098-014-0834-4âLeachate from waste landfill or treatment plants is a very complex and highly contaminated liquid effluent. In its composition, it is found dissolved organic matter, inorganic salts, heavy metals, and other xenobiotic organic compounds, so it can be toxic, carcinogenic, and capable of inducing a potential risk to biota and humans. European law does not allow such leachate to leave the premises without being depolluted. There are many procedures that enable debugging, always combining different techniques. Choosing the best method to use in each case is a complex decision, as it depends on many tangible and intangible factors that must be weighed to achieve a balance between technical, cost, and environmental sustainability. It is presenting a hybrid method for choosing the optimal combination of techniques to apply in each case, by combining a multicriteria hierarchical analysis based on expert data obtained by the Delphi method with an analysis by the method of VIKOR to reach a consensus solution.MartĂn Utrillas, MG.; Reyes Medina, M.; Curiel Esparza, J.; CantĂł PerellĂł, J. (2015). Hybrid method for selection of the optimal process of leachate treatment in waste treatment and valorization plants or landfills. Clean Technologies and Environmental Policy. 17(4):873-885. doi:10.1007/s10098-014-0834-4S873885174Abbas AA, Guo J, Ping LZ, Ya PY, Al-Rekabi WS (2009) Review on landfill leachate treatments. AJAS 6(4):672â684Abood AR, Bao J, Abudi Z, Zheng D, Gao C (2013) Pretreatment of nonbiodegradable landfill leachate by air stripping coupled with agitation as ammonia stripping and coagulationâflocculation processes. Clean Technol Environ Policy 15(6):1069â1076Ahn WY, Kang MS, Yim SK, Choi KH (2002) Advanced landfill leachate treatment using an integrated membrane process. Desalination 149(1â3):109â114Al-Subhi Al-Harbi KM (2001) Application of the AHP in project management. Int J Proj Manag 19:19â27Bernasconi M, Choirat C, Seri R (2014) Empirical properties of group preference aggregation methods employed in AHP: theory and evidence. Eur J Oper Res 232(3):584â592Boopathy R, Karthikeyan S, Mandal AB, Sekaran G (2013) Characterization and recovery of sodium chloride from salt-laden solid waste generated from leather industry. Clean Technol Environ Policy 15(1):117â124Brechet T, Tulkens H (2009) Beyond BAT: selecting optimal combinations of available techniques, with an example from the limestone industry. J Environ Manag 90:1790â1801Canto-Perello J, Curiel-Esparza J, Calvo V (2013) Criticality and threat analysis on utility tunnels for planning security policies of utilities in urban underground space. Expert Syst Appl 40(11):4707â4714Chen Y, Liu C, Nie J, Wu S, Wang D (2014) Removal of COD and decolorizing from landfill leachate by Fentonâs reagent advanced oxidation. Clean Technol Environ Policy 16(1):189â193Chiochetta CG, Goetten LC, Almeida SM, Quaranta G, Cotelle S, Radetski CM (2014) Leachates from solid wastes: chemical and eco(geno)toxicological differences between leachates obtained from fresh and stabilized industrial organic sludge. Environ Sci Pollut R 21:1090â1098Chiumenti A, da Borso F, Chiumenti R, Teri F, Segantin P (2013) Treatment of digestate from a co-digestion biogas plant by means of vacuum evaporation: tests for process optimization and environmental sustainability. Waste Manag 33(6):1339â1344Council Directive 1999/31/EC (1999) April 26th 1999, on the landfill of waste. European Union Council, Official Journal L 182, 16/07/1999 P. 0001â0019Curiel-Esparza J, Canto-Perello J (2012) Understanding the major drivers for implementation of municipal sustainable policies in underground space. Int J Sust Dev World 19(6):506â514Curiel-Esparza J, Canto-Perello J (2013) Selecting utilities placement techniques in urban underground engineering. Arch Civ Mech