Análisis de corrosión de válvulas de admisión y escape de un motor Diesel

En este proyecto se realizó el diagnostico de corrosión que se presentó en un conjunto de válvulas de admisión y escape de un motor diesel, Para llevar a cabo el análisis, se realizó una inspección visual del objeto de estudio, con apoyo de técnicas de caracterización como la microscopía óptica y medición de dureza. Los análisis de las muestras tomadas ayudaron a recopilar evidencias para aclarar el panorama general de la raíz de la falla. Despúes de estudiar la información recolectada, se concluye que la válvula falló por corrosión en forma de picaduras ocasionadas por el entorno al cual estaba expuesto. Esta clase de estudios ayuda a definir parámetros de diseño para evitar fallas en máquinas y estructuras, así como crear un historial de fallas con causas definidas que servirán como apoyo a futuros proyectos.In this project, the diagnosis of corrosion found in a valve of a diesel engine was made. To do this, a visual inspection of the object of study was carried out, with the support of characterization techniques such as optical microscopy and hardness measurement. . The analyzes of the samples also help to gather evidence to clarify the general picture of the root of the fault. After studying the information collected, it is concluded that the valve communicates corrosion in the form of bites caused by the environment to which it was already. This type of studies helps to define the design parameters to avoid faults in machines and structures, as well as a history of failures with the defined causes that will serve as support for future projects

Effects of the EU food safety regulation on cadmium on the cacao value chains of Colombia, Ecuador, and Peru

This briefing note combines information from three country reports conducted between 2021 and 2022, as well as relevant findings from the available literature to examine the current state of knowledge of the spatial distribution of Cd content in cacao farms in the three countries, how the EU regulation has affected different stakeholders, and how they are managing the problem. With the information presented in this document, we also improve and update literature available to date. The effects of the EU food safety regulations on cadmium in cacao (EU 488/2014 – EU 2021/1323 of 10 of August 2021) vary markedly between and within countries due to differences in markets and value chain structures. The regulation has caused severe localized impacts in specific cacao growing areas, nevertheless in general the impacts have been minor. Exporting companies and cooperatives are facing operational cost increases of up to 20%, related to Cd mapping, blending of cacao beans, increased traceability demands, marketing efforts, and additional laboratory testing. They also experience substantially lower prices and foregone incomes from changes in their clients. This has been critical for specialized cooperatives and producers in areas with high bean Cd. Changes in export destination for cacao during the last 4 years cannot solely be attributed to the regulation, but these represent foregone incomes in 2020 of nearly USD 3.4 million in Peru and USD 1.6 million in Colombia, equivalent to 2.4% and 6% of the countries’ cacao export value respectively. Adoption of similar food safety regulations by other importing countries may further limit the adaptation capacity of exporters and cooperatives

Efectos del reglamento alimentario de la UE sobre el contenido de cadmio en las cadenas de valor de cacao de Colombia, Ecuador y Perú

Esta nota informativo resume tres estudios a nivel de país efectuados entre 2021 y 2022 para presentar los hallazgos de la literatura diponible relacionada con la distribución espacial del Cd en los países, la forma en que el reglamento ha afectado a los distintos actores y las respuestas que han efectuado estos frente a la problemática. Con la información del presente documento, esperamos mejorar y actualizar la literatura disponible a la fecha. Los efectos del reglamento de inocuidad alimentaria de la UE sobre el contenido de cadmio en alimentos (UE 488/2014; UE2021/1323 del 10 de agosto de 2021) en las cadenas de valor de cacao de los países evaluados, varían dentro y entre sí, de acuerdo con sus estructuras y mercados atendidos. El reglamento ha tenido impactos severos y localizados en áreas donde coincide la producción de cacaos especiales y los altos contenidos de cadmio; no obstante, a nivel agregado, los impactos han sido menores. Las cooperativas y empresas exportadoras han enfrentado incrementos en sus costos operativos de hasta 20%, relacionados con mapeos de Cd, trazabilidad, mezcla de granos, gastos de mercadeo, y pruebas de laboratorio. También, han experimentado menores precios de exportación e ingresos dejados de percibir a causa de los cambios en su clientela. La adopción de reglamentos de inocuidad alimentaria similares por parte de otros países puede limitar la capacidad de adaptación que han demostrado los exportadores y cooperativas

