Evolution of instabilities in filament buckling processes

In this work we study the dynamical buckling process of a thin filament immersed in a highly viscous medium. We perform an experimental study to track the shape evolution of the filament during a constant velocity compression. Numerical simulations reproduce the dynamical features observed from the experimental data and allow quantifying the filament's load. We observe that both the filament's load and the wave number evolve in a stepwise manner. In order to achieve a physical insight of the process, we apply a theoretical model to describe the buckling of a filament in a viscous medium. We solve a hydrodynamic equation in terms of normal modes for clamped-clamped boundary conditions and constant applied load. We find a good agreement between experimental data and simulations, suggesting that the proposed mechanistic model captures the essential features underlying the dynamical buckling process.Fil: Monastra, Alejandro Gabriel. Universidad Nacional de General Sarmiento. Instituto de Ciencias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Carusela, María Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de General Sarmiento. Instituto de Ciencias; ArgentinaFil: Van Der Velde, Guido Gustavo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; ArgentinaFil: D'angelo, María Verónica. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ingeniería; ArgentinaFil: Bruno, Luciana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; Argentin

Experimental study of the buckling of a semi-flexible filament in a complex medium

En este trabajo se estudia la deformación por compresión de un filamento delgado inmerso en un fluido.Se estudia la forma del filamento variando la magnitud de la compresión aplicada y las propiedades reológicas del medio: puramente viscoso, puramente elástico y con comportamiento viscoelástico.Se observan transiciones entre regímenes de diferente estabilidad.In this work we study the deformation of a thin filament immersed in different fluids when subjected to a compressive force. The filament shape is analyzed for different magnitudes of the applied compression and for different rheological properties of the medium: purely viscous, purely elastic and displaying viscoelastic behavior. Transitions between different regimes are observed.Fil: Van Der Velde, Guido Gustavo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Física; ArgentinaFil: Gómez, C.. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Física; ArgentinaFil: Freytes, Verónica Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ingeniería. Departamento de Física. Grupo de Medios Porosos; ArgentinaFil: Bruno, L.. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Física; ArgentinaFil: D'angelo, María Verónica. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ingeniería. Departamento de Física. Grupo de Medios Porosos; Argentin

Behavior of silts mixed with sludge rich in diatoms and organic matter content

La alta generación de lodos, tanto de plantas potabilizadoras como depuradoras, es una problemática ambiental de gran interés en la actualidad. En la actualidad existe una tendencia de aprovechar estos lodos, bajo ciertas normativas que regulan su uso. Este trabajo presenta las principales propiedades físicas, químicas y mineralógicas de los lodos generados en la planta potabilizadora de agua ?Suquía? de la Ciudad de Córdoba, Argentina. Estos lodos, con un muy alto contenido de agua, en la actualidad se disponen con los residuos sólidos urbanos de la ciudad. El propósito de este trabajo es discutir las posibles alternativas de tratamiento de los lodos con el objeto de densificar los mismos y analizar su potencial uso como material inerte en mezclas de suelo-lodo. Las características estudiadas incluyen propiedades físicas, medición de granulometría, superficie específica, microscopía de barrido electrónico, análisis químicos y contenido de materia orgánica. En particular, se evalúa cómo la presencia de lodo afecta el comportamiento de limos recompactados con el objeto de poder construir terraplenes con este material. Los resultados obtenidos muestran que los lodos generados en la planta de tratamiento de agua pueden ser mezclados de manera segura con los suelos locales y utilizados en varias aplicaciones geotécnicas.he significant amount of sludge, even from water treatment or waste water treatment plants, is a important environmental issue. There is a tendency to reuse this material nowadays, under different regulations that restrict their usage. This work presents relevant physical, chemical and mechanical properties of the sludge from the “Suquía” water treatment plant in Cordoba city, Argentine. The sludge has a significant amount of water and, even that, is currently being disposed with municipal solid wastes. The purpose of this research is to present different alternative uses for the sludge and to analyze its use as inert material in soil-sludge mixtures. Characterization consists of measurements of physical properties, particle size, specific surface, scanning electronic microscope, chemical analysis and organic matter. Mixtures of silt with different amounts of the sludge material were tested to evaluate their potential use as a construction material for slides and embankments. Obtained results show that the sediments generated in the water treatment plant can be safely mixed with local soils and used for different geotechnical applications.Fil: Francisca, Franco Matias. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Bertolino, Silvana Raquel Alina. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; ArgentinaFil: Camara, Osvaldo Raul. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; ArgentinaFil: Van Der Velde, Guido Gustavo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Combined searches for the production of supersymmetric top quark partners in proton-proton collisions at root s=13 TeV

A combination of searches for top squark pair production using proton-proton collision data at a center-of-mass energy of 13 TeV at the CERN LHC, corresponding to an integrated luminosity of 137 fb(-1) collected by the CMS experiment, is presented. Signatures with at least 2 jets and large missing transverse momentum are categorized into events with 0, 1, or 2 leptons. New results for regions of parameter space where the kinematical properties of top squark pair production and top quark pair production are very similar are presented. Depending on themodel, the combined result excludes a top squarkmass up to 1325 GeV for amassless neutralino, and a neutralinomass up to 700 GeV for a top squarkmass of 1150 GeV. Top squarks with masses from 145 to 295 GeV, for neutralino masses from 0 to 100 GeV, with a mass difference between the top squark and the neutralino in a window of 30 GeV around the mass of the top quark, are excluded for the first time with CMS data. The results of theses searches are also interpreted in an alternative signal model of dark matter production via a spin-0 mediator in association with a top quark pair. Upper limits are set on the cross section for mediator particle masses of up to 420 GeV