Eng 13(2):276â285Curiel-Esparza J, Canto-Perello J, Calvo MA (2004) Establishing sustainable strategies in urban underground engineering. Sci Eng Ethics 10(3):523â530Dong Y, Zhang G, Hong WC, Xu Y (2010) Consensus models for AHP group decision making under row geometric mean prioritization method. Decis Support Syst 49:281â289Duckstein L, Opricovic S (1980) Multiobjective Optimization in River Basin Development. Water Resour Res 16(1):14â20Ersahin ME, Ozgun H, van Lier JB (2013) Effect of support material properties on dynamic membrane filtration performance. Separ Sci Technol 48(15):2263â2269Gracht HA (2012) Consensus measurement in Delphi studies, review and implications for future quality assurance. Forecast Soc Chang 79(8):1525â1536Grisey E, Laffray X, Contoz O, Cavalli E, Mudry J, Aleya L (2012) The bioaccumulation performance of reeds and cattails in a constructed treatment wetland for removal of heavy metals in landfill leachate treatment (Etueffont, France). Water Air Soil Pollut 223:1723â1741Guoliang Z, Lei Q, Qin M, Zheng F, Dexin W (2013) Aerobic SMBR/reverse osmosis system enhanced by Fenton oxidation for advanced treatment of old municipal landfill leachate. Bioresour Technol 142:261â268Gupta SK, Singh G (2007) Assessment of the Efficiency and Economic Viability of Various Methods of Treatment of Sanitary Landfill Leachate. Environ Monit Assess 135:107â117Heyer KU, Stegmann R (2005) Landfill systems, sanitary landfilling of solid wastes, and long-term problems with leachate. In: Jördening HJ, Winter J (eds) Environmental Biotechnology. Wiley-VCH, Weinheim, p 375Hsu CC, Sandord BA (2007) The Delphi technique: making sense of consensus. PARE 12(10):1â7Kjeldsen P, Barlaz MA, Rooker AP, Baun A, Ledin A, Christensen TH (2002) Present and long-term composition of MSW landfill leachate: a review. Crit Rev Environ Sci Technol 32(4):297â336Lee WS (2013) Merger and acquisition evaluation and decision making model. Serv Ind J 33(15â16):1473â1494Lee GKL, Chan EHW (2008) The analytic hierarchy process (AHP) approach for assessment of urban renewal proposals. Soc Indic Res 89(1):155â168Li G, Wang W, Du Q (2010) Applicability of nanofiltration for the advanced treatment of landfill leachate. J Appl Polym Sci 116(4):2343â2347Mela K, Tiainen T, Heinisuo M (2012) Comparative study of multiple criteria decision making methods for building design. Adv Eng Inform 26:716â726Ozdemir MS, Saaty TL (2006) The unknown in decision making, what to do about it. Eur J Oper Res 174(1):349â359Renou S, Givaudan JG, Poulain S, Dirassouyan F, Moulin P (2008) Landfill leachate treatment: review and opportunity. J Hazard Mater 150(3):468â493Ritzkowski M, Stegmann R (2012) Landfill aeration worldwide: concepts, indications and findings. Waste Manag 32(7):1411â1419Romero C, Ramos P, Costa C, Marquez MC (2013) Raw and digested municipal waste compost leachate as potential fertilizer: comparison with a commercial fertilizer. J Clean Prod 59:73â78Roubelat F (2011) The Delphi method as a ritual: inquiring the Delphi Oracle. Forecast Soc Chang 78(9):1491â1499Saaty TL (1980) The analytic hierarchy process. Mc Graw-Hill, New YorkSaaty TL (2001) Decision making with dependence and feedback: the analytic network process, 2nd edn. RWS Publications, PittsburghSaaty TL (2008) Decision making with the analytic hierarchy process. Int J Serv Sci 1(1):83â98Saaty TL (2012) Decision making for leaders. The analytic hierarchy process for decisions in a complex world, 3rd edn. RWS Publications, PittsburghSan Cristobal J (2012) Contractor selection using multicriteria decision-making methods. J Constr Eng M 138(6):751â758Sayadi MK, Heydari M, Shahanaghi K (2009) Extension of VIKOR method for decision making problem with interval numbers. Appl Math Model 33:2257â2262Statnikova RB, Bordetskya A, Statnikov A (2005) Multi-criteria