Measurement of the ratios of branching fractions R(D∗)\mathcal{R}(D^{*}) and R(D0)\mathcal{R}(D^{0})

The ratios of branching fractions $\mathcal{R}(D^{*})\equiv\mathcal{B}(\bar{B}\to D^{*}\tau^{-}\bar{\nu}_{\tau})/\mathcal{B}(\bar{B}\to D^{*}\mu^{-}\bar{\nu}_{\mu})$ and $\mathcal{R}(D^{0})\equiv\mathcal{B}(B^{-}\to D^{0}\tau^{-}\bar{\nu}_{\tau})/\mathcal{B}(B^{-}\to D^{0}\mu^{-}\bar{\nu}_{\mu})$ are measured, assuming isospin symmetry, using a sample of proton-proton collision data corresponding to 3.0 fb${ }^{-1}$ of integrated luminosity recorded by the LHCb experiment during 2011 and 2012. The tau lepton is identified in the decay mode $\tau^{-}\to\mu^{-}\nu_{\tau}\bar{\nu}_{\mu}$. The measured values are $\mathcal{R}(D^{*})=0.281\pm0.018\pm0.024$ and $\mathcal{R}(D^{0})=0.441\pm0.060\pm0.066$, where the first uncertainty is statistical and the second is systematic. The correlation between these measurements is $\rho=-0.43$. Results are consistent with the current average of these quantities and are at a combined 1.9 standard deviations from the predictions based on lepton flavor universality in the Standard Model.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-039.html (LHCb public pages

Caracterización de la elección de carreras universitarias en alumnos de undécimo grado de los colegios privados acoandes, adventista la libertad, afelsa, americano, alejandro galvis galvis, bucaramanga, cajasan tejados, cooperativo bucaramanga, cooperativo comfenalco, cooprofesores, divino amor, divino niño, fernando aragón, instituto andino, instituto santa maría micaela, integrado “jorge isaac”, josé acevedo y gómez, juan josé rondon, maría auxiliadora, nuestra señora del transito, presentación, príncipe asturias, príncipe san carlos, psicopedagógico carl rogers, sabio caldas, santa maría maggiore, sagrado corazón de jesús “bethlemitas”, santandereano de comercio, santa teresita del niño jesús, san vicente ferrer, sotomayor, u. C. C., virrey solís de bucaramanga