Search for new particles in events with energetic jets and large missing transverse momentum in proton-proton collisions at root s=13 TeV

A search is presented for new particles produced at the LHC in proton-proton collisions at root s = 13 TeV, using events with energetic jets and large missing transverse momentum. The analysis is based on a data sample corresponding to an integrated luminosity of 101 fb(-1), collected in 2017-2018 with the CMS detector. Machine learning techniques are used to define separate categories for events with narrow jets from initial-state radiation and events with large-radius jets consistent with a hadronic decay of a W or Z boson. A statistical combination is made with an earlier search based on a data sample of 36 fb(-1), collected in 2016. No significant excess of events is observed with respect to the standard model background expectation determined from control samples in data. The results are interpreted in terms of limits on the branching fraction of an invisible decay of the Higgs boson, as well as constraints on simplified models of dark matter, on first-generation scalar leptoquarks decaying to quarks and neutrinos, and on models with large extra dimensions. Several of the new limits, specifically for spin-1 dark matter mediators, pseudoscalar mediators, colored mediators, and leptoquarks, are the most restrictive to date.Peer reviewe

Probing effective field theory operators in the associated production of top quarks with a Z boson in multilepton final states at root s=13 TeV

Peer reviewe

Observation of tW production in the single-lepton channel in pp collisions at root s=13 TeV

A measurement of the cross section of the associated production of a single top quark and a W boson in final states with a muon or electron and jets in proton-proton collisions at root s = 13 TeV is presented. The data correspond to an integrated luminosity of 36 fb(-1) collected with the CMS detector at the CERN LHC in 2016. A boosted decision tree is used to separate the tW signal from the dominant t (t) over bar background, whilst the subleading W+jets and multijet backgrounds are constrained using data-based estimates. This result is the first observation of the tW process in final states containing a muon or electron and jets, with a significance exceeding 5 standard deviations. The cross section is determined to be 89 +/- 4 (stat) +/- 12 (syst) pb, consistent with the standard model.Peer reviewe

Measurements of Higgs boson production cross sections and couplings in the diphoton decay channel at root s=13 TeV

Measurements of Higgs boson production cross sections and couplings in events where the Higgs boson decays into a pair of photons are reported. Events are selected from a sample of proton-proton collisions at root s = 13TeV collected by the CMS detector at the LHC from 2016 to 2018, corresponding to an integrated luminosity of 137 fb(-1). Analysis categories enriched in Higgs boson events produced via gluon fusion, vector boson fusion, vector boson associated production, and production associated with top quarks are constructed. The total Higgs boson signal strength, relative to the standard model (SM) prediction, is measured to be 1.12 +/- 0.09. Other properties of the Higgs boson are measured, including SM signal strength modifiers, production cross sections, and its couplings to other particles. These include the most precise measurements of gluon fusion and vector boson fusion Higgs boson production in several different kinematic regions, the first measurement of Higgs boson production in association with a top quark pair in five regions of the Higgs boson transverse momentum, and an upper limit on the rate of Higgs boson production in association with a single top quark. All results are found to be in agreement with the SM expectations.Peer reviewe

Measurements of the Electroweak Diboson Production Cross Sections in Proton-Proton Collisions at root s=5.02 TeV Using Leptonic Decays

The first measurements of diboson production cross sections in proton-proton interactions at a center-of-mass energy of 5.02 TeV are reported. They are based on data collected with the CMS detector at the LHC, corresponding to an integrated luminosity of 302 pb(-1). Events with two, three, or four charged light leptons (electrons or muons) in the final state are analyzed. The WW, WZ, and ZZ total cross sections are measured as sigma(WW) = 37:0(-5.2)(+5.5) (stat)(-2.6)(+2.7) (syst) pb, sigma(WZ) = 6.4(-2.1)(+2.5) (stat)(-0.3)(+0.5)(syst) pb, and sigma(ZZ) = 5.3(-2.1)(+2.5)(stat)(-0.4)(+0.5) (syst) pb. All measurements are in good agreement with theoretical calculations at combined next-to-next-to-leading order quantum chromodynamics and next-to-leading order electroweak accuracy

Search for lepton-flavor violating decays of the Higgs boson in the mu tau and e tau final states in proton-proton collisions at root s=13 TeV

A search is presented for lepton-flavor violating decays of the Higgs boson to mu t and et. The dataset corresponds to an integrated luminosity of 137 fb(-1) collected at the LHC in proton-proton collisions at a center-of-mass energy of 13 TeV. No significant excess has been found, and the results are interpreted in terms of upper limits on lepton-flavor violating branching fractions of the Higgs boson. The observed (expected) upper limits on the branching fractions are, respectively, B(H -> mu t) e tau) < 0.22(0.16)% at 95% confidence level.Peer reviewe