analysis of real-life engineering optimization problems: statement and solution. Nonlinear Anal 63:685â696Syamsuddin J (2010) The use of AHP in security policy decision making: an open office calc application. JSW 5(10):1162â1169Thapa RB, Murayama Y (2010) Drivers of urban growth in the Kathmandu valley, Nepal: examining the efficacy of the analytic hierarchy process. App Geogr 30(1):70â83van Praagh M, Heerenklage J, Smidt E, Modin H, Stegmann R, Persson KM (2009) Potential emissions from two mechanicallyâbiologically pretreated (MBT) wastes. Waste Manag 29(2):859â868Vedaraman N, Shamshath BS, Srinivasan SV (2013) Response surface methodology for decolourisation of leather dye using ozonation in a packed bed reactor. Clean Technol Environ Policy 15(4):607â616Wang Q, Matsufuji Y, Dong L, Huang Q, Hirano F, Tanaka A (2006) Research on leachate recirculation from different types of landfills. Waste Manag 26:815â824Xing W, Lu W, Zhao Y (2013) Environmental impact assessment of leachate recirculation in landfill of municipal solid waste by comparing with evaporation and discharge (EASEWASTE). Waste Manag 33(2):382â389Yang W, Zhang KN, Chen YG, Zhou XZ, Jin FX (2013) Prediction on contaminant migration in aquifer of fractured granite substrata of landfill. J Cent South Univ 20(11):3193â3201Zavadskas EK, Turskis Z, Tamosaitiene J (2011) Selection of construction enterprises management strategy based on SWOT and multi-criteria analysis. ACME 11(4):1063â108
The 2017 May 20 stellar occultation by the elongated centaur (95626) 2002 GZ
We predicted a stellar occultation of the bright star Gaia DR1
4332852996360346368 (UCAC4 385-75921) (m= 14.0 mag) by the centaur
2002 GZ for 2017 May 20. Our latest shadow path prediction
was favourable to a large region in Europe. Observations were arranged in a
broad region inside the nominal shadow path. Series of images were obtained
with 29 telescopes throughout Europe and from six of them (five in Spain and
one in Greece) we detected the occultation. This is the fourth centaur, besides
Chariklo, Chiron and Bienor, for which a multi-chord stellar occultation is
reported. By means of an elliptical fit to the occultation chords we obtained
the limb of 2002 GZ during the occultation, resulting in an ellipse with
axes of 305 17 km 146 8 km. From this limb, thanks to a
rotational light curve obtained shortly after the occultation, we derived the
geometric albedo of 2002 GZ ( = 0.043 0.007) and a 3-D
ellipsoidal shape with axes 366 km 306 km 120 km. This shape
is not fully consistent with a homogeneous body in hydrostatic equilibrium for
the known rotation period of 2002 GZ. The size (albedo) obtained from
the occultation is respectively smaller (greater) than that derived from the
radiometric technique but compatible within error bars. No rings or debris
around 2002 GZ were detected from the occultation, but narrow and thin
rings cannot be discarded.Comment: Accepted for publication in MNRAS (8-Dec.-2020), 15 pages, 9 figure
Low spin spectroscopy of neutron-rich 43,44,45Cl via {\beta} and (\beta}n decay
{\beta} decay of neutron-rich isotopes 43,45 S,studied at the National
Superconducting Cyclotron Laboratory is reported here. {\beta} delayed {\gamma}
transitions were detected by an array of 16 clover detectors surrounding the
Beta Counting Station which consists of a 40x40 Double Sided Silicon Strip
Detector followed by a Single Sided Silicon Strip Detector. {\beta} decay
half-lives have been extracted for 43,45 S by correlating implants and decays
in the pixelated implant detector with further coincidence with {\gamma}
transitions in the daughter nucleus. The level structure of 43,45 Cl is
expanded by the addition of 20 new {\gamma} transitions in 43Cl and 8 in 45 Cl
with the observation of core excited negative-parity states for the first time.