El estudio investigativo sobre caracterización en la elección de carreras universitarias en alumnos de undécimo grado de los 33 colegios privados de Bucaramanga, desea encontrar respuestas a este planteamiento en ese contexto. La decisión de elegir una carrera universitaria, afecta a los estudiantes interesados en continuar sus estudios superiores, a los colegios de bachillerato, a las universidades, a las municipalidades, a las entidades rectoras de la educación en Colombia como el Ministerio de Educación, secretarias de educación departamentales, secretarias de educación municipales; y sobre todo a la sociedad en general. Se necesita saber qué desean estudiar en la universidad los aspirantes y por qué eligen determinada carrera. En tal sentido, la investigación se desarrolla en forma descriptiva. La delimitación de la investigación se enmarco en el universo a los estudiantes de undécimo grado de todos los 33 colegios privados de la ciudad de Bucaramanga, mediante un muestreo aleatorio estratificado y representativo de cada colegio. Se espera llegar a conocer el comportamiento de las variables referidas a sexo, edad, estado civil, actividad laboral, tiempo libre, características personales, aspectos familiares, aspectos económicos, información académica y aspiración a estudios superiores; y las carreras profesionales que se desean estudiar en la universidad. El objetivo final es saber las preferencias de la muestra estudiada, estableciendo un orden de mayor a menor de las carreras elegidas.1. Problemas y objetivos. -- 1.1 descripción del problema. -- 1.2 formulación del problema. -- 1.3 justificación. -- 1.4 objetivos. -- 1.4.1 objetivo general. -- 1.4.2 objetivos específicos. -- 2. Sustento teórico. -- 3. Desarrollo metodológico. -- 3.1 encuesta. -- 3.1.1 instrumento de medición. -- 3. 1. 2 métodos de supervisión. -- 3.1.3 método de muestreo. -- 3. 1. 4 tamaño de la muestra. -- 3.1.5 trabajo de campo. -- 3.2 procesamiento de la información. -- 3.3 análisis de resultados. -- 4. Caracterización de los estudiantes aspirantesa ingresar a estudiar una carrera universitaria. -- 4.1 sexo. -- 4.2 edad. -- 4.3 estado civil. -- 4.4 trabajo extra escolar. -- 4.5 tiempo libre. -- 4.6 cualidades o características. -- 4.7 núcleo familiar. -- 4.8 condición de los padres. -- 4.9 nivel de estudios de los padres. -- 4.9.1 nivel de estudios de la madre. -- 4.9.2 nivel de estudios del padre. -- 4.10 actividad económica de los padres. -- 4.10.1 actividad económica de la madre. -- 4.10.2 actividad económica del padre. -- 4.11 residencia. -- 4.12 ingresos económicos del núcleo familiar. -- 4.13 materias o asignaturas que mas se le facilitan. -- 4.14 continuación de estudios superiores. -- 4.15 modalidad. -- 4.16 jornada. -- 4.17 tipo de educación. -- 4.18 financiación de los estudios. -- 4.19 tipo de institución. -- 4.20 lugar en el que le gustaría estudiar. -- 4.21 carrera que desea estudiar. -- 5. Tabulación cruzada. -- 5.1 tabulación cruzada por sexo. -- 5.2 tabulación cruzada por edad. -- 5.3 tabulación cruzada por estado civil. -- 5.4 tabulación cruzada por actividad extra escolar. -- 5.5 tabulación cruzada por tiempo libre. -- 5.6 tabulación cruzada cualidades o características. -- 5.7 tabulación cruzada núcleo familiar. -- 5.8 tabulación cruzada condición de los padres. -- 5.9 tabulación cruzada nivel de estudio de los padres. -- 5.9.1 tabulación cruzada nivel de estudios de la madre. -- 5.9.2 tabulación cruzada nivel de estudios del padre. -- 5.10 tabulación cruzada actividad económica de los padres. --5.10.1 tabulación cruzada actividad económica de la madre. -- 5.10.1 tabulación cruzada actividad económica del padre. -- 5.11 tabulación cruzada reside en casa. -- 5.12 tabulación cruzada ingresos del núcleo familiar. -- 5.13 tabulación cruzada de materias que mas se le facilitan. -- 5.14 tabulación cruzada continuación de estudios superiores. -- 5.15 tabulación cruzada modalidad. -- 5.16 tabulación cruzada jornada. -- 5.17 tabulación cruzada tipo de educación. -- 5.18 tabulación cruzada financiación. -- 5.19 tabulación cruzada tipo de institución. -- 5.20 tabulación cruzada lugar en el que le gustaría. -- estudiar. -- conclusiones. – bibliografí[email protected]@[email protected]@campusucc.edu.cosocorrodelpilar.gonzá[email protected]@[email protected]@[email protected]@[email protected]@[email protected]@[email protected]@campusucc.edu.cosergio.serrano@[email protected]@[email protected]í[email protected]@[email protected]@campusucc.edu.coronald.martí[email protected]@[email protected]@[email protected]@[email protected]@[email protected]í[email protected]

Measurement of prompt D+D^+ and Ds+D^+_{s} production in pPbp\mathrm{Pb} collisions at sNN=5.02 \sqrt {s_{\mathrm{NN}}}=5.02\,TeV

International audienceThe production of prompt $D^+$ and $D^+_{s}$ mesons is studied in proton-lead collisions at a centre-of-mass energy of $\sqrt {s_{\mathrm{NN}}}=5.02\,$TeV. The data sample corresponding to an integrated luminosity of $(1.58\pm0.02)\mathrm{nb}^{-1}$ is collected by the LHCb experiment at the LHC. The differential production cross-sections are measured using $D^+$ and $D^+_{s}$ candidates with transverse momentum in the range of $0<p_{\mathrm{T}} <14\,\mathrm{GeV}/c$ and rapidities in the ranges of $1.5<y^*<4.0$ and $-5.0<y^*<-2.5$ in the nucleon-nucleon centre-of-mass system. For both particles, the nuclear modification factor and the forward-backward production ratio are determined. These results are compared with theoretical models that include initial-state nuclear effects. In addition, measurements of the cross-section ratios between $D^+$, $D^+_{s}$ and $D^0$ mesons are presented, providing a baseline for studying the charm hadronization in lead-lead collisions at LHC energies

Measurement of prompt D+D^+ and Ds+D^+_{s} production in pPbp\mathrm{Pb} collisions at sNN=5.02 \sqrt {s_{\mathrm{NN}}}=5.02\,TeV

International audienceThe production of prompt $D^+$ and $D^+_{s}$ mesons is studied in proton-lead collisions at a centre-of-mass energy of $\sqrt {s_{\mathrm{NN}}}=5.02\,$TeV. The data sample corresponding to an integrated luminosity of $(1.58\pm0.02)\mathrm{nb}^{-1}$ is collected by the LHCb experiment at the LHC. The differential production cross-sections are measured using $D^+$ and $D^+_{s}$ candidates with transverse momentum in the range of $0<p_{\mathrm{T}} <14\,\mathrm{GeV}/c$ and rapidities in the ranges of $1.5<y^*<4.0$ and $-5.0<y^*<-2.5$ in the nucleon-nucleon centre-of-mass system. For both particles, the nuclear modification factor and the forward-backward production ratio are determined. These results are compared with theoretical models that include initial-state nuclear effects. In addition, measurements of the cross-section ratios between $D^+$, $D^+_{s}$ and $D^0$ mesons are presented, providing a baseline for studying the charm hadronization in lead-lead collisions at LHC energies

Improved measurement of CPCP violation parameters in Bs0→J/ψK+K−B_s^0\to J/\psi K^+K^- decays in the vicinity of the ϕ(1020)\phi(1020) resonance

The decay-time-dependent $CP$ asymmetry in $B_s^0\to J/\psi(\to \mu^+\mu^-) K^+ K^-$ decays is measured using proton-proton collision data, corresponding to an integrated luminosity of $6 {\rm fb}^{-1}$, collected with the LHCb detector at a center-of-mass energy of 13 TeV. Using a sample of approximately 349 000 $B_s^0$ signal decays with an invariant $K^+ K^-$ mass in the vicinity of the $\phi(1020)$ resonance, the $CP$-violating phase $\phi_s$ is measured, along with the difference in decay widths of the light and heavy mass eigenstates of the $B_s^0$-$\overline{B}_s^0$ system, $\Delta\Gamma_s$, and the difference of the average $B_s^0$ and $B^0$ meson decay widths, $\Gamma_s-\Gamma_d$. The values obtained are $\phi_s = -0.039 \pm 0.022 \pm 0.006$ rad, $\Delta\Gamma_s = 0.0845 \pm 0.0044 \pm 0.0024 ~{\rm ps}^{-1}$ and $\Gamma_s-\Gamma_d = -0.056^{\:+\:0.0013}_{\:-\:0.0015} \pm 0.0014 ~{\rm ps}^{-1}$, where the first uncertainty is statistical and the second systematic. These are the most precise single measurements to date and are consistent with expectations based on the Standard Model and with the previous LHCb analyses of this decay. These results are combined with previous independent LHCb measurements. The phase $\phi_s$ is also measured independently for each polarization state of the $K^+K^-$ system and shows no evidence for polarization dependence.The decay-time-dependent $CP$ asymmetry in $B^0_s\to J/\psi(\to \mu^{+}\mu^{-}) K^{+}K^{-}$ decays is measured using proton-proton collision data, corresponding to an integrated luminosity of 6 $fb^{-1}$, collected with the LHCb detector at a center-of-mass energy of 13 TeV. Using a sample of approximately 349 000 $B^{0}_{s}$ signal decays with an invariant $K^{+}K^{-}$ mass in the vicinity of the $\phi(1020)$ resonance, the $CP$-violating phase $\phi_s$ is measured, along with the difference in decay widths of the light and heavy mass eigenstates of the $B^0_s$-$\bar{B}^0_s$ system, $\Delta\Gamma_s$, and the difference of the average $B^0_s$ and $B^0$ meson decay widths, $\Gamma_s-\Gamma_d$. The values obtained are $\phi_s = \ -0.039 \pm 0.022 \pm 0.006$ rad, $\Delta\Gamma_s = 0.0845 \pm 0.0044 \pm 0.0024$ ps$^{-1}$ and $\Gamma_s-\Gamma_d = -0.0056 ^{+ 0.0013}_{-0.0015} \pm 0.0014$ ps$^{-1}$, where the first uncertainty is statistical and the second systematic. These are the most precise single measurements to date and are consistent with expectations based on the Standard Model and with the previous LHCb analyses of this decay. These results are combined with previous independent LHCb measurements. The phase $\phi_s$ is also measured independently for each polarization state of the $K^{+}K^{-}$ system and shows no evidence for polarization dependence