For 45 S decay, a large fraction of the {\beta} decay strength goes to delayed
neutron emission populating states in 44 Cl which are also presented.
Comparison of experimental observations is made to detailed shell-model
calculations using the SDPFSDG-MU interaction to highlight the role of the
diminished N = 28 neutron shell gap and the near degeneracy of the proton s 1/2
and d 3/2 orbitals on the structure of the neutron-rich Cl isotopes. The
current work also provides further support to a ground state spin-parity
assignment of 3/2 + in 45 Cl
Constraints on the structure and seasonal variations of Triton's atmosphere from the 5 October 2017 stellar occultation and previous observations
CONTEXT: A stellar occultation by Neptuneâs main satellite, Triton, was observed on 5 October 2017 from Europe, North Africa, and the USA. We derived 90 light curves from this event, 42 of which yielded a central flash detection. AIMS: We aimed at constraining Tritonâs atmospheric structure and the seasonal variations of its atmospheric pressure since the Voyager 2 epoch (1989). We also derived the shape of the lower atmosphere from central flash analysis. METHODS: We used Abel inversions and direct ray-tracing code to provide the density, pressure, and temperature profiles in the altitude range ~8 km to ~190 km, corresponding to pressure levels from 9 ”bar down to a few nanobars. RESULTS: A pressure of 1.18 ± 0.03 ”bar is found at a reference radius of 1400 km (47 km altitude). (ii) A new analysis of the Voyager 2 radio science occultation shows that this is consistent with an extrapolation of pressure down to the surface pressure obtained in 1989. (iii) A survey of occultations obtained between 1989 and 2017 suggests that an enhancement in surface pressure as reported during the 1990s might be real, but debatable, due to very few high S/N light curves and data accessible for reanalysis. The volatile transport model analysed supports a moderate increase in surface pressure, with a maximum value around 2005-2015 no higher than 23 ”bar. The pressures observed in 1995-1997 and 2017 appear mutually inconsistent with the volatile transport model presented here. (iv) The central flash structure does not show evidence of an atmospheric distortion. We find an upper limit of 0.0011 for the apparent oblateness of the atmosphere near the 8 km altitude
Top-quark physics at the CLIC electron-positron linear collider
ABSTRACT: The Compact Linear Collider (CLIC) is a proposed future high-luminosity linear electron-positron collider operating at three energy stages, with nominal centre-of-mass energies âs = 380 GeV, 1.5 TeV, and 3 TeV. Its aim is to explore the energy frontier, providing sensitivity to physics beyond the Standard Model (BSM) and precision measurements of Standard Model processes with an emphasis on Higgs boson and top-quark physics. The opportunities for top-quark physics at CLIC are discussed in this paper. The initial stage of operation focuses on top-quark pair production measurements, as well as the search for rare flavour-changing neutral current (FCNC) top-quark decays. It also includes a top-quark pair production threshold scan around 350 GeV which provides a precise measurement of the top-quark mass in a well-defined theoretical framework. At the higher-energy stages, studies are made of top-quark pairs produced in association with other particles. A study of tÌtH production including the extraction of the top Yukawa coupling is presented as well as a study of vector boson fusion (VBF) production, which gives direct access to high-energy electroweak interactions. Operation above 1 TeV leads to more highly collimated jet environments where dedicated methods are used to analyse the jet constituents. These techniques enable studies of the top-quark pair production, and hence the sensitivity to BSM physics, to be extended to higher energies. This paper also includes phenomenological interpretations that may be performed using the results from the extensive top-quark physics programme at CLIC.the Spanish Ministry of Economy, Industry and Competitiveness under projects MINEICO/FEDER-UE, FPA2015-65652-C4-3-R, FPA2015-71292-C2-1-Pand FPA2015-71956-REDT; and the MECD grant FPA2016-78645-P, Spai
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