Associated production of prompt J/ψJ/\psi and Υ\mathit{\Upsilon} mesons in pppp collisions at s=13 TeV\sqrt{s}=13\,\mathrm{TeV}

International audienceThe associated production of prompt $J/\psi$ and $\mathit{\mathit{\Upsilon}}$ mesons in $pp$ collisions at a centre-of-mass energy of $\sqrt{s}=13\,\mathrm{TeV}$ is studied using LHCb data, corresponding to an integrated luminosity of $4\,\mathrm{fb}^{-1}$. The measurement is performed for $J/\psi$ ($\mathit{\Upsilon}$) mesons with a transverse momentum $p_{\mathrm{T}}<10\,(30)\,\mathrm{GeV}/c$ in the rapidity range $2.0<y<4.5$. In this kinematic range, the cross-section of the associated production of prompt $J/\psi$ and $\mathit{\Upsilon}(1S)$ mesons is measured to be $133 \pm 22 \pm 7 \pm 3 \, \mathrm{pb}$, with a significance of $7.9\,\sigma$, and that of prompt $J/\psi$ and $\mathit{\Upsilon}(2S)$ mesons to be $76\pm 21 \pm 4 \pm 7 \, \mathrm{pb}$, with a significance of $4.9\,\sigma$. The first uncertainty is statistical, the second systematic, and the third due to uncertainties on the used branching fractions. This is the first observation of the associated production of $J/\psi$ and $\mathit{\Upsilon}(1S)$ in proton-proton collisions. Differential cross-sections are measured as function of variables that are sensitive to kinematic correlations between the $J/\psi$ and $\mathit{\Upsilon}(1S)$ mesons. The effective cross-sections of the associated production of prompt $J/\psi$ and $\mathit{\Upsilon}$ mesons are obtained and found to be compatible with measurements using other particle productions

Test of lepton flavour universality using B0→D∗−τ+ντB^0 \to D^{*-}\tau^+\nu_{\tau} decays with hadronic τ\tau channels

International audienceThe branching fraction $\mathcal{B}(B^0 \to D^{*-}\tau^+\nu_{\tau})$ is measured relative to that of the normalisation mode $B^0 \to D^{*-}\pi^+\pi^-\pi^+$ using hadronic $\tau^+ \to \pi^+\pi^-\pi^+(\pi^0)\bar{\nu}_{\tau}$ decays in proton-proton collision data at a centre-of-mass energy of 13 TeV collected by the LHCb experiment, corresponding to an integrated luminosity of 2 fb$^{-1}$. The measured ratio is $\mathcal{B}(B^0 \to D^{*-}\tau^+\nu_{\tau})/\mathcal{B}(B^0 \to D^{*-}\pi^+\pi^-\pi^+)= 1.70 \pm 0.10^{+0.11}_{-0.10}$, where the first uncertainty is statistical and the second is related to systematic effects. Using established branching fractions for the $B^0 \to D^{*-}\pi^+\pi^-\pi^+$ and $B^0 \to D^{*-} \mu^+\nu_\mu$ modes, the lepton universality test, $\mathcal{R}(D^{*-}) \equiv \mathcal{B}(B^0 \to D^{*-}\tau^+\nu_{\tau})/\mathcal{B}(B^0 \to D^{*-} \mu^+\nu_\mu)$ is calculated, $$\mathcal{R}(D^{*-}) = 0.247 \pm 0.015 \pm 0.015 \pm 0.012\, ,$$ where the third uncertainty is due to the uncertainties on the external branching fractions. This result is consistent with the Standard Model prediction and with previous measurements